AKS Racing

I thought some of you might be able to give some insight in regards to the following problem.

My combination: ATI Procharged, intercooled, 408 (350 based), 210AFR headed, MRII, CC SR, combo.

I have spoken of the fact that the PCV and header discharged crankcase
evacuation system maintained at minimum 3-4" HG on the crankcase at all
time.

On Sun, after some high speed, hard running, I theorize that the oil had
built up in the valve covers on the AFR heads (remember somewhat less than
ideal oil return). The oil level increased to the point that it covered up the baffle area where my -10AN line connects and sucks through a one-way
valve located on the collector. At such time, a column of oil must have accumulated directly on top of the valve, and the header no longer
provided negative pressure in the crankcase. Since one valve cover has a PCV
inserted, and the other has a vent to the header collector (basically
plugged with the column of oil), with no breather anywhere in the system, there was no place for the pressure to go, thus allowing nearly every possible orifice on the engine to spew oil (mainly the distributor shaft). This allowed the engine to dump what I estimate ½ -1 qt of oil through the collector and down the back of the block. This made a very big mess not to mention all the smoke out of the exhaust.

My questions are:
Is the electric vacuum pumps that has been spoken of on the forum capable of pulling the necessary vacuum required to support a blown application? What are the P/N for both the diesel OEM application, and the Ford OEM application? Also, what are the connection sizes? I have thought about simply running the passenger valve cover vent (currently connected to the header) through a "knock out" (possibly with return to the crankcase) and then to the inlet side of the blower. What about running directly to an overflow canister with vent to atmosphere, though I know this does not apply negative pressure under boost conditions to the crankcase.

Any thoughts are greatly appreciated.

Aaron

gkull

On my S/C Dragster I had header evacuation. We had clear plastic tubing. so you could see exactly when the vacuum valve pops (backfire protection valve on the header) open because you would see when it was pulling water mist through it. Or if you put your palm over the tube you could feel the vacuum over 3000 rpm. So in my opinion they don't work worth a dam if you have any kind of exhaust system after the collector (other than collector extentions). Any back pressure would make them ineffective untill really high rpm.

I don't believe that oil in a line could not flow through an open valve. especially if it has vacuum. I'm saying the header evacuation doesn't work on a street car. So all the vacuum your crank case ever sees is from the PVC. As we all know at anywhere near WOT the motor is not creating vacuum in the intake track. So of course your going to have oil blow out where ever it can.

Just as a side note we really played with the positioning of the header evacuation pipe inside the collector to get the max inches of vac. before we welded it up

The only cure - just like thousands of race cars before you, is to use a racing vacuum pump. About $400 or just go all out and go with a dry sump system. Dry sumps create more than 20 inches of vacuum so they install an adjustable air bleed vent to the cam valley to adjust the vacuum to not exceed 20 inches :cheers:


[Modified by gkull, 9:45 AM 3/6/2002]

AKS Racing

gkull,
Thanks for the reply.

Any thoughts on the implications of just running (maybe temporarily) the vent from the valvecover to one of the summit breather tanks. This would allow the system to be able to breathe, but doe not provide negative pressure under boost. It's got to be better than what I have now.

Thanks,

gcrouse

My ATI instructions said remove the PCV valve and run 1/2" hose from both valve covers to the K&N at the SC inlet to get some vacuum. Next best is a couple breather caps or remote tank (no vacuum). But you have to get those blowby gases out- don't want any kind of valve or exhaust pressure restricting things!

SPD DMN

That is an idea...not sure of the implications though. Since mine is a '94, it has the attachment on the air filter housing for the AIR pump. I could simply run the breather to that hole and it may provide a little vacuum to keep from blowing oil through the seals. I think I will try that this weekend and see if it helps.

Bowtie8

I have crossed this path many of times and found that the system I am currently using is suffecient for now.
I am utilizing a stock PCV system on the left valve cover and a breather with a hose attached to the TB on the passenger side.
During Idleing and mid throttle, the PCV keeps adequete negative pressure, however at WOT or atmosphere, there is no vacuum, thus the breather connected to the TB begins to draw from the passenger side.
Pro - inexpensive and no oil leaks
Con - Oil migrates into the intake even through I have good baffleing.

Regards
John
http://bowtye8.tzo.com/bowtie8/eng1.20.jpg

AKS Racing

Thanks guys for all the replies.

Bowtie 8,
Your system was more than adequate for me as well, untill you factor in boost. When the intake tract including forward of the TB is under 10+ psi, there is no longer any available negative psi, and the whole system runs into psi. Thus the psi looks for every avenue to escape the crankcase, valley and vc areas. With this psi escape, also comes oil. This is very messy. I have settled on a tentative fix of a simple K&N breather mounted off the -10AN fitting. Long term, I am looking at a knock out that returns to the oil pan, with negative psi applied by something like the Cobra R electric vacuum pump. I am also looking into the vacuum pump available from summit, that would run off the serpentine assy.

