Mustang 428 Cobra Jet Registry Forum

Discussion => General Discussion => Topic started by: markharvey9077@gmail.com on September 23, 2018, 02:09:20 am

Title: 355 HP...really
Post by: markharvey9077@gmail.com on September 23, 2018, 02:09:20 am
I just had my 69 428 CJ buit...and it shows 355 HP and 455 torque...it was on the dyno outside of the car...it was bored .30 over...a 25 cam....I was expecting more like 400 hp...am I off?
Title: Re: 355 HP...really
Post by: RoyceP on September 23, 2018, 07:44:24 am
They make more than that in factory stock condition. So something is not as Ford delivered it. Perhaps you changed compression, camshaft, or something else that caused you to lose 50+ horsepower.



I just had my 69 428 CJ buit...and it shows 355 HP and 455 torque...it was on the dyno outside of the car...it was bored .30 over...a 25 cam....I was expecting more like 400 hp...am I off?
Title: Re: 355 HP...really
Post by: rickmustang on September 23, 2018, 09:44:04 am
Or that dyno calibration is off.
Title: Re: 355 HP...really
Post by: crossboss on September 23, 2018, 10:18:03 am
FWIW,
My stone stock '69 CJ Fastback made 270 on the rear dyno rollers. That equates out to about 355 HP. This was with a fully loaded engine A/C, P/S, air cleaner attached, all belts running with a C-6 automatic and 350 gears. Why does everyone think that a stock Muscle Car made 400-450 HP? It didn't. Now, that said, your engine with the modifications done could have been built incorrectly to make 'only' 355 on an engine dyno. My worthless two cents...
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on September 23, 2018, 10:52:06 am
Mine has flat top pistons decked block ,heads cut down to 68 cc, stock lift but better solid cam ,manifolds ,compression ratio around 11.7 to 11.8, cast iron intake stock carb and made 475 at 5900 and started to float the valves due to weak springs .Had it at 38 degrees and they usually like 40 probably a bit of hp there too . Was still gaining 6.2 hp from 5800 -5900 if we get it to 6300 with the new springs it should make right at 500 hp. This is not a dyno that is known for giving big numbers either. The engine builder thought the new valve springs will pick it up 20-30 hp .The maximum torque was 476 but made in the 400 plus range from 2600 to 6000 . Some dynos are stingy some make numbers to impress its adjustable by the operator .A small piece of gunk in the passenger side jet knocked the AF on that side and dropped the numbers by 180 hp .Popped another carb on and it made all of it back plus another 30 hp over the previos high at 5500 rpm.
Lots of factors in dynos but it will still be a fun engine at 355 hp and 455 torque .
Title: Re: 355 HP...really
Post by: rockhouse66 on September 23, 2018, 12:11:07 pm
Lots of little details can contribute to any dyno results.  As said, some are just "happy" and some are "stingy".  But some jetting changes, playing with the timing, etc. can possibly make your 355 into 375, which I think is pretty strong.  Was it run with headers or manifolds?  Driving the water pump or not?
Title: Re: 355 HP...really
Post by: geraldt52 on September 23, 2018, 12:12:55 pm

...Lots of factors in dynos....

That's really the bottom line.  Repeating a bit of what rockhouse66 said: (because I'm too lazy to retype)

Knowing nothing about the dyno in question, and nothing about the dyno setup used, a number of 355hp means very little...except maybe in comparison to the engines tested on the same dyno, immediately before and immediately after your engine.  When was the dyno calibrated?  Was the engine broken in prior to test?  Being fed cool air at a specific barometric pressure?  Complete air filter assembly used?  All belts on?  Water pump driven by a belt or by an electric motor?  Manifolds, headers, or dyno headers...mufflers?  Play with the a/f ratio and timing?  It's possible to play all sorts of games with numbers off of a dyno, which is why manufacturer's tests are now done to a specific SAE standard for net hp.

I wouldn't worry about the number.  In the end, the only number that matters comes from the 1320' asphalt dyno. 
Title: Re: 355 HP...really
Post by: redscj on September 23, 2018, 12:27:57 pm
     Why did you expect a higher hp? It sounds like a fairly stock build plus you don't mention that any tuning was done. Literally every engine needs to be tweeked to get the best numbers.
     Then as Gerald is getting at. I remember a top name pro stock driver. His highest hp motor was not the quickest in the 1/4 mile. Go figure!
Title: Re: 355 HP...really
Post by: crossboss on September 23, 2018, 12:41:03 pm
     Why did you expect a higher hp? It sounds like a fairly stock build plus you don't mention that any tuning was done. Literally every engine needs to be tweeked to get the best numbers.
     Then as Gerald is getting at. I remember a top name pro stock driver. His highest hp motor was not the quickest in the 1/4 mile. Go figure!




