Oil in the heads intake runners...
same problem here. except mine is fouling out #3,#7,#8 cylinder and smokes at idle. My engine has less than a 1,000 miles on it and ran a 6.88 @101 on motor and pump gas. So I don't think I have a ring/comp. problem. Its a 408 with ported LS3 heads.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
What pistons ? rings ? bore clearance ?
I'm convinced the long 4.0" stroke combined with a piston-bore clearance that is loose contributes to poor ring sealing, regardless of what a compression test might show.
Also the very small piston skirts most use wouldnt help, as again this allows the piston to rock about too much.
I'm convinced the long 4.0" stroke combined with a piston-bore clearance that is loose contributes to poor ring sealing, regardless of what a compression test might show.
Also the very small piston skirts most use wouldnt help, as again this allows the piston to rock about too much.
What pistons ? rings ? bore clearance ?
I'm convinced the long 4.0" stroke combined with a piston-bore clearance that is loose contributes to poor ring sealing, regardless of what a compression test might show.
Also the very small piston skirts most use wouldnt help, as again this allows the piston to rock about too much.
I'm convinced the long 4.0" stroke combined with a piston-bore clearance that is loose contributes to poor ring sealing, regardless of what a compression test might show.
Also the very small piston skirts most use wouldnt help, as again this allows the piston to rock about too much.
Same problem here. I have a 39,000mi LS6 with new PRC 215 59cc heads. I'm running a GMZ Motorsports vacuum pump kit, all pcv & air inlets are plugged off, & I still have light oil on my intake runners & light blow by at 6,500 +rpm. I'm even running 10w40 oil. I think I'm experiencing ring flutter & oil is going past my scraper rings & into my intake runners. Although, this seems impossible with the vacuum pump, so I'm obviously confused. Someone tell me what my problem is so I will stop going crazy. Maybe I should go ahead & do the 402 stroker I've been thinking about.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Same problem here. I have a 39,000mi LS6 with new PRC 215 59cc heads. I'm running a GMZ Motorsports vacuum pump kit, all pcv & air inlets are plugged off, & I still have light oil on my intake runners & light blow by at 6,500 +rpm. I'm even running 10w40 oil. I think I'm experiencing ring flutter & oil is going past my scraper rings & into my intake runners. Although, this seems impossible with the vacuum pump, so I'm obviously confused. Someone tell me what my problem is so I will stop going crazy. Maybe I should go ahead & do the 402 stroker I've been thinking about.
So dont do it for that reason
Teching In
Joined: Feb 2011
Posts: 5
Likes: 1
From: Canton, GA
Check your rocker arm studs. It's quick and easy. If the threads are covered with oil, that is your culprit. You'll have to seal the threads with RTV. Some head porting, especially on LS3 heads, will expose the threads of the rocker arm studs to the ports. It happened on my build and very easy to overlook. If you already covered this, then my apologies. :>)
Mike C
Mike C
Teching In
Joined: Apr 2007
Posts: 34
Likes: 0
From: Hutto, TX
well, the only thing I can think of is build it tight, vent/suck the crankcase somewhere other than the intake manifold, and use something that provides enough pressure to fully seal the crankcase with negative pressure like a vacuum pump. i can sell you my kit if you want. :-)
yes i know... old thread...
Higgs, you still got that LS vacuum pump setup laying around?
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