View Full Version : RB25DET COMPRESSION NUMBERS!!any good?
Busted_daily
06-24-2015, 10:22 PM
I picked up a rb25det s2 swap all stock compression numbers were
#1-150
#2-175
#3-150
#4-150
#5-175
#6-150
ive read alot and alot of people are saying 150 is fine no problem i just want to double check that these numbers are good and not bad since this is my first time owning a Rb25 but everytime i read someones answer on a thread always differs from another just want someone with better knowledge to check this out and let me know thank you guys .
Mitsubayati
06-24-2015, 10:27 PM
There's more than a 10% variance in compression between cylinders. Regardless of the nominal compression number, that is already a sign that something is wrong. 175 is where your compression should be around. If it's lower then you should contemplate a rebuild. Do a leakdown test to verify percentage of leakage and where the leak may be coming from but it's most likely your rings.
Busted_daily
06-24-2015, 10:35 PM
=( i dont want to rebuild lol and ill call them see what we can do
Seems like the resolution of the tool you were using was in 25psi per mark. So it was either 150 or 175 and nothing in between. Try again with a different tool
Busted_daily
06-24-2015, 11:09 PM
alright you think that would change it?
I think with a different tool instead of getting either a 150 or 175, you would get a better resolution number.
Resolution - n. The smallest interval measurable by a scientific (especially optical) instrument; the resolving power.
Kingtal0n
06-28-2015, 04:25 PM
I think with a different tool instead of getting either a 150 or 175, you would get a better resolution number.
Resolution - n. The smallest interval measurable by a scientific (especially optical) instrument; the resolving power.
this.
Your numbers should be plus or minus 2 or 3, not plus or minus 25.
Right off the bat I would say its just been sitting.
Busted_daily
06-29-2015, 01:28 PM
Im going to try with a new tester i bought a compression tester from harbor freight i have been busy sorry have not responded back to you guys but i will for sure try it as soon as i get the chance and i just hope the motor doesn't need rebuild and yea i got the motor from a importer in FL so im hopeing its just from sitting and nothing major
Kingtal0n
06-29-2015, 02:10 PM
for example, you want to see this
125
123
124
125
126
123
then, you want to add a cap-ful of oil, and see this:
127
126
125
127
129
124
Busted_daily
06-30-2015, 08:00 PM
well i bought i about month and a half ago it could of been sitting at the importer but if numbers do not change is it a chance of the rings just sticking from sitting and once i crank it in car it would change ? if that makes any sense
vBulletin® v3.8.11, Copyright ©2000-2021, vBulletin Solutions Inc.