Exactly! 355HP will put your car in the 13s with 'tuning' as mentioned….it did with my old heap.
Btw, just because someone 'rebuilds' an engine, they expect it to make 500HP. IF that was the case, every small block Chevy would be making 1,000HP!  lol
Seriously, don't worry on just the 'numbers' from a dyno….Remember, a dyno does not win a race. I beat cars with better HP numbers at the track and on the street.
Title: Re: 355 HP...really
Post by: redscj on September 23, 2018, 07:10:36 pm
     +1, amen.
Title: Re: 355 HP...really
Post by: Richard Todd on September 23, 2018, 08:53:22 pm
Being someone who owns an engine dyno shop (closed due to health) I think its important to know 2 important pieces of information. First were your HP numbers actual HP or corrected HP? It should say this on your dyno sheet. Corrected HP is sea level (29.92 Barometer at 60 deg. FH ) Also what was the vapor pressure ( moisture content ) of the air during the test? An eng. dyno test in Denver Co. would produce far less actual HP than the same eng. in NY thus the correction factor. Also the air temp. must be taken at the carb. intake and may vary as the test progresses. One slight miscalculation in input data can make a big difference in the HP. I am in no way questioning your dyno shop or operator just saying I personally have made this mistake more than once. One more thought would be the eng. acceleration rate. For example a SuperFlow Dyno you can set this and 300 RPM per sec. is considered the standard acceleration rate for high gear. The faster you accelerate an eng. the less time the cylinders have to fill (Volumetric Efficiency) the less HP the eng. will make. Inertia dynos are different so that's another factor. Bottom line here is your eng. might be a lot stronger than you think. Without seeing your dyno sheets I am sorry I cannot help more. Just remember an eng. dyno is just a complex tool and not all are set up for the same purpose. A maximum dyno HP eng. is NEVER as fast as an eng. tuned for maximum acceleration. Learned by accident but never forgotten.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on September 23, 2018, 11:35:13 pm
I have attached the dyno sheet...please review...not that I am a numbers guy...but I need to confirm I do no have an issue...bored and a racing cam ought to have done better...the test was run after he broke the cam in...fright after the rebuild.
Thanks
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on September 24, 2018, 12:58:14 am
I see some strange things on your dyno sheet . You are running a lot bigger jets than my engine that makes more power  .I have 64's in the front and 72's in the back . How much total timing did he try . All your numbers fall of real fast before 5000 rpm for some reason might be the cam  .
Your air fuel seems a bit odd being one sides numbers are a fair amount different from side to side .Your oil pressure seems a bit low to me looking at mine it was making over 50lbs from 5000 up and 45+ from 3000.Your engine makes great torque numbers and should feel good driving on the street .
Title: Re: 355 HP...really
Post by: 67428GT500 on September 24, 2018, 02:15:58 am
What's the cam specs?
Title: Re: 355 HP...really
Post by: rockhouse66 on September 24, 2018, 07:36:53 am
Several things to wonder about from this dyno sheet, as Steve mentioned.  Also, does that one line say 9:1 compression?  If so, that is pretty low and more cam probably won't like that.  I assume the 28 degrees noted is the max mechanical advance in the distributor and has nothing to do with the actual engine timing on the dyno?  Wonder where the timing was?

And, again, was it run with headers or what on the exhaust?
Title: Re: 355 HP...really
Post by: Vcode on September 24, 2018, 08:14:03 am
The stroke call out must be a typo 3.394?
428's are 3.98
Title: Re: 355 HP...really
Post by: RoyceP on September 24, 2018, 08:45:36 am
The dyno sheet ells the tale. Stock these engines have 10.5 to one compression. Yours has been lowered to 9:1 in order to be able to use the 91 octane fuel that was used for the dyno run. It says timing was 28 degrees, that alone would knock off 15 - 20 horsepower compared to the stock setting of 40 - ish degrees.

So you are probably losing 30 - 40 horsepower from the lowered compression / lousy gas.
Another 15 - 20 from the timing being way retarded.
Probably 10 horsepower loss due to rich jetting on the carb.

The cam might be another problem, it falls off in power really early compared to a stock cam. Maybe the cam timing is retarded for some reason? It looks to me that this engine could make better power if it were tuned and maybe a different cam installed. 
Title: Re: 355 HP...really
Post by: Jiffy on September 24, 2018, 08:53:35 am
If that’s a ‘racing cam’ then it seemed to fall over pretty early, everything was done by late 4,000’s and I’d have thought that there was more head room in a ‘racing cam’
Title: Re: 355 HP...really
Post by: crossboss on September 24, 2018, 09:31:44 am
I also see some issues. As mentioned the cam/valve springs, AND Pertronix ignition (junk). During my 'tuning' days with my CJ, I had installed a bad camshaft grind that would not rev past 4200. Swapping in a 'good' cam, it picked up over a half a second and approx 4-5 mph the drag strip (that equates to about a 30HP difference). Btw, my engine also had 9.5 to 1 compression for street pump gas, with jetting @ 66/76, so in my opinion your good there. I believe some 'tuning' is in order to achieve better results.
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on September 24, 2018, 04:32:53 pm
The dyno sheet ells the tale. Stock these engines have 10.5 to one compression. Yours has been lowered to 9:1 in order to be able to use the 91 octane fuel that was used for the dyno run. It says timing was 28 degrees, that alone would knock off 15 - 20 horsepower compared to the stock setting of 40 - ish degrees.

So you are probably losing 30 - 40 horsepower from the lowered compression / lousy gas.
Another 15 - 20 from the timing being way retarded.
Probably 10 horsepower loss due to rich jetting on the carb.

The cam might be another problem, it falls off in power really early compared to a stock cam. Maybe the cam timing is retarded for some reason? It looks to me that this engine could make better power if it were tuned and maybe a different cam installed.


