Joseph Pawletko writes>
>My TR6 is burning oil, and I was wondering if there is a straightforward
>(or even a convoluted) way to determine if the cause is the piston rings,
>or the valves.
One way is to do a compression test and then do a second compression test after
shooting some thick oil into the cylinder. If the compression gets a lot
better, the problem is rings.
Do you see a lot of blue smoke from the exhaust? If the smoke is worse on
trailing throttle, suspect rings.
If you let the car idle for a while and then it smokes like crazy for a while
after you take off, suspect valve guides.
If you get good results from a compression test, and still burn oil, suspect
valve guides.
A process I have had explained to me (but never tried) seems to be the
ne plus ultra of ways to figure this out. It is called a leakdown test.
You could ask if anyone knows a good shop in the Sunnyvale area to do a
leakdown test. Or maybe someone in the Sunnyvale area can help you in your
garage or his (hers). Jerry referred to the process in this recent piece of
MGB advice:
----------------------
Another technique is to hook up an air line from your compressor to the
sparkplug hole. Make sure the piston is on the compression stroke. Then
listen. If you hear bubbles from the radiator, you have
a leak.
Auto-parts stores sell the airline-to-sparkplug-hole adaptors. They are
used to hold the valves up in the head while changing valve springs.
I found this technique quite by accident: I was changing the Clankster's
valve springs, holding the valves up with the air compressor, when I heard this
"glub-blub-blub" sound from the radiator. :-)
- Jerry Kaidor <jerry_kaidor@engtwomac.synoptics.com>
----------------------
Use a tube or stethoscope to listen to various places on the car for leakage.
If leakdown test is good, and you don't hear hissing anywhere, your oil burning
is from valve guides (the valves are both closed in a leakdown test, so the
valve guides are not exposed).
If you hear a lot of hissing from the dipstick hole, your rings are bad.
If you hear a lot of hissing from the tailpipe, you have a bad exhaust valve.
If you hear a lot of hissing from the carbs, you have a bad intake valve.
I have the method for making and using your own leakdown tester salted away.
If you are interested, I could Email it to you. Netter Steve Soar wrote it.
Phil Ethier, THE RIGHT LINE, 672 Orleans Street, Saint Paul, MN 55107-2676
h (612) 224-3105 w (612) 298-5324 phile@pwcs.stpaul.gov
"Michael drives the canyons in a high-speed Lotus." - Joni Mitchell
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