[JekylandHyde]

A month ago I posted Hyde's current compression numbers:
Cyl #1 - 165
Cyl #2 - 157
Cyl #3 - 164
Cyl #4 - 164

Here are the results of Hyde's leakdown test:
Cyl #1 - 5%
Cyl #2 - 20%
Cyl #3 - 5%
Cyl #4 - 5%

Apparently #2 is starting to show wear.
My mechanic said that when he did the leak down, that number sounded like the air was coming out of the intake side ... so I may have an intake valve not seating properly.

Otherwise compression is good and we are moving forward ...

 

[AndrewMcG]

Sweet. I cant believe your engine is so healthy. How is the modding coming along, or have you not started that yet?

 

[JDSingh]

My brother's galant had the problem of his valve not sealing properly....Turned out to be carbon build up...some seafoam cleaned it right up.

-JD

 

[AndrewMcG]

He has water injection so shouldnt have much of a problem with carbon buildup. It might have something to do with being 200,000 miles old though.

 

[Quickblue2]

can anyone steer me in the right direction as in the difference between a compression test. and a leakdown test?

compressoin testing individual cylinder's ability to compress the air

leakdown - ?!?!?

james

 

[flynhighaf23]

here is an analogy. i might be right or i might be wrong....if i'm wrong someone PLEASE correct me!!

compression= how much air the balloon is holding. anything about 150-160 is good.
leakdown= where the air is coming out of the balloon (if any). i don't know what is good/bad

 

[emopunk96]

A compression test tells you how much compression a cylinder can make...

a leakdown tester is much better for diagnosing what is actually wrong with your car...you screw the peice into each spark plug hole and it compresses air into your engine, while the cylinder is at TDC(so both valves are closed)...if you have a leak the air will leak past and you can listen for it. Jekyl said they heard it coming through the intake, so the air is bypassing the intake valve that is suppost to be closed. If you hear it coming through your tailpipe, you may have an exhaust valve leaking, through another spark plug hole, you may have a blown gasket between cylinders ect...it has a gauge hooked onto the fitting that tells you the percentage of leaking in your cylinder, your manual should indicate how much leakage is acceptable. its MUCH better than a compression tester

 

[jerzefigga]

A compression test tells you how much compression a cylinder can make...so it will tell you if your head gasket is leaking ect..)

a compression test doesnt detect a blown HG, the leakdown will do that. the HG has nothing to do with how much air is compressed.

 

[emopunk96]

good call, was mixing things up

 

[diabolical1]

jekylandhyde ~
even though i noted the comment about your running water injection and it makes sense that your cylinders, pistons and chambers should already be relatively clean, maybe you should try running some MMO through a few tanks of gas, it might help clean some things up in there.

 

[JekylandHyde]

I may look into that ... right now I am pleased with where the engine is at considering the mileage and the abuse