Author Topic: 355 HP...really  (Read 4416 times)

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Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #45 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.

Offline rockhouse66

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Re: 355 HP...really
« Reply #46 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.
Jim

'69 Grande CJ

Offline corbins

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Re: 355 HP...really
« Reply #47 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?
Steve Corbin

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #48 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?

Offline rockhouse66

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Re: 355 HP...really
« Reply #49 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?

Jim

'69 Grande CJ

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #50 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.....

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #51 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?

Offline 428 CJ hardtops

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Re: 355 HP...really
« Reply #52 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 .
had many 428 CJ and SCJ cars over the last 30 years.I currently own a 68 1/2 coupe and a 69 R code SCJ Coupe and a 70 R code SCJ Cougar Eliminator .I am looking for a 70 428 coupe if anybody knows of one for sale.

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #53 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....

Offline Jiffy

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Re: 355 HP...really
« Reply #54 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

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #55 on: October 07, 2018, 12:45:00 am »
ummmm….no sure I know how to measure all that....comments?

Offline 428 CJ hardtops

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Re: 355 HP...really
« Reply #56 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 ..
had many 428 CJ and SCJ cars over the last 30 years.I currently own a 68 1/2 coupe and a 69 R code SCJ Coupe and a 70 R code SCJ Cougar Eliminator .I am looking for a 70 428 coupe if anybody knows of one for sale.

Offline rockhouse66

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Re: 355 HP...really
« Reply #57 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....

Jim

'69 Grande CJ

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #58 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.

Offline rockhouse66

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Re: 355 HP...really
« Reply #59 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.
Jim

'69 Grande CJ