mogulmike

I was doing some checks on my car last night and I found the most puzzeling thing. My car was 2 1/2 qts low on oil and I just changed it a month ago. I have no leaks. I'm told I have some smoke when I get on the gas. I'm also told when I let off the gas I get some smoke but that is normal. If I drive it conservativly the car burns clean, so I'm told. I have been road tuning the carb and some other adjustments so I have been getting on it a lot more than I normally would. I also have a dipstick that reads a little south because when I changed the oil I added 6qts and it read add another qt. Should I be concerned?

66427-450

when's the last time you freshened up the valve guides/seals?

mogulmike

I've only had the car a month. The previous owner said he had a rebuild done. I remember a few years back at the homecoming in BG, KY they had the race track opened and I watch all the cars run. It seemed to me all mid years blew smoke on the shift so I just thought it was normal.

ghostrider20

I would not say it is normal.

If you are tuning in a carb, and or getting on it often, with a fat carb, it would dilute the oil, and if anything raise the level.

I am in line with valve guides. I have used the first start of the day after a night off sitting to gauge valve guide wear. A small puff is normal, anything more indicates wear. I have had vehicles (Chevy’s) that blow a larger then normal amount and used about a quart every 3K miles. Not to big of a deal. 2 quarts in a month, depending on miles, I think should be addressed.

There may also be a chance that something in the PCV system is not configured correctly, incorrect parts or missing parts. I will not speculate, as I am not familiar with the PCV system on the 66 BB.

(Maybe Commissioner Gordon will get on the red phone and call Duke or JohnZ).


Mark

396 RAT

Its my understanding solid BB's did use oil from day one.
How much? I am not sure.
My car burns about a qt or so every 500- 1000 mi.
Curious myself as to what's normal?





[Modified by 396 RAT, 7:25 PM 9/2/2003]

DansYellow66

My experiences are they will use a little oil. But it can depend on the weight of oil, condition of PVC system, even the type of oil, in addition to the usual mechanical things that can go wrong. When I first bought my big block it used about 2 to 3 quarts per tank getting it home. After putting seveal hundred highway miles on it and changing the oil to 20W50 synthetic it settled down and now uses no perceivable oil in 4 to 500 miles. Don't get that many miles on an oil change however. I would make sure your PVC valve is in good shape, motor is well tuned, and maybe try a different brand of oil as an experiment. Buying or borrowing a leak down tester and running a leak down test would be the next move. :steering:

clem zahrobsky

i owned 4 new BBC,65 and 66 corvettes and 74 pickup and 76 impala and none got more than 600 miles to the quart. one good thing about it was the exhaust systems never rusted out. :D :chevy


[Modified by clem zahrobsky, 8:31 PM 9/2/2003]

L79vette

Ditto. My '72 big block Chevelle burned a quart of straight 40 weight every 500 miles, and everyone assured me at the time it was normal. I wonder how much it would have burned with 10W30.

hot1corvette1

Interesting that almost all of the replies indicate that their BB burns oil.
I have put about 2000 miles on my L72 and it has not burned any oil (at least the level on the dipstick has not changed). There is no smoke at all.
I am aware that the engine was rebuilt in 1991 and was bored over .060.
Engine runs/starts absolutely perfectly.

Ironically, my C5 burns about 1 qt. every 1800 miles. Not a problem, just an interesting twist.

Mark

mrg

If memory serves there was a mention in the local newspaper auto column a while back which stated that a quart of oil burned every 1500 miles was considered "normal". I don't remember if a baseline engine size was mentioned. One word to describe excessive oil consumption: SATURN .. ! ..

wombvette

I wasnt going to comment on this, because I consider any oil smoke to be not normal, and a car burning more that a quart per 500 miles will usually smoke some. But I have to tell you the story of my 67-390. The original owner states that it used oil from the begining and that he had worked on many times until it got out of warranty. He eventually sold it and some years later I bought it. It continued to use oil, and was embarasing, so I pulled it down to put a set of rings in it. They never seated either and in later years I decided to fix it once and for all. After 65K miles it had less than one thousanths wear, even after three sets of rings. I found brinell hardness test marks all over it, with several on each journal area. Turns out the block was hard as a brick, and that leads me to believe that Chevy may have selected harder blocks for the Corvette. I am sure that this contributed to the oil burning problem, so I opted to install plain cast iron rings. My engine man was horrified, said that I would wear out the block. Who cares, I have a long way to go to .030, and I will not live long enough to wear that block out at 2K miles a year. BTW there is absolutely no smoke, the tail pipes are white and no oil burning.

wallyknoch

Done correct, they will not burn or use oil. If they do, something is wrong. I have 6 big block pieces and all with high HP, none of them burn oil. :thumbs: The only difference between a BB and a SB is the size of the pump, 265, 283, 327, 350 for the SB`s and 396, 427, and 454`s and bigger as BB`s. Refering to the cubic inches not any thing else. They are all built the same way. :cheers:


[Modified by wallyknoch, 3:10 PM 9/3/2003]

clem zahrobsky

if the engines have been rebuilt with later technology oil ring package oil burning should not be a problem but the orignal ring package was not good and they all used oil. the orignal valve stem seals had the same problem. if the engine has the orignal factory parts they used oil. :chevy

396 RAT

Thanks Clem. Thats what I have always been told
by my Vette peers.
A qt every 500-1000 is more or less normal.
Were spoiled with our new cars! LOL LOL
I never think to check the oil on our daily drivers.
Never burn a drop between the 3000 mi oil changes.
And it always looks clean when I do? :lol:

67's

One of my profs in college Ed Fay, was a line supervisor at Tonowanda in the late sixties, he told me a story once of pressure comming down the line from GM about the Bigblocks burning alot of oil, went out to the line, took some pistons and they could all be put in with the rings on by hand the clearences were so slack.


Tom

mogulmike

Thanks to all. The PCV system is fine, it rattles when you shake it. When I was tuning my carb I took the PVC off and did see some faint smoke while the engine was running. I will change oil though, Vavaloine 5w30 high millage isn't cutting it. I'm going to let a buddy drive it and then follow him and get an idea just how much smoke is coming out of the car. Thanks again.

clem zahrobsky

a after market PCV valve can cause oil burning also. i had a friend that had his engine rebuilt and it still burned oil so i changed the the PCV valve to a genuine GM and the problem went away. :chevy

chewy

BBs don't burn any more oil than anything else if done right. The problem is with performance cams the tend to loosen up valve guides and there is your oil problem. The LS-5 that I stuck in my 66 has been there for 25 years and still doesn't burn a quart between changes.

cbernhardt

In 1968 I bought a new '68 427, 435 HP, L89 convertible. The engine was broken in correctly and used 1 quart of oil about every 500 miles from the time it was new until the time I sold the car with about 30,000 miles on it.
Charles

DansYellow66

I would say that 5W30 oil isn't a good choice unless the engine was specifically built for it. I use 20W50 Mobile 1 in mine and seem to be having good luck with it. :steering: