DC2R Compression test

[DC2RKID]

ey guys doin a comp test moro on my dc2r rather then finding a book for the specs does anyone know the ideal comp on a dry test off the top of there head ?? any help will be greatly appreciated

[Elwood]

Redbook says 11:1.

I was under the impression 11.5:1.

Dude stop making threads..

[DC2RKID]

im talkin psi...on a guage....whats wrong with making threads ? i aint gunna change a subject in someone elses thread ?

[fatboyz39]

Depending on your gauge. 210-230psi is the norm.

Your looking for consistency across the 4 cyclinders. They should be within 5-10psi.

[ChargeR]

Here is what the USDM ITR manual has to say on the matter. Anywhere from 135 psi to 270 psi with a maximum variance of 28psi:

[DC2RKID]

thanks heaps guys

[tinkerbell]

Depending on your gauge. 210-230psi is the norm.

Your looking for consistency across the 4 cyclinders. They should be within 5-10psi.

yep, this guy is pretty much correct.

[DC2RKID]

ok thanks man just wanna see if previous owner built a decent motor lol

[tinkerbell]

using OEM parts, it would be hard not to...

[DC2RKID]

yeah well thats what im affraid he didnt do...soon find out wont i ha!

[ewendc2r]

lol.. what a variance. 135 - 270psi? Thats crazy..

I'm scared to do a compression test until I have the cash for a new motor.

[milkman]

I think its more to do with consistency over the 4 cyls..

[ewendc2r]

surely there is more to it than that. I don't know how the pressure is calculated but I thought you crank the motor with the compression gauge connected and it reads the total pressure of compression stroke created. Yes important to have consistent, but if they are 100psi off the stock / new rating then surely this indicates that a significant amount of power is being lost through worn rings etc? I mean, there is a reason why you need to rebuild / re-hone and replace rings if you drop to 130psi, so surely this indicates a drop in performance / sealing capacity of the rings as the engine wears. I just can't believe there is such a large allowable threshold / gap..

UNLESS.

Due to High RPM nature of B18C7 motor ovality is likely in fewer km's than lower RPM motors (given same block / friction / wear rate), so to keep the 'reliability' of the motor in check as far as Honda is concerned they have made a larger threshold of acceptable compression figures before requiring an engine build.

I always thought it amazing that you only have to rebuild a B18C7 motor every 100,000kms - 150,000kms ---- Perhaps common sense is right and they should actually be rebuilt more often to retain the same power characteristics as new when compared with a low rpm motor of same age. (i.e. % power loss / km (1000) )



I've read too many bloody maths things lately sorry ..

[tinkerbell]

I just can't believe there is such a large allowable threshold / gap..

ummm, no.

you seem confused.

the low number above on the Honda Manual = the "minimum"

it could mean the "minimum required to get the engine to fire"

it could mean *minimum* anything!

importantly - see how the re is no "service limit" listed?

i guess they believe that their mechanics are smart enough to know when a rebuild is required?

[bigbadbeau]

yeah well thats what im affraid he didnt do...soon find out wont i ha!

why didnt u check this before buying?