If it only had 28 degrees the hp loss would be more like 75 hp maybe more .Have seen the difference at the track and its huge .
Title: Re: 355 HP...really
Post by: Richard Todd on September 24, 2018, 08:54:07 pm
When I first saw your dyno sheet the issue I feel that is most important is that your valve springs are too week to control the valves. Your valves appear to start bouncing on the seat at around 4200 RPM and by 4800 RPM the valves are in full float. I have seen this many times over the years on my dyno and you need to address this problem now before you damage your engine. This problem is very hard on your valve locks (keepers) and the end result is never good. My first suggestion would be to contact the company who made your cam and see what springs they recommend. You might also post your cam card to let us know what your running. The valve springs must be installed at the correct height and seat pressure to be effective. Changing valve springs although time consuming is not that difficult especially with the engine out of the car. If you have to pay to have it done it will be money well spent.
Title: Re: 355 HP...really
Post by: geraldt52 on September 24, 2018, 10:45:27 pm
When I first saw your dyno sheet the issue I feel that is most important is that your valve springs are too week to control the valves. Your valves appear to start bouncing on the seat at around 4200 RPM and by 4800 RPM the valves are in full float...

It begs the question if the engine builder may have intentionally used weak springs for the purpose of breaking in the cam, with the expectation that they'd be changed out before a full rpm test was run.  It's hard to imagine those are the springs recommended by the cam manufacturer.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on September 25, 2018, 01:07:24 am
thanks for all the comments...I will get the information and post it...I am a novice engine builder so I outsourced it...
Title: Re: 355 HP...really
Post by: Richard Todd on September 25, 2018, 07:18:04 am
After my post I flipped thru my old dyno files and I found a test session I did on a 390 which had a similar problem. When I tested the spring pressure they were all good with the seat and open pressure within 10 lbs. of spec. The HP numbers seemed low and it was done by 4500. I replaced the rocker arms with a set of stock Ford adjustable rockers and push rods an adjusted the valves to 0 lash plus 1/8 turn of preload and it cured the problem. The engine ran to 6000 RPM an picked up 55 HP. With the stock non adjustable rockers the pushrods had to much preload in the lifters and as the RPM and oil pressure increased the lifters pumped up and held the valves open. 99 times out of 100 its a valve spring problem but this time it was not. My point here is you need to test the springs before you do anything else. What rocker arms are you running on you engine?
Title: Re: 355 HP...really
Post by: lr68cj on September 25, 2018, 10:36:34 am
Losing 100 hp from 4700 to 5200 sound like valve springs to me. Hydraulic cam should rev to 6200 with no issues. Torque should fall off after 5252, but hp should still be going up or at least leveling off. Had a 351c of mine on the Dyno and wouldn't rev past 5500. Springs we're bouncing all over the place. Not enough spring pressure closed or open. First place I'd look. My 2¢.
Title: Re: 355 HP...really
Post by: geraldt52 on September 25, 2018, 12:01:33 pm
... With the stock non adjustable rockers the pushrods had to much preload in the lifters and as the RPM and oil pressure increased the lifters pumped up and held the valves open...

I've never heard of that, but I don't doubt it and it's really interesting.  You probably don't remember, but had the deck and heads on the engine been heavily milled?  Was there a high pressure oil pump involved?  Were the valve stem heights within specs?
Title: Re: 355 HP...really
Post by: Richard Todd on September 25, 2018, 02:13:33 pm
Don't know how much the heads and deck were cut on the 390. I was not involved in the build, just the dyno test. The oil pressure did run in the 80-90 psi range which I considered too high but the engine is still running strong. I did not check the valve stem heights as the owner had asked me to try to make what was there work if at all possible. Since shimming the rocker stands on a street/strip engine did not seem to be a sound option I went with the rockers. I agree that 99 out of 100 times it will be the springs but my point of this post is that the springs need to be checked before replacing them just to be sure.
Title: Re: 355 HP...really
Post by: geraldt52 on September 25, 2018, 03:29:59 pm
... the owner had asked me to try to make what was there work if at all possible. Since shimming the rocker stands on a street/strip engine did not seem to be a sound option I went with the rockers...

