Oil consumption & smoke on a 327/350 hp

[Michael H.]

Re: Oil consumption & smoke on a 327/350 hp

If a freshly rebuilt engine consumes a quart of oil in 100 miles then there is very likely a major problem with the valve guides/seals or piston rings/cylinder walls. If the engine idles properly at 750 with the mixture screws out 1-1.5 turns then I doubt if manifold sealing is a problem as it will also cause a vacuum leak, which will result in very poor idle quality at nominal carburetor settings.


Duke

I agree. Some brand new Corvettes came with a high pressure oil pump and it didn't seem to have any effect on oil consumption. My brand new 365 HP 64 coupe didn't use an excessive amount of oil. As I remember, it was about a quart in 800-1000 miles. That's about the same amount a new 300 HP 327 car with the low pressure pump would use.


And don't buy the old story from an engine builder about how it takes many miles to break in the rings. That's nonsense.

If exchanging a high pressure pump for a conventional low pressure pump cures an oil consumption problem, the pump wasn't the original problem.

[Dennis O.]

Re: Oil consumption & smoke on a 327/350 hp

I agree. Some brand new Corvettes came with a high pressure oil pump and it didn't seem to have any effect on oil consumption. My brand new 365 HP 64 coupe didn't use an excessive amount of oil. As I remember, it was about a quart in 800-1000 miles. That's about the same amount a new 300 HP 327 car with the low pressure pump would use.


And don't buy the old story from an engine builder about how it takes many miles to break in the rings. That's nonsense.

If exchanging a high pressure pump for a conventional low pressure pump cures an oil consumption problem, the pump wasn't the original problem.

Mike,

Could you explain your last statement to me? Do you fully understand that hi-volume and hi-pressure are two separate things in regards to oil pumps? The maximum pressure is controlled by the relief spring, while the volume is controlled by the length of the gears in the pump. The gears in the pump I removed from my engine were fully 3/8" longer than the ones in the pump I replaced it with. I would imagine it moved at least one quarter to 1/3 more oil through the system than a standard pump would. One last thing; if one is planning on having his car judged, that kind of oil pressure will cost you on OPS or PV. I think all of us on here are interested in original factory spec cars. Even if the only symptom that was solved was the high oil pressure readings, I still would have been glad I changed it. Given the other possible benefits, I think changing the pump is a no-brainer.

Denny

[Michael H.]

Re: Oil consumption & smoke on a 327/350 hp

Mike,Could you explain your last statement to me? Do you fully understand that hi-volume and hi-pressure are two separate things in regards to oil pumps? The maximum pressure is controlled by the relief spring, while the volume is controlled by the length of the gears in the pump. The gears in the pump I removed from my engine were fully 3/8" longer than the ones in the pump I replaced it with. I would imagine it moved at least one quarter to 1/3 more oil through the system than a standard pump would. One last thing; if one is planning on having his car judged, that kind of oil pressure will cost you on OPS or PV. I think all of us on here are interested in original factory spec cars. Even if the only symptom that was solved was the high oil pressure readings, I still would have been glad I changed it. Given the other benefits, I think changing the pump is a no-brainer.Denny

I guess I wasn't paying attention and missed the part about it being high pressure and high volume.

I was in no way suggesting that anyone use a high pressure (or high volume) oil pump. (unless the car was originally equipped with a solid lifter 63-65 engine that was assembled with a high pressure pump)

The oil pump is that weird shaped thing in the oil pan, right??

[Joe L.]

Re: Oil consumption & smoke on a 327/350 hp

I agree. Some brand new Corvettes came with a high pressure oil pump and it didn't seem to have any effect on oil consumption. My brand new 365 HP 64 coupe didn't use an excessive amount of oil. As I remember, it was about a quart in 800-1000 miles. That's about the same amount a new 300 HP 327 car with the low pressure pump would use.


And don't buy the old story from an engine builder about how it takes many miles to break in the rings. That's nonsense.

If exchanging a high pressure pump for a conventional low pressure pump cures an oil consumption problem, the pump wasn't the original problem.

Michael-----


Yes, unless he used some really old rings or chrome rings, no "break-in" is required. Modern moly rings are pre-lapped at the manufacturing plant and require no "break-in" period.

[Joe L.]

Re: Oil consumption & smoke on a 327/350 hp

Here is the link with the pictures of the heads I pulled off. https://www.forums.ncrs.org/showthre...999#post671999 The car seems to run better with the 194 heads too then the 202's but it's not a 5500+RPM engine either

Gary-----


I once had a problem just like this with an engine I built from a brand new Chevrolet short block assembly. I used original re-conditioned heads. Major oil burning problems from the get-go. I tried EVERYTHING to solve it----a new set of GM heads, 3 different intake manifolds, every type gasket you could imagine, every type sealer you could imagine including aerospace and fluroelastomer, every type valve seal you could imagine. I NEVER succeeded in stopping the oil burning.

