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Oil smells like gas

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Old 01-30-2007 | 05:46 PM
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Zrated83's Avatar
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From: Buckley AFB, CO / Crestview, FL
Car: 83 Z-28
Engine: LG4
Transmission: 700R4
Axle/Gears: 02 WS6 Rear w/3:42
Oil smells like gas

I broke my new cam in the other day so I changed my oil today. I drained the old oil out and it smelt like gas. What could cause this? During the cam swap I installed a new fuel pump. Could the new pump be faulty? Also while I was breaking the cam in, we noticed fuel coming out of the carb and base. Maybe that is related to why I have fuel in my oil.

Last edited by Zrated83; 01-30-2007 at 06:35 PM.
Old 01-30-2007 | 05:53 PM
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From: rochester,in.
Car: Forrest 91 t/a
Engine: 5.0 tpi w/underdrive/accel,full 3"
Transmission: 700r4
Axle/Gears: 3.73 pos
sounds like u didn't have it timed correctly. The intake valve was still open during compression.
Old 01-30-2007 | 05:58 PM
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Timing won't put fuel in the oil.

And before somebody else feels tempted to throw the other universal superstition scapegoat out there, it's not the EGR either.
fuel coming out of the carb and base
Sounds to me like you have a defective carb. Not too hard to figure that out... pour enough raw fuel down in a motor, to the point that it doesn't all burn, some of it is bound to get in the oil. Especially if it leaks when it's not running; like if it just sits there and empties the fuel bowls into the intake.

Try another carb, or fix that one so it doesn't leak, and see if it's any better..

Also, see my signature for helpful advice on troubleshooting.

Last edited by sofakingdom; 01-30-2007 at 06:04 PM.
Old 01-30-2007 | 06:14 PM
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From: rochester,in.
Car: Forrest 91 t/a
Engine: 5.0 tpi w/underdrive/accel,full 3"
Transmission: 700r4
Axle/Gears: 3.73 pos
Timing will cause fuel to be pushed back up into the intake manifold and time ing will f**k up a cam which at that point could let fuel into the oil by way of the valve that may have stuck open do to the "broken cam". I'm sure he tried to start it after the cam broke.

that were i was a common from
Old 01-30-2007 | 06:16 PM
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Apart from none of that making sense, who said anything about a broken cam?
Old 01-30-2007 | 08:17 PM
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Timing will cause fuel to be pushed back up into the intake manifold and time ing will f**k up a cam
Ummmm..... no, and no.

Meanwhile, he said he "broke in" his cam; not "broke" it. Not that that has anything to do with a leaky carb dripping fuel into the motor.

"Timing" has nothing to do with it.

You REALLY need to read my signature.
Old 02-01-2007 | 10:38 PM
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From: FLA (US) & PTY
Car: Z-28
Engine: 355
Transmission: T-56
Axle/Gears: Stock
This may not be related, but when I built y firt engine I used Molly rings that for some reason did not "broke in", so I have combustiona leakage. I have high oil comsuption, oil look dirty and did smell like gas... however I never had the blue smoke at the pipes!

Hope this helps!
Old 02-02-2007 | 02:03 AM
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From: houston
Car: 83 POS monte carlo 2015 chevy P/U
Engine: 92 5.7 tpi 5.3
Transmission: 700r4 6L60E
Axle/Gears: 2.42 too high
did you use a stock pump or a high performance?
if its a high performance pump & you have a new carb, before you mess with it check the fuel pressure. i have run into a few high performance mechanical pumps that produced more pressure than the carb could handle, some as high as around 10 PSI at idle. if the pressure is too high, an adjustable regulator should take care of it. if its a stock pump or an old carb, then do like sofa said.
Old 02-03-2007 | 11:38 AM
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From: BC Canada
Car: 1985 pontiac trans am
Engine: 350 with carb and headers
Transmission: borg warner 5speed
Ive had this problem of fuel mixing with oil before. in my case the fuel pump was the culprit. also make sure the fuel pump bolts are nice and tight.
Old 02-03-2007 | 05:33 PM
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From: Buckley AFB, CO / Crestview, FL
Car: 83 Z-28
Engine: LG4
Transmission: 700R4
Axle/Gears: 02 WS6 Rear w/3:42
Originally Posted by DENN_SHAH
did you use a stock pump or a high performance?
if its a high performance pump & you have a new carb, before you mess with it check the fuel pressure. i have run into a few high performance mechanical pumps that produced more pressure than the carb could handle, some as high as around 10 PSI at idle. if the pressure is too high, an adjustable regulator should take care of it. if its a stock pump or an old carb, then do like sofa said.
I bought a stock replacement pump from Autozone. Im in the process of rebuilding my carb now
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