Oil Consumption cause by head rework?
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
Oil Consumption cause by head rework?
Before I rebuilt the upper end (new cam, timing chain and gears, lifters and pushrods) I never had an oil consumption problem. Now it is using quite a bit of oil which it never did before. I am thinking when I had the heads reworked they did not use the tulip style valve guide seals. Does this sound logical and will adding these type seals help the oil consumption or is there other sources I should look for? 
Thanks for any advise/suggestions.
YBnormal...drive a vette
Thanks for any advise/suggestions.
YBnormal...drive a vette
Drifting
Joined: Jul 2001
Posts: 1,418
Likes: 1
In the old days say the 70's you could just count on an oil burner with a high mile lower end and fresh heads on it . The worn rings and ring lands could not handle the increased chamber pressures .
Like the above post it could be sucking oil from the lifter valley into the intake port
What is tulip style valve guide seals ?
Like the above post it could be sucking oil from the lifter valley into the intake port
What is tulip style valve guide seals ?
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
Some people call them umbrella style seals. If I was sucking oil from the galley would I notice any peformance problems. I have 16 in. vacuum constant at idle. How can I tell if it is a leak from the galley? I suppose I could check the plugs and see if it is one cylinder that shows consumption or all of them. If all, I would think maybe the valve guide seals. Any thoughts or suggestions?
Thanks for the replies,
YBnormal...drive a vette
Thanks for the replies,
YBnormal...drive a vette
Instructor
Joined: Aug 2004
Posts: 191
Likes: 0
From: Drayton Ontario
I had this same problem with my Camaro . I took it apart a couple of times and still it kept using oil. Well I finally found out what the problem was and believe me do I feel stupid . It seems the aluminum valve covers I put on had no baffle for the pvc and the oil was shooting directly at the pcv valve and well you can guess the rest. So I installed a baffle and problem fixed.I don't know if this is your problem or not but just thought I would throw this in.
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
Thanks for bringing that up, as a mater of fact mine have no baffel either. I will check that as soon as it warms up a bit, the hose running to the carb should be full of oil it that is the problem. Thanks for mentioning it.
YBnormal...drive a vette
YBnormal...drive a vette
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
When I slapped on 64cc heads on my 73 I let the guy who did the valve job assemble the heads. He used crappy umbrella seals. I was using a qt about every 150 miles and fouling plugs. I switched to postive seals and the the problem was eliminated. Positive seals fit down over the guide and stay there. The umbrella seals ride up and down with the stem and can allow oil to be sucked down the guide. A telltail sign of bad valve seals is fresh oil deposits around the plug threads. Pull em and check em.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
Thanks that is what I'm thinking, do positive seals require any special machining? If not, maybe I should go that route. As soon as it warms up a bit I'm going to pull the plugs and see what I find. Its a cool 51 degrees here in alabama this morning.
Thanks again,
YBnormal...drive a vette
Thanks again,
YBnormal...drive a vette
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Originally Posted by Ybnormal
Thanks that is what I'm thinking, do positive seals require any special machining? If not, maybe I should go that route. As soon as it warms up a bit I'm going to pull the plugs and see what I find. Its a cool 51 degrees here in alabama this morning.
Thanks again,
YBnormal...drive a vette
Thanks again,
YBnormal...drive a vette
Race Director
Joined: May 2004
Posts: 11,920
Likes: 2
Originally Posted by Jvette73
Some do, some dont. Guide diameter can varry. You'll need to check that before ordering seals. Check the diameter of all the guides not just one. You may need a different part # for exhausts and intakes. Or if one of the guides was ever replaced it could have a different diameter. If machining is needed, a tool can be purchased to do the job yourself. Its a tool that has a pilot that fits into the guide bore. Put it on your hand drill and cut away. Hopefully you can find seals that dont require cutting. They're out there. Mine didnt require cutting. I'de give you the PN but they were discontinued by Crane. What the heck, it was 99819. Maybe Crane can help you locate similar.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Put these Crane positive #99819s on a 1979 two days ago. No machining required and they snap into place very snugly on stock guides. I did not know they were discontinued but I am sure Crane has an equivalent replacement product.
The old tulip/umbrella seals were flapping in the breeze up and down the valve stems. And some had disintegrated owing to the thin-wall design (they harden and crack). I just followed that car today on a 60-mile road tour. The blue smoke is gone.
The old tulip/umbrella seals were flapping in the breeze up and down the valve stems. And some had disintegrated owing to the thin-wall design (they harden and crack). I just followed that car today on a 60-mile road tour. The blue smoke is gone.
