When my car was on the dyno and when it hit boost I could see a ton of blow-by coming out the valve cover breather (i have a filter on it). The motor is completely built up: arias 8.8:1 pistons .020 over, ams sportsman rods, clevite bearings, bc cams, and bc dual valve springs. The motor has been bored, honed, decked, and hot tanked. The head has been resurfaced, 3 angle valve job, and hot tanked.
Right now the crankcase vent is not hooked up the best way, its currently running from the crankcase to the turbo intake. Am thinking maybe its the way its set-up causing this? Or maybe the crankcase vent is clogged?
Last time I did a compression check it was good, maybe a leak down test could tell me more?
Also the pressure is so much that it keeps blowing out the oil pan gasket, I have changed the oil pan gasket 3 times, I originally thought the pan was warped or somehow I was screwing up the gasket during install. Anyways anybody have any ideas?
Lots of Blow-by
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spooled240
- Posts: 6487
- Joined: Sat Jan 20, 2007 8:45 pm
- Car: kouki s14
Re: Lots of Blow-by (NizzmoS13)
Compression is around 140 across the board, running 7psi.
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spooled240
- Posts: 6487
- Joined: Sat Jan 20, 2007 8:45 pm
- Car: kouki s14
Re: Lots of Blow-by (NizzmoS13)
I have read that with forged pistons you were not looking for how high the numbers are but how close the numbers are to each other. I have even read of other motors running compression numbers like mine and running fine.
Re: Lots of Blow-by (NizzmoS13)
You have an oil pan gasket??? Weird , I just have silicon or is that what you meant. Be careful you could blow your turbo with a lot of blow by, because the excessive pressure in the pan goes up the oil drain and can stop or really reduce oil flow especially w/ BB turbos that use a restricter. Check your pcv valve it might be stuck open venting boost into the crankcase.
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nelson8708
- Posts: 1008
- Joined: Tue Dec 14, 2004 1:20 pm
- Car: 1989 Nissan 240sx Fastback
1994 Acura Integra LS - Contact:
Re: Lots of Blow-by (D-UNIT)
with my single cam (8.6:1) i get around 145psi. Since you have 8.8:1 your compression is a little low but, it wont put out stock cylinder pressure since stock is what......9.5:1 iirc.
Re: Lots of Blow-by (NizzmoS13)
First off, dont use an oil pan gasket on a Ka. Use Permatex Ultra Grey, or i have found that the new RTV nissan just came out with kicks a**.. More on that later.
Second, did you break the motor in? Or just build it and toss it up on the dyno.
Nelson, so many things effect the actual compression numbers you get in each cylinder. So its not really possible to say "well i have 8.5 CR pistons so i will have 155 compression across the board."
Second, did you break the motor in? Or just build it and toss it up on the dyno.
Nelson, so many things effect the actual compression numbers you get in each cylinder. So its not really possible to say "well i have 8.5 CR pistons so i will have 155 compression across the board."
Re: Lots of Blow-by (NizzmoS13)
No the motor is broken in. Yaa I guess am gonna have to go with some of that Permatex Ultra Grey or some of that nissan stuff.
If the compression was a problem would it show up on the dyno results? I ran 7psi and made 210whp and 250wtq and I could still probably gain 15 more hp with a little tuning maybe even more. But I am thinking more that there could be maybe one cylinder causing all this blowby and the motor is still making power.
Am going to be picking up a leakdown tester next week and ill let everyone know what it tells me.
If the compression was a problem would it show up on the dyno results? I ran 7psi and made 210whp and 250wtq and I could still probably gain 15 more hp with a little tuning maybe even more. But I am thinking more that there could be maybe one cylinder causing all this blowby and the motor is still making power.
Am going to be picking up a leakdown tester next week and ill let everyone know what it tells me.
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nelson8708
- Posts: 1008
- Joined: Tue Dec 14, 2004 1:20 pm
- Car: 1989 Nissan 240sx Fastback
1994 Acura Integra LS - Contact:
Re: Lots of Blow-by (NizzmoS13)
thats not what i said but, unless he decked the the hell out of block and head and is running a MLS gasket i dont think he has a problem just because he didn't get 180psi of compression. As long as they a close across the board i wouldn't worry about it.
Re: Lots of Blow-by (nelson8708)
^^ Yea i know it wasnt exactly what you said but idk, it can be read that way.. Kind of. Im not tryen to bust your balls.
I agree with you 100 percent though.
OP - Still man, you havnt told us.. How many miles on the motor? Did you break it in? If the motors still fresh, your gona get blow by in most situations.
I agree with you 100 percent though.
OP - Still man, you havnt told us.. How many miles on the motor? Did you break it in? If the motors still fresh, your gona get blow by in most situations.
Re: (C-Kwik)
Hehe good sang, i always forget about that. Boosted crank cases and extra turbo lag FTL....
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240sxvaj
- Posts: 2076
- Joined: Fri Dec 22, 2006 1:57 pm
- Car: 1991 240sx fastback KA-T- SOLD!
1994 MKIV TT-Daily/Track - Location: So-Cal
Re: Lots of Blow-by (NizzmoS13)
we have almost the same set-up..same arias piston size and compression, just that i have eagle rods. bc stg2cams, dual vavlespring etc....well before i broke in my motor i was reading 150 through all the piston. i need to check mine again since it should be completely broken-in and i'll compare it w/ you. i do get blowby but not a lot but my blow-by is between the pcv vavle and intake manifold. oh almost forgot i am n/a until i can get more $$ for my new turbo set-up.
well.....GL
well.....GL