Wrong dipstick and overfilling? Does it lose a quart, or so, and then stop using oil?
Maybe you guys can help me with this. Plugs aren’t fouling, appear to be burning clean. Have about 4000 miles on them. No oil burning smoke, seems to have good power. Compression test runs 140 to 152.
Low tension rings (by themselves) won't cause a quart of oil consumption every 150 miles. Something is wrong. Give us some more information about the engine. I'd rather find the cause of your oil vanishing problem than recommend you an oil.
How long ago was it built and how many miles on it since the build?
How is it typically used? (low rpm cruise, stop and go city traffic, drag racing, towing, garage ornament, etc...)
What temp thermostat are you using and what's the typical operating temp?
What's your static and dynamic compression?
Rod and main bearing clearance?
What camshaft exactly?
What oil pump?
Perhaps most importantly... how was the break-in done?
I've seen this once before with a .030" over 454 BBC (460ci) where the "builder" put cheap slugs in it that were .020" shorter than stock and with a -12cc dish. (may have been -15cc, not sure) They were .040-.045" in the hole with a .040" gasket and the typical massive 119 cc combustion chambers of smog era BBC iron heads. The static compression was in the toilet at barely >7:1. To make matters worse, it had a rather hefty cam in it that was ~235-240 @ .050" with a DCR down ~5.5:1. This engine didn't want to idle below 1000 rpm and was an unresponsive turd. He had a similar issue with oil disappearing though it was every 300-400 miles, not 150. When the oil pan was pulled to start investigating, you couldn't see the pistons in the bores due to a black tar (sludge) coating the bottom of the pistons. It was bad enough that you had to scrape it out of the way to see the lock rings on the pins. Running the DCR so low and lugging it caused very high piston temperatures which coked the cheap oil he was using. Same as you, no blue smoke, no oil on the plugs, no external leaks, etc... it was all evaporating and coking around the pistons and cylinder walls. As you probably imagine, this engine had a bad overheating problem as well.
Trying to diagnose these kinds of things online is usually a futile exercise.
I did notice one time I had the carb removed that there was a lot of oil underneath the carb in the intake.
Yes, I sealed the intake bolts that passed thru the intake canels.So an 8.1 vortec. Also why is it consuming so much. Do you have blowby when you take the cap off. Have you compression tested it. Has it had regular oil changes or a good flush and the pcv valve? Have you also tried replacing the intake manifold bolts which is a fix gm issued for the 8.1.
What's the pan capacity 5qt? ( 65 corvette) Dump the oil and put in a pint under the pan capacity then look at your dipstick, This is your new "FULL" line.I think the dipstick is correct but not absolutely sure. I never let it get below a quart.
Nope! I eat 327 Vettes!What's the pan capacity 5qt? ( 65 corvette) Dump the oil and put in a pint under the pan capacity then look at your dipstick, This is your new "FULL" line.
Man I would sell that lump and put a hot 327 in there.
BBC and Vette = nope.
BBC are for B and C bodies. thus the Big B & C
good luck and have fun!
Wouldn’t that affect the idle? Also, vacuum. Getting a steady 10” at idle.@496BBC
If you rip the intake off, coat both the intake and the heads with some dykem. Lay the intake with the gaskets back on the motor, lightly torque it, make sure it seals correctly.
I can't tell you how many cam in block motors I worked on that either the block or heads were decked and the intake was sucking oil from the valley.
Not necessarily. It could be such a small mismatch between the heads and intake, it could be happening at the transition between low vacuum, ie on throttle and high vacuum, stepping off throttle. That "shock" between the two extremes could be sucking in the oil.Wouldn’t that affect the idle? Also, vacuum. Getting a steady 10” at idle.
How do you know the pan capacity? I always put in 5 quarts w/filter and that puts it on the dipstick full line.Nope! I eat 327 Vettes!
You stated are an old guy and afraid of the power, but now you are go out and eat 327's.Nope! I eat 327 Vettes!
Didn’t have to totally get on it to take that 327 365hp!You stated are an old guy and afraid of the power, but now you are go out and eat 327's.
Maybe. Dusting grampa Joey B. in his 3-2-7 and Aviators. What an accomplishment
But it's not a muscle car. You took your 'vette to the gym and stuck it's hiney with T-Roni Roid juice.
In all seriousness,
Was this originally a L78 BB car?