Determining Correct Pushrod Length

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89FHPSSP

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Recently bought an '89 SSP. It has minor mods; Edelbrock intake, GT40P heads, headers, etc. It had some pretty serious lifter/rocker noise. Pulled the valve covers and found most of the rockers are REALLY lose. I ordered new hydraulic lifters and I need to get the correct length push rods. I bought the measurement tool, but once I get the "zero lash" measurement should I add any length to preload the lifters since they are new? I have read/watched quite a few procedures, but none of them address my specific situation. The car ran good, but just trying to fix A LOT of upgrade sins that were committed by one of the previous owners. Thanks in advance.

 

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Monkeybutt2000

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Are they still pedestal mount rockers.

 

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89FHPSSP

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Monkeybutt2000 said:

Are they still pedestal mount rockers.

Click to expand...

Yes, sorry they are still pedestal mount.

 

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Monkeybutt2000

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89FHPSSP said:

Yes, sorry they are still pedestal mount.

Click to expand...

It's been a long minute since I've messed with pedestal rockers. You're supposed to just bolt them down with a certain torque value. Are they roller rockers? If so what ratio? Stock cam?

 

limp

wrap a little cheese around it and its a done

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1. Adjust the intake valve, when you see the exhaust valve start to open....
2. Adjust the exhaust valve as the intake valve starts to close....
3. adjust to zero lash....
You want 1/4 to 1 full turn past zero lash torqued to 20ftlbs.....( need to confirm the torque. )
If you cannot get that, there are shims you can buy or you have to get longer pushrods, depending on which way you cannot adjust them to spec...
Probably should take some blueing or grease and check the contact area with the top of the valve stem....
Summit has some pushrods with small increases in length over the 6.250 that stock is ( 6.248 I "think" to be exact") if you need longer pushrods..
Getting close to doing this to my new engine......

 

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89FHPSSP

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Monkeybutt2000 said:

It's been a long minute since I've messed with pedestal rockers. You're supposed to just bolt them down with a certain torque value. Are they roller rockers? If so what ratio? Stock cam?

Click to expand...

It has an E cam, stock rockers and close to stock hydraulic lifters.

 

AeroCoupe

lube between the nut and the face. I know my lubes

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E cam with stock rockers? Does that even work geometry wise?

 

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89FHPSSP

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AeroCoupe said:

E cam with stock rockers? Does that even work geometry wise?

Click to expand...

It ran pretty good before, it just sounded like a bunch of sick sewing machines. I have read online about people running this setup. But, you guys are a lot more knowledgeable than I am.

 

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89FHPSSP

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limp said:

1. Adjust the intake valve, when you see the exhaust valve start to open....
2. Adjust the exhaust valve as the intake valve starts to close....
3. adjust to zero lash....
You want 1/4 to 1 full turn past zero lash torqued to 20ftlbs.....( need to confirm the torque. )
If you cannot get that, there are shims you can buy or you have to get longer pushrods, depending on which way you cannot adjust them to spec...
Probably should take some blueing or grease and check the contact area with the top of the valve stem....
Summit has some pushrods with small increases in length over the 6.250 that stock is ( 6.248 I "think" to be exact") if you need longer pushrods..
Getting close to doing this to my new engine......

Click to expand...

Okay. Thank you very much.

 

AeroCoupe

lube between the nut and the face. I know my lubes

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#10

• Dec 31, 2022

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I was asking as I honestly don’t know. So I did some digging and according to Jay Allen (custom cam guru) the limit is 0.500” of lift with a stock pedestal. It has to do with the slot in the stock rocker fulcrum. Good info here:

https://www.corral.net/threads/lift-limit-on-the-stock-bolt-pedestal-rockers-on-a-roller-motor.1153765/

The E cam is spec’d at 0.498 int./0.498 exh. valve lift with the factory rocker arm ratio so you are right up on the limit Jay suggests.

If the funds are available you may consider moving up to stud mount roller rockers. Granted they can require some measuring to get the setup right as well but definitely better performance wise.

 

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Monkeybutt2000

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#11

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I ran an E cam on a 130k stock 302,no troubles. And I sure wouldn't put any $$ into converting those heads to stud mount.

 

CAMTWO1070

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#12

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If Im building an engine without using rail mounted rockers Im definately going to put beefier studs and make it a adjustable valvetrain with better heads for lots of good reasons... Main reason is those 5/16" bolts are weak and youre trying to build performance

With most builds a E303 camshaft can actually lose horsepower in a 302 too with stock heads...The valvesprings need to be done and spring height etc so why not get heads that work alot better with your setup

Another thing is with the e303 youre giving up a substantial amount of lowend torque compared to the stock 302 camshaft and with stock heads it can be more.......Youre gonna have to advance the camshaft at the t-chain atleast 3 degrees to gain back some lowend grunt///

It doesnt matter if its pedestal mount the valvetrain geometry must be done correctly....People dont realize that a pushrod even .015" too long or too short can throw off the effectiveness of the camshafts efficiency, total lift etc....

To dial-in pedestal mount rockers you use pedestal shims and/or longer.shorter pushrods depending on the lifters you use and the plunger height etc....


Even the B303 isnt a straight forward install.....Watch the video and see ..

View: https://www.youtube.com/watch?v=X-MKFhLeMCo&t=224s

View: https://www.youtube.com/watch?v=3V6IkLXj9F8

 

Last edited: Jan 1, 2023

96pushrod

I think they're a little easier to get off

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#13

• Jan 1, 2023

• #13

As long as the rocker isn’t binding in the slot you’re fine. I had a trickflow stage 1 with stock rockers and upgraded valve springs/pushrods. No issue at all.

With all hydraulic lifters you need preload. At 20ftlb of torque on the rocker bolt there should be between 1/4-1 turn of preload on the lifter. The stock non roller rockers have a good big of wiggle room as far as pushrod length goes, so it would have to be pretty far off to cause issue.

 

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8

89FHPSSP

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#14

• Jan 3, 2023

• #14

Thank you for all of the help. I measured for pushrod length at zero lash and came up with 6.275 inches. Read that .04-.06 inches is acceptable preload for hydraulic roller lifters. Checking the internet shows that evidently there is a global shortage of 6.3 inch pushrods though.

 

AeroCoupe

lube between the nut and the face. I know my lubes

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#15

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Will these work?

https://www.summitracing.com/parts/cca-7622-16

 

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Monkeybutt2000

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#16

• Jan 4, 2023

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That's a stock length pushrod.

 

AeroCoupe

lube between the nut and the face. I know my lubes

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#17

• Jan 4, 2023

• #17

I’ve seen stock length as 6.272” and 6.250”. The 6.250” was described as measuring from oil hole to oil hole being the material that was there prior to the holes is what made it measure 6.272”. Me personally I check the length and order what I need and zero F’s given about what stock was or should be.

Hell we had to remove the rocker studs on the Edelbrock Performer RPM heads and weld the holes shut and move the stud location on every valve. Known issue with these heads when using cams that have over 0.500” lift. I say “we” but it was my engine builder who showed me the issue and explained the correction in the geometry that was needed. Got it done and installed longer rocker arm studs (fulcrum was down on the stock Edelbrock studs) and geometry issue was fixed.

Long story short (dong on titties) measure and order what you need.