Compression test came back... What do ya think?
12-22-2009, 07:06 PM
#13
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Originally Posted by Saki GT,Dec 22 2009, 07:14 PM
As long as the "duffs good", you're good. 
For one I'm under the impression that if someone has 255 255 245 255
0 for example that my car is underpowered because compression test resulted in 220 220 220 215...
I guess I'm not formilliar with this sort of thing but the guy above talking about scoring bores and bent valves freaks me out.
This car is private sale, I paid the guy $100 bucks because he said that's what the dealership was going to charge and did charge to do a compression test and drive it to inspect the differential, trans and clutch too. The dealership typed up all notes and report. They said it's good besides the front brakes needing to be done fairly soon ( pads )
12-22-2009, 08:24 PM
#14
It sounds fine. And that's not how a compression test works. You can replace the front pads yourself in ~30 minutes. Plenty of used pads around for sale. Shouldn't cost you more than ~$30-50 total.
12-22-2009, 08:58 PM
#15
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Look, I'm not sure where you guys are getting your info, but 200 psi is very NOT fine on an S2000. Relatively new and healthy and in good shape they blow 245 psi, consistently, cold. One with some miles and carbon on the pistons that's healthy can make as much as 255 psi.
The only S2k's I've seen that have blown less than about 235 psi had issues with either valve or bores.
It's important that the cylinders be within about 5-10 psi of each other, otherwise there's likely an issue with one cylinder that the other doesn't have.
If you blow 200 or 220 psi on all 4 holes on an S2k that tells me that all 4 have similarly bent valves or worn cylinders or the tester (equipment or person) is screwed up.
The only S2k's I've seen that have blown less than about 235 psi had issues with either valve or bores.
It's important that the cylinders be within about 5-10 psi of each other, otherwise there's likely an issue with one cylinder that the other doesn't have.
If you blow 200 or 220 psi on all 4 holes on an S2k that tells me that all 4 have similarly bent valves or worn cylinders or the tester (equipment or person) is screwed up.
12-22-2009, 09:33 PM
#16
Originally Posted by marcucci,Dec 22 2009, 07:01 PM
Impossible to tell without checking the tester (both equipment and person) against a reference.
Basically what you are saying is that no compression test is valid or trustworthy unless the tester and test equipment are "checked against a reference".
I wish the OP luck on figuring this one out.
12-23-2009, 06:24 AM
#18
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And it is true. I've seen experienced techs not hold the starter long enough or not check the o-ring on the tester to make sure it's not leaking.
Your best bet is to lay down $30 on a new tester and do the test yourself. It's simple enough and with a new tester and doing it right... it's pretty trustworthy.
Also, as a side note, you'd have to screw up the test pretty bad to get 200psi on a healthy S. Most techs wouldn't make that mistake. 220 is a little easier, holding the starter for maybe 5 seconds instead of 7 or 10.
Also, don't compare other motors to the S. Your average Honda which is lower compression might blow anywhere from 180-200 psi and that might be good. "Good" numbers from healthy motors vary a fair bit from engine to engine depending on compression ratio and other factors.
FWIW, I've opened up a bunch of Hondas in my time, and on the F2xC 235-255 is typical for a healthy one, 225-235 usually indicates some valve pitting/wear, and anything lower than 225 or so usually indicates the beginnings of cylinder scoring.
Your best bet is to lay down $30 on a new tester and do the test yourself. It's simple enough and with a new tester and doing it right... it's pretty trustworthy.
Also, as a side note, you'd have to screw up the test pretty bad to get 200psi on a healthy S. Most techs wouldn't make that mistake. 220 is a little easier, holding the starter for maybe 5 seconds instead of 7 or 10.
Also, don't compare other motors to the S. Your average Honda which is lower compression might blow anywhere from 180-200 psi and that might be good. "Good" numbers from healthy motors vary a fair bit from engine to engine depending on compression ratio and other factors.
FWIW, I've opened up a bunch of Hondas in my time, and on the F2xC 235-255 is typical for a healthy one, 225-235 usually indicates some valve pitting/wear, and anything lower than 225 or so usually indicates the beginnings of cylinder scoring.
12-23-2009, 07:43 AM
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Originally Posted by marcucci,Dec 23 2009, 07:24 AM
And it is true. I've seen experienced techs not hold the starter long enough or not check the o-ring on the tester to make sure it's not leaking.
Your best bet is to lay down $30 on a new tester and do the test yourself. It's simple enough and with a new tester and doing it right... it's pretty trustworthy.
Also, as a side note, you'd have to screw up the test pretty bad to get 200psi on a healthy S. Most techs wouldn't make that mistake. 220 is a little easier, holding the starter for maybe 5 seconds instead of 7 or 10.
Also, don't compare other motors to the S. Your average Honda which is lower compression might blow anywhere from 180-200 psi and that might be good. "Good" numbers from healthy motors vary a fair bit from engine to engine depending on compression ratio and other factors.
FWIW, I've opened up a bunch of Hondas in my time, and on the F2xC 235-255 is typical for a healthy one, 225-235 usually indicates some valve pitting/wear, and anything lower than 225 or so usually indicates the beginnings of cylinder scoring.
Your best bet is to lay down $30 on a new tester and do the test yourself. It's simple enough and with a new tester and doing it right... it's pretty trustworthy.
Also, as a side note, you'd have to screw up the test pretty bad to get 200psi on a healthy S. Most techs wouldn't make that mistake. 220 is a little easier, holding the starter for maybe 5 seconds instead of 7 or 10.
Also, don't compare other motors to the S. Your average Honda which is lower compression might blow anywhere from 180-200 psi and that might be good. "Good" numbers from healthy motors vary a fair bit from engine to engine depending on compression ratio and other factors.
FWIW, I've opened up a bunch of Hondas in my time, and on the F2xC 235-255 is typical for a healthy one, 225-235 usually indicates some valve pitting/wear, and anything lower than 225 or so usually indicates the beginnings of cylinder scoring.
12-23-2009, 07:55 AM
#20
Yeah I wouldn't feel so comfortable with 200. But at 220, I wouldn't sweat it. As others have pointed out, that's within the realm of variability.
I'd love to see you shop for an older German car.
I'd love to see you shop for an older German car.