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-   -   High crankcase pressure and low oil pressure??? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/high-crankcase-pressure-low-oil-pressure-848014/)

lzamboni 06-24-09 10:53 PM

High crankcase pressure and low oil pressure???
 
Hi, I just posted this also on the Single Turbo forum. I hope that doesnt contradict any forum laws :)
I have been having a real nightmare trying to get my car to be finished by the shop where I took it almost 9 months ago. I prefer not to disclose the name of the shop yet but it is a reputable rotary one.
The engine has been thru every possible stupid problem it can have.
To give a little back story: The car went to get the typical Single turbo conversion. GT35, bigger SMIC, dual oil coolers, HKS Twin Power, etc. But also it had a FRESH REBUILT with a half bridge port.
So, after many unbelieavabler problems that I will not get inot right now, the last interesting issue is that the car is spitting some oil while getting tune in the Dyno and if the venting holes get closed, then the car starts smoking heavily.
Now, there is 1 shop that did the engine and the other one next to it installs and tunes everything. The guys that installed the engine told me that it simply looks like the engine is generating too much crankcase pressure that is blowing the oil.
The shop that rebuilt the engine said that it was because the car was missing some connections that it should have had and it did a PCV valve connection going back into the turbo piping. So now the engine doesnt blow the oil but it is ingesting it and still smokes slightly but noticeably and also it is not the normal way for an engine that is supposed to be a high performance one.
The car was supossed to make close to 500 whp ( dynojet readings) with the water/methanol injection at around 21 PSI and it was actually making close to 415 whp ( Mustang Dyno readings) at 18 PSI so it was getting close.
But the fact that it will have the oil going back into the engine will hurt performance now.
Besides, the engine had the oil performance modifications and it is getting no more than 70 PSI at high rpm's that seems kinda stock and maybe not enough for a 500 whp engine?
Well, the questions are these: Can the crankcase pressure be generated because a side seal is not good? Or what other thing could cause that?
Also, if I keep the PCV setup, will it hurt the performance enough to feel it?
And lastly, the oil pressure at no more than 70 PSI ( for heavy street use and a possible few track uses ) is going to hurt the engine or should be ok?
Thank you very much for any insight you may give me on this matter since this is killing me slowly and I dont think I can take so much more of this bull... that I am getting from the shop.
Thank you.
Leo

IRPerformance 06-25-09 09:11 AM

Are you running the proper restricter on the oil feed line? Is the drain an adequate size and unobstructed? What are you using to monitor oil pressure? The stock gauge is worthless.

Dudemaaanownsanrx7 06-25-09 11:45 AM

The pcv should be connected before the turbo or after the throttle body with a check valve. Not on the pressure pipes. Mounted on the pressure pipes will make it hard for the crankcase to vent. I prefer to run a vented catch can with no pcv. A large vent on top of the oil filler cap allows plenty of venting.

lzamboni 06-25-09 11:52 PM

Well regarding the restrictors, I dont know since I dont have the car here and the shop is more than 4 hours away from me. I would guess the guy building it will have placed the appropriate restrictors if needed since he has been working with rotaries and racing cars for way too long so he should know his stuff. But I could be wrong of course.
As for the drain, the same thing.
And regarding the oil pressure gauge, I dont have more than the stock one but I think they are using an external one while Dynoing the car.
The problem is that even if using a Catch can (that is what I am going to end up doing) the car is blowing so much oil that the guy on the shop told me it would fill the catch can in a few hours. So it is a ridiculous amount. So they are going to do a Catch can with a return to the oil pan so that it doesnt accumulate.
Thank you for your insights.
Leo


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