I'm not questioning that choice at all.  Shorter pushrods could have been used, but the adjustable rockers would have allowed you to play with/diagnose it, while pushrods have to be ordered to a specific length.
Title: Re: 355 HP...really
Post by: Richard Todd on September 25, 2018, 04:56:19 pm
So true about the push rods but I did not have the luxury of time. I had 3 sets of bushed adjustable rockers left over from my FE stock class drag car and a large number of good used push rods so it was a no wait option. When I had to halt a session to order parts I would have to remove the engine from the dyno for the next job then put it back on when the parts arrived. Lots of extra work which some time you have no choice but if I could find a way around it without compromising the quality I would take it. He got a great deal on the parts.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on September 26, 2018, 11:49:59 pm
the cam is 214/224 duration 50 thou lift...520/546 valv lift...lod110....I asked for a modest cam that will have the sound but not a vacuum stall issue...I do not race...just pickup Chevy guy's wives...I iwll have the exhaust info in a day...I have the 735 holley with 68/72 jets..
Title: Re: 355 HP...really
Post by: rockhouse66 on September 27, 2018, 07:17:10 am
I have been involved in two very stock builds that came out in the 350-375 HP range through manifolds (not headers).  That is a very mild cam and I think your 355 result is typical.  Some tuning could certainly be done to improve it a little though, from the looks of things.  That drop off at the higher revs is not typical.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on September 27, 2018, 11:26:57 pm
just spoke with builder...cam is .214/224 duration 50 thousands....valve lift is .520/546 lob 110...(hope i copied that correctly) and the dyno was run with headers...comments? recommendations?
Title: Re: 355 HP...really
Post by: 69scj428 on September 28, 2018, 07:29:34 am
I would have to ask why the compression is so low if it is in fact 9:1. I have run 10.5:1 on the street using super unleaded for years without and detonation issues. I do have to keep my
timing from being too advanced, but that is not an issue for the horsepower difference. Valve springs are a concern as stated above. They need to match the cam to ensure the valves open and close properly without valve float. I have, however, used factory springs in a 428cj before with a crane .561 lift 290 duration cam without an issue. I am not sure why your dyno sheet shows as if the valves are floating--strange to me!! I think you need to start from scratch with the cam, springs, and check out the carb. Is the carb a Holley street avenger by any chance?? Just curious because I have seen low performance before from those particular carbs. Another recommendation is to use hardened rocker arm shafts as I have had them break before with high lift cams. Who degreed the cam shaft?? Was it done in accordance with the cam card or did the builder use a stock type timing chain without multiple key indexes?? A retarded camshaft outside of the manufactures' specs could also cause the issue that you have. Your engine makes good torque which is what really makes a street car fun. I think it would run okay, but for reliability purposes, I think you should check out some of the recommendations made in these posts. Most notably, I would be concerned about the valve springs and the stock rocker shafts if you re-used them. Just my 2 cents--hope it helps-------Donald :) :)
Title: Re: 355 HP...really
Post by: 69cobrajetrugae2 on September 28, 2018, 08:12:15 am
As we know every one of our engines squeezes and swirls the burning fuel charge differently, some better than others.  Higher compression does not guarantee success, in fact through the years one of the engine masters here has tried to steer us away from that sort of dinosaur logic.

 When Bob built the first version of the 428 CJ the engine surprised everybody.  As I recall, a mismatched intake head gasket or something along those lines created tremendous port velocity down in the dirt which might have gone unnoticed if the compression was higher.

A higher compression ratio has no effect on power production until the piston is about 10 degrees of TDC.  At that point the rate of burn is increased which increases the temperature which increases the pressure which does make more power as compared to a engine with a lower C/R at least on paper.  In reality the fuel is also consumed faster so the peak cylinder pressure might not jive with the optimum crank angle resulting in greater pumping losses.  Add more fuel and less advance is a partial solution but what about the high temperature of compression and the fuel auto igniting?

 As the piston progresses in it's power stroke the rate of burn has increased so much due to the temperature of high compression it may detonate.  Quench at TDC is tight fit between part of the piston crown and the head which does what the word implies, it puts out part of the burning charge to avoid detonation but since some burn temperature is lost in the quench so is the pressure and so is some of the power.

 Carbon in the combustion chamber and piston crown hinder heat transfer creating a hot chamber.  When the relatively cool fuel charge is drawn in and then rapidly heats up, less of the charge can enter before the valve closes but even so that charge is potentially power packed.

 A guy that knows this can pull back his total advance and play with the A/F ratio and make more power but if he leans it out too much he'll know it because the engine will perform better than ever at the top end.  If he's experienced steps will be taken to back off the power, which is to back off the temperature and therefore the pressure to "save the hardware".

  Unless leaded racing fuel is used and one is a master engine fellow, high compression ratios is very poor judgment in my opinion.  Look elsewhere for high temperatures and pressures that are not so destructive and unpredictable.
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on September 28, 2018, 08:55:29 pm
Wow headers probably added 25 to 40 hp over manifolds .Yes something isn't right but it explain bigger jetting .
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on September 29, 2018, 01:33:53 am
talked to the builder...and he tells me this is a compcam ...and I looked up on the website ahd the 926-16 is all that comes close...and he used Manley springs...but I will get part numbers to confirm he had a match..why would he not buy the cam/springs in a kit...?  When I get the part number ...what spec on the springs am I looking for...the seat load...etc...what would be a number that would cause me to change them....I found a local dyno shop that I may have him change out the springs.  What would be a fair price to have them change them out....

Second...as for the cam...I was not looking for a racing cam...just a non smooth idle...is this the correct one or should I upgrade...to what...

Do I reduce the jets to 66/79 stock? ....this is a 735 cfm original rebuilt.
Title: Re: 355 HP...really
Post by: RoyceP on September 29, 2018, 08:44:18 am
Google is your friend -

https://www.jegs.com/i/COMP-Cams/249/926-16/10002/-1


talked to the builder...and he tells me this is a compcam ...and I looked up on the website ahd the 926-16 is all that comes close...and he used Manley springs...but I will get part numbers to confirm he had a match..why would he not buy the cam/springs in a kit...?  When I get the part number ...what spec on the springs am I looking for...the seat load...etc...what would be a number that would cause me to change them....I found a local dyno shop that I may have him change out the springs.  What would be a fair price to have them change them out....

Second...as for the cam...I was not looking for a racing cam...just a non smooth idle...is this the correct one or should I upgrade...to what...

