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Old 05-06-2010, 08:29 PM
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302 Ford valve spring height confusion.

My factory original 302 heads has different length valve springs for intake and exhaust as well as different seated spring heights for int. and exh. Also, the retainer thickness is different for the intakes and for the exhausts.

I purchased Edelbrock replacement springs (#5822) to match my cam specs. But when I got the springs I discovered they were all the same height. The installation instructions for the springs says to set all spring heights at 1.66. However, the installation instructions for the Edelbrock Performer cam (which specifically calls for the #5822 replacement springs) says to "...check and set spring height to factory specifications for your year and model".

So I'm confused as to whether it is preferable to use the stock Ford retainers which will set the springs at factory spec as called for in the cam instructions or to order up Edelbrock retainers, which are all the same thickness, and I assume will put the spring heights all at 1.66 which is what the valve spring instruction sheet calls for.

Dazed and confused.

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Old 05-06-2010, 08:37 PM
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For equal pressures they will all have to be set at the same height. I would use the Edelbrock retainers or a similar replacement, some of the Ford stock stuff is pretty flimsy on some years of heads.

Are all the spring seat depths and valve lengths(to the keeper groove, not including the tip) going to come out at that 1.66" installed height or are you going to have to shim the exhaust springs(or vice versa)?

Man, I hate Ford and all their crazy changes made every few years.
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Old 05-06-2010, 09:57 PM
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Quote:
Originally Posted by ericnova72
For equal pressures they will all have to be set at the same height.
But then the question would be, are they SUPPOSED to be equal pressures. It seems clear that on the stock heads, the pressures were different. Different length springs, different spring heights when assembled, and different retainer thicknesses. I can't imagine the engineers would go to all the trouble of making all those components different..in order to achieve equal pressures as a final result.

And Edelbrock does not do much to clarify the issue, in one instance saying to set the spring heights according to Ford recommendations and shortly afterward saying to set the spring heights uniformly according to Edelbrock recommendation.

Personally, I couldn't care one way or the other. I have retainers to go either way. I just wish Edelbrock would make up their mind and decide whether the heights should be set according to Ford specs or their specs.
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Old 05-06-2010, 10:05 PM
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Standard performance practice is to have all the spring installed heights the same, which equals the same pressures. Only exception to this would be if you are running different rocker ratio's on the intake and exhaust, but this is only really done on really big solid roller cams where small amounts of spring force might be the make or break for something running good or destroying itself.

I gave up trying to figure out all the "better ideas" from Ford a long time ago, most don't matter to anybody but the engineers who are redesigning stuff every two years to justify thier place at the company...

It is no longer a stock cam, why would anything stock spec in the valvetrain be automatically correct??
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Old 05-07-2010, 12:10 AM
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All the older Fords that I've done headwork on have had equal springs. In fact I ran 351W springs on my 302 because they were equal height and would work, but gave me more spring pressure than the stock 302 which helped out on higher RPM's and floating valves. I know several guys who run the newer 5.0's are changing things around by buying two sets of rocker arms. They are using the 1.6 on the intake valves and 1.7 rocker arms on the exhaust (or vice versa, not sure???) which really makes a difference in performance. With the taller springs or using 1.7 rocker arms, you need to be careful on which cam your using to avoid the valves from hitting the piston head if clearance is an issue. I would go with Ford specs to be safe. Sometimes Edelbrock gets confusing with their tech support and instructions.
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Old 05-07-2010, 12:17 AM
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Spring height has nothing to do with valve to piston clearance.

I wouldn't call Ford spec's "safe", I have seen instances where they will cause problems when you involve aftermarket parts.

The springs have an installed height spec that is there to insure proper pressure, that is the main spec to be adhered to despite what any conflicting instructions say.
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Old 05-07-2010, 12:30 AM
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Do you think that maybe the stock grind on the cam lobes is so different between the intake and exhaust that they required different spring hight's?
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Old 05-07-2010, 10:11 AM
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Quote:
Originally Posted by ericnova72
Spring height has nothing to do with valve to piston clearance.

