Does anybody know how to turn the smog pump into a vacuum pump? I read a real tiny blurb in Car Craft about being able to modify an air pump into a vacuum pump. I haven't even messed with mine yet, but I was curious if anybody else has heard of this or done it.

 

Go check out Mr. Gasket #6003. It looks like a smog pump they use in a vacuum kit.

Here's a pic.
Maybe you can look at the picture, and figure out how it works.


Ron

 

I used a smog pump from a Toyota. You need one that has an inlet and outlet port. Many GM and Ford pumps have the inlet as an opening behind the pulley. It will look like a little fan behind the pulley. The Toyota pump that I picked up has an inlet port that gets it's fresh air from the air cleaner.

My setup now works too well. At an idle I pull about 12" of vacuum and when I rev it up it goes to around 28". I need to install a vacuum relief valve to keep the vacuum below 18" or it will suck the bearings and wrist pins dry.

The aftermarket kits are around $500

 

Wow! They must be really proud of those systems. For that much money, you could install a brake booster from aa Astro van with hydraulic assist, and make a lot more space in the engine compartment. As long as you still use a power steering pump, you've got brakes - vacuum be damned!

 

get a GM pump off of ebay. They came on caddies. I got one for 40bucks.

 

It depends on what you want the vacuum pump for. The electric pumps in the GM's are used for vacuum assist for the power brakes. They work good for that but don't have enough volume for a crankcase evac system.

The one I use and that one in the picture above is for pulling the crankcase down into a vacuum. It can be good for up to an extra 30 HP. The Moroso 4 vane pump is over $500.