The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 64' 292 6 CYL. USING TOO MUCH OIL !!

hey guys...i have a 64' chevy C-10 with a 292 6 cyl. the engine runs great, sounds good but uses way too much oil. don't know too much about the history. block is clean and painted black (might be re-manuf. or re-build ?). i was told it has a new head on it. the plugs all read clean and fine, compression was down in 2 cylinders (75-80, the rest were 110-125). i poured some sea foam in them hoping to free up some stuck rings and have not re-checked the compression. i don't see any signs of leaks. some smoke when i start it and rev it up after idling but don't notice it when i am driving. don't smell oil burning either. i put some "no-smoke" thick additive in it and drove it about 100 miles on sat. and it used 2 qts of oil. what could be causing this other than wore out rings ? maybe valve seals ?? any ideas or thoughts on what to check ? thanks for any help....john

Using 2 quarts in 100 miles should make it smoke like a mosquito fogger if the oil is getting past the rings. Is the inside of the tailpipe oily? I'd start looking for very badly worn exhaust valve guides that are allowing oil to go directly to the exhhaust system without being burned in the combustion chamber. Get a piston up the the top of the stroke so the valve can't drop into the cylinder, take an exhaust valve spring off, and try to wobble the valve stem back and forth in the guide. If it's got more than a very slight amount of slop, you're probably dealing with bad guides. Next question- - - -is the general condition of the engine worth a cylinder head rebuild? You might be doing the equivalent of a facelift on a patient with terminal cancer. The low compression on a couple of cylinders does not sound good.
Jerry

thanks for the response and ideas. i will check the tailpipe. i agree that using 2 qts. in 100 miles should make it smoke much worse than what i am seeing that is why i am puzzled. the head is suposed to be brand new but i don't know how long it sat around and am wondering if the valve seals dried out. i need to check the compression again after using the sea foam and driving it more. the truck hadn't been tagged in 15 years so i was hoping to find just some stuck rings that would free up with some driving.

try 80/90

Hotrods got the engine internals covered. The factory manual list compression at 130# per cylinder, so your in the ball park. Except for those two cylinders, probably the head gasket between them. When you check the tail pipe check the underneath the truck for oil. It's not in the water. I had a crack in the oil gallery above the cam, and the oil got into the water not the crankcase.

It's got to be someplace.

Larry

great advice ! i the compression in the cylinders (1-6) is: 90/95/110/100/100/100. one odd thing is that when i checked the compression last week i was getting 135 in #5 now i get 100. the tail pipe is sooty but not oily. looks like it is running rich in the pipe. the water in the radiator does look brown. i just thought it was rust. could this be a sign of something ?

1/2 gallon of oil in 100 miles? If you're burning it, you'd see the smoke; if it's leaking into the exhaust, it would stink; if it leaked that much into the coolant it would be brown sludge.

You dripping any?

The oil leak I had into the water was nothing like what you are losing. The oil was floating on the water maybe a couple of tablespoons. For as much oil as you are losing I would expect the water to be a milky brown and thick, if not just rust. The compression looks like what mine was before the rebuild, maybe a little better. I also had a definite piston slap till it warmed up. I was using a quart about every 200 miles.

btw I lost that block when the thermostat stuck, and it over heated badly.

Larry

i will take a closer look at the radiator and water. what i can see in the cap it looks like light brown coffee. may try to drain it and flush it and see if i get any oil in it. i seem to remember that the water looked more like green anti freeze a few months ago but may be thinking of one of my other cars. i did replace the temp. light sending unit and i am sure it was not brown like it is now. is this sounding like a leaking head gasket ? i could put valve seals (i am a big fan of the cup style that fits over the head castings) and a new head gasket in it. i might be getting ahead of myself but if i do pull the head off when i put it back together, can i adjust the valves like on a new re-build where i take the lash out with the valves closed and then 3/4 turn down or do i have to adjust them with the engine running since the lifters are used ? i never had good luck adjusting valves with the engine running. always liked the cold ajustment better.

The engine-stopped adjustment is the way the factory manual says it should be done. Just be sure the cylinder is at the top of the compression stroke before making the adjustment by watching the distributor rotor or the valves on the "companion cylinder" halfway around the firing order.
Jerry

Edit- - - -there's no need to pull the head to change valve guide seals. Get the piston topped out in the cylinder, and you can remove the valve springs with a spring-compressing tool built for the job. The valves will drop down against the piston without coming out of the guides. You can install new valve stem seals and reinstall the springs without disturbing the head gasket or removing the intake/exhaust manifolds. Just do one cylinder at a time, and make sure the piston is all the way up before removing the valve springs.
Jerry

2 quarts in a 100 miles is way more than valve seals. I would expect piston and/or cylinder wall scoring or very tired rings. Last vehicle I repaired with that kind of oil consumption, every ring was seized in carbon which required a complete re-ring job,
Scott

thanks jerry - i have never used the style spring compressor that works with the head on the engine but i will look into it. sounds like the way to go. the only reason i was thinking of doing the head gasket too is because of the condition of the coolant........looks like it might have either rust or oil in it. might try the valve seals first like you suggested. thanks - john

It's probably a combination of all the above. But without smoke, it seems to me to be a leakage problem.
An "outside" leak would show up on the engine, trans, firewall, crossmember, etc. We've all seen what a mess even a small amount of oil can make.
A few quarts of oil in the cooling system...hmm...I would think there would be oil floating in the radiator, unless it's being spewed out the overflow.
A few quarts of oil in the exhaust system might not show up anywhere until the low spots are filled: muffler, dips in the piping, etc.
It's possible it's burning some without making much smoke, and the compression numbers are not encouraging. A few quarts through the cylinders would probably show up on the plugs, though, so...
There's some incriminating evidence suggesting some thorough investigation is required. I hope it's something easy and inexpensive to fix. If a rebuild is necessary, it's a good time to hop it up a bit!

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