what size pushrods?

[JAKEJR]

WRONG. it is only the cylinder heads, Block deck height and CH gasket thickness that affects the length of the pushrods.
camshaft,rockers and valvestems has nothing to do with PR length.

Well, CompCams would disagree.

According to CompCams, page 264, Master Reference Guide # 106-07, here are a few other things that effect the correct pushrod length:


Rocker Arm Brand/Design
Cam Base Circle Size
Valve Stem Length
Lifter Design/Brand/Pushrod Seat Height
Head Stud Boss Height


Jake

[Spartan7]

WRONG. it is only the cylinder heads, Block deck height and CH gasket thickness that affects the length of the pushrods.
camshaft,rockers and valvestems has nothing to do with PR length.

You should take another look at the valvetrain and rethink that statement.

[TRIPOD]

Question????
Just so we can all be on the same page here......

Has anyone had to change push rod length because of a cam/rr only swap????

[RamAir95TA]

Question????
Just so we can all be on the same page here......

Has anyone had to change push rod length because of a cam/rr only swap????

I did a cam install on my T/A 5 years ago switching to Crane Golds. I measured the pushrods and found that 7.20" were just fine.

[monster81]

Well, CompCams would disagree.

According to CompCams, page 264, Master Reference Guide # 106-07, here are a few other things that effect the correct pushrod length:


Rocker Arm Brand/Design
Cam Base Circle Size
Valve Stem Length
Lifter Design/Brand/Pushrod Seat Height
Head Stud Boss Height


Jake

yes, exactly ,,i agree but thats only if ur going with after market heads or modified stock heads.. but according to the OPs post , hes reusing the stock components. so why should he measure?
maybe my previous post was not directed, but thats what i meant.it was refering to the OPs post

[Spartan7]

yes, exactly ,,i agree but thats only if ur going with after market heads or modified stock heads.. but according to the OPs post , hes reusing the stock components. so why should he measure?
maybe my previous post was not directed, but thats what i meant.it was refering to the OPs post

No, all those components affect pushrod length on every application, not just a head swap. The correct answer is, always measure, don't just assume based on a similar setup. But hey, it's your engine.

[BlackBird87]

If i have a set of pushrods already but dont know if they will work how do i go about checking that?

[RamAir95TA]

If i have a set of pushrods already but dont know if they will work how do i go about checking that?

You have to measure them, after you measure the length of pushrod you need.

[JAKEJR]

No, all those components affect pushrod length on every application, not just a head swap. The correct answer is, always measure, don't just assume based on a similar setup. But hey, it's your engine.

Absolutely! ALWAYS measure (and I rarely use such emphatic terms like "ALWAYS", "NEVER", etc.)

Without measuring you won't REALLY know. In fact, virtually everything that I read from the cam companies says to measure. All the premier engine builders do it. They also specifically say NOT to assume that because someone else didn't need a different pushrod length you won't either.

Basically, it's not until a failure or premature wear occurs that you'll become aware of your error by not measuring.

"Assuming" is probably one of the worse mistakes made in modifying an engine. Attention to Detail (which precludes "Assuming") runs neck and neck with "cleanliness". To me, those are the two most important aspects in building/modifying our engines.

From decades of working on engines I long ago realized that paying strict Attention to Detail - including careful inspection of even brand-new, out-of-the-box parts - is essential to a strong, consistently well-performing engine. However, many don't want to expend the energy and concentration needed to inspect everything. This is especially true with younger guys who tend to be very impatient. Seems they are so intent to finish the job they fail to carefully inspect and measure. Just can't wait to fire it up!

Another area for those who opt to use the dot to dot method of installing a new cam, instead of degreeing it, they only realize that tolerance stack has reared it's ugly head after the engine is run. One example of that is a recent, very detailed account from a member on another Forum when his new cam caused the engine to run like crap. Only after he tore everything back down and degreed it did he find it was like 7 degrees off. It wasn't a mis-ground cam either; mis-stamped crank/cam gear dots, Woodruff key position, etc., all contributed to the cam being off. This is just one example of how Attention to Detail would have saved him a LOT of work.

Bottom line is to measure and NOT ASSUME. To do otherwise is like rolling the dice.

Jake