Do I reduce the jets to 66/79 stock? ....this is a 735 cfm original rebuilt.
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on September 29, 2018, 09:18:20 am
I think the installed height is higher than those springs are rated at .Closer to 2 inches than the 1.8 they are measured at .Would make a huge difference in performance .
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on September 29, 2018, 02:46:52 pm
so ...I find the part number of springs he installed and see if they compare to the 2" 415 recommended...if that is the correct cam....and upgrade myself...???

The dyno guy I talked to wanted $1000 for a before and after dyno ...with me changing the springs...seems a bit high...and wanted $4k more to change the cam/springs....but he did say a 224 cam would drop off after 4200...seems a little weak....

Wish I had the sense and tech to go here first...and direct the builder to install the right cam...

Title: Re: 355 HP...really
Post by: RoyceP on September 30, 2018, 08:21:12 am
The stock cam is a real snoozer but it runs up to 5500 before it starts falling off. Your cam is slightly, and I mean very slightly, more than a stock cam. It ought to perform a little better than a stock cam, provided everything else is proper.

I've never seen spending money on dyno runs as very cost effective. I would get the timing and carburetion squared away and go to the drag strip. Lots more fun for a lot less money. You might be pleasantly surprised at how much difference it will make getting the advance back where it should be.


so ...I find the part number of springs he installed and see if they compare to the 2" 415 recommended...if that is the correct cam....and upgrade myself...???

The dyno guy I talked to wanted $1000 for a before and after dyno ...with me changing the springs...seems a bit high...and wanted $4k more to change the cam/springs....but he did say a 224 cam would drop off after 4200...seems a little weak....

Wish I had the sense and tech to go here first...and direct the builder to install the right cam...
Title: Re: 355 HP...really
Post by: geraldt52 on September 30, 2018, 02:31:07 pm


...Wish I had the sense and tech to go here first...and direct the builder to install the right cam...

Your builder's selection of cam, which isn't bad at all, would not explain the way the engine is dying from 4K on up...you need to figure why that's happening, and it isn't the fault of the cam based on its specs.  You've gotten good suggestions regarding checking lifter preload and checking spring heights/forces...which would seem the most likely snafus.

Before I did anything further though, I'd disconnect the vacuum advance and put a timing light and vacuum gage on the engine and gently run it up to a bit over 4K looking for either the vacuum or the advance to go erratic.  It's possible that the advance is bouncing all over the place above 4K and killing the power.  Then I'd remove both valve covers and turn the engine over just looking to see that the valve train is operating as expected.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 02, 2018, 04:06:07 pm
I think I found the issue....I got the part numbers and the cam may not be right...but the springs are...Cam is a 33-238-4 (218 intake/224 exhaust, lift ast .513/.52 110 deg separation...lob lift at .298.)  This shows as a heavy towing in 428 with gears...that sounds like a truck engine and explains the high torque and low HP...springs are 926-16 as specified.  Not sure if he is feeding me a line as he said Manley springs the first time.

I believe a 33-226-4 with 224/224, 519/519 is better suited at a minimum....the next higher cam shows aftermarket stall issue...at 230 duration.  How high could I go without stalls and an excessive rough idle.

I am capable of the cam change...is this worth it...

Comments please
Title: Re: 355 HP...really
Post by: crossboss on October 02, 2018, 04:18:25 pm
As Royce and many others (including myself) had mentioned, a stock cam will go to 5,500. FIRST, I would ditch the junk Pertronix with a reliable and quality electronic ignition like the OEM Ford Dura-Spark set up. SECOND, make sure your springs/installed height is correct. THIRD, check for lifter preload/valve train geometry. FOURTH, and most important, make sure EVERYTHING is with in spec. Remember, just because you purchased a 'new' cam, that does not mean it is good. I had a very similar situation with a bad cam grind. Good luck, and keep us posted!
Title: Re: 355 HP...really
Post by: rockhouse66 on October 02, 2018, 05:43:24 pm
Note that the cam card for the cam you have now says it is good to 5500 RPM, so you really need to figure out the issue with the drop off in power so early.  As mentioned, valve spring setup (not just the spring rating), ignition timing, etc.  Yes, the 270H would be a step in the right direction IMO.  Especially if you plan to run headers on your car (do you?).  The "stall" comment is related to automatic transmission cars - is yours an automatic?
Title: Re: 355 HP...really
Post by: geraldt52 on October 02, 2018, 07:46:45 pm
That cam has slightly longer durations and higher lifts than the factory 428CJ cam.  There is really nothing wrong with it, and I surely wouldn't waste my time/money changing it out at this point. 

Besides, you really need to figure out why the dyno run fell off so dramatically over 4K, or you may change out the cam and end up right back where you are.  Something is wrong that needs fixing, but that cam selection is not the culprit.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 02, 2018, 08:34:19 pm
Thanks...Jim, yes I am running headers....and this is a 4 speed..so I believe I am hearing no stall issues or vacuum issue with the brakes...IF>...I did upgrade the cam. (BTW, you said 270h...what was that in reference to...)

I will check the springs...I take it I measure the installed height to spec?  Any other check...???  I an nearly out of my tech....

The Pertronics is a rebuilt one...from Jim Warino in LA...supposed to know what he was doing...could that be the issue and I need to replace?  I would prefer I fix this before I install in DEc...and then decide to pull the cam.
Title: Re: 355 HP...really
Post by: rockhouse66 on October 02, 2018, 10:20:10 pm
Your second Comp number is a 270H.  Disregard the stall comments with a 4-speed.  You will still need sufficient vacuum for power brakes (if that is what you have) but the 270H is mild enough to be a non-issue.

