Roller Lifter Problem?

[Hotrod46]

The engine I built for my T has a 99 Vortec block with roller cam. I reused the stock hydraulic roller lifters on a GM Ramjet 350 roller cam. This is my first roller cam engine.

After starting it for the first time it ran OK, but not really good. Had an irregular miss and an occansional sharp pop in the exhaust. Tuning (timing and mixture) made it a little better, but didn't completely clear up the miss. This miss occured at any RPM, not just idle. While tuning it today, it went completely sour and got to the point where it will hardly run.

I decided to readjust the valves just in case I screwed it up the first time. I noticed the lifters are bleeding down really fast. You can turn the engine over and watch the lifters bleed down literally in seconds. A valve that is fully open will bleed down until it is nearly closed.

I've read that these lifters do bleed down faster than older flat tappets, but this seems way too fast. This can't be normal. I'm thinking I need new lifters. I think the lifters are leaking down while running and causing the irregular miss.

Is this fast bleed down normal for these lifters?

 

[Duke]

It is near impossible to set valves right with soft lifters. Yes they will bleed down, but so slow you shouldn't notice. I think new cam, new lifters. Good luck

 

[Nas T]

I hate to be the one to tell you that you have to spend some more $$$ but what you are saying really seems to be a bad lifter problem, you should not be able to watch the lifter bleed down that quick, maybe if you sit there for awhile. Dont start anymore and cause other problems.

just my 2 cents :sad::sad:

 

[Hotrod46]

Yes they will bleed down, but so slow you shouldn't notice.

you should not be able to watch the lifter bleed down that quick, maybe if you sit there for awhile.

Yeah, that's what I was thinking. I should have bought new lifters when I built the engine, but was told (and read) that it was OK to reuse the old ones. With flat tappets, I always used new lifters. I have no past experience with these roller cams, but couldn't believe that their bleed down rates were that much different from flat tappets.

It's beginning to look like it's going to go to the wire as to whether I'll get this car on the road for the March car shows I wanted to go to.

Well, I guess I'm going to be tearing into an engine this weekend!:sad::sad::sad:

Thanks for the replies. May be bad news, but it's still nice to get other opinions.

Mike

 

[donsrods]

Mike, it could be that with the more agressive cam profile it affects the lifter. Maybe with the stock cam they were passable but now are not up to the task. It could be you have another problem, but as long as the used lifters are in there you won't know if that is what is causing it or not. I'd pop them out and put new ones in.


Don

 

[old round fart]

Can you run an oil pressure primer ( like an old distributer with the teeth ground off) while you adjust the lifters? Seems like lifters will not leak down with constant pressure.

 

[Hotrod46]

Mike, it could be that with the more agressive cam profile it affects the lifter. Maybe with the stock cam they were passable but now are not up to the task. It could be you have another problem, but as long as the used lifters are in there you won't know if that is what is causing it or not. I'd pop them out and put new ones in.


Don

Don

That's what I am thinking, too. The 1.6 rockers and stiffer valve springs don't help either.

Once I get the intake off, I can check for any other problems. I checked the cam timing at assembly with a degree wheel, so I'm sure it was right. I'll double check it though just to make sure something didn't let go.

On the bright side, the rings appear to have seated right away and the oil pressure was 40-60 psi depending on RPM.

I actually had it running pretty good at one point and it went downhill in a matter of minutes. I think the old lifter internals loosened up after a few minutes of running and started leaking. Sure sounded good for a few minutes, though.

The new parts should be here on Thursday and with luck I'll have it straightened out by Friday afternoon. If it goes that well, I'll only be out an extra day of build time. Keep your fingers crossed.

I'll be sure to post a follow-up when I get it running again.

Thanks to everyone.

 

[Hotrod46]

Well it's running again.

Good thing I pulled it down to change the lifters since I had a leak on the intake gaskets. Had some antifreeze in the top of the engine. Had a little in the pan too. Luckily, it only ran about 15 or 20 minutes before I decided to change the lifters. Could have been a real disaster. This water probably leaked after it was shut down since it had never emulsified with the oil.

Purrs like a kitten now.

Thanks again.

Mike