Thread: Push rods too short?

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you posted that the cam was .498 ex lift---that will be at the valve of course and with a 1.5 rocker means that cam lift will be aprox .332------ put an indicaror on the lifter and see how much lift your getting----------I'm betting cam is wiping out---------


another thing----with it running does the pushrod rotate?????????????means the lifter rotates!!!!!!!!!!! no rotation--cam wiped


what oil did you use????break in stuff??????

When I first read the first post, I thought, lifter problem. But if you can get the valve adjustment back in range, only to have it go away again, sorry but it has to be a cam lobe going away. Nothing to do with pushrod length. Looks like teardown time!

Sounds like the cam lobe is gone.

Sounds like the cam lobe is gone.

Originally Posted by HWORRELL

Sounds like the cam lobe is gone.

yep seen it more then one time last 4 engine out of my shop are rollers two ford 385 big engines .one 440 and 400 pontaic . so cam and lifters are not hard to get .seen one 454 20years ago that was a fresh rebuild good friend did it it was right. i did fire it and did the break in .the owner did let it idle down to soon but was not all at fault .i rebuilt the engine and went to roller .the way it was with hyd flat lifter cam less then 30 miles took the bottom of lifter off did bleed down .this is a reall bad deal sound like you have some money in this engine you may not want to hear this but engine needs to come part wash all cam junk out and fix any thing that the added hard cam lobe did when ground up. buy a roller cam kit put it back together

Originally Posted by R Pope

When I first read the first post, I thought, lifter problem. But if you can get the valve adjustment back in range, only to have it go away again, sorry but it has to be a cam lobe going away. Nothing to do with pushrod length. Looks like teardown time!

Just that as part of any cam install, checking for and installing the correct length pushrods is critical to get the valve train geometry correct!

if a steel stamped shoe rocker is used your only going to get so good and close but a mile away compared to a big $$ valve train and that is somewhat ok if its very mild engine and very low rpm small lift very well could not give you full net lift with valve train geometry as good as it could be? many push rods come only 050. up or down with a full adjustable valve train with a shoe rocker with a small lift cam you can get away with a lot. long as nothing did not bottom out.... i would say that this in it self did not wipe the cam .was it right nope . some rockers arms that are rollers just will not mid lift .with rockers like this i shoot for center of valve stem and small contack point along with checking full lift numbers you can be .050up or down may move the net lift some . engines that run way past 6500 with big lift cams .need to be dead on. a shaft jesel.T&D, yellaterra. set up you want this on the money and spent many hours in doing so .there is roller rocker arms out there that will not set up with the mid lift plan. comp .crane and some other will. some will not i spent manys hours playing with this .when trying you find out it can not be done .the way some may think is right will not get net lift . true geometry can not be check with a plastic checker it needs to be checked with the rocker you going to use . there no SAE on roller rocker arms geometry on them is not the same brand to brand .so if you bust a crane and use a harlandsharp will work but geometry will be off. there not all working with mild lift plan. more like net lift so you can only hope to just stay on the center of the valve stem . there a hand full of rocker companys that do this

Oh Boy - sorry for the delayed response, just got home from the shop and then some food for me n the kid and now here I am...

here is the report so far-

witched out the 7.74 for the 7.90 and got it a turn past zero lash and guess what- noise still there.

As I banged my head against the effing open hood I was sitting under I thought to myself "slef, lets just run it and adjust out the noise and check the compression"

So I did.


And once the noise was gone by tightening the adjuster, yup, zero compression. So, I back it off under starter rotation and watch the compression gauge to 175 and call it good, irritated as hell put the valve cover on and call it good for the night, i am done with this mess for the night, screw it.

go get kid, run to local watering hole and when we get there, son gets out of truck and I swear I don't hear the knock.

I ask kid, you hear that noise? he says "what, the fan?"

Noise gone.

engine totally lumpy, no lifer knock, all is well - the xmas angles have sung.

let 'er cool down during dinner, come out - noise there a bit more, diminished from normal, once we get home, no more noise.


At this point I seriously have no idea..

