I did search this first, but didnt find exactly what I needed. I have a 98 Eagle Talon 420A Turbo of course. I have Hahn S-20G, Front Mount, built engine, Portfueler, etc, etc. When I tried to do a dyno run we had to stop on the first try because it popped the dipstick and sent oil everywhere. The second try it was coming from the valve cover gasket on the front side between the number 1 and 2 cylinder. I know this is most likely because the engine is building pressure in the bottom end. But why is it doing this? Now when I am driving and I hit high boost I get black smoke like hell out the exhaust and oil blowing out the valve cover between the 1 and 2 piston area. I have not tuned it yet, so I know I am running pig rich. I don't believe it's the head gasket because I have no oil in water, no water in oil and the compression is 200 across the board. What can I do about the buildup pressure? I checked the PCV valve and it's good, my PCV valve hose was crimped between the valve cover and intake mani, I fixed that. I have just a straight hose on the breather side of the valve cover, no filter on the end. Is it possible that I have a vale not sealing right causing the pressure in the vale cover and maybe pushing oil into the cylinder causing the black smoke out the exhaust? Any help would be appreciated. As for the Dyno run, lol. AFter the run I realized my intake cam was off one tooth negative, retarted I suppose. I fixed that as well. The oil spurting out on the dyno runs starts at about 3200 rpms in 4th gear which is as high as we got on both runs. But the dyno results were very weird. My A/F ratio was a pig rich 8.5 to 9.0. I believe the optimum is 10.5 or 11? But the both dyno results were 260HP and lol, 620FT/LBs torque. The dyno is local and have heard many things, but those dyno results are funny. Either way I need help with why I am building pressure and how to fix it. Thanks. Jim

--JIM--
98' Eagle Talon FWD
HahnRaceCraft S-20G Stage V

HRC S-20G @18PSI, Front Mount, 3" Turbo Back Exhaust, PortFueler, JE Pistons, Crower Rods, Spec Stage 4 Clutch, Quaife LSD, MSD Dis2 Ignition, Crower #14 Cams, 1mm oversize valves, Ported Head, Melling Oil Pump, etc. etc

Your PCV may be "good" but that doesn't mean it will stop boost from entering the crankcase. i've never seen a PCV value that would, in fact. I added a large secondary checkvalve inline with the PCV to prevent exactly what you're seeing.

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'97 Talon ESi-T (poor impulse control)
'99 Eclipse RS-T (daily beater)
'13 Evo X (mostly stock)
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Factory Service Manuals: http://nawdu.de/files/

Here is the upgraded PCV I installed. It makes sure that Boost doesnt pressurize the crankcase. However you should add a hose on the OTHER NIPPLE . I added a hose then put a catch case on it, the other end comes out of the catch can and feeds back in front of the turbo. This way the crankcase has a vacuum on it all the time.



Here is how I did it
http://upgradecar.blogspot.com/2007/12/pcv-upgrade-for-eagle-talon-420a-turbo.html

This covers the part where the PCV was installed. I am making another post for the catch can. I use to have a Breather on the other nipple but the blowby while under boost would spray oil up and out of the breather. ( this was greatly caused by the PCV letting boost by of which I fixed I believe)

Upgradecar.blogspot.com for the Candy Red Turbocharged 420a, Xbox Talon

Dreamcasteclipse.blogspot.com for the Raspberry 4g63T Dreamcast GST

Thanks Noogabox for the informative information. I will go get the TSI PCV valve tomorrow and hopefully that will solve the problem. When you talk about running a catch can on the breater side and another line in front of the turbo, Where exactly are you talking about? Are you going to weld a bung onto the exhaust? Is this going to make your exhaust smoke alot? I would like to see whatever it is you are doing when you are done.

Hello DarkOne, I have not talked with you in a while. My Nick on DSMTalk is TurboTalon1. I have talked with you before, many years ago, in a galaxy far, far away. Thanks alot guys. Jim

--JIM--
98' Eagle Talon FWD
HahnRaceCraft S-20G Stage V

HRC S-20G @18PSI, Front Mount, 3" Turbo Back Exhaust, PortFueler, JE Pistons, Crower Rods, Spec Stage 4 Clutch, Quaife LSD, MSD Dis2 Ignition, Crower #14 Cams, 1mm oversize valves, Ported Head, Melling Oil Pump, etc. etc

I will make a write up and post is on my blog soon as I do it.

Here is a Illistration of how to maintain a PCV system just like the GST does to get blowby out of the Crank Case. Blow by can contaminate oil and cause friction and wear.



Upgradecar.blogspot.com 420a Turbo Microsoft Talon

This is a Catch can, you can find them on ebay. They prevent oil from getting everywhere, or in the intake where it can cause build up and foul sensors

Upgradecar.blogspot.com for the Candy Red Turbocharged 420a, Xbox Talon

Dreamcasteclipse.blogspot.com for the Raspberry 4g63T Dreamcast GST

99 RS-T
"New bottom end(8.6:1 w/long rods)"
Turbonetics 60-1/Portfueler/etc!!!!!

Pretty good litle writeup Noogabox, I might have to give this a try since I hate the stock plastic PCV valves. Where did you pick up that Talon one, an autoparts store or dealership?

Mike D
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Crankcase pressure will always build up inside the motor unless you have some means of relieving it. Remember, yours pistons have two sides -- they create pressure on both sides.

The PCV only works under high vacuum situations, like idle and decel. Otherwise, it is suppose to be closed to prevent positive pressure entering. Running a check valve will help prevent boost from pressurizing the crankcase further, but it still doesnt allow crank case pressure that builds up normally any where to escape. Thats why your dipstick tube is getting blown out (and also why supras like to blow front main seals)

the v8 guys have run vacuum pumps on track cars to pull that crankcase pressure out -- having the crankcase under constant vacuum also allows the rings to seal better and reduces drag in the motor...high horsepower v8 cars will see gains as high as 40-60hp using a vacuum setup. (as well as having much cleaner oil).

Mechanical vacuum pumps are great because theyre pulley driven and give a linear relation in motor speed and how much vacuum is pulled, but theyre expensive and need frequent rebuilds. Electronic vacuum pumps can be had for less (smog pumps), but they dont tend to last long and its difficult to set them up so that they draw more vacuum at higher rpm/boost and less at lower rpm/boost.

Another means to have a constant vacuum source is using slashcuts in the exhaust -- they generate vacuum through the bernoulli effect. This eliminates crankcase pressure and keeps the crankcase in vacuum. Moroso, Summit, Mr.Gasket, etc all sell kits that include slashcuts and check valves (to keep exhaust from entering the crankcase in case of a backfire).

The supra crowd picked up on this method a while back too




You can either just burn off the blow-by in the exhaust, or run a sealed catch can inline to avoid smoke from buring blow-by

The problem with using the pre-turbo intake as your vacuum source is that very little vacuum is generated pre turbo unless you have a very restrictive intake.

You can try to just vent the crankcase to atmosphere, but it doesnt appear to be an adequate means of relieving crankcase pressure -- take a look at the supras who blow front mains frequently and most of them will just be venting the crankcase instead of having some type of vacuum source to pull pressure out

added benefit of having the crankcase in vacuum is that any oil leaks will suck in instead of blowing out -- meaning they will either be sealed or suck air in instead of blowing oil out.




With my most recent build, I was researching all the different ways Ive seen pcv and catch can setups and the exhaust evac setup seems to be most ideal: constant state of vacuum that increase as the engine is driven harder (more exhaust flow creates more vacuum) and total isolation of blow-by and crank case gasses from the intake tract

95 Avenger
ATX->MTX Swap
Holset HX40 @ 26 psi