what happen?
Thread Starter
Racer
Joined: Oct 2001
Posts: 279
Likes: 1
From: Stonewall N.C.
what happen?
My L98 is just off a fresh re-built bottom to top, .060 chrome moly rings. Ran real good, strong, then the third week she started smoking white -gray. Checked the plugs and just one was full of black deposit, can someone tell me what happened? :confused: :U
Melting Slicks
Joined: Aug 2000
Posts: 2,009
Likes: 1
From: Springfield MO
Re: what happen? (vettedreams)
does it smoke at WOT and at idle or just at idle? Just one plug fouled out? Could be as troublesome as a blown head gasket or as easy as a bad valve stem seal or two. The person who assembled my heads used cheap stem seals and I had to replace them all because they were all lifting and allowing oil to seep in.
Thread Starter
Racer
Joined: Oct 2001
Posts: 279
Likes: 1
From: Stonewall N.C.
Re: what happen? (AS84)
The smoke is coming from the tail pipe, I hope what you said is the pproblem, I'll pull the valve cover and find out. I did a compression check on that cylinder when the engine was cold, it read 145 psi. then squirted oil in there and the pressure read 165, any thoughts?
Melting Slicks
Joined: Aug 2000
Posts: 2,009
Likes: 1
From: Springfield MO
Re: what happen? (vettedreams)
145 is respectable, the reason oil bumped it up is becuase it reduced friction on the rings. If you were down around 115 then I would say you had a ring problem but 145 is ok in my book. I hope its an easy fix for ya.
Thread Starter
Racer
Joined: Oct 2001
Posts: 279
Likes: 1
From: Stonewall N.C.
Re: what happen? (Goody)
I didn't check the other cylinders for compression, I did change the valve stem seal thought the other one didn't look to bad. With it being so cold I won't be able to try it yet.
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Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: what happen? (vettedreams)
Valve guide seals keep oil out of the cylinders. Oil burns BLUE. Oil will cause a wet, slippery, black, spark plug. Gasoline leaves plugs with a comparitively dry, fluffy, black, deposit and rarely do you gas foul only ONE plug. My '84 with 140,000 miles has 165-175 lbs of compression. 165 is fine for a new engine, especially if the rings haven't full seated, yet. All cylinders should be within 10 % of each other in comp pressure. The jump from 145# dry, to 165# wet, indicates a ring sealing problem...but white smoke indicates WATER. Antifreeze can leave plugs black. A .060 overbore is marginal on some late model sbc castings. To me, the prime suspect is a cracked leaking cylinder wall. I hope I'm wrong, but that is the best guess I come up with based on the information you've provided. In any case, I'm convinced that it is water that is causing your white smoke. I hope it IS a gasket. Good luck.
