Engine Lifter preload on GT40 pedestal rockers

limp

wrap a little cheese around it and its a done

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#1

• Apr 5, 2023

• #1

My question here is how much difference would it make by using 6.250 pushrods instead of the stock 6.248....
Checking the preload with the 6.248 old pushrods and I get just a tick less than 3/4 of a turn which is just right....

If I buy new pushrods, I would like to get some 080 wall thickness and they are easier to find at the 6.250 length..

Anyone been here before? Will it change my preload turns much?? I have the shims, but would prefer not to have to mess with them....
What does anyone think about reusing the old pushrods?? Cleaned up 4 in my solvent tank and they look fine???

Thanks..

 

96pushrod

I think they're a little easier to get off

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#2

• Apr 5, 2023

• #2

We’re talking 2 thousandth of an inch here, which is negligible.

If doing any sort of aftermarket valve spring I’d recommend at least an .080 wall pushrod.

 

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rednotch

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#3

• Apr 6, 2023

• #3

Mic them.... Stock and old ford racing l302 measure exact same as 6.250 lunati hardened 1 pc on last set I used... The just measure them differently.. Think the old ford racing replacement where listed as 6.272

 

limp

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#4

• Apr 6, 2023

• #4

rednotch said:

Mic them.... Stock and old ford racing l302 measure exact same as 6.250 lunati hardened 1 pc on last set I used... The just measure them differently.. Think the old ford racing replacement where listed as 6.272

Click to expand...

Wish I could, my mic only goes to 6"..... I used a tape measure on the originals from the engine and they are a hair under 6.250..
Some companies measure the pushrod before the ends are drilled... Alex's parts has an article on that....

 

Last edited: Apr 13, 2023

limp

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#5

• Apr 6, 2023

• #5

96pushrod said:

We’re talking 2 thousandth of an inch here, which is negligible.

If doing any sort of aftermarket valve spring I’d recommend at least an .080 wall pushrod.

Click to expand...

Agree with your thinking, just hoping someone with real life experience has done this??
I Purchased beehive springs from Alex's parts and they told me heavier walled pushrods are unnecessary and not needed....
Read alot of articles about using thicker pushrods and have thought if I do get new ones, I would like to upgrade to some 080 walls.... Any thicker would be a waste of money on this grocery getter engine.... I did see some cutaway pics ( Smith bros website I think) of thicker walled pushrods and the oiling hole gets pretty tiny.....
And again, what about RE using my old pushrods??

 

Last edited: Apr 6, 2023

AeroCoupe

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#6

• Apr 6, 2023

• #6

Put the old ones in and send it.

 

96pushrod

I think they're a little easier to get off

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#7

• Apr 6, 2023

• #7

limp said:

Agree with your thinking, just hoping someone with real life experience has done this??
I Purchased beehive springs from Alex's parts and they told me heavier walled pushrods are unnecessary and not needed....
Read alot of articles about using thicker pushrods and have thought if I do get new ones, I would like to upgrade to some 080 walls.... Any thicker would be a waste of money on this grocery getter engine.... I did see some cutaway pics ( Smith bros website I think) of thicker walled pushrods and the oiling hole gets pretty tiny.....
And again, what about RE using my old pushrods??

Click to expand...

Beehive springs are sort of the exception to what I said as the rates are usually considerably less than a double spring, to attain the same level of valve control.

You would be fine to reuse your old ones.

 

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limp

wrap a little cheese around it and its a done

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#8

• Apr 6, 2023

• #8

AeroCoupe said:

Put the old ones in and send it.

Click to expand...

LOL....... The votes seem to be 50/50 on tossing them or using them......

 

Last edited: Apr 8, 2023

limp

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Apr 8, 2023

#9

• Apr 8, 2023

• #9

I ended up with these ( ordered anyways) pushrods... Everything else is new and I just couldn't see using the old pushrods....
I got one piece ( no welded balls at each end) 080 wall thickness ( stock is 060) and they havent pushed on a valve spring a couple of trillion times.. Yes, a bit of overkill for my engine......
I do appreciate the comments and I know the old ones probably would have been fine.... oh well.....
These are Trick flow 6.250 pushrods from Summit......

 

Last edited: Apr 8, 2023

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limp

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Apr 13, 2023

#10

• Apr 13, 2023

• #10

PIcs of the new and old pushrods.... Middle pushrod has been cleaned up in the solvent tank....

 

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limp

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Apr 17, 2023

#11

• Apr 17, 2023

• #11

All installed and preload is +/- 3/4 of a turn......
I wasn't comfortable with the pass side bank so after sleeping on it I loosened them all up re did them..... They were fine..
Tried out the smallest shim I have just for fun ( 010) and was surprised at how much it changed the preload... Be advised if you need to use the shims for preload adjustment...... Numbers on the packs are after I mic'd them.....
Watched #1 intake cycle and ran the timing to 10 degrees to help set the distributor for a hopefully quick first start......
And yes, there will be a new heater hose fitting on the intake......

 

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General karthief

wonder how much it would cost to ship you a pair

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#12

• Apr 17, 2023

• #12

You just knew I would say something bout that crusty hose connector didn't you

 

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limp

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#13

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• #13

General karthief said:

You just knew I would say something bout that crusty hose connector didn't you

Click to expand...

What can I say? OLD guys think alike......

 

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