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
Update...Well I pulled all the plugs, every one shows oil consumption so the local business that did the $300 valve job actually made things worse than before I had the heads reworked. So I tore into it and started taking things off. 
Heads should be off today and will be installing positive seals...thanks for all the advise guys. Do the positive seals work along with the seals I have on the heads now or are they replacements for what is on there now? I have never replaced these before (should have and saved the $300).
Thanks again...
YBnormal...drive a vette
So I tore into it and started taking things off. Heads should be off today and will be installing positive seals...thanks for all the advise guys. Do the positive seals work along with the seals I have on the heads now or are they replacements for what is on there now? I have never replaced these before (should have and saved the $300).Thanks again...
YBnormal...drive a vette
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
TT yes I'm planning on pulling the heads, since the machine shop screwed me I want to check the valve guides also "while I'm at it". I use to burn a quart of oil every 6 months before the head job now it is 3quarts in 600 mi. I'm hoping it is the valve guides but want to check the manifold for leaks also, so off they come.
Will keep you posted on how the positive seals work, found a local crane dealer here local, going to check with them today as soon as I wind out the size of the guides.
Thanks everyone
YBnormal...drive a vette
Will keep you posted on how the positive seals work, found a local crane dealer here local, going to check with them today as soon as I wind out the size of the guides.
Thanks everyone
YBnormal...drive a vette
Drifting
Joined: Jul 2001
Posts: 1,418
Likes: 1
Federal Mogul makes those seals in the pic ,,,, two I.D's available .
They must be concentric with the guide chimney or they will fail early and they will not work with dual springs .
Thing is I really doubt it's a guide problem with that much oil burning .
I would not have pulled the heads quite yet , there are other ways to gleen a glimpse at possible guides being loose .
They must be concentric with the guide chimney or they will fail early and they will not work with dual springs .
Thing is I really doubt it's a guide problem with that much oil burning .
I would not have pulled the heads quite yet , there are other ways to gleen a glimpse at possible guides being loose .
Last edited by mountainmotor; Sep 21, 2004 at 06:11 AM.
Thread Starter
Racer
Joined: Nov 2001
Posts: 478
Likes: 3
From: Huntsville AL
Yes they are stock heads, with the original guides still there. We pulled the valves and springs yesterday and they had good seals on them, like in the picture above (I expected to find just the O ring type). What we did notice is some had some play between the valve and guide but nothing extremely excessive. We also noticed the valves were dished, looks like when they did the head job they just ground the seats and not the valves. This is what I don't understand, before I took the heads to be reworked it did not consume oil at all. After rework 3qts in 600 miles . I am wondering now if they swapped heads on me at the shop. There is a local place (not the same one I used before!!!) that I'm going to see today to see about getting new valve guides installed. The saga continues
YBnormal...drive a vette
. I am wondering now if they swapped heads on me at the shop. There is a local place (not the same one I used before!!!) that I'm going to see today to see about getting new valve guides installed. The saga continues YBnormal...drive a vette
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
My advice is do all the above, you need not pull the heads, just fill each chamber with air through the spark plug hole to hold the valves closed, or failing that, take a piece of clothesline and put about a foot of it into the cylinder through the spark plug hole, and gently flip the engine to bring piston up, with valves closed, it will jamb up there and hold them closed while you change seals, you need one for the intake and one for the exhause...go aftermarket, GM still has NO clue bet on that....
second off, if the heads were milled any, allmost bet that angle of intake gasket to head gasket is changed, I had this problem, and so the gasket on bottom does not seal tightly, even though it looks as if it's compressed, oil gets by the lower section/lifter valley edge of the intake gasket....evidenced by oil soat and oil in the intake passages.....it will use oil like a **** that way....
most machine shops will for some reason just replace the umbrella type valve stem seals on the intake side, and ignore the exhaust,....giving the blue smoke on startup symptom....for christsakes, how lazy/cheap can they get???
GENE
second off, if the heads were milled any, allmost bet that angle of intake gasket to head gasket is changed, I had this problem, and so the gasket on bottom does not seal tightly, even though it looks as if it's compressed, oil gets by the lower section/lifter valley edge of the intake gasket....evidenced by oil soat and oil in the intake passages.....it will use oil like a **** that way....
most machine shops will for some reason just replace the umbrella type valve stem seals on the intake side, and ignore the exhaust,....giving the blue smoke on startup symptom....for christsakes, how lazy/cheap can they get???
GENE