I wouldn't call Ford spec's "safe", I have seen instances where they will cause problems when you involve aftermarket parts.

The springs have an installed height spec that is there to insure proper pressure, that is the main spec to be adhered to despite what any conflicting instructions say.
Your right, Let me correct myself. The spring height will not determine the clearance from valve to piston. What I referred to was the changing of the rocker arms. 1.6 to 1.7 rocker arms will cause the valve to open more, combined with a different cam that has a higher lift, then you have clearance issues to be concerned with. I wrote my post after my bedtime last night so it didn't come out right. Thanks for correcting me!
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Old 05-07-2010, 10:17 AM
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Quote:
Originally Posted by sqzbox
Do you think that maybe the stock grind on the cam lobes is so different between the intake and exhaust that they required different spring hight's?
No, like Eric said, the spring height is designed to hold pressure on the valve. The cam would only regulate how far the valve opens and closes and the duration.
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Old 05-07-2010, 11:56 AM
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Dewey - I'm assuming that you are running stock Ford valves and if so, is the retainer at the same height from the head surface(rocker side). That is, are the valves "locked" at the same height by the retainers and locks - meaning the valves are the same dimensions head to lock groove. If indeed they are, then follow Edelbrock's recommendations. I ran into a bit of that problem then said the heck with it and ordered Crane retainers, locks and 1.7 rockers. I then set them to the recommended height determined by the Crane instructions as that determined opening and closed pressure plus kept me away from spring bind. I used Crane as they are who ground most of Ford's roller SVT camshafts plus supplied the top end hardware. On previous engines I've used both Edelbrock and Lunati and used their 'kit' then followed their instruction sheet.

For the non-Ford guys - it can be a challenge, but when done, sooooo satisfying to watch the Chebbies get smaller in your rear view mirror

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Old 05-08-2010, 01:42 PM
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Quote:
Originally Posted by Irelands child
...That is, are the valves "locked" at the same height by the retainers and locks...
Yes, I'm running stock valves in E7 heads. And on those heads, the locks (lock notches) are at different heights for intake and exhaust. Measured from the top (rocker end) of the valve down to the top of the locks...the intakes are .0240" down from the tip and the exhausts are .0335" down from the tips. The valves themselves, are all the same overall length. So it is the lock notches which vary.

I've got Edelbrock retainers on the way, but I'm assuming they will be all identical. Which means that when they are installed, I would still end up with different spring heights. Correct?

I assume in your situation, you got your solution to work because you had valves with the notches at the same distance from the head surface (or from the valve tip if you measure from the other direction).

Again, I'm a bit miffed by the installation instructions from Edelbrock since they are 302 specific but they make no mention of the different valve lock positions or how to obtain equal spring heights once installed.
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Old 05-08-2010, 02:34 PM
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Quote:
Originally Posted by sqzbox
Do you think that maybe the stock grind on the cam lobes is so different between the intake and exhaust that they required different spring hight's?
OEM cams do sometimes have different base circles on intake as opposed to exhaust lobes.

Chevy has used exhaust valve rotators w/the same springs but w/different installed height (and pressure) on both the BBC and SBC in the past.

That Ford uses different lock groove dimensions resulting in different spring installed height doesn't surprise me, any more than the things all the OEM's have done.

This doesn't address cboy's problem, though.

Unless the Eddy retainers are made to compensate for the different lock groove dimension, there's no way the installed heights will be equal, exhaust to intake.

Unless the spring will have too little clearance between coils @ full lift, or god forbid coil bind at the shorter installed height of the exhaust valves, you could run them as-is.

Otherwise, as I see it, the choices are to replace the exhaust valves w/lock grooves like the intakes, or use different retainers/locks to equalize the installed heights between intake and exhaust to the Edelbrock-recommended 1.66", or use different length/rate springs on the exhaust valves.

