[Guest]

Is it guides, or what? It's not seals, 'cause those are new, and it doesn't do what leaking seals would do. Smokes during deceleration on compression only. Nothing at startup, nothing at idle, nothing cruising, nothing at launch. Comp and leakdown show good. The motor is a 351C 4v, and the guides only have about 2k miles on 'em, and are original. They sat unused for some thirty years almost. It's certainly oil burning, and more from the driver's side. Tailpipes get sooty kinda quick. I should say, it seems that oil is being drawn into the combustion chamber when decelerating on compression, if you decel hard for two seconds at high rpm, enough oil gets sucked in to burn off for a couple cycles. I suspect I'm pulling heads soon, just figgered I'd run it by you.

Dave

 

[Axnjxn]

What kind of compression are you running, and could it be PCV related? Is your PCV valve only dumping on to one side of the manifold?

WAGs here.

 

[Guest]

Compression is 9.5:1, and I run Moroso breathers on both heads, none of that emission stuff...

Dave

 

[Axnjxn]

Well that's not terribly high compression. I was trying to think of ways it could be ring related as opposed to coming in from the heads. I really doesn't sound like it's coming in through the guides, and if it is, it may only be one or two on each side.

Are you using rubber valve stem seals or teflon? Could the smoke be from a rich carb, or are you certain it's oil smoke?

 

[Bucket Lister]

Try using the PCV valve again. If your not sucking the blow by back into the carb, its gotta go somewhere. That's what your seeing.

 

[Guest]

Yeah? I'm not sure - I never use pcv valves, open breathers on both covers, a little messy on the chrome under the hood, but that's not where my smoke is coming from /forums/images/icons/smile.gif

Dave

 

[Guest]

Yeah, my compression is mild - I have a blower for this motor, but that little project never got going, and so I kinda wish the comp was up a point. If I ever tear it down, I'll bump it. I got enough power for this car anyway. I just put in teflon seals. The smoke looks like oil, smells like oil. Could be carbon, but the air/fuel isn't that rich. I don't claim to be able to perform spectrum analysis on smoke with my eyes, but it's oil, you know?

Dave