Gun Jam

Im not real solid on I6 geometry but I think if that pushrod was long enough it would stop the valve from seating....those valves maybe always open now even if its just a fraction of an inch. That might explain the poor engine run.

Shims not a good idea but correct pushrod lenght is. They make measuring pushrods that are a mock up rod that is a known lenght and the base can unscrew and each turn causes a known amount of lenght increase...but you gotta know what they should be set to I dont thats an I6 dude question. If you pull a push rod does it have the lenght stamped on it some place maybe take it into sunlight and roll it over real careful and see.

as for the banging sound I'm not sure...I wouldn't think so but it seems like you have a critical lenght that is now out of tolerance and causing bind thats never good...

Paul Deasy

Going to order shorter pushrods Monday.

Also knocking problem sorted - don't know how it happen but over the course of restoration the oil pan got the smallest dent, one of the con rods was banging off the oil pan making a horrible metal banging noise.

Thank you so much Gun for your time and knowledge.
Have a great weekend
Paul.

Gun Jam

how do you know how much shorter they need to be?

bop11

The adjustment for a 6 is by changing the push rods. The clearance is measured with the tappet on the low spot of the cam, then allowing the the tappet to fully collapse. The rod clearance should be .066 to .216 ". Push rods come in std, .06" longer and .06" shorter sizes. I believe they are color coded. That is it for valve adjustment.

Gun Jam

a 1/4"?? I dont understand how thats a usable value... What do you mean by clearance are you talking feeler gauge under rocker arm and valve stem? Or end play (up and down) between the pushrod and the rocker arm?

-Gun

bop11

Gun Jam

I see they are physically bleeding down the lifter by squeezing the oil out of it so its fully collapsed.

None of the lifters ive ever used on the v8s bleed down. Once they are pumped up good luck (maybe thats were that special tool comes in)

Thanks for the clarification.

-Gun