1FastRedSC

I had a sealing problem with one of my valves, so i took the head out, and a local machinist "kissed" the seat and valve and now they seal. Then i put it together and it was making some noise, so i took it back out to find a bad valve lifter. So i replaced it, and now the same/similar knocking noise is coming from the motor. What could it be now?

special tool

Did you check the stem height the first time you cut the seat?
Did you check installed spring height the second time?
You cannot machine the valve seat and throw it back together without checking specs into the thousandths.

streckfu's

I take it you are refering to a cam follower (commonly called a lifter). Did you soak it in light weight oil before installing it? I had a similar issue after putting the head on my 951. It worked itself out as the engine was run over a week or so. I think it was an issue of getting the air out of the follower.

1FastRedSC

Your probably right, i'll take it out again.

1FastRedSC

New followers have air in them?

streckfu's

They need to be soaked in a light weight oil at least for a few hours. If you can inject a small amount of oil through the very small hole in the side, even better. However, even after soaking mine in a 5w oil for 3 days, one ticked for a little while. <100 miles later, the tick is gone.

1FastRedSC

Well let me detail the situation a little better. The head was a fresh rebuild from performance developments who i highly recommend. Neal is a real stand up guy, and have me 17 pages of data on all the work he did and all the numbers measured. Now first run in the car everything was fine but it lost some water through the block drain and overheated. Luckily the tec2 has an emergency shut off at high temps and totally shut off. However after finding the culprit, one valve was leaking ever so slightly. The machinist here took is and said he removed the least amount of material just enough for it to seal correctly. In doing so, he said the most it would have deflected inward from it's previous position is .005. Then i assembled everything again however now there a noticable knocking sound coming from the cam housing. I took it out and one follower was shot (i pushed the center contact in with my finger with little resistance). So i replaced the follower with the new one i recieved today, i took it out of the bag, rubbed some oil with my finger around the follower so that it slides into it's bore, assembled it, fired it up, and took it out for a short drive. And it still makes the same or similar noise.

streckfu's

It sounds dry. I had a follower ticking after installing my head. It worked itself out after a few miles. Don't stress yet. I think it will clear once you get some oil pushed through it.

1FastRedSC

Cool thanks

special tool

These lifters might take 1/2 hour to pump up.

The proper way to test is to hit the side oil hole with 75 psi from a rubber-tipped compressor blow-gun. It should immediately harden.

m42racer

1FastRedSC,

I think you will find the noise is a lifter that has yet to be pressurised. Its possible that the 1 that would not fill, was the major leak in the system, and therefore the others would not pump up to max. Now one of or more may require more time to pump up. ZYou only need 1 to create a leak a,d the others will push down with the Cam, and with a leak in the system, all will have trouble pumping up.

Glad you like the service and detail from PD. Its amazing what you get. Very hard to explain here. The difference is worth checking out.

1FastRedSC

Quick update, that overheating issue i had from awhile back ended up doing more damage that i thought. Turns out one of the pistons is slapping the the wall, which is making the noise. Going to have to pull out the steel sleeves when the new budget is available and try again.

johntorg

I just thought I'd add one more possible reason for "valve" noise. My freshly assembeled head developed a noise which turned out to be a loose cam gear, which chewed up the key, cam and pulley. ther are two different torque specs for the cam pulley bolt one for the allen head and a higher one for the triple square. I suspect that the wrong spec was used in my case.