22r propane turbo PCV/ vac issues

[ProbablyBroke]

I have a propane turbo 22r. Truck developed an oil leak from the front of the motor after 1 road mile. I believe the PCV and catch can were getting boost pressure because of how the hoses were routed and pressurizing the crank case.


There are two nipples for 5/16 hose coming off the intake manifold. When one is capped off and the other is open, motor starts and runs well. When both are capped, the motor won’t start or run. When one is capped, and the motor running, vacuum is present at the open nipple. I’ve blown air into both nipples and can feel it come out the other. Friends with very similar set ups have the nipple capped and no issues. I’m open to suggestions.

 

[ProbablyBroke]

This is how I had it set up when (I think) it was pressurizing the crank case.

 

[ProbablyBroke]

@Scottal @GONOVRIT

 

[GONOVRIT]

Not sure about that one. Hopefully Alex will.

 

[Monkeynono]

Have you done a leak down test on the cylinders? Rings okay? Headgasket? If the ports are into the intake then once boost comes in anything after the throttle body will have pressure. I have seen most will vent the crankcase to atmosphere or run the hose to a port on the inlet side of the turbo somewhere between the air filter and turbo inlet which should be negative pressure.

 

[Scottal]

Those need to go to the atmosphere. Crank case pressure needs out bad with boost. My old motor would blow the dipstick out of it even with the pcv pulled out and ran straight to atmosphere.

 

[Croatan_Kid]

You can vent to atmosphere, use a check valve, or move one end of the hose pre-turbo. The last option would be my choice.

I prefer a closed loop catch can whenever possible. It has constant vacuum and is always evacuating crankcase fumes/pressure and it's somewhat proportional as far as boost vs crankcase pressure. That's how my RZR Turbo is setup as well.