High crankcase pressure and low oil pressure???
06-24-09, 10:51 PM
#1
High crankcase pressure and low oil pressure???
Hi, 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
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
06-24-09, 11:39 PM
#2
You either burn the ventilation oil up like the car does from the factory, or you put it in a catch can. No production car is going to vent it to the open atmosphere from the factory, and they do just fine. It may not be "ideal" but I don't think it's the end of the world if your car is burning up blowby vapors. Also, the PCV valve has nothing to do with blowby under load and there was no point in hooking it up if you don't care about visual emissions tests IMO. It draws in crankcase pressure only when the engine is under low load:
As for the oil pressure issue:
Your oiling system and your crankcase ventilation system are functioning like stock. While stock may not be "ideal," it's not necessarily "wrong." For the oil pressure issue: how many people using good oil with properly assembled and maintained street engines actually have spun bearings? This isn't a Vr-4 or a Mark III Supra, two cars notorious for oiling and bearing problems.
Now there can be more blowby due to worn seals or sloppy clearances. But you didn't ask to get the engine blueprinted or anything so you have to trust that everything was at least in the factory spec. But some of the factory specs have a very wide tolerance, and you can be "in spec" but less-than-ideal. For example, the spec for clearance between the side seal and the corner seal is around 2 to 6 thousandths of an inch. In some ways that's like a torque spec of 50 to 150 foot pounds.
But here's the thing: if it has a rich tune and no emissions equipment, that increases the chance of it making some level of smoke under load. Do you have any details on the tune?
As for the oil pressure issue:
Your oiling system and your crankcase ventilation system are functioning like stock. While stock may not be "ideal," it's not necessarily "wrong." For the oil pressure issue: how many people using good oil with properly assembled and maintained street engines actually have spun bearings? This isn't a Vr-4 or a Mark III Supra, two cars notorious for oiling and bearing problems.
Now there can be more blowby due to worn seals or sloppy clearances. But you didn't ask to get the engine blueprinted or anything so you have to trust that everything was at least in the factory spec. But some of the factory specs have a very wide tolerance, and you can be "in spec" but less-than-ideal. For example, the spec for clearance between the side seal and the corner seal is around 2 to 6 thousandths of an inch. In some ways that's like a torque spec of 50 to 150 foot pounds.
But here's the thing: if it has a rich tune and no emissions equipment, that increases the chance of it making some level of smoke under load. Do you have any details on the tune?
06-25-09, 01:09 AM
#3
Thank you very much for the reply and the useful info. I understand that the fact that the car has up to 70 PSI is not totally bad but since the car is making way more power than stock and hearing from other people that Rotaries like this make up to 100 or more PSI, I thought it was a little too low.
The other interesting thing is that, before they opened the engine for the third time because of some ridiculous problem on the assembly, the engine was not blowing any oil at all.
Ok, the longer story, the engine got built and placed on the car, after almost 800 miles of breaking in ( and good running ) by the shop guys on the Dyno, suddenly, the engine broke something inside. They opened it and found a rotor and housing grenaded by "something". No one could ever find what it was and each one was softly trying to blame the other one of course. Anyway, the engine got built again and then placed in the car.
After that, the engine started having low oil pressure, no more than 35 to 40 PSI at high rpm's. So the guys had to take the engine to the builder again to get it open and checked. the builder said they could not find anything even after checking all the possible places so they tried the pressure again and "miraculously" it had more oil pressure now.
So they place the engine back in with more oil pressure but the car starts making a weird noise. They take it back and it happened to be the flywheel that somehow got one bolt slightly loose and not completely seated so it was vibrating. The builder apologized and they fixed that.
Then they start it again and the car starts having the problem with the oil pressure ( even though higher than before ) but still not over stock levels and the beautiful oil spewing that made a mess on the floor.
So that is the story and that is why I get so worried because it was not doing it before.
I dont have the specs of the tune right now but I have been talking to the guy that is doing it and he tries to stay away from getting it too rich. He of course never gets it lean either but I will try to see if I can get a copy of the tuning specs.
Thank you again and hope you have some more ideas...
Leo
The other interesting thing is that, before they opened the engine for the third time because of some ridiculous problem on the assembly, the engine was not blowing any oil at all.
Ok, the longer story, the engine got built and placed on the car, after almost 800 miles of breaking in ( and good running ) by the shop guys on the Dyno, suddenly, the engine broke something inside. They opened it and found a rotor and housing grenaded by "something". No one could ever find what it was and each one was softly trying to blame the other one of course. Anyway, the engine got built again and then placed in the car.
After that, the engine started having low oil pressure, no more than 35 to 40 PSI at high rpm's. So the guys had to take the engine to the builder again to get it open and checked. the builder said they could not find anything even after checking all the possible places so they tried the pressure again and "miraculously" it had more oil pressure now.
So they place the engine back in with more oil pressure but the car starts making a weird noise. They take it back and it happened to be the flywheel that somehow got one bolt slightly loose and not completely seated so it was vibrating. The builder apologized and they fixed that.
Then they start it again and the car starts having the problem with the oil pressure ( even though higher than before ) but still not over stock levels and the beautiful oil spewing that made a mess on the floor.
So that is the story and that is why I get so worried because it was not doing it before.
I dont have the specs of the tune right now but I have been talking to the guy that is doing it and he tries to stay away from getting it too rich. He of course never gets it lean either but I will try to see if I can get a copy of the tuning specs.
Thank you again and hope you have some more ideas...
Leo
06-25-09, 02:07 AM
#4
I think the only problem here are the people working on your car. Whether there really are problems or not, they've now got you freaking out about every little thing. We can leave all the names out of this thread, but I would ditch all of them. I would find a new tuner, or tune it yourself because you couldn't do any worse than they have been doing so far. I would also find a new builder or do it yourself, because it's not like you are saving any time or trouble by paying someone else to do it at this point.
The best thing I ever did for my car was educate myself to the point where I could start seeing shops as peers and consultants rather than someone with which to trust every detail of my build. Maybe it's because I don't live up the street from Mazdatrix or another top tier specialty shop, but I always feel a lot better when I **** something up on my car and learn from my mistake than when I pay someone else to do a mediocre job or just plain drop the ball.
The best thing I ever did for my car was educate myself to the point where I could start seeing shops as peers and consultants rather than someone with which to trust every detail of my build. Maybe it's because I don't live up the street from Mazdatrix or another top tier specialty shop, but I always feel a lot better when I **** something up on my car and learn from my mistake than when I pay someone else to do a mediocre job or just plain drop the ball.
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