20v Blacktop compression test

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speedmaster
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20v Blacktop compression test

Postby speedmaster » Sun Mar 17, 2013 6:20 am

what is a good compression? i just tested dry compression for my BT is 165psi. is that a fair result?
Im using 0.5mm metal gasket and 82mm piston

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Re: 20v Blacktop compression test

Postby yoshimitsuspeed » Sun Mar 17, 2013 10:28 am

I'm being too lazy to look up the actual spec right now but that is pretty low. What's your elevation? It should be closer to 200 stock at sea level but will be a lot lower if you live at a considerable altitude.
It is also possible for different gauges to be off and other variables to change the result. Bigger cams will tend to lower the static result. Something like cam/crank timing being off could seriously effect compression too.

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Re: 20v Blacktop compression test

Postby speedmaster » Sun Mar 17, 2013 3:55 pm

i will try again with a healthy battery. my battery was going flat then.

yea i youtubed a few compression test vids. and most of them got around 200-210

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Re: 20v Blacktop compression test

Postby onnaj » Mon Mar 18, 2013 6:52 am

Minimum spec is 156 PSI, standard 193 or more. Max difference between each cylinder is 14 psi or less.
Check my 4AGE 20V BT teardown, rebuild and transplantation over here --> http://club4ag.com/forums/viewtopic.php?f=7&t=3382

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Re: 20v Blacktop compression test

Postby speedmaster » Mon Mar 18, 2013 9:15 am

just did a "wet" test. result was 240 270 260 250. good enuf for me.

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Re: 20v Blacktop compression test

Postby runkillerrabbit » Mon Mar 18, 2013 11:40 am

i learned that dry test arent accurate. if you can wet test. you gotta do the leak down test
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Re: 20v Blacktop compression test

Postby speedmaster » Mon Mar 18, 2013 8:06 pm

I will look up on that, tq