Anyone with any additional thoughts?

Thanks,
Aaron

gkull

All the racing vac. pumps I have seen are all standard V-Belt. I have a buddy who has a 9 second Camero. He runs an electric motor through a V-Belt to his standard aluminum water pump. so he can run the water pump to cool between round. I'm wondering if you could do the same with a vacuum pump. Then you could place the small 12 volt motor and pump anywhere you wanted and plum it into one of the valve covers.

Just a thought.

MJ

Chris I did this on my '96 and had two things happen.
1. had a light coating of oil in my MAF
2. lost an opti fairly soon. (2 months)
My theory: contaminated air with oil in suspension got sucked into the opti thru the opti intake tube in front of the throttle body. The oil in the MAF, same thing. I went back to a catch can with a small breather on it.
Just a heads up. :cheers:

SPD DMN

Thanks for the heads up Mike. Right now I am just using the stock PCV setup and it seems to be working better than just breathers on the valve covers. I would rather inject a little oil than leave it on the pavement everywhere I go. I too am looking into the Cobra electric pump as a solution.

Red5

I ing the ATI 600b set up on my L98. Sim problems. I ran the hoses from the valve covers to the K&N and fouled many MAFs and conitinually had error codes. I ended up buying many extra power and burn off relays as well.
You know, I never did figure out a method that would work without fouling the air/fuel metoring system.
Good luck.
:confused:

MCAF84

There was talk about an Electeic vaccum pump. I tracked down the part number 22062562 at GM partsdirect cost 117.68 list 235.37. I hope this helps I ordered one for myself. good luck Mike

SPD DMN

Do you have any pump dimensions? Connector sizes, etc? post them when you get the pump, and a pic if you can. Gracias.

MJ

I really want to hear about how that works out. Yours too Chris. :)

AKS Racing

The GM vacuum pump is available on 85-86 and a few early 87 Cadillac Sedan DeVilles. It was a "supplimental" vacuum system to aid the power brake booster. The dimensions including the motor assy are roughly 7" x 6" x 4" with 12V DC power and a single 3/8" (-6AN) inlet connection. My cost is roughly $125.

I have reviewed how Calloway handled boost conditions. Both valve covers utilize baffles that have plumbing that is tied into a single vapor/liquid (ie air/oil) seperator (approx 3" in diameter by 5" tall), where the vacuum is drawn from the inlet side side of the turbo, and the oil is returned to the pan. It also utilizes a single PCV valve that draws back to the intake like a factory NA L-98 would do. Under boost, the check valve in the PCV closes, and the seperator draws from the inlet side of the turbo. Unfortunately, all seperators have some amount of carryover, which means that the MAF and the intercoolers get a steady dose of oil vapor when operating under serious boost (increases as engines are modified). This is not a good situation!

I am looking at the following. Locate a decent seperator, and will plumb both valvecovers (with baffles) into the seperator, with the oil return plumbed into the -8AN blower oil return directly to the pan, and the air directed to the eletric vacuum pump.

In the interim while the above system is being completed, I am using a single K&N directly off the pasenger vc plumbed onto the existing -10AN connection. The factory PCV on the driver's remains intact feeding into the side of the MRII.

Hope this helps some of you guys experiencing similar problems.

Aaron

AKS Racing

Update:

2 weekends ago, I put a -12AN straight fitting inside a K&N filter with the 1-1/4" clamp mount. When the clamp is tightened to provide the seal, hose fitting acts as a standpipe. I screwed this complete assy on the passenger vc. At an idle and at lower RPMs, the breather has serious vacuum drawn through it, but there is evidence of some of the filter oil being expelled when the engine is loaded for longer periods of time, but no engine oil. Matter of fact, no oil from anywhere on the engine. This was an easy, relatively cheap cure.

Long term, I would still like to add the vapor/liquid seperation and either the GM electric vacuum pump, or the belt driven, but at least this cures the massive oil leakage from the intake down the back and sides of the engine.

Now if I could just cure the blown plug boot issues, I could get back to tuning for more hp.

Thanks for all the input from all of you,
Aaron

HWoods

Aaron, check with Randy at Conley Racing in Houston. Meet him recently. He builds some monster turbo buick V-6's for the street as well as havine a 383, whipple supercharged Suburban. http://www.conleyracing.com or 281-219-4343 or 281-540-3872. Maybe he has run across this problem already.

MCAF84

Got my vacuum pump in. mounted it were the battery used to be. there was a small but noticable improvement in performance thru out the RPM range. there was no oil vapor odor after a sustained 5000 rpm run. In my opinon I think it was a worth while purchase. sorry no pics. Mike