I'd like to make a vaccum pump for crankcase evacuation purpouses, using a stock smog pump.... anyone know how?

Q

 

Mid '80's cadillac's with the 8-6-4 V8s had a belt driven
vaccuum pump. Mid 80's gm front wheel drive (Cavalier)
had an electric vaccuum pump.
These might be easier to do in the long run.
Lots of 'em in the wreckers.

 

I tried using the early 80's Cavalier electric pump. Although it will pull the crankcase into a vaccum I found it didn't have enough volume. When I did a burnout or when the engine was under a load the crankcase went from a vaccum to a boost. It was blowing the dipstick off the engine.

I now use a belt driven smog pump from a Toyota. It has an inlet and outlet port. You can't use a smog pump that has an inlet port behind the pulley. There's no way to hook it up to the engine.

You only want to suck the crankcase down to no more than 16" of vaccum. My smog pump can pull 29". You can buy a vaccum relief valve to keep the amount to a reasonable level. I don't have one yet. I just made a vaccum leak in the other valve cover for now.

The reason you don't want excess vaccum is that it will start to pull the oil from the bearings and wrist pins.

 

Cool- have any pics??

 

Nope. Everything is custom made. I mounted the pump down low on the driver side. The inlet hose runs to the valve cover and the outlet goes to a catch can so I can drain off the moisture after a run.

 

Good Stuff!!!

 

Well I threw a belt tonight and broke the mount on the pump. Looks like I'm going back to using the exhaust as a crackcase evac system until I figure out another belt driven pump system.