Build Thread: 325iC Turbo - Total Restoration

[E34DIYer]

Any thoughts on crankcase ventilation w/vacuum? Specifically, I'd like to see recommendations for catch can/air-oil separator setups with a vacuum source to optimize internal engine sealing. I see four options for venting the valve cover breather to a vacuum source, with or without a catch can/air-oil separator:

1. Vent to exhaust w/tapered bung, using venturi effect from exhaust gas to create vacuum
2. Vent to throttle body (stock) w/check valve, meaning no crankcase vacuum under boost (when blowby seems to be the biggest risk)
3. Vent to intake piping just upstream of the turbo compressor inlet, where both the pulling action of the compressor sucking in air and the inrush of air will create vacuum; probably use a tapered bung as in #1
4. Vent to an air-oil separator connected to an external vacuum pump (probably electric in our application)

I'm leaning towards options #1 or #3 as a good combination of performance, simplicity, and cost. I almost certainly want to use an oil/air separator or oil catch can. I'd prefer to have the separator/can self-drain into the oil pan, possibly by adding a tee fitting to the -10AN fitting on the oil pan that I had welded on for turbo oil drain.

For the separator, I was thinking something like this:

[E34DIYer]

Thanks! We get a lot of compliments on the throttle body. These guys did the work:

http://www.bestmetalpolishingllc.com/

Great price, quick, excellent quality.

[88BlackS-ETA]

DAMN! I almost shit my self seeing that. Great build so far. Sub'd

[E34DIYer]

Well... we paid somebody else to polish that for us. Best Metals in Lilburn, GA did it for $125 - not bad for the money! We did the blockoff plate ourselves...

[Mr. Tasty]

Believe it or not, that's just aluminum that we wet-sanded and polished. Thanks! :)

for the throttle body? Dear lord that must have taken forever rofl.

[G-Man the Visionary]

I really like this thread.

[E34DIYer]

Believe it or not, that's just aluminum that we wet-sanded and polished. Thanks! :)

[Mr. Tasty]

digging the chrome plating.

[E34DIYer]

Our pricey new engine wiring harness arrived from Germany today:

[E34DIYer]

May use an auto M20 TPS; I'm reading that they work as potentiometers vs. manual TPS. I ordered the EH wiring harness so I have the six pin TPS connector.

[sayed ali]

M20/M50 TPS adapter plate - who has one?

Not difficult to make one ..

Great build though :)

[E34DIYer]

M20/M50 TPS adapter plate - who has one?

[E34DIYer]

Now we need an all-inclusive coolant hose kit. I see that Ireland Engineering sells the silicone hose kit for $81, with the expansion hose a separate $55. Is there a better option for the money?

[E34DIYer]

Received, polished, and mounted distributor blockoff plate:

[E34DIYer]

Crankcase breather pipe installed. Engine wiring harness should be on site in a few days.