Oil blowby detonation help?

Howdy.

We have here an LS1 with particularily sloppy piston slap and a good deal of oil blow by. 1-1.5 quarts Synthetic per 1000 miles. (Thicker real dino juice is faring better)...

On a li'l dry shot of 75 HP N20 (NOS 5177) we got detonation, I figure Oil vapor in the cylinder exacerbated things. :eek: OK, I immediatly stopped doing that!

I'm not into tearing the motor down for new forged pistons, etc. just yet....

Instead I am looking for a bandaid due to cash shortage. I was thinking Snow Meth/water injection to stave off detonation while lightly spraying 75 shot, diagnostic monitoring....then try a 100 shot.....

What U think Guys? Sorry for long sig...It's the SS. C1 Cam, Ls6 intake not mentioned



Ram:bow:
Rbenson@cepiallc.com

I'm thinking more like a retard box, but I don't have any experience with water/alky injection.

I've found one thing to be true over the years- nitrous will kill a hurt motor real quick no matter what you do. Bad rings and nitrous is almost as bad as running lean (hey, you're not running lean, are you??). It's gonna find the weak point and keep hammering on it until it lets go.

It's possible you've already hurt the piston/rings from the detonation (busted ring land leading to poor ring seal, collpsed piston skirt also causing bad ring seal) and there's absolutely nothing you can do if that's the case but fix the motor. Under load the rings absolutely won't seal up worth a damn and it will all spiral downhill quickly.

I ran my supercharged 383 for almost a year after I had destroyed a chunk of the top ringlands on #1 & #8. I knew it would eventually let go, and it did in fairly spectacular fashion, but for almost a year I drove it around like that. I could even hammer on it through the first 2 gears for a few seconds. But all laid out in top gear for more than about 10 seconds would dust the plugs with aluminum off the pistons from the detonation again in only those cylinders. It was hurt and that's all there was to it- no way to crutch mechanical damage with electrical or chemical fixes.

Thanks again Damon for the advice.

Since we can't see ring lands or collapsed piston skirts we can only guess. I'll wait until funds are available for a long block / eagle rods / forged pistons before we go pounding on it.

Running lean? I don't know, that was back with a stock tune. Haven't run it on the newer cam tune. Afraid to!

THANKS and BEst to ya, Ram

Oil contamination in the combustion chamber lowers the octane of your fuel considerably. Pop goes the weasel.

-Mindgame

Right, thus the temporary bandaid idea of "raising" the octane with some meth/water injection to offset the oil vapor. The idea was it might keep the knock gremlins at bay, monitoring with diagnostics, long enough to afford a new engine with forged pistons, good rods, etc....

Or... as Damon suggested, if it's got a broken ring land or collapsed piston skirt already (no puffing out the oil filler port though) ...which might be the reason it uses a lot of oil in the first place...I guess it'll just go that much sooner!

How can you tell without tearing the motor down? Rent a Boroscope? I dont' think you can see ring lands from top or bottom, maybe a collapsed skirt...

Looks like I'll wait till the tooth fairy comes. Thanks guys.