Last spring i had mike kleman (mikey) at Rapidmotorsports.com do a head and cam package for me! car made impressive power..425 rwhp thru cats and stock cat back, but i noticed i was burning a little oil by noticing my oil levels dropping. i also noticed a black residue existing thru my tailpipes but was told its normal with any major work like head and cam.

this spring i noticed the smoke coming from my exhaust more and more, usually under a heavy load and its now getting it more under less load. i figured it was a piston ring/seal or something on the bottom end, and mikey thinks its the same. well a couple weeks ago, the car seemed to lose alot of power, like it was running on 7 cylinders, so i replaced the plugs and noticed all the plugs but 1 were in decent shape. They all had a touch of oil on the plug, but the spark areas were dry, except the plug in the far back on drivers side (#7 i believe) was caked in oil, hence the power loss! replaced all and the car has gained 95% of its power back! i think its the oil burning is hurting it a little. i had a leak down test done last year once i noticed the oil consumption, but it checked out ok. not great, but manageable. i think it was something around 12.

OK, theres the background to my situation, but i am wondering if its the bottom end that needs to be looked at, or could it be a bad head gasket or some sorta other issue! like i said, i am not sure why only 1 plug was fouled while the others were in good shape especially knowing its burning oil. the car still is blowing smoke out the rear and has that burning odor.

all help is greatly appreciated, i just dont want to spend $4+ on a bottom end rebuild and end up wasting my money when it could be something alot easier or cheaper!

thanks in advance

dave

 

Your pretty much gonna have to pull the head. It may be something like a valve seal.

 

#7 Cylinder is known for breaking the piston. It will lift the ring land. I would bet your hurt that cylinder and that is where your oil problem is coming from.

 

A leakdown test will tell the story for sure, and I'd want to know before the heads came off.

Don't settle for a compression test as they're not always conclusive, find a shop with a leakdown tester and have it done on all 8 cyls.

If you have access to a compressor that can deliver 100 psig, you can buy a leakdown tester for about what a shop will charge to do the test. Jegs sells one by Total Seal that I like for around $100. Just bring each cyl to TDC firing, install the tester into the spark plug hole, and pressurize to 100 psi. Read the 2nd gauge on the tester for the results...91psi means 9% leakage, for example.

 

Even before doing a leakdown, I would do a "wet" compression test on the "bad" cylinder. This will tell you whether you've got a problem with leakdown past the rings or have a burned or non-seating valve. Get an initial compression reading, then squirt about two squirts of oil (about a teaspoon) from an oil can into the spark-plug hole (sometimes it helps to put a piece of vacuum hose over the oil squirter to direct it into a difficult hole). When you do the compression test again, the oil will seal up any ring-seating problems. Now, if your test still comes up low, the leakdown must be from the valves. If the compression comes up significantly, you've got a ring problem. I've used this test for many years, and it's pretty reliable, since most of the time the "wet" reading is way higher when there are ring issues.

If compression does not seem to be way off in that cylinder, you might also have a bad intake valve seal. Depending on how much valve-guide wear you have, it's possible to suck in a lot of oil when there's a bad intake valve seal.

Good luck!

 

I've had 1-2 bad valve seals that literally sucked down a quart of oil in less than 500 miles. You'll need to pull the rockers to do a leakdown anyway so while your in there, I'd replace the valve seals. That is assuming the results of the compression/leakdown tests are ok.

 

Brent....at what power levels is this common? Head / cam cars? N2O/FI cars? Is it easily visible with the head off? Thanks.

 

this happend with mine... it was a valve stem seal.... go back and make sure they are all seated firmly....

when was the last time you checked your oil?
i ask because you might find a clue on the drain plug magnet

 

mostly forced induction. However I had this happen on my own car years ago. Running hi compression, pump gas and generic superchips tune. I never heard it detonate but it did. It actually closed the gap on the plug in my case.
I put a new plug in it and the car ran fine. It passed a compression test within 10 PSI of the other cylinders.
A leak down test told the story , 30% on that cylinder. When I pulled the head it had half of the top ring exposed by missing piston
A leakdown test will point out the problem. I would take it back to Mikey and have him check it out as I have heard good things about his shop.

 

It's unlikely that there's a seal problem. I am gonna have to go with Brent and say it's your 7th piston. Who ported the heads?