MasterDave

Before I pull the engine for a freshening up (rings/bearings) I am asking for some advice. If I were to drive the car a hundred miles it would probably use 1-2 quarts of oil. Been like this for a few years now. It oil fouls plugs regularly but not the same plugs. Seems to move around. A new set of plugs will have the engine running great. The valve helper springs in the heads have broken on a few occasions tearing up the valve seals. I've replaced with the blue vitron seals. (I will have to check the springs/seals again). There doesn't seem to be blue smoke from the exhaust but you can smell the oil. This is a .30 over 350 with forged Speed Pro pistons. It has an Isky 270/280 Mega cam and 64cc World Products Sportsman II Iron heads. 8 quart oil pan with hi-vol oil pump. 650 DP with Weiand alum intake. I have a open breather on one valve cover and a PCV on the other going to the vacuum on the carb. I am at a loss here, I've went through (in my mind) a few things such as PCV issues, valve spring bind, etc. and don't know where to go next. Any advice would be most helpful.

Nowhere Man

it sounds like my first 396 in my Chevelle. would burn a quart every 75 miles. it was like driving a smoke machine. after the tare down it was a bad bore job

66jack

What about a warped intake?

MasterDave

Well, I will be taking the intake off so I will check the gasket surfaces for signs of a leak. Thanks...

Bluestripe67

Since it's so simple, do a leakdown and cylinder pressure test first. See what the results are. How many miles since it was built, although it may not matter considering the oil consumption rate and symptoms. I'm betting on a bad final hone and incorrect rings, coupled with valve guide/seal problems. Full on rebuild time! Dennis

Frankie the Fink

I can't imagine that level of oil consumption with no smoke.
Perhaps a leak....have you checked your coolant for signs of oil ?

MikeM

When you get the intake off, look in the intake ports of the head on the backside of the intake valves for oil or heavy, baked on deposits which would indicate oil coming down the guides.

cardo0

Just as Mr. Blue said u should always check the cylinders health with a compression and then leakdown testing. Show us the results if u want more help there. Always clamp open the carb throttle plate and try and test compression with engine warm as possible (careful removing plugs w/engine/exh pipes hot). Use adequate source press for leakdown (at least 70psi) and test cyl locked at TDC with both vlvs shut.

If u have good compression and good leakdown numbers then pull the oil pan and ditch that high press oil pump - heck i would ditch that hi-press oil pump first.

For PCV test u can install a glass jar in line with intake hose to visually see oil entrainment - just put the 2 hoses in the jar cap.

Last make sure your intake bolts have sealer on them. Well u should have used sealer on the head bolts too but that would normaly make it a coolant leak issue.

Hope this helps.

MasterDave

Off to get the leak-down tool. Intake bolts do have sealer on them. Sorry, I meant hi-VOL oil pump. I agree that one is not needed and will change it to a normal pump. No oil in water, does not overheat even in Az. More info to come. Thanks...

Easy Rhino

There is a rough dynamic "leak down" test available that requires no special tools. It actually uses the engines own vacuum to pull in oil past rings and valve guides. You'll need only to have a spare driver and a decent stretch of roughly level road where you will not hamper other drivers.

How done: Get the car fully warmed up with oil topped off. Have a driver accelerate quickly to highway speeds, then coast down to the lowest speed that your car can stay in top gear, then have him/her accelerate - punching the gas pedal. You follow and watch for the blue smoke cloud at the moment that they punch it.

This is a gross test only, but was routinely used back in the day when old school mechanics did not have leak down tools, and engines routinely needed new rings and bearing at 50K miles or less.

The engine vacuum pulls oil past seals and rings, and it collects in the cylinders, but does not all burn off. If you have lots of leakage, lots of oil gets by the rings/seals, and you will see the tell tale puff of blue smoke when the driver punches down low.

Yes, it is not exact. but it's a free and easy rough test.

59BlueSilver

Good to know. Thanks!

1COOL60

Be sure to observe the gaskets themselves, for crush at the top of the ports versus crush at the bottom of the ports. My car was using a like amount of oil, and I finally found that the seal at the intake manifold/head was not square. Had more crush at the top than the bottom.

I was also using World Product heads (S/R Torquers).
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Westlotorn

Great advice given, If your problem was piston rings the problem would not float around it would stay with the bad cylinder.
It is possible all the cylinders were prepared badly but a simple compression check could rule this out. If you have good compression the rings are working fine, go back to checking the intake manifold and valve stem seals for the source of your leak.

When you look at the old manifold gasket for signs that it had more crush on top than on bottom use a micrometer, draw a outline of your gasket on cardboard then measure top and bottom and several points across the top and the bottom. Write down your measurements on the cardboard outline. If you have a fit issue it will show up in the measurements.
This same trick works well for finding signs of a engine overheat by measuring the head gaskets on an outline. The part of the engine that overheats will crush the head gasket only in areas that overheated. High temp makes metal grow, when the metal cools it shrinks back to original size but the head gasket will not rebound, it will hold the crushed area for future measurement.

The crush variance will be found in thousands of an inch, your eye will not see that but your micrometer will find it. If you find .005 or more variance you probably found the leak but as mentioned above you will see oil in the ports. You should have zero oil in your ports.
If the intake ports are clean and dry pull the exhaust manifold and check inside the exhaust ports. They should be chalky dry and dark gray to flat black. If they are wet and oily to the touch you have oil burning and maybe you can spot which cylinders the problem is in.

MikeM

Another excellent point.

cardo0

I forgot to ask if u had the block deck and or heads machined down at all? If u had machine work on the block deck or heads the intake needs to be matched. Elongating the holes or different thickness gaskets are band-aids for what is a deeper wound needing stitches.

tubman

I had the same problem when some "Race Engine Expert" rebuilt my otherwise stock '67 L79 with with a Mellings "HV" pump. BTW : All Mellings pumps come with the high pressure spring installed and have a medium pressure spring as an "option". I had to get a regular (49 pound) spring from them separately. The Hi-Pr Hi-VL pump will fill your rocker covers with oil and force it through the valve guides and ruin them. I put a standard pump with the standard spring in my car and it solved all of the problems EXCEPT oil consumption. I will be replacing the valve guide seals when I get back to Minnesota next spring.

Why do they do this? The Melling "HV" pump is half the price of a standard pump (check it out). The engine builders can offer a perceived "Upgrade" to your build and save $50.

MasterDave

How did you fix the issue?

MasterDave

No decking or machine work. I unboxed and installed the heads as received.

MasterDave

Interesting if true. Not sure how oil can ruin a valve guide seals.

1COOL60

I was using an Edelbrock Performer manifold with the World Product heads. I spoke to a local machine shop about what I found, and asked if the manifold could be milled somewhat to correct the problem. Rather than that he recommended checking with Edelbrock regarding what gasket to use. I went to the Edelbrock website to see what gaskets they recommended, and used whatever Felpro they recommended and was extra careful about torquing the intake. It didn't completely solve the problem, but it cut consumption by a significant amount. Edelbrock also recommended Gasgacinch.

I have since replaced the Performer intake with a TPI; still using the World Product heads. Again, I was very careful torqueing the base plate down (don't remember exactly which Felpro gasket I'm using). I also used sealer around the ports. Consumption is now 1 quart every 2500 miles.

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