bbc motor smoking

Old 09-22-2009, 02:45 PM
  #21  
ssmonte70
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Default bbc motor smoking

i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,
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Old 09-22-2009, 02:50 PM
  #22  
DirkaDirka
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Default Re: bbc motor smoking

Originally Posted by ssmonte70
i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,
Just wondering shouldnt they have a higher psi than 175?? I would think that since it is a new motor that they would be in the 200 range.
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Old 09-22-2009, 02:55 PM
  #23  
OneBadGMC
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Default Re: bbc motor smoking

Originally Posted by ssmonte70
i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,
It's not something silly, like the rings are on the pistons upside down?

Or low tension oil rings?

Or sucking oil from the intake via a vacuum leak? Are the intake gaskets oil wet at the bottom?

There's a limited number of places you can introduce oil into the cylinder above the piston.

Rings, valve seals, intake gaskets, vacuum line via carb from valve cover (pcv) or transmission...

If it's not sucking trans fluid via a vacuum line from the trans to the carb, and the intake gaskets aren't wet at the bottom, and it has new valve seals (which I don't run any and my junk don't smoke), then the only other way I can think of would be the rings installed upside down.
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Old 09-22-2009, 02:58 PM
  #24  
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Default Re: bbc motor smoking

Originally Posted by OneBadGMC
Originally Posted by ssmonte70
i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,
It's not something silly, like the rings are on the pistons upside down?

Or low tension oil rings?

Or sucking oil from the intake via a vacuum leak? Are the intake gaskets oil wet at the bottom?

There's a limited number of places you can introduce oil into the cylinder above the piston.

Rings, valve seals, intake gaskets, vacuum line via carb from valve cover (pcv) or transmission...

If it's not sucking trans fluid via a vacuum line from the trans to the carb, and the intake gaskets aren't wet at the bottom, and it has new valve seals (which I don't run any and my junk don't smoke), then the only other way I can think of would be the rings installed upside down.
I didnt even know you could put rings on upside down. I thought they could go any way. I learned something today. :lol: :lol:
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Old 09-22-2009, 03:05 PM
  #25  
fla1976
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Default Oil burning

Have you tried draining the fuel system? Maybe there is oil in the fuel. Outside of the things ONEBADGMC stated there isn't anything left. I'm inclined to belive the rings are upside down. Are all the plugs showing signs of oil or just a few?
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Old 09-22-2009, 03:30 PM
  #26  
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Default Re: bbc motor smoking

Originally Posted by DirkaDirka
I didnt even know you could put rings on upside down. I thought they could go any way. I learned something today. :lol: :lol:
http://www.totalseal.com/TechPage.as...plessPistRings

There's a picture about mid way down on that page showing the different ring designs and the direction they are to be installed in the bore.
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Old 09-22-2009, 03:41 PM
  #27  
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Thanks for that site. I learned even more. It was very informative for me.
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Old 09-22-2009, 04:01 PM
  #28  
ssmonte70
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Default bbc motor smoking

no oil in the fuel, drain the oil and there was a little fuel in the oil,i dont believe with 0 leak down and 175 compression that the rings are in upside down on both sides,10.5 pump gas motor, is it possible that the carb may be to big, 1095 king demon , thanks
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Old 09-22-2009, 07:24 PM
  #29  
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Default Re: bbc motor smoking

Originally Posted by ssmonte70
no oil in the fuel, drain the oil and there was a little fuel in the oil,i dont believe with 0 leak down and 175 compression that the rings are in upside down on both sides,10.5 pump gas motor, is it possible that the carb may be to big, 1095 king demon , thanks
Well there's the other issue, which sounds like you hit on it...

Anytime there's enough gasoline to see it in the oil the carb is washing the cylinders dry and it's not sealing properly.

No offense, but I find it hard to believe it's 0% leakdown. A really good motor is going to leak 6-8% when hot. If you can get a cold leak of 10-12%, the rings should be fine.

If the carb is washing the cylinders down though, it's gonna smoke.

Doubt the carb is too big for it to idle. Lean out the idle mixture screws and see if it stops smoking.
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Old 09-22-2009, 07:57 PM
  #30  
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Yea, i dont care who you are, your not going to get a engine to have zero leak down. What does your engine builder you got it from say?
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