#3 cylinder oiling

[twowheelhorse]

New Venture owner here. I just purchased a 84 Venture. It has 36K on it and is cosmetically in great shape. The problem is that #3 cylinder is oiling out the exhaust.....alot. So much so that it will eventually foul the plug. Goes without saying that it smokes terribly. The kicker here is that it won't start smoking until the engine has been running for 2 or 3 minutes. I would think that if it were rings, that it would start smoking at startup. I am wondering if I have a cracked head, possibly near a valve guide that the crack opens up as the head heats up. Anyone have any opinions on this? BTW, great site. Lots of great info here.

[Cruser]

It sounds more like valve guide seals to me if the oil builds up when it starts pumping to the top of the engine.

[skydoc_17]

Hey Bernie,

Welcome to the site! It's a shame you are not closer. My guess would be that you have a damaged Valve Stem Seal. If it were a "cracked head", a compression check of the #3 cylinder would tell the tale after warm up. It is by no means a fun job but it has been done, you can remove the valve cover, pump the valves up with compressed air, remove the cams for that cylinder, compress the valve springs, remove the valve spring keepers, and install new valve seals for that cylinder. Like I said, not a fun job, but doable. A compression check will give you loads of information about that engine.

Earl

[twowheelhorse]

Thanks for the replys guys. Well I did a compression check on the engine, and my worst fears are realized. #3 cylinder has no compression. It is not just down on compression, but actually has none. Won't even move the gauge a little bit. The other 3 cylinders range from 170 to 180#. Looks like the engine is coming out and the head removed to see what is going on. If this thing wasn't so nice otherwise, I wouldn't bother, but I can't just knock it in the head. It deserves to be fixed.

[Dano]

Pressurize the cylinder, then listen for air coming out of the exhaust. If none, remove the air box cover and air filter and listen there. A valve may be stuck open for some reason. If no air detected there, remove the oil fill cap and listen for air there. That would be the rings passing air. This way you'll know whats going on before you start yanking stuff apart.

 

Good luck and let us know whats going on, we'll help you sort it out.

 

Dan