crispydee

Got a bit of an odd one here, ever since i put forged interals in ive had a little smoke from the breather but its not gotten any worse and compression is fine.
It smells like petrol so i assumed i might be getting a bit of bore wash but my wide band is reading between 11.5 and 12 so i dont see how. Any ideas? or is it just the old built motor symdrome because of the extra clearances.

99B16Si

its blow-by thats why it smells like fuel...combustion gases are getting by the rings into the crankcase and out the valvecover.

also its not a good thing

093turbo16

iTrader: (2)

blow-by, since I was informed that I am being an ***, I should add some more info. Get a catch can, but still probably won't cure all of it.


Modified by 93turbo16 at 11:54 AM 3/24/2005

drvfast

It's normal with built motors.

SOHC_MShue

soundsl like blowby. Are you burning oil?

platinum00

how much smoke are you talking about. is it like a white smoke. a little bit is aceptable.

mrbsponge

yep its blow by, who built the motor??

what are the rings gapped at and what was the piston to wall clearance??

these are what most built motors suffer from, forged internals depending on what piston brand you go with, have different thermal expansion rates designed to deal with the heat and abuse from turbo chargers and blowers.

for example my JEs are silly loud when i start the car, but when it gets to operating temp, it is just fine and sounds like a stock honda.

CPs on the other hand are alittle different because of the silica content in the piston.


but if it starts pourig out like a freight train its ringlands, and they are more than likely melted, if it does this

leadfoot78

As long as your oil stays clean, you are not burning any oil and you don't have any coolant/oil mixing problems don't worry about it. I've had a little smoke coming out of my Endyn breather ever since I built my motor, but I gave no problems at all, made 342WHP at 9.6psi and now the motor has 2000miles on it and the compression went up but smoke is still coming out of the breather can. I wouldn't get worried when people say it's blow by or rings, it's just not that simple, it could be smoking for many reasons. Also I noticed that when I was doing my max power runs on the dyno, in the higher rpms the can stopped smoking completely.

crispydee

Im glad to hear most people agree that it does not sound serious. They are arias pistons and are loud when cold but as said get quieter as it warms up. The rings are gapped at 0.015" and the wall clearance is 0.003 - 0.004" (i wiill have to check both of these as i carnt remember for sure). I had the ring lands go before on stock pistons and it was a lot worse than it is now and broke a ring about three days later, where this time it has done it since the pistons went in 2 months ago.
I have a catch can but it does not get barly any thing in it and the oil has done 1200 miles including 2 track days and its still clear and within the marks on the stick. It has burned a little but no more than .5 litre which is pretty good really concidering the hammering its taken.