Hey HT,
So I'm looking to pick up an integra GSR. The owner before the current seller rebuilt the motor to OEM spec so I asked the current seller to do an compression test before I decided to buy it. The results came back 157, 158, 155, 157. I've been searching around and these numbers seem really low. What do you guys think? Thanks

 

Motor has about 12K on the rebuild

 

well its kinda is but the thing is that the numbers are consistent. i recently did the comp test on my b20 and i hit 170 across the board. a brand new engine should be hitting around that (170-190psi) also you should check to see if he even did it correctly..some ppl just dont know what they are doing

 

supposedly he took it to a shop. Hes sending me copies of the receipts later tonight. I'm assuming they know what they're doing at the shop.
Looking around online, most people are hitting 250ish across the board. Just worries me that this engine is getting almost 100psi less on each cylinder and its freshly built.

 

I don't even hit 250 across the board on my mild build with ITR pistons.

Not all gauges read the same. Consistency is what matters. If timing was off it would also cause low reading results but consistent numbers as well.

 

sounds good. I guess I'll just see how it drives and if I decide to pick it up I might just take it to a shop for a full diagnostic. Thanks guys

 

250 across the board??that cant be right..

 

i beleive it matters how many time they carnk the motor for the compression reading

but i believe minimum is 140 each cylinder

 

the numbers are consistent, which is good. but those numbers are low for any gauge imo. according to honda, nominal compression would be around 270. minimum is 140.

did they not depress the gas pedal? motor not up to operating temp?

 

i would get a second opinion on the compression reading,like freaks smksaid the person or shop who did it might not know whats going on lol ....

have it rechecked for sure before u buy IMO

 

thanks guys, asked the seller to get another reading at a different shop.
Just wondering, what do the low numbers indicate?

 

The most common issue would be rings are on their way out. That would make sense with a 17 year old gsr... Add some oil to each cylinder, do the test again, if the numbers go up there's your problem.

 

the motor is heathy that is just low compression about 7.2:1
oem obd1 b18c1 should be higher at 225 across the board

THERE IS NO THIS THE LOWEST 140 PSI it all depends on what current rod piston head set up you have

 

my old gsr was down to 140psi across before i fragged a valve. that was at 172k miles. as these motors wear it's natural for compression to drop. if it's at 160 after a rebuild something is wrong. if it was never rebuilt that would make much more sense as it would be common for 150k miles

this most recent itr engine i have for example has 230psi cold on all 4 holes. mileage is unknown but claimed to be 32,000 which would seem about right for those numbers.

the b18c really does show it's health on a compression gauge.

also note if you drive it easy it's possible to go as far as 300k on one. one of the older mods here did it. i have the oddest feeling that car rarely hit vtec.

so, in short, the more you spin it up the shorter life you'll have. the rings and cylinder walls take a beating

props for doing a compression test on a B series vtec before you buy it. it's the single most important test and most folks don't do it