oil use
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6th Gear
Joined: Aug 2009
Posts: 6
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oil use
I have a 69 big block(427/435 with three two's. Te block was completely rebuilt about 10 years ago.Recently the oil usuage has been a quart to 100 miles.My mechanic believes this is due to a carburator leaking gas into the cyclinder and washing the oil away.We can find no oil residue on any surface,none under the car or out of the exhaust.Do you think he is correct or does anyone have some other idea.I won't redo the block,so that's out.The carburator problem has been fixed.Help
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Joined: Feb 2010
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Could very well be what he said among 20 other things but we hope it was the carb.
If carb is fixed then drain oil and put in a good multi weight and see if it stops.
Also not sure if you built the engine but if it was a real good job and of late you went to a 20w50 or a straight weight oil that can also cause major sheering of oil.
My 454 I built with rollers and alum heads and after 500 miles of breakin with 15w40, I had burned a quart, went with Mobil-1 0w20 and now have 3500 miles on it and as of Sunday down a 1/2 quart.
A lot of my problem could be the 850 carb when driven in city and I could also be deluding the oil but I figured that up front.
Another note, racing type oils, if a true racing oil, can cause you problems also with excessive buring.
If carb is fixed then drain oil and put in a good multi weight and see if it stops.
Also not sure if you built the engine but if it was a real good job and of late you went to a 20w50 or a straight weight oil that can also cause major sheering of oil.
My 454 I built with rollers and alum heads and after 500 miles of breakin with 15w40, I had burned a quart, went with Mobil-1 0w20 and now have 3500 miles on it and as of Sunday down a 1/2 quart.
A lot of my problem could be the 850 carb when driven in city and I could also be deluding the oil but I figured that up front.
Another note, racing type oils, if a true racing oil, can cause you problems also with excessive buring.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Leak-down test is the first check to find where it's going. 
http://www.carcraft.com/techarticles...r/viewall.html
If you were having that much fuel wash, your engine would be trash because the oil would be highly diluted.
http://www.carcraft.com/techarticles...r/viewall.html
If you were having that much fuel wash, your engine would be trash because the oil would be highly diluted.
Last edited by billla; Aug 14, 2012 at 08:09 PM.
