Re-route pressure relief to DS tank

[type1.racer]

Just wanted to follow up on this. Pulled about 10 hours today, got the motor back in the car and all the lines connected. Fired it up and let it run for 45-60 seconds. I saw ~38 psi of oil pressure, little low but I should be able to adjust that and bring it up a bit.

Shut it down to check on things, and when i pulled the dip stick a small amount of oil shot out. At this point I felt defeated. I decided to look in the tank and the level was about the same. That left me wondering, if the level in the tank is about the same how would I have so much oil in the case?

Thats when I realized, the small amount of oil that came out was because the case was under pressure. Like removing a radiator cap on a hot engine. I pulled the dipstick again, this time wiped it clean. Stuck it back in the case and it came out bone dry. Exactly what i've been hoping for. Seems as if the scavenge side was actually creating a vacuum, which is a good sign.

I've got a few other items that need fixing before I can drive it and I need to get a baseline on the carbs before anything. So far though, things seem to be working as expected. Fingers crossed the problem is solved.

[Piledriver]

I use a hd silicone spark plug boot I scrounged on the dipstick tube that seals on the od of the dipstick flange... Admittedly a street engine, I usually pull a slight vacuum on the case from the intake via a check valve and a 2mm restrictor (the late Vanagon have heated restrictors for this)
All this is plumbed through a ~1L catch can with its own drain.

Best practice is to also run the breather to the DS tank... but note too much case vacuum can be detrimental to scavenging, and you may need to reverse the orientation of the crank seals, while setting up the PCV setup on my Cabby I kept getting this intense screaming noise that turned out to be coming from the main crank seal at the flex plate... was a bit too successful with the case vacuum setup.

I eventually ended up using an air cleaner fed vacuum break connected to the 1/3 rocker box breather to only feed pressure on that side to assist oil return.
(on the cabby I used a lesser vacuum source from the cis meter engine side)

[Steve Arndt]

How would oil shoot out if the case is under lower pressure than atmospheric? It should suck in, not blow out when you pull the dip stick.

When you run the engine if you pull the dip stick is there vacuum there?

[Ol'fogasaurus]

How would oil shoot out if the case is under lower pressure than atmospheric? It should suck in, not blow out when you pull the dip stick.

When you run the engine if you pull the dip stick is there vacuum there?

Steve, you forgot that he is dealing with inanimate objects who don't deal with rules... bwahahahahah!

Lightly putting the finger on top of the dipstick tube to check for a vacuum is an old trick and I think is still a useful trick.

Lee

[Steve Arndt]

Here is a video where I am measuring pressure for my crank case evac setup. You could do the same with the tube hooked to your dip stick tube.

https://www.youtube.com/watch?v=0xi6MilZUBA

[Piledriver]

I think he said the case was initially under (some) pressure...

[type1.racer]

How would oil shoot out if the case is under lower pressure than atmospheric? It should suck in, not blow out when you pull the dip stick.

When you run the engine if you pull the dip stick is there vacuum there?

Well, let me explain. When you've been working on it for 16 hours, its 1am and finally the motor is running; All logic goes out the window.

Case is under pressure, there is no vacuum. I had a plug in the alt stand port, pulled that out and its good to go now. If pressure becomes an issue i'll have to vent from more locations. For now, seems fine.

Took the car out this weekend to a local cars & coffee; It ran pretty good, all side streets. Super lean up top so I had stay on the idle circuit (IDAs). Oil pressure cold is around 35psi. Goes up to ~ 45 or so with some light revs (cold). Warm/hot (~190 oil temp) idle, pressure sits about 13psi. Pretty happy with that. Temp gauge is in line with the scavenge side. So that is the oil temp coming out, should be cooler going in (haven't hooked that sensor up yet).

Need to dial in the carbs so I can push it harder and make sure the pressure comes up to and doesn't exceed acceptable value with RPM.

[Bruce.m]

Remember the pulley has a thread to suck in air and push it into the case as positive venting which should exit out of the alt stand.

[type1.racer]

Remember the pulley has a thread to suck in air and push it into the case as positive venting which should exit out of the alt stand.

This doesn't work with a sand seal setup which I'm pretty sure all dry sump setups are.