Valve spring installed height is important to get the pressures you need to control the valves so it needs to be checked.  The springs won't meet spec unless they are installed to the correct height.

I have found the Pertronix I to work fine.  No experience with other versions.  Issues with these are usually found very early, like most electronic stuff.  DOA or soon after if they are bad.  Clearly, others have had bad experiences and recommend against them.  I think the Pertonix II and III are more troublesome.
Title: Re: 355 HP...really
Post by: corbins on October 03, 2018, 09:40:53 pm
That comp 270 is still a fairly mild cam for an FE.... and why did the builder not get the matching springs from Comp? Like others, I think you'll find your problem somewhere else, timing, spring installed height, etc.  Good luck
BTW, hw is the car idling? Any chance a lob was wiped during breakin?
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 04, 2018, 01:25:49 am
The engine is on a stand in garage and I cannot start......builder told me he used Manley springs at first and when I asked for the part number he gave me the proper part for the comp cam...I am suspect...just how will I know I fixed this without another dyno?
Title: Re: 355 HP...really
Post by: rockhouse66 on October 04, 2018, 07:55:15 am
Just for fun, and regardless of which spring is actually installed, why not remove a valve cover and measure the spring height?

Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 06, 2018, 08:55:20 pm
I pulled the springs and measured....tell if I you see an issue...I measured out of the head and measured 2.170, Jegs has the height of the recommended at 1.3.

I measured the installed height and have 1.75 and jegs has them at 1.8....while I am not sure if1.75 to 1.8 is an issue and within my measure error.....there are no shims.

Does anyone believe I have the correct springs.....
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 06, 2018, 09:02:51 pm
anyone...not sure I understand how to tell if these are the right springs....just how do you tell an uncompressed spring is the right one?
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on October 06, 2018, 09:35:18 pm
I pulled the springs and measured....tell if I you see an issue...I measured out of the head and measured 2.170, Jegs has the height of the recommended at 1.3.

I measured the installed height and have 1.75 and jegs has them at 1.8....while I am not sure if1.75 to 1.8 is an issue and within my measure error.....there are no shims.

Does anyone believe I have the correct springs.....

I think mine were at right around + 2 inches installed height if I recall correctly .if your at 2.17 your springs are not compressed enough to give proper tension if your springs are meant for a 1.8 installed height you has lost a lot of spring pressure and would explain things .
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 06, 2018, 09:42:07 pm
thought so...where can I get the spec for 926-16....I am not seeing it on the website or JEgs. There should be a way to measure a spring and confirm it is or is not the correct one....
Title: Re: 355 HP...really
Post by: Jiffy on October 06, 2018, 11:58:21 pm
So, if I read that correctly, you’re 2.17 inches with the springs out and sitting on your bench and 1.75 when installed? They don’t sound wrong but the way to measure them is to measure the pressure it takes to initially open the valves and how much pressure the springs have when the valve is fully open
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 07, 2018, 12:45:00 am
ummmm….no sure I know how to measure all that....comments?
Title: Re: 355 HP...really
Post by: 428 CJ hardtops on October 07, 2018, 07:20:20 am
So, if I read that correctly, you’re 2.17 inches with the springs out and sitting on your bench and 1.75 when installed? They don’t sound wrong but the way to measure them is to measure the pressure it takes to initially open the valves and how much pressure the springs have when the valve is fully open

I am quite sure mine are a bit over 2 inches installed .Something doesn't sound right ..
Title: Re: 355 HP...really
Post by: rockhouse66 on October 07, 2018, 07:40:48 am
thought so...where can I get the spec for 926-16....I am not seeing it on the website or JEgs. There should be a way to measure a spring and confirm it is or is not the correct one....

Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 07, 2018, 12:35:08 pm
Jim, thanks...but that is installed and pressure at certain heights....what is the height uninstalled to validate they are the correct valves...and given the chart you sent...how do I validate these strengths....mine uninstalled measure 2.17...what would a 926-16 measure...I need to confirm the builder put in the correct springs....he told me Manley on the first call..and later said he put in the matching springs to the head...not sure I believe him now.
Title: Re: 355 HP...really
Post by: rockhouse66 on October 07, 2018, 04:05:31 pm
They are supposed to be 415 #/inch spring rate.  So, if you can, put a known heavy weight on one spring and measure it's height.  The unloaded height - the loaded height will be the deflection.  If it is 1/4", for example, take 1/4 of 415 and that should equal the heavy weight you used to produce the 1/4" deflection.  This is crude, I know, but would at least tell you if your springs are in the ballpark of the ones Comp recommends.

There are actual spring checkers that do this precisely, but without one you are left with ingenuity and junk you have around the shop.
Title: Re: 355 HP...really
Post by: 67428GT500 on October 07, 2018, 04:11:27 pm
Thanks...Jim, yes I am running headers....and this is a 4 speed..so I believe I am hearing no stall issues or vacuum issue with the brakes...IF>...I did upgrade the cam. (BTW, you said 270h...what was that in reference to...)

I will check the springs...I take it I measure the installed height to spec?  Any other check...???  I an nearly out of my tech....