Ths assumes that you can get the correct installed height of 1.66" using the intake valves and retainers/locks the way they are, and that they aren't "too long", making the exhaust valves "correct", at 1.66" installed height w/their retainers and locks.
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Old 05-08-2010, 02:38 PM
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Dewey

There are at least 4 different types of retainer/lock configurations that Ford used plus they can be 7 and 10 degrees though seldom will you see the 10 as they are high performance versions. Did you order new locks with the new retainers as a set. If so, no problem here. With the fact that you have different height lock grooves in the valve stems, then I would then, with the new retainers and locks, set the spring height according to Edelbrock's instructions. The only other alternative is new valves - and that really isn't necessary.

This is from Ford's Performance book (my saved version is 2008, pg 115 and pg 220)

"1977 and later 302 engines have different installed heights for intake and exhaust valves"

"Valve springs are a critical part of valve train
operation. They’re designed to exert a specific
load at a specific installed height, thus spring
selection and installation are important"

I think that you have no problems, just a concept that seems 'different' which needs clearing in your mind.

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Old 05-08-2010, 03:43 PM
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Quote:
Originally Posted by Irelands child
Did you order new locks with the new retainers as a set.
No. I only oredered the retainers figuring to use my stock locks since they are brand new and both locks are 7 degree locks.

Quote:
Originally Posted by Irelands child
... with the new retainers and locks, set the spring height according to Edelbrock's instructions...
First, I made a decimal point error in my prior post. The measurement of valve tip to lock tops is .335 for exh and .240 for intakes. So the lock notches are about .09" apart, not .009" as my erroneous reporting would have indicated.

With that in mind, I don't understand how it would be possible to set all the heights at 1.66 as per EB instructions. Edelbrocks locks (at least the ones I'm looking at in the cataloges) are all basically the same. There are no special locks I've seen for SB fords that compensate for the different lock positions on the valve stems. Yes, I suppose you could somehow shim from the top down...but then you would end up with two different spring pressures...one for int. and another for exhaust. If you simply use the EB retainers with stock locks (or EB locks for that matter) you'll end up with the springs at different heights. Yes, with EB retainers the exhausts will be at the recommended 1.66 height, but the intakes will be at about 1.75.

Quote:
Originally Posted by Irelands child
I think that you have no problems, just a concept that seems 'different' which needs clearing in your mind.
I hope that is the case. But with my decimal point error factored in, do you still think this will work by simply installing the EB retainers (and EB locks if they would make some sort of difference)?
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Old 05-08-2010, 04:01 PM
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Quote:
Originally Posted by cobalt327
...Unless the Eddy retainers are made to compensate for the different lock groove dimension, there's no way the installed heights will be equal, exhaust to intake.
I don't have the EB retainers in hand yet, but I'm 99% certain they are all the same. They are listed in the kits and such with just one number (I'd expect two numbers if there was one retainer for int. and another for exhaust) and there is no indication anywhere in the literature that they come in two different configurations.

Quote:
Originally Posted by cobalt327
Unless the spring will have too little clearance between coils @ full lift, or god forbid coil bind at the shorter installed height of the exhaust valves, you could run them as-is.
I don't think coil clearance is a problem since at most the springs would be .06 tighter than the EB setting of 1.66 on the exhaust side and would be "looser" on the intake side by about 0.12". Coil bind might be a different story, however, since I'm not sure of a practical way to determine when a coil will bind up.

Quote:
Originally Posted by cobalt327
...Ths assumes that you can get the correct installed height of 1.66" using the intake valves and retainers/locks the way they are,
I think you meant exhaust, not intakes here, and by my estimation, I would end up at 1.60 if I use the stock exhaust valves, not 1.66 as per EB instructions. (Keep in mind, however, that EB instructions also say to set the spring heights per FORD manual. It just depends on what part of the instructions you are reading.)
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