I am still trying to get the gremlins out of my freshly restored 67 convertible. The engine was rebuilt at the time of restoration about a year ago. It has 500 miles on it. It started smoking this week. The passenger side exhaust is smoking white smoke. Definitely oil related, not coolant. Repeat, there is no coolant in the oil or coming out the exhaust. The oil in the engine smells of gas. The drivers side exhaust smells normal, but the passenger side smells like gas. I changed the plugs and no change. #8 cylinder was fouled, but the rest looked okay. The driver side plugs looked normal, but the passenger plugs looked a bit more carboned up. Trying not to take the engine out. Any ideas of how to diagnose? Of course it is the passenger side of an A/C car just to make things difficult.
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Re: 1967 White smoke on passenger side exhaust
Lee,
Sounds like your 67 has been sitting around and not getting exercised enough. Take it out for a long drive on the highway and see if these things don't clear up by themselves. Run it out in every gear several times and drive it 70 for 20 or 30 miles. Bet she will have a smile on her face when you get her back in the stable.
JR -
Re: 1967 White smoke on passenger side exhaust
Composition or steel head gaskets? Do you retorque the headbolts? If not, do it now and keep track of which were loose. To me, Blue =s oil, white =s water. Not so sure I would jump into a long cruise.......Comment
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Re: 1967 White smoke on passenger side exhaust
The 'white smoke' your seeing very well may be steam....potentially a bad head gasket allowing water to seep into the piston area. Should you take the care for a drive denote water level in radiator before and after drive.Comment
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Re: 1967 White smoke on passenger side exhaust
Lee - So up until you hit around 500 miles, the newly rebuilt engine was running okay? If things were fine up until recently, you'd think there wouldn't be a problem with something like the intake manifold gasket which should have shown itself early on. Was a new fuel pump installed at the time of the rebuild? Just wondering if by chance the fuel is leaking into the engine that way.Mike T. - Prescott AZ.Comment
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Re: 1967 White smoke on passenger side exhaust
Sounds like a coolant leak into a cylinder. First thing I would do is re-torque the heads.Comment
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Re: 1967 White smoke on passenger side exhaust
Lee,
These are all good suggestion above, can you tell me if the spark plug wires were replaced with the rebuild, and is the carburetor a Holley? If you have a dead miss on #8 it's understandable there would be white smoke. This side has the heat riser and the exhaust pipe is not as hot as the drivers side until the engine fully warms and even then.
Were the A/F emulsion screws adjusted after the engine fully warmed. On these Holley's, there is a pin hole just under the secondary transfer slot and the size is approx .021+- but if it's larger the engine can get rich fast. Hard to give advice on where to actually start, I would eliminate the above suggestions and find out why #8 fouled. What color were the other plugs..Comment
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Re: 1967 White smoke on passenger side exhaust
Thanks for the replies, but let me answer some questions. The car is a 4 speed so no automatic trans fluid burning off. Everything on the car was replace at the time of rebuild. It is a Holley carb and I have blocked the 2 holes in the manifold that heat the carb up, not the crossover. I did adjust the A/F mixture screws after the car was warm, and they are out exactly 1 turn. That is what the vacuum gauge says is best. The plugs on the drivers side were brownish, but the plugs on the passenger bank were carboned up with the #8 being really bad. The longer the car runs, the worse the smoke gets. It is not steam. I am an engineer and know the difference between steam and smoke. When I wipe the inside of the tailpipes, the passenger side is wet and oily and the drivers side is dry with carbon. I am out of town until Saturday afternoon, so I cannot run any tests until then, but please post any more suggestions, I will be checking the forum. I am going to try a compression test on the passenger side Saturday, just ran out of time.
Thanks again,
LeeComment
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Re: 1967 White smoke on passenger side exhaust
Run a compression check & I suspect a broken ring(s) but it could be a bad valve seal on # 8 intake.Comment
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Re: 1967 White smoke on passenger side exhaust
Okay, I ran a compression test on the cylinders and they were as follows: passenger side front to back 150, 160, 167, 157. Drivers side were all between 160 and 170. The head bolts might have been 4 or 5 ft-lbs under torque but nothing significant. Before I put it all back together, is there anything else I should test? And more importantly any other ideas? I will say that the #8 plug smelled of gas when it came out and was pretty fouled.Comment
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Re: 1967 White smoke on passenger side exhaust
Because the #8 plug is fouling, the gas you smell is likely the unburnt fuel coming out of the #8 cylinder. It might be fouled because of oil leaking past the valve guide seal. What type of seals did you or your builder use?Comment
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Re: 1967 White smoke on passenger side exhaust
No idea. I will ask tomorrow. The guy who finished up my car had his brothers shop rebuild it. Runs great, strong and sounds great, but just started smoking. I am thinking of just pulling the head and taking it to another guy who does great work. I am just dreading trying to get it out from under that air conditioner.Comment
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Re: 1967 White smoke on passenger side exhaust
Assume they used stock GM valve seals and they should be adequate on a rebuilt engine. If oil is running down the valve stem it is most apt to be a poor fitting valve guide. But oil down the cylinder does not give off white cloud it would be blue or if bad enough black.
A broken ring will show the same but why would one not be fitted correctly and the rest be ok? Possible installed upside down? Take a look at head gaskets or possible crack. White cloud and black plugs sounds like more than one problem.Comment
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Re: 1967 White smoke on passenger side exhaust
If it were mine I would clean or replace the spark plugs and take it for a nice long ride and see if the problems persist before taking anything apart.Comment
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Re: 1967 White smoke on passenger side exhaust
Lee, check the intake bolt torque, I have seen oil being drawn into cylinders from loose intake bolts, another sign is oil puddles on the center two intake bolts on either side. GM had a service bulletin many years ago about this problem. also note that if there is oil coming up these bolts removed them and clean the threads on bolts and head and install pipe thread sealant.New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.Comment
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