marshal135

Good Morning Forum,
Since I see we have several motor builders on this great forum, I'd like to pose a question.
I'm looking for direction in solving an oil consumption issue.
I have a '68 427/390 coupe with 81,000 miles.
Last winter I replaced all valve seals. It cleared up the blue puff on start up I previously was experiencing.
While replacing the valve seals I noticed the heads were redone.
I called the previous owner of vehicle and he knew nothing about it.
He owned it from 2008-2011 only.
Must have been done by the man he purchased the car from as he owned it since the 1990's.
So without having any motor maintainence history, I can only report what I physically observed.
The block appears to be a decked replacement.
There are no visible vin#, nor Towanda build info nor CE# on the deckface of block.
It is a late 1967 casting... 321 block in a June 1968 car.
I know its too early for this build.
The compression in each cylinder is in the 180's range.
Is it possible when they decked the block, they did not plane the intake manifold?
It has the orig. Winters aluminum intake for a quadrajet.
The car runs excellent but after 100-150 mile ride I'm 1/2 qt low.
Several rides later, approx 250-300 mile range its a qt low.
My tail pipes are blackened like soot. I believe it maybe running a bit rich?
Before I attack the intake and have it shaved to match heads, Am I overlooking any other obvious oil consumption remedies?
I have no leaks underneath vehicle, orange painted block is clean upon random inspections.It appears to be misting out some where.
PVC is not clogged and I get good circulation/pressure on oil gauge.
Vac is pulling 16-17 lbs at idle.
Kinda long but appreciate all feedback, comments, criticism, and satire is welcome.
Thanks in Advance,
Marshal

REELAV8R

The oil consumption problem existed prior to the valve guide seal replacement as well i"m guessing? Has it always used oil like this or is this a recent development? If recent then something has worn out or the valve guide seal/s were not put on all the way and now is/are letting oil by the valve stem.
Which plugs are fouled by the oil?
If it is all of them equally then you may be on the right track suspecting the intake manifold gasket.
If only one then perhaps ring wear or problem with just that cylinder.
With that kind of consumption by the engine you should be able to see blue smoke out the back.
What about this misting thing you mentioned. Is that an oil leak? Bottom of the car have a nice coating of oil?
Are you sure of the quantity of oil in your sump. Ie is it possible that it is getting overfilled.
Just a few ideas that come immediately to mind.

Crafty12

Sounds a lot like the problem I'm having. No drips, but I go through a quart of oil a month, and its not a daily driver.

I ran down the intake first, had it planed, and all the seals replaced. Since that didn't solve my issue my shop thinks it is a stuck/damaged oil control ring. I get 190 psi on all 8 cylinders, so it's not a compression ring. I get puffs of blue smoke out of the right side on hard decels.

marshal135

Gents,
Thank you for taking the time to respond.
I believe the oil consumption existed before repacing the valve seals.
I had hoped the consumption rate was due the worn/missing intake seals.
No more blue puffs on a restart after a ride.
Being decked it was wishful thinking on my part that a bottom end job
was also done so I didn't suspect an oil ring on piston(s)?????
I was going after oil getting by an improperly seated intake manifold after machine work?
Crafty, you have completed similar task to your intake and it did not solve the oil use?
Again, I have no oil leaks underside of car.
My cardboard on my garage floor is clean.
After a ride, I would expect to see drippage if it was leaking out between seal and engine component.
I changed my spark plugs while they were out during the valve seal replacement and they were blackened slightly, again appearing to me as a rich condition matching the inside of my tail pipe extentions.
All eight plugs looked similar so I did not suspect a problem in any particular cylinder.
I used the term "misting" because I do not see a major leak.
I was thinking it was being sucked out through the intake and there for
not showing as a leak.
It's gotta be going some where
I'd like to resolve as it's $6.00 a qt for Brad Penn oil.
I complain enough about it costing $60.00 to fill her with premium, but that's understandable if I want to drive somewhere. As others have stated here we don't buy these vintage muscle cars for their mileage per gallon attributes.
I do not want to tear the motor out to have a looksy.
Hence, I can use all the experienced engine builders here to point to a possible cause.
I'll hold off on addressing the intake till I hear more from Crafty what he did and why it didn't work.
Thank you again.
Marshal

REELAV8R

If you remove the oil filler cap on the valve cover while it's running is there a lot of pressure coming out of the hole. Does it "pop" the cap off?
If you look down into the intake manifold can you see oil pooling in any way in the bottom? Open the secondaries or take off the carb to get a good look.
For stuck oil rings I would think a top end conditioner like marvel mystery oil or something similar might free those up if that were the case. I'd try it in the oil and the fuel to get best effect.

redwhitekat

I'm going through the same problem after replacing my seals didn't do a thing I've done lots if research when I get the money and time I'm doing a leak down test to find out if its a ring problem or a valve guide problem. If its valve guides I'm just buying new heads as to repair my stock ones will cost more.

