does anybody have or know how to build an air compressor from an old engine. I heard of one that is being used on a tire shop truck made from a buick v-6 but I never found out how they did it. I'm sure if I gave it deep thought I could prolly do this through trial and error but I'd rather start with other peoples knowledge first.

 

I don't know about an old engine as an aircompressor, but you can make them out of A/C compressors real easy.

 

true but the cool part about the engine was that it ran on 3 cyl. and compressed with the other 3.

 

thats exatally how it works you use the compression being made on the 3 cyl to create pressure and let the other three fire to keep the engine going. you have to make sure there is no fuel getting to the 3 cyl that are making the pressure

 

you need to make a special head for the bank of cylinders that will compress the air. Very popular for air cooled VW engines

 

Why a special head? Won't coolant still flow to the other 3 cyls?

I guess you'd "take" the air from the spark plug holes; but wouldn't you need a check valve on each plug hole to keep the air from escaping?

 

You can remove the rocker arms to make sure that the valves stay closed. Then you take an old spark plug and remove the center electrode and the insulator. Weld a pipe with a T on the the hex nut that is left of the spark plug. Then you use two check valves, one on each part of the T. That way the air can only enter from one side and exit on the other. Do this on all the cylinders one one bank.

 

The reason they use a special head is an air compressor head has no chamber. When the piston in an air compressor is at TDC, there must be a minimal amount of volume between the top of the piston and the valves. If you think of it like an internal combustion engine, you want the highest possible compression ratio, this increases the pressure and efficiency. Yes, you could do as suggested with some check valves and a pipe into the sparkplug hole, but lets say the original engine has 8:1 compression, then we add in the increase in volume at TDC caused by the extra space inside the pipe in the sparkplug hole, the T, and some of the check valves, lets say this lowers the compression ratio to 5:1, you now have a compressor that will barely generate 75 psi at sea level assuming no losses anywhere else in the system. A hell of a lot of trouble just to get 75 psi. Sure, we could use small pipes and T's to keep the internal volume down, but then we kill the flow.

There used to be setups that replaced one sparkplug to get compressed air in an emergency, but pumping a combustible mixture into a tire turned out to not be such a good idea.

 

Ouch.

Thanks for the info!

 

You could have two cylinders pumping air into a small tank. The third one could suck from that tank and pump into the final tank. Then you get higher final pressure, but not as much air.

 

yeah, you would get more pressure that way, but it woulds still be a lot of trouble for a really lousy performing compressor

 

question.

will a SBC 305 run on only one bank of cyls?


and will a 1" thick piece of alum work for a "head"

just bolt it down, then use the T shaped check valves that you mentioned.....



hmmmm.......

 

sure, it will run, and a 1" plate will work fine, but you still meed to put the valves as close to the piston as possible. You want the lowest volume possible when the piston is at tdc

 

i would just use my sears card!

 

lol! that defeats the purpose of the idea to make something out of old stuff laying around though.