Compressor has bad belt slap

by Bill
(Philly, PA)

I built a Devilbiss 445 with parts i had laying around. The tank is a 200 gal. Devilbiss with a right and left compressor pad, prob. set up for center mounted electric motor.


The first rendering was with a 13 hp gas engine and 4" motor sheave, which spun the pump just fast enough to be in spec. This was a proof of concept thing, i knew the engine wouldn't last, and it didn't.

Now I have a 28 hp Diahatsu diesel, i'm using a 8.25" sheave and a 3 groove BX105 banded belt. The issue is with both motors, i have the most insane belt slap ever. Both the work and coast side of the belt.

I made a spring loaded idler pulley for the coast side, then added 3 more fixed. It helps but its just covering up the problem.

Is there some strange magic I don't know of going on here?

My main form of work is large scale HVAC so i know about belt alignment and all that stuff. If i didn't know any better id think the pulses from the pump are at war with the motor.

Comments for Compressor has bad belt slap

Click here to add your own comments

Feb 07, 2017
bad belt slap
by: Doug in s.d.ca.

Nice pump.

I take it you're certain that's the right belt for your sheaves?

And if you turn (*IF* you can) the pump by hand, it's not binding or anything?

Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Gasoline Powered Air Compressor Issues.