I even re-ringed the engine even though I knew the problem had to be coming from "up-stairs"------there's no way that a ring problem could be causing raw oil in the intake runners.

My hypothesis is that the genesis of the problem is oil vapor being drawn in from the lifter valley because of a leak in the intake gaskets (despite every attempt to seal it) OR oil being drawn in through the PCV system.

By the way, my problem was not caused by a high volume oil pump. I installed the pump and it was without question a GM standard volume, standard pressure pump.

[Gerald C.]

Re: Oil consumption & smoke on a 327/350 hp

Dennis,

At hot idle, the gauge drops to the middle of the gauge.

Jerry

[Dennis O.]

Re: Oil consumption & smoke on a 327/350 hp

Dennis,

At hot idle, the gauge drops to the middle of the gauge.

Jerry

Jerry,

Sounds to me like you may have the standard pump with the high pressure spring. As I said earlier, the pump comes with the high pressure spring installed and a medium pressure spring in a plastic envelope; the is no standard spring in the package. In this case, I don't know what to tell you. It looks like you have the same problem I had; I couldn't find out exactly what they installed, so I had to take it out to make sure. What I said about a pegged gauge not meeting spec and causing judging problems still stands. Just for grins, I have attached a picture of the HV/HP pump I took out of my engine. If you are familiar with stock pumps, you will immediately notice the longer housing that contains the longer gears. Note the "M55HV" on the casting.

Denny

002.jpg

[Gerald C.]

Re: Oil consumption & smoke on a 327/350 hp

Guys,

I'm buying a Digital Inspection Camera and will take the carburetor off (instead of the intake at this point) so I can take a look into the intake, etc. I'll let you know what I see (or don't see). I'll keep trying to figure this out before the snow flies here in the Northeast!

jerry

[Gary R.]

Re: Oil consumption & smoke on a 327/350 hp

Jerry, One thing. I didn't see any oil in my runners until after I pulled the heads and left them on the bench for an hour. Prior to that I swapped out the intake gaskets and checked the runners but really didn't see much.

[Timothy B.]

Re: Oil consumption & smoke on a 327/350 hp

Jerry,

Can you post some pics of the fouled spark plugs and are you using the stock PCV set up. Cranking compression pressure sounds fine, I would be thinking about the valve guides. What machine work was done to the heads?

[Gerald C.]

Re: Oil consumption & smoke on a 327/350 hp

Guys,

1. After scoping what I could, everything looks clean inside.
2. I'm repalcing the PCV valve and see what that gets me.
3. The plugs are fouled around the outer edge of the plug with the tip having a little corrosion.
4. If this replacement of the PCV valve doesn't work, I'll probably have the valce seals replaced in the springtime.
5. Tim, all new valves, valve guides, seals,etc. were done with the heads being done.

Thanks,

Jerry

[Gary R.]

Re: Oil consumption & smoke on a 327/350 hp

I had some time to get back to my car today to see if the oil burning issue was resolved. As mentioned I swapped heads 3 months ago but never had a chance to fine tune it and see how it was. Today I changed the oil from 15-40 to 10-40, set the timing using the paper by Lars', Duke, and John, rejetted the Holley and set it. Took the car for 100 mile shakedown and -0- smoke was seen. Before with the WP Torquer heads and umbrella seals it would be smoking after about 10 minutes of running, foul plugs in 400-500 miles. The heads I installed were the original '72 194 heads that had a basic rebuild but the guides were not replaced, just positive seals installed. Now the car lites up the tires at will, doesn't smoke, hot oil pressure is 35 psi, and the idle is much better. Hope you get it resolved.

[Gerald C.]

Re: Oil consumption & smoke on a 327/350 hp

I replaced the PCV valve last night and it was raining so I couldn't take the car out to see if I can burn some of this oil off. maybe tonight. If that doesn't work, my path of least resistance would be to start with removing the intake and see what the seals/gaskets/valley look like. Any telltale signs I should look for? If all that is clean, my next step would be to have the valve seals replaced. I guess that is all I could look at from the top part of the motor. This is a PITA!

Any other thoughts?

Thanks everyone for your feedback.

Jerry

[Steven B.]

Re: Oil consumption & smoke on a 327/350 hp

As a side I ordered a '99 Suburban 350 and at the onset had 80 pounds at cold idle. When warmed at any speed it was 60 pounds. I was concerned and went back to the dealer immediately and they said it was normal. I questioned that and the regional rep told me the same thing. I changed oil at 3,000 usually and never had to add oil between changes. I reluctantly sold it three weeks ago with 236,000 miles. Pressure remained within 5 pounds with the 236,000 miles. It seemed high but never had problems except had to replace fuel pump. Also, I consistently got 20-22 mpg at 70 mph.

[Timothy B.]

Re: Oil consumption & smoke on a 327/350 hp

Jerry,

Have you given any thought to the fuel pump. If gas can get in the oil can oil get into the gas and pumped to the carburetor.