Compression test results
10-18-2016, 05:55 PM
#1
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Compression test results
What do you guys think of these two cyls:
#7
#1
-- Joe
#7
#1
-- Joe
Low , here's a Friend's 1969 Rambler 390 at 75K miles , all cyls were within a few PSI of this .
10-18-2016, 06:38 PM
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Compression test results
It's a 9:1 blower motor. I meant more of the needle movement rather than the final pressure.
-- Joe
-- Joe
10-19-2016, 06:44 AM
#4
Re: Compression test results
As to the movement , it looked normal to me . I know that any time Ive ever done compression tests the needle usually bumps up once or twice to a final pressure like yours did , in fact I can't ever recall seeing one do one big push up to it's top pressure with no further increases , if that's what your asking .
10-20-2016, 05:53 AM
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Compression test results
The #7 cylinder has a final psi reading of almost 10 lower than all the others. This cylinder was also glowing the header primary at idle. Trying to determine if it is bad injector, or valve issue.
As far as the engine rotating slowly, I've never been able to figure that one out. It's got 150psi compression which isn't high at all, and my bearing clearances are loose. Yet it is hard to turn over by hand or starter.
-- Joe
As far as the engine rotating slowly, I've never been able to figure that one out. It's got 150psi compression which isn't high at all, and my bearing clearances are loose. Yet it is hard to turn over by hand or starter.
-- Joe
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10-20-2016, 04:37 PM
#8
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Compression test results
Forgot to post the plugs. #7 and #8 look sooty (well moreso than the rest). The ground electrode anyhow, where it's clean on the others.
Overall the motor seems rich, although the wideband indicated like 15:1.. My plug gap was .045 though, which might be too wide for these chambers. I dunno.
Overall the motor seems rich, although the wideband indicated like 15:1.. My plug gap was .045 though, which might be too wide for these chambers. I dunno.