Oil Consumption-I need to know your thoughts

[denial]

Early this year my 94 3.4L started smoking on startup. Has 153K miles. It gradually has gotten worse. Burns a quart every 100 miles now. Can't see smoke very well when driving, but I'm sure it's burning oil all the time. Changed PCV already. The vacuum line that PCV valve is in always has oil in it. When I pull the PCV out, oil drips off it. At least SOME of my oil loss is going through that line. The line comes from the cover in the center of the top of the block (not sure what that cover is called.) I did a compression test. Results were high.....205-220psi. I figured it was high because of oil on top of the pistons. At least they were pretty close to eachother. I had a 'smoke test' done to see if the intake manifold was leaking. Someone told me that can cause it to consume oil. The shop said it tested OK. They did make a comment about not being able to get at the intake manifold very well. Makes me wonder if the test was very accurate. Anyway, I'm getting ready to take the heads off and take them in to have them gone through.......valve guides, etc. I figured that's what it probably is. What does everyone think? Any other ideas on what it could be? Should I pull the engine and get it re-ringed while I've got it apart? Lastly, the machine shop I spoke to about a re-ring said the sprockets on the ends of the cams have clutches in them. He said when those are taken off they have to be replaced.....they are one-time use parts. He said they're $300-$400 a set. I read through the Haynes manual and it doesn't say anything about replacing these when reassembling the cam carriers. Do these have to be replaced if I take them apart?
Thanks for any advice/help.
Denial

[Kohburn]

guy is full of shit about the cam cogs

[RednBlack]

Clutches on cams...Hmmm. Now that is an interesting thought. I would have this engine checked by a mechanic with less imagination. May not be as bad you think.

[93Oldsdroptop]

I never even heard of clutches being on cam cogs! What a line of BS! Don't walk, run from that guy.

[SappySE107]

Yeah, and if the intake gaskets leak, you aren't going to consume any oil. Guy hasn't got a clue on this motor it seems. The oil problem is probably the oil distribution block under the lower intake. Thats a high rate of oil consumption though, I get about a quart every 450 miles or so from that damn PCV setup. I haven't replaced my oil distro block yet but it has a PCV and I see oil in that line all the time.

It could be the rings but its hard to tell. Id work on the PCV setup first and see if that takes care of it. I wouldn't run just a breather on it for long but you can try pulling the PCV stuff off the plenum and then plugging the connection on the intake. Its right behind the throttlebody. At least you would know if its PCV or internal/seals/rings at that point.

[denial]

Thanks a lot guys!!! I appreciate the help. sappyse107.....I thought of pulling that line off and plugging the hole at the intake, but what do I do with the hose then? I can't plug that line up, right? Won't oil keep coming out of it?

[SappySE107]

The only reason oil is coming out is because of the vacuum draw from the intake manifold. Now, its bad to leave it unplugged cause that vacuum is needed to help with the pressure inside the block. You could cause oil to go past your rings if the PCV system isn't plugged in for a while, and I noticed a performance increase from hooking mine back up after it had been bypassed and just setup with a breather filter. Breathers will help get rid of the pressure but obviously a vacuum does a better job of that. Vacuum pumps are dyno proven to gain power.

[oleman]

At that amount of milege, you are rearranging the chairs on the Titanic.
You can determine how bad the rings are with a leak-down test.
I would go for an overhaul if it is a car you need or like, else walmart has oil for .85 per qt.

[SappySE107]

The milage really doesn't concern me too much, as I have seen other motors go well past that without needing any work on the bottom end. The leak down test is a very good idea though. There is a TSB on oil consumption as well, which is why I question the rings with decent compression right now. Its just too common for these motors to eat the oil. I wish I could find the CD I have with all the TSBs, id copy the info for you. Next time I see it ill be sure to print off all the common shit for this motor in the TSBs.

