How to use a compression tester
Thread Starter
Super Moderator
Joined: Sep 2002
Posts: 5,425
From: Tallahassee, FL
I just bought one of these, and have a couple questions.
1. Isn't there a way to disable the mechanism that makes the needle hold at it's highest position?
2. This thing has a "quick connect", the same type as on my hose that I use for my air compressor. If I connect this hose to it, so I could sit in the driver seat with one hand on the ignition, and the other holding the gauge, will the added length of the hose skew the reading?
1. Isn't there a way to disable the mechanism that makes the needle hold at it's highest position?
2. This thing has a "quick connect", the same type as on my hose that I use for my air compressor. If I connect this hose to it, so I could sit in the driver seat with one hand on the ignition, and the other holding the gauge, will the added length of the hose skew the reading?
Senior Member
Joined: May 2002
Posts: 22,465
From: California
1. yes, you can remove it, or maybe hold it down?
2. it might drop the readings, but not enough to matter, and b) you're not looking for the actual number, but more key is 3 even bounces. the compression guages vary with temp, age, humidity, etc etc
2. it might drop the readings, but not enough to matter, and b) you're not looking for the actual number, but more key is 3 even bounces. the compression guages vary with temp, age, humidity, etc etc
Senior Member
Joined: Jun 2006
Posts: 175
From: Vermont
Originally Posted by j9fd3s' post='846073' date='Nov 20 2006, 03:21 PM
1. yes, you can remove it, or maybe hold it down?
2. it might drop the readings, but not enough to matter, and b) you're not looking for the actual number, but more key is 3 even bounces. the compression guages vary with temp, age, humidity, etc etc
So your actually looking for the needle to bounce 3 times? Whats this indicate?
Thread Starter
Super Moderator
Joined: Sep 2002
Posts: 5,425
From: Tallahassee, FL
You remove a spark plug, and it threads into the spark plug hole. You disable the fuel (and spark? I'm not sure), and crank the starter. The needle bounces as the combustion chamber compresses each time.
3 even bounces would indicate compression on all 3 sides of the rotor. If there were 1 big bounce and 2 very small ones, this would indicate a busted apex seal.
3 even bounces would indicate compression on all 3 sides of the rotor. If there were 1 big bounce and 2 very small ones, this would indicate a busted apex seal.
Senior Member
Joined: May 2002
Posts: 22,465
From: California
Originally Posted by Baldy' post='846157' date='Nov 21 2006, 05:36 AM
You remove a spark plug, and it threads into the spark plug hole. You disable the fuel (and spark? I'm not sure), and crank the starter. The needle bounces as the combustion chamber compresses each time.
3 even bounces would indicate compression on all 3 sides of the rotor. If there were 1 big bounce and 2 very small ones, this would indicate a busted apex seal.
exactly!
Senior Member
Joined: Nov 2001
Posts: 125
From: Grape town baby
Originally Posted by ExplicitRotary' post='846161' date='Nov 21 2006, 05:49 AM
how do you disable the fuel?? never had to do any of this but theres no time to learn like the present.
Steve
