compression test---> does engine HAVE to be warm?
- Thread starter DavidT
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Off Road SHO
Moderator
David,
You do not have to take the intake off to run the compression test.
The reason for the warm engine is due to the fact that all of the internal parts will be expanded to their operating temperature size AND cylinder walls will have oil on them below the oil rings.
It's not going to make that much difference on value. What you want to see is that all 6 cylinders read within 10-15% of each other.
Tom
You do not have to take the intake off to run the compression test.
The reason for the warm engine is due to the fact that all of the internal parts will be expanded to their operating temperature size AND cylinder walls will have oil on them below the oil rings.
It's not going to make that much difference on value. What you want to see is that all 6 cylinders read within 10-15% of each other.
Tom
Bizzy
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I don't know a thing about how to properly preform a compression test but, thats the first time I've seen Tom's Aluminum timing cover. WOW!!!! that is really really nice. Sorry for the slight thread hijack.
Off Road SHO
Moderator
Thanks for the compliments guys, it's been a long road to walk on that piece.
Anyway, back to your compression test. What type of tester do you have? The rigid tube type or the flexible hose type?
You'll need the flexible hose, screw in type. Preferably one with a long hose, and a good o-ring seal.
Years ago I made an extension out of an old spark plug, some stainless steel braided line and some quick dis-connects. It helped me reach some of the more distant plugs on these sidewinder motors.
Our motors, with the lousy plug well design, tend to get oil, water, road grit and God knows what else in the tubes and the grit settles to the bottom. Right where we try and get the spark plug's crush washer to seal on the head.
This grit, if not removed completely BEFORE you take out the spark plug, will get into the cylinder when you do take it out. And if you put the spark plug back without a thorough cleaning of the well, the spark plug will grind that grit into the heads' sealing surface, making it difficult for your compression tester and future spark plugs to make a good seal.
I'm working on a permanent fix for our plugwell problem but that is for another thread.
Tom
Anyway, back to your compression test. What type of tester do you have? The rigid tube type or the flexible hose type?
You'll need the flexible hose, screw in type. Preferably one with a long hose, and a good o-ring seal.
Years ago I made an extension out of an old spark plug, some stainless steel braided line and some quick dis-connects. It helped me reach some of the more distant plugs on these sidewinder motors.
Our motors, with the lousy plug well design, tend to get oil, water, road grit and God knows what else in the tubes and the grit settles to the bottom. Right where we try and get the spark plug's crush washer to seal on the head.
This grit, if not removed completely BEFORE you take out the spark plug, will get into the cylinder when you do take it out. And if you put the spark plug back without a thorough cleaning of the well, the spark plug will grind that grit into the heads' sealing surface, making it difficult for your compression tester and future spark plugs to make a good seal.
I'm working on a permanent fix for our plugwell problem but that is for another thread.
Tom
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