Compression test results
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Outstanding HDF Member
Joined: May 2014
Posts: 3,410
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From: Palm Desert,CA
Compression test results
Hi all,
After a long hot season I've finally gotten the first couple hundred miles on my new build. I think I'm ready to bring it to my Dyno guy who's about an hour and a half away.
I waited until now to do the compression test and ensure rings were set etc.
Hoping you can tell me if the compression results are fine and what ultimately they mean to me if anything:
Everything was purchased through Kirby at Veetwin (amazing as always), installed by myself.
Build is S&S 107in cylinders, Wiseco pistons, stage 2 heads, .030 head gaskets, 50mm TB with 4.9 injectors, HPI AC.
First crank had the rear cylinder at 215, but each one afterwards had it at 200 on the nose.
Front cylinder also 200 on the nose.
Questions:
1. Should I be concerned that I couldn't duplicate the first reading on the rear cylinder?
2. Since both read 200 now, how do I correlate that to my compression and what does it mean to me?
thanks as always!
After a long hot season I've finally gotten the first couple hundred miles on my new build. I think I'm ready to bring it to my Dyno guy who's about an hour and a half away.
I waited until now to do the compression test and ensure rings were set etc.
Hoping you can tell me if the compression results are fine and what ultimately they mean to me if anything:
Everything was purchased through Kirby at Veetwin (amazing as always), installed by myself.
Build is S&S 107in cylinders, Wiseco pistons, stage 2 heads, .030 head gaskets, 50mm TB with 4.9 injectors, HPI AC.
First crank had the rear cylinder at 215, but each one afterwards had it at 200 on the nose.
Front cylinder also 200 on the nose.
Questions:
1. Should I be concerned that I couldn't duplicate the first reading on the rear cylinder?
2. Since both read 200 now, how do I correlate that to my compression and what does it mean to me?
thanks as always!
Last edited by robbyville; Sep 8, 2017 at 12:21 PM.
Thread Starter
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Outstanding HDF Member
Joined: May 2014
Posts: 3,410
Likes: 143
From: Palm Desert,CA
Ok, edit time...
REalized that I wasn't holding the throttle open during the test. Once I did this both cylinders registered 215 each time.
Throttle fully opened cranking until needle stops. Engine cold, charger plugged in.
REalized that I wasn't holding the throttle open during the test. Once I did this both cylinders registered 215 each time.
Throttle fully opened cranking until needle stops. Engine cold, charger plugged in.
Thread Starter
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Outstanding HDF Member
Joined: May 2014
Posts: 3,410
Likes: 143
From: Palm Desert,CA
I'm not sure. I bought the heads and Fueling 574 cams from Kirby over a year ago and they went on the stock cylinders/pistons with a .030 gasket but I don't have the notes from the build anymore. Maybe 10.5:1 sounds familiar... If it helps the heads were 81cc. I added the cylinders and pistons a couple months ago, but it's taken this long to get break in done.
Last edited by robbyville; Sep 8, 2017 at 01:05 PM.
Thread Starter
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Outstanding HDF Member
Joined: May 2014
Posts: 3,410
Likes: 143
From: Palm Desert,CA
Gotcha thanks! it cold cranked at 215 so guess that's pretty close?
How does this effect the engine performance? Guess I should go google, unless someone wants to share the cliff notes version
How does this effect the engine performance? Guess I should go google, unless someone wants to share the cliff notes version
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From: Poolville
215 is a lot for the street and you should look at may be knocking your timing back a little bit cuz it's going to tend to get hot with that type of CCP...
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