[tornado-tech]

Got a 408 sbc redone by a reputable shop last winter. It has Keith Black flat-tops with 3/16 Total Seal TSS rings and World Products S/R heads and a Comp 280/288 .510/.520 hydraulic roller. The heads spring pockets were opened to accept 1.437 springs and new seals were put in at that time. It now is using an extreme amount of oil (1 quart in 50 miles). I did a compression test on all cylinders and was running 175psi on 7 cylinders except number one which was 155psi. Number 5 plug is oil fouled on a regular basis with the rest at a light brown. My vaccum holds at steady 15" at 900 rpm. The intake runners inside got a small amount of oil inside and the drivers side exhaust has the smoke out of it which would explain number 5 being oil fouled. I am running a hi-volume oil pump which Total Seal says will cause the motor to use oil. I am stumped since got good pressure in number 5 cylinder along with good vaccum for the cam I run and cylinder pressure. Would a bad valve guide cause this much oil consumption or am I missing something obvious?

 

[machine shop tom]

You definitely have a problem with #5. If it were a guide, you'd probably hear it clicking. It's also possible that a seal is missing from a valve in that cylinder. There shouldn't be any oil in the intake ports, either.

tom

 

[johnsongrass1]

Some say a higher volume oil pump will use more oil because of the increased oil being pumped to the valves springs. I think it's a scapegoat for reason. I say if you have good seals, you have nothing to worry about.

You problem seems to be coming from a few miles on stock type guides. Higher lift's cause the valve tip to bend toward the header side as the stock type rocker slides over the tip putting undue stress on the guides. They will wear out within 10,000 miles in some cases. As far as low crank press., Start by adding a little oil to the cylinder and try again. If the result's changed, it's likely to be a scored cylinder or excessive piston to wall clearance.

 

[GoneNova/406]

i think i'd take the head back off and check the head gasket,valve seals and look at all your valves to see if they have a build up of soot or oil caking on them.iput a hi pres.hi vol. pump on mine because of a extra long dual remote oil filters and oil coolers but it wasn't needed.it had tons of pres. but when looking at the valves it had oil caking throughout the head.i'm going back to a big block pump(30%+vol.) or just reg.sbc pump with greater spring pressure.melling has color coded springs,plain 40-45,yellow 55 and pink 65-70.mr.gasket and gm both have a white spring 65-70 lbs.they should only be around $4-$10.anyway with 20 lbs difference in cylinder pres. there is a problem.only way to find out is to take it apart.

 

[[email protected]]

Also check your intake manifold seal. I once had a customer with the similar problem and it turned out to be a leaking intake gasket on the lower side. A thicker Fel-Pro gasket cured the problem.

 

[tornado-tech]

I first noticed it 2 weeks ago and put new intake gaskets in it(Fel-Pro 1204's). The other 1204's had a tear on number 5. I thought I had it fixed but it is getting worse. I plan on tearing it down this winter to have the heads pocket-ported. Some racing buds say I got a broken ring but with my vacuum holding dead still at 15 and running 175psi, I can't see that. As far as the guides or seals, I'll check into that. Thanks

 

[edge]

Ditto - Check the Intake Gasket

Also check your intake manifold seal. I once had a customer with the similar problem and it turned out to be a leaking intake gasket on the lower side. A thicker Fel-Pro gasket cured the problem.

I had the intake slip slightly while installing the intake by myself (engine in the car). The sliver of gasket separating #1 & 3 intake ports slipped enough to allow oil to enter the #3 cylinder. The picture below speaks for itself, although it wasn't torn until I removed the gasket.

Pull the manifold first and inspect the gaskets. You'll have to this anyway if you end up pulling the heads. Good luck solving your problem, Ed www.edgesz28.com

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