Okay guys my question is what would be the cause for air to come out of the intake? Now with that keep in mind a compression test has been done and all cylinders are within spec. The engine is recently rebuilt as well. All clearances checked multiple times and within spec. Vacuum is also correctly routed and o2 sensor is not throwing any codes. Any thoughts on what would cause this? Thanks in advance everyone!

Edit: The air coming out of the intake only happens in the higher rpm's.


[Modified by Integra-T, 12:32 AM 1/24/2003]

 

I would check your timing. Sounds like it is backfiring.

 

Timing is on par as well, 16 degrees. Thanks for the reply!

Edit: Cam timing is also at 0,0.


[Modified by Integra-T, 5:27 AM 1/24/2003]

 

do a leak down ur intake valves might and i do mean might be fucked. Run a leakdown, if air comes out of the exhaust mani then ex valves screwed, if its out of the intake then intake valves are jacked, if out of dip stick or oil cap breather then ur rings are more then likely gone. Have fun.

 

the cam/valve timing has to be off. think about it. thats the only way air can move backwards. good luck
edit- unless an intake valve is leaking, would be more likely if it only does it at high RPMs


[Modified by 22lbGS-R, 9:42 AM 1/24/2003]

 

If you have your cam timing 180 degrees off what it should be set at when the motor is at TDC... Your motor wouldn't run and you would destroy all your valves if you cranked the motors...haha How does the motor run?? Peace


[Modified by Kataku2K3, 7:45 AM 1/24/2003]

 

I know I could do a leakdown test but I don't think it is necessary seeing that compression was perfect all the way across. If valves were bent or something they would not seat and I would lose compression. As far as rings go they should be sealing properly because again the compression check was perfect, 255 with two cylinders being off by only one or two psi. Thank you everyone for your help so far, keep it coming.

 

22lbGS-R I agree. That is the only logical thing I can come to think of right now. I have checked all my timing marks and they are correct though. lol weird huh? I can't even begin to think what the hell else it could be.

Kataku2K3 the motor runs fine until I get on it. Hesitation also occurs at tip in throttle and wot. If I keep the throttle open all the way it will eventually fall below 1k rpms and stall.



[Modified by Integra-T, 5:56 AM 1/24/2003]

 

i got an idea- weak intake valvesprings. youre floatin the intake valves at high RPMs. get some skunk2 dual valvesprings or something. this is pretty much the only other thing it can be

 

I would guess that it is this, or milling the head caused your cam/valve timing to be off as well as overlap. If you get adjustable cam gears, you can correct this.

 

I am thinking that as well now. Head has not been milled though. I do have adjustable gears as well, Skunk2. I recall sgT saying that the S2 gears are not true TDC and that has been running through my mind as well. I need to get a degree wheel to find out. Again thank you to everyone who has posted.

 

If anyone has anything else to input then please by all means do. Thanks.

 

hey, does your name mean that youre turbocharged? if it does then i would bet money that youre floatin the intake springs/valves. boost is extra pressure on the valvesprings to leave the valves open longer

 

Yup. for every 1 lb of boost pressure, take that pressure of your spring seat pressure.

so say you had a 40 lb spring that would seat untill 8k n/a ... Say you turbocharged it and were running 10 lbs of boost... you would then need ~50 ft/lb springs to acheive the same seat level (with the same valves of course) and still keep your 8k redline due to the extra pressure that is put on the intake valves.

 

lol no I'm not turbocharged. I own an Integra and my first name starts with a "T" put em together and made Integra-T so it also sounds like "integrity". Lazerus thanks man. Thanks again all!

 

Anyone else have some input on this? Thanks!