Compression Test? How to? anyone know....
Thread Starter
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
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From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
Compression Test? How to? anyone know....
Ok so with all the talk going around here about people over-revving their motors plus would be cool to just know the internal health of ones motor...
I am wondering how one does a compression test on the LS1 motor in our C5 vettes. Anybody have a writeup or website with link. I always like to learn new things and this looks like something that could always be beneficial knowing how to do.
Also if anyone has time to explain what is the difference and possibly show what is involved with a "leak down" test?
I am wondering how one does a compression test on the LS1 motor in our C5 vettes. Anybody have a writeup or website with link. I always like to learn new things and this looks like something that could always be beneficial knowing how to do.
Also if anyone has time to explain what is the difference and possibly show what is involved with a "leak down" test?
Race Director
Joined: Mar 2004
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From: Fort Wayne IN
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Go to the part store and pick yourself up a compression testing gauge kit. Probably run you $40-60 for an actron kit.
Remove the plug wires, and depending if you want to do a wet or dry compression test, pull the injector fuses or pump fuse.
Attach adapter to end of hose going to gauge, and remove spark plug from cylinder. Attach gauge/hose/adapter to open hole left by spark plug. Crank motor until gauge stops climbing, and you've got your compression on that cylinder. Remove, replace plug, move to next cylinder.
A leakdown test you have to pressurize the cylinder and using a manifold gauge set, you are checking for pressure leakdown over a specified period of time in each cylinder.
Remove the plug wires, and depending if you want to do a wet or dry compression test, pull the injector fuses or pump fuse.
Attach adapter to end of hose going to gauge, and remove spark plug from cylinder. Attach gauge/hose/adapter to open hole left by spark plug. Crank motor until gauge stops climbing, and you've got your compression on that cylinder. Remove, replace plug, move to next cylinder.
A leakdown test you have to pressurize the cylinder and using a manifold gauge set, you are checking for pressure leakdown over a specified period of time in each cylinder.
Racer
Joined: Dec 2006
Posts: 320
Likes: 74
From: Chandler AZ
Is there a fuse or connector that needs to be pulled so the ignition system is not damaged? If so, where is it located?
Where is the fuel pump fuse?
I'm going to look at on 01 this weekend that I want to check before I buy it.
Where is the fuel pump fuse?
I'm going to look at on 01 this weekend that I want to check before I buy it.
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
These tests are easy BUT time consuming. You need the tools (compression tester maybe $50 for a decent one and $75 for the leakdown tester and an air compressor for the leakdown tester). ALL THE PLUGS HAVE TO COME OUT, you will most likely break 1 or more plug wires doing this so plan on buying the seller a set of wires, you have to tread each tool into each cylinder (16 chances for tearing up your knuckles). You have to spin the engine for the compression test (easy) but you have to have the cylinder your testing at Top Dead Center for the leakdown test.
