Is It A Big Deal To Adjust The Valve on A GPU?

[snielsen]

I'm wondering how big of a job it is to pull the valve covers and adjust the valves. What is the required clearances? Are there any special tools required? I have a funny noise well its not realy funny its irritating that occurs at certian RPMs .

 

[Des Moines Boater]

Let me guess, at low rpm you have what sounds like a hydraulic lifter clacking? I had that on an intake valve. I pulled the lifter out and replaced it and the noise went away. Do you know which lifter is making the noise? Someone suggested I get a longer pushrod but that doesn't make a lifter better. At higher rpms the lifter would get enough oil to keep it pumped up but at low rpms there just wasn't enough oil to fix the weak sister.

 

[snielsen]

Yea i have the lifter noise but I also have another at mid RPM that I can't nail down. With ear muffs on it sounds like the cage is vibrating but with out muffs is sounds internal to the engine, but only at certain RPM range.

 

[ricmey1]

GPU lifters are not adjustable, but yes you can make longer pushrods. I did it to mine about 2 years ago and have had no problems. If the lifter noise is that hard to pinpoint don't worry about it, it will stay together. Is your oil pressure OK ?

 

[snielsen]

Yea the oil pressure is great 45 cold idle and 30+ hot.

 

[Des Moines Boater]

Sounds like you may have some bad lifters. Pull the valve covers off the cylinders and check the clearance between the valve stems and rocker arms. I think they should be .030 to .110. You can replace the lifters without removing the cylinder. It is tricky removing the retaining clip but not impossible. I left the retaining clip off after I replaced a lifter because it was too hard to get it back on. I'll put new clips in when I do the next overhaul on the engine.

I wouldn't go with longer push rods to fix the problem. It may stop the noise but it doesn't fix a bad lifter.

 

[MavDog]

i agree with d.b. putting longer push rods will only stop the noise but the valve will not operate correctly. the valve will stay closed longer and not opening all the way, prob. causing overheat issues at the very least.. not a good combo on the motor. definitely robbing you of a few of those ponies we are all chasing!! (all of this only pertains to automotive motors, but should still apply.

Marvel mystery oil can do wonders to bring back a stuck or collapsed lifter. again, at least in auto application. don't know if compatible with ashless a/c oil but if so, put so drain 1 qt and replace with m.m.oil. let her run till she good and warmed. sometimes if you dont drain any just add to it (dont leave overfull) so it brings oil pressure up and somtimes will help unstick. drsin oil and refill and ride out!) if not, well maybe somebody else knows some other trick without replacing GOOD LUCK!!