The Pertronics is a rebuilt one...from Jim Warino in LA...supposed to know what he was doing...could that be the issue and I need to replace?  I would prefer I fix this before I install in DEc...and then decide to pull the cam.
The dyno sheet ells the tale. Stock these engines have 10.5 to one compression. Yours has been lowered to 9:1 in order to be able to use the 91 octane fuel that was used for the dyno run. It says timing was 28 degrees, that alone would knock off 15 - 20 horsepower compared to the stock setting of 40 - ish degrees.

So you are probably losing 30 - 40 horsepower from the lowered compression / lousy gas.
Another 15 - 20 from the timing being way retarded.
Probably 10 horsepower loss due to rich jetting on the carb.

The cam might be another problem, it falls off in power really early compared to a stock cam. Maybe the cam timing is retarded for some reason? It looks to me that this engine could make better power if it were tuned and maybe a different cam installed.


If it only had 28 degrees the hp loss would be more like 75 hp maybe more .Have seen the difference at the track and its huge .

Pertronix is junk? Your opinion isn't anything but your opinion. I am running the Pertronix II. The only issue was powering it so it didn't affect the factory tach in my shelby. They are a far cry better than playing with dual points.  The reason for MOST failures is that people can't read and follow directions. 12V isn't a suggestion, it's required. Low voltage makes them act up and fail early. 15 years with a Ignitor II. Not one issue.  I don't have to set the dwell and the car starts much easier than it did with points.

As stated above: Pertronix II isn't an issue, but you cannot use them without 12V constant. I pulled mine before the tach and ran a power wire directly to the positive of the module.
Title: Re: 355 HP...really
Post by: geraldt52 on October 07, 2018, 05:37:00 pm
The valve spring specs for a stock CJ are in the service manuals.

Installed height = 1-13/16",  measured from the seat to the retainer.
Valve closed spring force...80-90# @ 1.82"
Valve open spring force...255-280# @1.32"

The cam in question has a bit more lift, so the spring forces could stand being a bit higher...but a stock CJ with stock springs will get to 6K before things really start to go to hell, so if you're in the neighborhood you should be OK.  If your springs don't have at least the forces of the stock CJ springs, then you've probably found your problem.

Any auto machine shop should have a proper spring checker and check a couple of your springs for a little bit of nothing.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 11, 2018, 12:13:45 pm
I found another copy of a dyno taken minutes after the first one...and the HP does not drop off as bad...comments?

I will have the tool to measure the springs this weekend...

Also, I called compcam and they prefer the HP on the 118/224 cam over the 230 cam...says it will have more HP...really?

This forum highly recommends the 230 cam??

Thanks
Title: Re: 355 HP...really
Post by: geraldt52 on October 11, 2018, 07:50:26 pm
I found another copy of a dyno taken minutes after the first one...and the HP does not drop off as bad...comments?

That looks a lot better than the prior run you posted, but it only highlights that something is amiss.

Looking just at 5200 rpm, the first run was 251 hp, and the second run was 311 hp...60 hp difference...for "no" reason?  Did the dyno operator have any explanation?  You still should verify your springs and installation height, but I'm now having trouble associating those two dyno results with the valves floating...seems a huge difference run to run, when I'd expect it to be more or less repeatable.  Maybe the secondaries in the carburetor are malfunctioning?

I forget now, is your engine on a stand and can't be run, or is it in the car and can be run?  If you can run it I'd still suggest you put a timing light and vacuum gage on it and see if you can see anything happening above 4K, and I'd also suggest you verify proper operation of the secondaries.

I hope this link works, and this is what a more or less stock CJ should look like:
http://www.fepower.net/Dyno%20Results/dyno_results_2.html (http://www.fepower.net/Dyno%20Results/dyno_results_2.html)

Did your dyno operator give you a graph?  If not, you might want to graph your results and compare to the images.  The horsepower naturally flattens out above 5K rpm, but nothing like your engine. 
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 11, 2018, 09:13:13 pm
Thanks for the comments...the engine is on a stand in the garage (2x4s), so I cannot check with a timing light...the cam is a 218/224 for low end torque...and that concerns me a little...I have had comments from both ends on good and bad...  I have attached a graph I did in excel.

I suspect the first run was without correct timing and that is the difference..I hope....and I suspect the carb is over jetted...that I have the jets and will fix once I get running.

I will check for the correct springs this weekend..but do not see the value spring issue as before...but I was expecting higher HP...and may replace the carb next year...and looking for comments if the cam and or disti is not ideal...
Title: Re: 355 HP...really
Post by: geraldt52 on October 12, 2018, 12:17:27 pm
A few comments about your last dyno sheet.

The "timing" listed at 28*, is the same as the first run, and isn't very informative, since we don't know what that refers to.  If it refers to total advance, then that is a mile off what is required.  If it refers to just the mechanical advance, then initial advance settings between 6 and 12* would give you a total advance of between 34 and 40*, which would be workable.  It's not possible to determine what's going on there from the dyno sheet.

After the listing for "bore" and "stroke", there is an entry of "9.00-1", and I don't think you ever answered the question as to whether that indicates that the compression ratio is 9:1.  If it is 9:1, and you're wondering why the horsepower is lower than you were expecting, that's your answer.  There's still some other reason why horsepower drops off a cliff at 5K though...a low compression ratio won't act like that.   
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 13, 2018, 08:46:17 pm
I checked teh springs and they test at the correct springs....926-16

The oil pump is the M57 and this si the one where he used a rebuilt one first and was blowing over 100 psi...and replaced that one with a stock...thoughts if that blew out a galley plug?