Originally Posted by JustaChevyGuy

Oh Boy - sorry for the delayed response, just got home from the shop and then some food for me n the kid and now here I am...

here is the report so far-

witched out the 7.74 for the 7.90 and got it a turn past zero lash and guess what- noise still there.

As I banged my head against the effing open hood I was sitting under I thought to myself "slef, lets just run it and adjust out the noise and check the compression"

So I did.


And once the noise was gone by tightening the adjuster, yup, zero compression. So, I back it off under starter rotation and watch the compression gauge to 175 and call it good, irritated as hell put the valve cover on and call it good for the night, i am done with this mess for the night, screw it.

go get kid, run to local watering hole and when we get there, son gets out of truck and I swear I don't hear the knock.

I ask kid, you hear that noise? he says "what, the fan?"

Noise gone.

engine totally lumpy, no lifer knock, all is well - the xmas angles have sung.

let 'er cool down during dinner, come out - noise there a bit more, diminished from normal, once we get home, no more noise.


At this point I seriously have no idea..

junk in lifter valving lash down to far holding valves off seats if you did not wipe the cam go and play the lotto

Originally Posted by pat mccarthy

-------- if you did not wipe the cam go and play the lotto

Yeah. The Megamillions is over $400 mil; if you're on a roll, - -- - -----

Originally Posted by pat mccarthy

-------- if you did not wipe the cam go and play the lotto

Yeah. The Megamillions is over $400 mil; if you're on a roll, - -- - -----

ok, ticket was bought.


So here is my problem with this-

This noise was here BEFORE the cam was replaced, and is there after-

Cam was broke in correctly, so, unless they sold me a flat (number one exhaust lobe ONLY mind you) that is just not adding up in my head.

Not entirely sure where the junk in the lifter came from since the lifter was new, that would be another mystery to me.

When this started, to get the noise to go completely away all we had to do was place a 5/8 socket ON the adjuster nut and it would vanish. Not a butt-hair of adjustment, just placing the socket on the nut would eliminate all the knockknock.

The noise is still there but almost gone once it warms up - not sure what the next move is but I am open to suggestion...

as the engine picks up in rpm, driving down the road - knock is gone

Not knocking the advice, but i can't understand how that can be the issue when the noise was there with a brand new cam-

Originally Posted by JustaChevyGuy

ok, ticket was bought.


So here is my problem with this-

This noise was here BEFORE the cam was replaced, and is there after-

Cam was broke in correctly, so, unless they sold me a flat (number one exhaust lobe ONLY mind you) that is just not adding up in my head.

Not entirely sure where the junk in the lifter came from since the lifter was new, that would be another mystery to me.

When this started, to get the noise to go completely away all we had to do was place a 5/8 socket ON the adjuster nut and it would vanish. Not a butt-hair of adjustment, just placing the socket on the nut would eliminate all the knockknock.

The noise is still there but almost gone once it warms up - not sure what the next move is but I am open to suggestion...

as the engine picks up in rpm, driving down the road - knock is gone

Not knocking the advice, but i can't understand how that can be the issue when the noise was there with a brand new cam-

there is been some bad lifters out there .as for dirt could came from the block or crap in oil any were seen the lifter galleys have sharp iron hanging off the lifter bore . hell i had new lifters in a box were the box was not clean and breaking down so junk. sounds like the nuts you have are worn out ? you using poly nut s or the stock self lockers if so sounds like there backing off. pick up a new nut check the treads on the stud i seen some studs get eaten up by locking nuts . you need to oil the hell out of the studs you never said it had this sound before did you?

now that I review the post, I didn't mention the noise was there specifically after the new cam, I'm sorry about that...

We considered that the lifter was dead - but that would make two in a row and my machine shop (who has been doing this for 30 years plus) thought that the chances of this were about slim to none- I replaced the lifter before the cam to eliminate that possibility and then once the cam continued to go south from a previously bad break in, replaced the cam and we are still where we are.

Which reminds me of a question I don't think that I addressed earlier, the break in oil was dumped from the engine after the break in, and it was good break in oil that was used and the oil in it now has the zinc add...

Sorry this is such a pain in the a$$ to evaluate-

I do appreciate the direction...

also, poly lock being used, with new head stud-