My 1959 230 h.p. exhibits oil smoke especially when idling. Any good way to determine if cause is valve guides/seals or oil rings other than tearing down?
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Bearings.
If it isn't worse after sitting for a while but consistent at idle, the cause is excess oil getting past the rings but because worn bearings allow the crank to sling more under under the oil rings than they can scrape. Does more oil come out of one tailpipe than the other? That is a sure sign of excessive bearing clearance.
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Re: VALVE GUIDES OR RINGS?
See if you can beg, borrow, steal, or as a last resort, buy a LEAK-DOWN tester. You'll need an air compressor to use it. Get the engine warmed up. This is VERY important. Bring the piston to approximately TDC with an Eastwood whistle or balancer mark or whatever. screw in the hose to the plug hole and apply about 100 psi of air from the compressor. This is usually read on the left guage. Read the right guage. If it says 94 psi you are leaking 6 psi somewhere. This reflects as a 6% leak down. This is a pretty good figure for a working engine. 10% should be cause for minor concern but 15% or more means real trouble! The beauty of a leakdown tester is that you can find out WHAT the problem is without tearing anything down.
Say you are leaking 20% for instance. Put you ear on the exhaust pipe. If the exhaust valve is bad you'll hear the air escaping through the exhaust pipe. Put your ear to the the carb. If you hear air, the intake valve is burned. Listen to the oil filler tube. If you got rings, you'll hear air escaping into the crank case. If you don't hear any air from the filler tube, AND the plug is clearly oil fouled then it's probably rings.
If you remove a valve cover and run the engine while holding a propane torch (unlit) around the valve seals, you should identify worn seals/valve guides.
My Donovan aluminum small block was leaking anywhere from 26% (best) to 55% (worst) when I yanked it from the 62 driver. 185,000 miles! I was going through oil like Sherman went through Atlanta!
Hope the above helps.
Varooom!Comment
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Re: Bearings.
Bearing wear is a second order cause in this case. Number 5 and number 7, being next to each other physically and in the firing order always run hotter and wear rings faster than the other cylinders. This fact would cause more oil in the left pipe but caused by ring wear, not bearing wear. I ain't saying that bearings should be ruled out altogether but I think them an unlikely source of trouble. The leak down will pin point the trouble.
The Rev. Varooom!Comment
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If no leak down testor is available...............
here's what ya do, an' ya don't need a compressor either. Do a compression check, record all the readings, next squirt some 50 weight oil in a cylinder, do the compression check again and record the reading, do this for all cylinders. Compare the readings. If the readings increased, then the culprit is rings, if the readings did not change, the guides are the problem.Comment
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CRUDE APPROACH
George I almost agree with you except my experience with compression checks almost always leaves me with more to be desired. Most people don't warm the engine first and few know enough to hold the throttle plates open during the test. Also, ya gotta unscrew the hose to get the oil in and then screw it back in afterwards. Compression checking is a crude approach that may be best for big blocks BUT the sophistication inherent in small block design requires a more exacting approach. Leak testers are available at all automotive supply stores and compressors at rental houses. If I'm gonna go to the trouble of a compression test then I might as well have the complete picture of engine health. I really like the propane test for valve guide seals. That's quick and easy!
Rev. Varooom!Comment
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Propane test?
Jeff,Dale, and George, Thanks for good advice. Will run those tests but one question. What is the propane test? Thanks, JimComment
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Re: Propane test?
Take a burnz-o-matic and open the valve but don't light it. Remove a valve cover and idle the engine. Direct the propane on top of the valve guide seals. This ain't a very good test but sometimes it is revealing. Make sure the rings are OK first!
The RevComment
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KABOOOOOOM!!!!!!!!!!!!!!!!!!!!!!
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