crazyfokker

iTrader: (2)

I just finished my 408 and I have about 800-1000 miles (speedo was unhooked for awhile or I would give exact miles) and on cold starts it will puff a little blue smoke. But once the engine is up to 195+ degrees it stops, to me this sounds like valve stem seals, but im wondering if the rings just havent seated yet? Im running Mahle standard tensions on a set of wiseco k394a3 pistons. Everything in this motor is brand new, Ive got new patriot stage 3 heads so I dont see them having bad valve stem seals. Anyone else had this issue?

Adrenaline_Z

The rings should have seated by now.

The obvious questions are:

What ring type are you using?

What are the 1st and 2nd ring gaps?

Do you know what hone finish was used by the machine shop?

Explain your break-in procedure upon start-up.

THE_SUPRA

^ditto.

WE TODD DID

iTrader: (2)

Depending on the rings, most of the time they are seated within a few minutes of engine running.

CNC BLOCKS N/E

On the 400 its a must to have them plate honed, A shop down the street from me borrows mine to hone the 400 blocks as he was having trouble with the engines using oil and this seem to cure the problem.

Here is a link I did on plate honing.
http://www.camaros.net/forums/showthread.php?t=58964

crazyfokker

iTrader: (2)

I should have been a little more in depth with my description. Its a Lq9/ls1 style 408 iron block stroker motor in a 2000 z-28, not a gen 1 style 400 small block.The rings were the plasma moly type. But I did get it torque plate honed when I had all the machine work done. I think I might have found my problem last night. Its probably a pcv related issue. I pulled the throttle body and found a good bit of oil around the pcv port on the inside of the intake.

brad8266

iTrader: (23)

The PCV problem can be from excessive crackcase pressure due to blowby from leaky piston rings. So your problem still could lead you to your rings.

crazyfokker

iTrader: (2)

True...good point

brad8266

iTrader: (23)

You should do a leakdown and compression test to see whats going on. After you read the compression dry go ahead and squirt a bit of oil in the plug hole and then recheck the compression again. If it goes up with the squirt of oil then your rings are likely worn/unseated. The leakdown test will let you hear where any air is escaping from if its leaking.

gun5l1ng3r

I agree, a wet compression test would be a good way to see how well your rings are sealing...

jmalibuss

Any info on what the honing procedure was on that block?

DeltaT

iTrader: (5)

I had visible vapor coming out of my crancase/valve cover catch can (the kind with the drain on the bottom and a K&N on top) for about 3500 miles on a newly built motor. There would also be maybe 1/4 cup of oil in the catch can after a 100 mile drive. Then it stopped and has been virtually dry since then. Maybe a half teaspoon of oil in there every 500 miles. A compression test was very consistent at about 155 across all 8 cylinders. They are Speed-Pro moly rings, file fit by me.

Jim

jmalibuss

What kind of oil were you running? I have seen this happen a couple of times before. A BBC I built drank oil like crazy. About 1 quart every 500 miles. No visible smoke. Then one day my buddy told my it quit using oil! Cold turkey. After about 3000 miles or so.

DeltaT

iTrader: (5)

I was running Shell Rotella non-synthetic. I wonder if having boosted (Vortech S-trim) motor makes a difference? Certainly more blowby, and I made some more changes to my engine ventilation system during that 3500 miles.

Jim

My Site: http://home.mindspring.com/~jim_fisk/id1.html

jmalibuss

This was a supercharged engine also. I think we had Catrol in it. Non synthetic also.
Interesting