I am about to pull the cam after I pull the manifold and see if he is missing a plug...thinking about a 33-230-4
Title: Re: 355 HP...really
Post by: 69cobrajetrugae2 on October 14, 2018, 01:22:48 am
Here is a post from Holman Moody Stroppe Vette.   https://www.fordfe.com/installing-non-adjustable-rocker-arms-just-bolt-do-t91706.html

I agree with Gerald that something is amiss with the dyno reports insofar that they are 3 minutes 26 seconds apart and the result is vastly different.  Usually another dyno run is preceded by a engine inspection and tuning session. 
Title: Re: 355 HP...really
Post by: geraldt52 on October 14, 2018, 07:44:31 pm
Here is a post from Holman Moody Stroppe Vette.   https://www.fordfe.com/installing-non-adjustable-rocker-arms-just-bolt-do-t91706.html

Holy cow, I don't know who that Holman Moody Stroppe Vet is, but he appears to be a frustrated novelist  :D !

I think this might be a more understandable read on checking/setting lifter preload...there's also special tools, but this works:
http://www.laneautomotive.com/PumpItUp.htm (http://www.laneautomotive.com/PumpItUp.htm)

Title: Re: 355 HP...really
Post by: 69cobrajetrugae2 on October 14, 2018, 09:59:56 pm
I learned a racing secret with respect to setting up a 428 CJ engine's valve train.  If a fellow doesn't understand all of it he would be well advised not to mess with any of it.

I'll bet that some guys make their own bleed down lifters and find out that they took off a little too much and she's bleeding bad at idle, clanking and clattering and got 10 pounds of oil pressure but she has a top end that won't quit.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 15, 2018, 08:13:58 pm
under the heading..."you just cannot make this up"....I called the dyno guy....

The fuel setting..he is not sure if his sensors are off...and does not know if he has a leak on one side...and does not look between engine to engine to compare...
He says he is not sure if the oil pressure is reading low or not....I asked him why does he have a gauge if he does not review it.
He reports the compression of 9:1 is a pressure guage during the run (that sound right)
He says the stroke was what he was told...and just entered it....it is wrong for a 428
When I asked him why he ran it twice and why the first was so bad...he says ...he thinks the throttle on this one dropped so he restarted it...go figure the drop.....but the second one is still weak.
The 28 dgreee timing he said was correct for a small block Ford...and set it that way on the balancer....I had to tell him a 428 was a large block....that just might account for the HP.

So much for paying for a dyno to diagnose an engine...all results are now suspect..I will replace the cam and take it to someone once I get it installed.

Comments?
Title: Re: 355 HP...really
Post by: geraldt52 on October 16, 2018, 12:06:52 pm

...all results are now suspect..

That would seem to be the bottom line.  The guy's "explanations" of the results seem largely unintelligible...to me at least.  Sometimes things just don't go the way we hoped they would.  Personally, I wouldn't make any decisions based on those dyno "results", including replacing the cam.  Your call, but I seriously doubt that a lot of performance is to be gained by replacing that cam with the other one you're looking at.  If it's horsepower you're after, I'd be more concerned about the compression ratio than I would about that cam.  Surely whoever assembled the engine could tell you what the intended static compression ratio was?

Since you can't run the engine, you might want to have someone set up your distributor on a machine...so you know what's there next time you start it up.  Timing can make a huge difference.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 16, 2018, 01:34:32 pm
thanks...I will get the distri reviewed....
Title: 355 HP...really
Post by: FN on October 16, 2018, 05:24:41 pm
Take your engine to a shop that knows what they doing, you are wasting your time with this fellow.
Title: Re: 355 HP...really
Post by: redscj on October 16, 2018, 08:39:29 pm
Take your engine to a shop that knows what they doing, you are wasting your time with this fellow.
     Ah, let me think for a minute......forget his name & number. Don't be shy telling other car guys to spend their hard earned dollars somewhere else. The market will fix him. A little bad press weighs more than a bunch of good press. I doubt that this guy has much good press to begin with.
     There is no reason to tolerate this kind of bad work from a place/guy that has advertised himself as a professional. Please move on, all he can offer you is tall tales & heartache. Sorry for the rough advice but.......well no buts.
Title: Re: 355 HP...really
Post by: markharvey9077@gmail.com on October 16, 2018, 11:51:18 pm
good idea....

L&R Engines and Dyno Motive...avoid at all costs.
Title: Re: 355 HP...really
Post by: redscj on October 17, 2018, 09:41:22 am
     Businesses have changed over the years. Customer feedback has become valuable. Owners have realized the power of their customers opinions vs their advertising dollars. No sense being mean or petty. Honest, civil feedback works with those that care. Those that don't care are not likely to succeed in todays business climate.
     Just an old man on the internets opinion.
     Oh, btw I have 2 sets of the springs that you used set aside for my builds. I was a little concerned because the max cam lift is not much higher than your cam's lift. I made sure to read everyones recommendations. I didn't notice anyone say that your springs were wrong so looks like I don't have to upgrade my purchase. I won't sweat my spring choice now.