Let me know how you go about resolving this problem
My mechanic was quick to replace valve seals with checking the whole system first 500 bucks down the drain he'll I would have been half way to all new heads

I don't know much about the internal of the engine but after reading here I know alot more.
That's why I'm not happy with the way my mechanic went about charging me 500 bucks and to have the same problem. Trust no one Do your own research

marshal135

RedWhiteKat,
So so very true!
I do all my own work minus say an alignment.
My heads were sent to a machine shop sometime in the 1990's??, only guessing. This would have been two owners ago.
They replaced the valves as they look brand new.
I can still see the x marking on the top of the stem with the rockers off.
Guides appear to be replaced.
They forced the wrong size positive control type seals on the intake (too small).500 on a .560 guides and they were mashed, probably during first start up.
I located the proper size PC seals in viton and replaced.
For what ever reason the exhaust guides were not touched.
Those I installed stock umbrella type on the guides.
They remain at stock size .610.
The internals, using a bore light, looking inside the head ports and spark plug holes looked clean.
I'm speculating the previous owner skimped on having the intake mated to the lowered heads after the block was decked.
I can't see a machine shop doing half a job unless the customer only
authorized a half assessed job.
I do not want to pay for unnecessary machine work on the intake if it is not the root of my oil loss problem.
I'll keep all info on this topic up to date on this thread as I learn em.
Thanks so far to everyone.
Keep the fixes and sugesstions coming as there are now 3 of us with the same problem
Marshal

REELAV8R

How about worn out valve guides. This could happen due to bad geometry or just time. Even with new seals if the valve stem moves enough it will release the seal on the guide and allow oil to be drawn in. Could be checked by removing one rocker and spring and seeing if the valve wobbles excessively in it's bore.

This happens sometimes on Motorcycle forks. A guy will forever be changing seals wondering why each new set leaks in short order when the real problem is the bushings are worn out allowing the fork to move to one side compromising the seal and allowing oil out.

marshal135

Guides were checked while the seals were off.
Guides looked replaced
Thanks again,
Marshal

REELAV8R

Well.... could be the rings are simply worn out. Consumption seems high for that but have you tried squirting a little oil in the bore then checking the compression to see if there is a significant rise? Leak down would indicate this too if that is within your abilities and you have the equipment.
I was indicating excessive blow by pressures due to worn rings with my suggestion of oil cap wanting to blow off. This might increase crankcase pressure sufficently to force oil mist into the intake track past the gasket if it's fit is not perfect or out the PCV valve to be burned via that route. 180 sounds good but we don't know what CR engine this is. So maybe it's supposed to be 200 psi?

marshal135

Reelav8ter,
Thanks I understand what you are referring to now.
I guess a leak down test would show lower end issues.
The engine is the 390 hp with 10.5 :1 compression.
Not sure if 180 is in spec for this motor stock configuration.
Marshal

learje

ymmv, i was burnin at least a qt every 500 miles, no smoke, no puddles. switched from mobil 15w40 synthetic to 10w40 bred penn dino. after almost 2 k miles i added 1/2 a qt just to make me feel like i was doing something. mild 1971 402BB here. might be worth a try..if ur using synthetic now

gl

marshal135

Learje,
Thanks for the tip.
I'm running Brad Penn 10/30 syn blend now.
427 takes 6 Qts.
I have the longer oil filter too.
It fits with stock exhaust manifolds.
Not sure where it is going
I guess a leak down test will confirm if its getting past the
Oil rings and burning
Marshal

Crafty12

My situation is a bit strange. I bought my car, and immediately after getting it running I took it to the shop. I only drove the car twice before taking it in, and one of those drives was to drop it off. I didn't notice the smoke before taking it to the shop, but I barely drove, so can't say for sure if it was puffing before the work or not.

While it was at the shop I had them replace an Edelbrock intake with a stock Winters intake. On my first drive after getting it back I noticed puffs of blue smoke on deceleration. I immediately thought intake, so I took it back to have the work re-done. While the intake was off the second time they noticed that there was some slight warpage, and they planed it back to square. Then re-installed using extra thick gaskets and RTV. However the problem persists.

The shop I take mine to is Masterworks in Madison Heights MI. While no shop is perfect, I trust their work, especially since its now been done twice.

My brother who is a GM mechanic has told me that Cadillac Northstar engines had problems with carbon build up on the oil rings. The fix they used at the dealership was to drain the oil out and spray GM top engine cleaner into the plug holes. Apparently this will work down the sides of the pistons and break up the carbon. At least that is the theory. I'll be trying this within the next few weeks. If that doesn't clear it up I guess I'll be having the motor pulled.

marshal135

Crafty12,
Would you let us know how the engine cleaner works out for you?
I'd love to get off the hook that easy
Marshal

DC3

I came across this article from Amsoil regarding oil consumption issues. Maybe it'll help someone.

http://www.amsoil.com/techservicesbu...onsumption.pdf

DC

Crafty12

I sure will. I feel the same way. If that solves my problem I will be so excited. And my checking account will thank me.

marshal135

DC,
Thanks for the article a very good read.
Crafty, yeah getting off light is not in the corvette owners vocabulary.
My friend has a jeep and he said it stands for "just empty every pocket"
I'm thinking how does c o r v e t t e work into that acronym?
marshal

Crafty12

I got started last night. Drained the oil and pulled the plugs. Getting the stuff into the cylinders which I figured would be the easy part was more difficult than everything else. Pretty sure I got way more on the garage floor than I did in the cylinders. The stuff foams up when you spray it, and the can has to be straight up and down to get any out.

I used a 5 inch piece of fuel line and modified the nozzle. It was still messy as hell though.

I'll post up any results after I let the stuff work for a few days.

marshal135

Crafty12,
Hey thank you.
I'm praying it works so maybe we'll be onto something.
Otherwise Brad Penn Oil is going to get allot of my $$.
Marshal