Low compression

Low compression

Joined: June 11th, 2011, 1:21 am

August 11th, 2011, 2:46 am #1

Hi ya'll, A bit of an issue

Me and my dad are in the process of rebuilding our first performance motor and I just got the heads on and torqued down when my Dad went to go and check the compression of the motor and it had maybe 30 psi.

Could this be because the engine wasn't warm? or that the pushrods were not installed yet causing it not to suck in air?

We are kinda at a loss right no and don't want to go any further tell we get this figured out. btw it's a 393 stroker with 4V Open Chamber heads.

Thanks
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Joined: April 30th, 2005, 7:32 am

August 11th, 2011, 5:07 am #2

how far along is the assembly and how are you checking for compression?
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Joined: December 16th, 2003, 1:59 am

August 11th, 2011, 7:58 am #3

Hi ya'll, A bit of an issue

Me and my dad are in the process of rebuilding our first performance motor and I just got the heads on and torqued down when my Dad went to go and check the compression of the motor and it had maybe 30 psi.

Could this be because the engine wasn't warm? or that the pushrods were not installed yet causing it not to suck in air?

We are kinda at a loss right no and don't want to go any further tell we get this figured out. btw it's a 393 stroker with 4V Open Chamber heads.

Thanks
checking compression with no pushrods, you might want to go ahead and get them installed before passing judgment on your test results

are you turning the engine by hand or cranking it with the starter?

i always do the test with all spark plugs removed and thge throttles propped open so it can breathe by itself, of course with no carb you're OK too.

i crank 4 or 5 pulses on each cylinder but always the same throughout the test, that way the oil pressure will come up to operate the hydro lifters

there'll be phantoms, there'll be fires on the road... and the white man dancing
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Joined: February 13th, 2006, 4:59 am

August 11th, 2011, 12:14 pm #4

You have to have the pushrods as there is no way for the engine to pull in air. The only air it will have is what's in cylinder during assembly.
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Joined: May 20th, 2005, 4:48 pm

August 11th, 2011, 12:47 pm #5



Brent Lykins
B2 Motorsports, LLC






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Joined: June 11th, 2011, 1:21 am

August 11th, 2011, 11:42 pm #6

Thanks for all your responses.

After sleeping on it I realized I was worried for nothing since like tinman and brent have said you can't compress was isn't there.

Thanks again
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Joined: April 30th, 2005, 7:32 am

August 12th, 2011, 4:54 am #7

before I respond
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