oil problem...totally pissed

[Hozer 88GTConv]

I am fouling number 5 plug almost instantly.

I have r/r the heads. Replaced valve seals twice. The guides are good. All other cylinders/plugs are perfect. I did a comp check and I thought it was fine. No discernable difference in PSI in any of the cylinders and all were within 10 percent, dry and wet.

I am totally frustrated. I am travelling with the car but can do some maintenance.

Anybody have any tricks to isolate this? I go through a quart of oil in a week. The plug fouls right away. With that much oil, I'd think the psi would be crap with bad rings but it seems good.

Thanks in advance.

[~The Jester~]

Well to start narrowing it down, I would switch the heads. ie: take them off the engine, and swap banks with them. Then if you start fouling #4 instead you KNOW your problem is in the head. If the problem is still #5, then it has to be rings.

When you R/R the heads last time, did you put them on the same side? Were they marked at all so you knew which was which? How did that cylinder wall look when you had the heads off?

I'm gonna bet you have a BROKEN piston ring, not necessarily a worn ring.

[Hozer 88GTConv]

When I had the heads off, the cylinder walls looked fine, so I didn't mic them.

I was convinced that it had to be in the heads at the time. Now, I'm not so sure. So, even with a broken ring, a cylinder would pass a comp check?

Thanks for the tip.

[~The Jester~]

Sure will! Keep in mind that ALL the rings have a gap at the ends, and they hold compression. Problem with a broken one is it can no longer contain a liquid, ie oil. After the oil gets past the "complex" oil ring, it just runs around the piston until it finds the gap in the next ring, and up it goes.

Either that, or the gaps on the rings lined themselves up. I've seen that ONCE in all my years, so that's doubtful. With this volume of oil loss, I'd be looking at the head gaskets, or the block. Make sure the block/gasket/heads look good around the oil return holes (Hole towards the exhaust side of the block) too.

Kepp plugging away, we'll find it sooner or later.

[88fivepointoh]

I bet a bad ring as well... any oil in the coolant?

[crazypete]

Just a tip from someone who used to go through a quart of oil in a week too:

Are you using synthetic 10w-30? I shot a quart of that out my tailpipes about every week. I switched to cheap goop $1 a quart 10w-30 regular oil and viola!

I burn 1/2 a quart every 2 months.

Thin oil will find every possible means to escape your engine. Try using regular thick oil and see what happens.

Might be cheaper and easier than rebuilding things.

[Hozer 88GTConv]

I also replaced the dipstick when I put the rebuilt motor in. What are the odds that I installed the wrong one?

It's only 23 1/4" long from the lower tip to flush with the tube. Part number E7SE-6750-BA. I know it's a longshot, but I want to be sure.

Thanks.