Numbers from compression test

[strat1960s]

If you all recall, I have been burning a bit of oil over the last couple of months. Here are my numbers and what I am leaning towards.

Cyl: 1 2 3 4 5 6

dry: 160 160 160 145 160 160

wet: 200 200 200 185 200 200


I was told that as long as my readings are within 75% of the highest reading I am still within specs.
So, 160 PSI x .75= 120 PSI and 200 PSI x .75= 150 PSI

I am not sure if the 75% rule applies to the wet compression test, though. I will contact the machine shop the built my motor for me and see what they think. I am leaning towards valve guides. I say this because it only smokes when the motor is cold and I start it up. Once the motor reaches 180 to 190 the smoke is gone. That may be due to the valve guides expanding from the heat.
Please let me know if you have any comments on this.
Thanks
Ted

 

[Lazy JW]

Sounds like a good engine to me. I would need some other compelling reason to tear down an engine with those compression numbers and only burns "a bit" of oil. Valve guide seals maybe. How many miles on the engine?
Joe

 

[wsa111]

Ted, you have a valve guide concern & or valve guide seal problem. You need the all teflon seals with the spring at the top to put sealing pressure on the valve stem. Mike sell them at www.fordsixparts.com
Any time you have a non stock cam & headers you have more vacuum trying to pull oil down the guides.
Do this & i believe your condition will be solved. After you put some more miles on the engine, run another compression check. If you still have a low cylinder check the spark plug for any evidence of different color than the other cylinder or oil fouling. If oil fouling is present, pull that piston & check for a broken ring,cylinder wall condition or piston condition. Good luck william

 

[strat1960s]

Joe,

I went through about 1.5 quarts in just 1 month. That is my concern. I probably have about 6,000 miles on the motor.

William,

The number 4 spark plug did show mild signs of oil fouling.

Thanks.

Ted

 

[Lazy JW]

Is this a new development or has it always burned oil since new? Maybe the #4 hole never seated the rings. I'm with William on the seals.
Joe