I just rebuilt my b18c jdm ITR with an ls crank, eagle rods and 12.5:1 CP pistons. everything else on it is stock besides intake and and 2.5" exhaust. Shortly after i started it for the first time, i took the oil cap off and there is a medium to heavy flow of air coming out of the valve cover. I figured it may be the PCV valve so i checked it. I also inspected the breather canister on the back and the other hose coming off and everything is working properly as far as I can tell. It seems to run fine other than an oil leak coming from the crank seal in the oil pump. its a brand new seal so im thinking the pressure in the motor is forcing the leak. I have already had it tuned and the motor has the proper power for what it is so i doubt theres any problems with the pistons rings ect. I do not know what else would cause this? i would appriciate any ideas or suggestions.

 

This is normal, this is why people have large catch can systems on their cars, to help vent these gasses rather than relying on the little tube running to the intake piping. It's mostly from blowby.

Go take the oil filler cap off of any other car that's running.

https://honda-tech.com/forums/honda-accord-1990-2002-2/air-comes-out-oil-cap-when-engine-runs-2609232/

 

I put a breather filter on the back of the valve cover instead of the tube that runs to the intake and it seemed to reduce the amount of oil leaking out. the amount of air being produced seemed to have increased though. when I took the oil cap off after a week or so of driving, it seems like there is even more air coming out then when I first posted this. could it be bad exahust valve seals? If it is normal as mentioned above, does that mean it wont hurt anything or effect the performance at all.

 

u need to run that tube from valve cover to the intake so the intake can suck the crank case pressure out

 

well when i had the tube in, most of the pressure was still there and instead of having a filter to easily exist the motor, i think it was pushing out around the crank seal on the timingbelt side of the motor which was createing a oil leak. does anyone know where this much pressure is coming from? seems to be a lot for just crank ventaltion.

 

blowby. what's your ring gap?

 

check rng gap or your comression rng could be upside down

 

when i had this problem i had cracked ringlands

 

what is ringland? the ring gaps were within stock specs when i put them in. im pretty sure i put the rings in the right way, but there is always a possiblity i could have flipped one. if i check the compression of each cylinder will it be obvious if one is reversed?

 

yes do a leakdown and compression test. i had a issue and i could tell what cylinder the problem was in, so i torn it down and saw this.

 

all four busted? what do you think caused that?

 

me? uncontrolled detonation. i ran into a bad batch of gas and caused that, i remembered awhile back that i had that issue, realized it to late and thought i caught it in time but i didnt and the problems slowly came.

BTW only 3 were toast