[denial]

That would be great sappyse107 if you found those TSB's!!! Kind of funny.....I had one shop tell me there weren't any TSB's on oil consumption on these. I have heard from others that these motors have pretty good bottom ends, and I have pretty good compression numbers to back that up.......even if they were boosted by oil on the pistons. What does the oil distribution block do? If Oil is coming out of there can I take it out and fix/replace it? My plan now could be to take that PCV line off and drive 50 miles with it to see if it still consumes oil. Are you saying I'm not going to be able to tell the difference in oil consumption because of oil going past the rings? I'm going to have to find out what a leak down test is. I haven't heard of that before. Wish the guy who did the smoke test would have suggested doing that when I had it in there. (he isn't the same one who told me the cams had clutches, by the way. different shop.)

[SappySE107]

You can run it for that long without the PCV hooked up to see if the oil consumption stops. Ill look for that cd as im about to head out of the shop here in a sec. The oil distro is a plate that can be removed easily with the lower intake off. You can still get it new from GM too I think, less than 30 bucks too last I checked. What it does is take the oil from the bottom end and feeds it to each cam carrier. Pretty much a main atery for oilflow. The PCV part doesn't do shit for that though, it just relieves the pressure from the block. If you disconnect the PCV setup from the motor, leave it open at very least, with a filter on it would be best. Plugging that off is very bad news, so don't plug the lines, just the intake manifold connection.

Just asked my friend about the leak down test to verify I knew what was up with it:P There is a special tool that you use along with an air compressor. With both valves closed (duh), you run about 100 PSI of air into the chamber through the spark plug hole. 1 gauge tells you how much air is regulated going in, and the other tells you how much is leaking out. I dunno if this is the only way to test it though but he is a mechanic (certified and all, im a newbie compared to him:P)

[Juglenaut]

Ha ha the clutch cam thing.......

PCV system is very important I would not permanently remove it.

I doubt you need rings, however a sure fact is oil fouled with fuel on a engine that is running at stiotch. The cylinder pressure would show low even though it has oil in the cylinder on a hot engine.

Possiblilities are unique cylinder head gasket wear, yielded oil leak into cylinder, worn valve seals, improperly worked or worn valve guides, and bent valve stem(s) or worn valve stem.

Any oil on the ground??

[denial]

Thanks Juglenaut. But what do you mean "oil fouled with fuel on a engine that is running at stiotch."?
I do not plan on running any more than necessary to check out this possible "oil distribution plate" possibility.........speaking of that:
I have now run the car for a bit without the pcv connected to the intake. I disconnected the hose at the plenum and plugged it's branch of the vacuum tree there. I put an extension hose onto the PCV line and ran it into a home made breather......an empty quart oil container. I took the cap off and secured some foam filter material to the opening. I did not notice any oil at the end of my extension hose until just this last time I drove the car. I pulled the extension hose out of the quart container and there was oil at the end. I think it just took longer to work its way there without the vacuum. My oil level did not drop and I did not smoke on startup like I was. The conclusion I draw from it: all my oil consumption was through that line. I plan on ordering the oil distribution plate to see if that fixes it. I'm the type of person who likes to understand how something works or why something is going wrong. I don't really understand how this oil distribution plate is causing my problem, and I don't like that, but I guess I'll change it since I can't see what else could be causing this after the test I just did. Sappyse107, have you ever actually seen or spoken to someone who has had that happen, or has anyone else? I would like to know if anyone has experienced this before.
Thanks again everyone.

[SappySE107]

Forget that plate, I thought the other part of it was PCV but it was the anti drain back valve. Looks like there is no point in swapping the plate out cause its an open breather setup to the PCV valve. Even a new PCV is doing the same crap to me so I am guessing we need a catch can setup to keep the oil out of the intake.

[denial]

I thought about that too, but there's got to be something else wrong. It didn't do this before and I want to know why it's doing it now. Now I want to take that plate off and see if that line is just open to the crankcase. I want to know how oil is getting up to it if that's the case.