Devilbiss 423 compressor done.

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Devilbiss 423 compressor done.

Postby Richard-TX » Sat Jan 12, 2013 1:03 am

Rated at a maximum of 29 CFM@175 PSI, it is a monster. It will take a block and tackle and two men to get it moved.

The compressor pulley is a three groove 28" diameter beast that requires three 5/8" wide v-belts. The pulley alone weighs about 80 lbs. The compressor weight is 273 lbs.

I plan on running it at less than maximum. Maximum CFM is at 1200 RPM. I plan to run it at about 700 RPM. When run at that speed I will get about 18CFM@175psi. It will require a 5 hp motor to attain that. I could run it with a 3 hp motor but would be limited to about 450 RPM or 10CFM@175 PSI.

The cylinders are heavy and big enough that it takes two men to install.

The design is interesting. To keep the compressor balanced, the small pistons are made of steel and the large pistons are made of aluminum. The rings are extra wide. Almost 1/4" wide. The valves can be replaced in a couple of minutes and without removing the head.

Now I know why rebuilt 432 compressors cost well over $1000. They are a PITA to do a major overhaul on.

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Re: Devilbiss 423 compressor done.

Postby Rickbaro » Sat Jan 12, 2013 9:46 am

That's a monster looking compressor. Are the air tubes cast iron as well? That must be a huge amount of work that thing does if you need cast iron heat sinks.

I imagine that the need for 175psi would be pretty rare, so you probably get a really good CFM at lower pressures?
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Re: Devilbiss 423 compressor done.

Postby Richard-TX » Sat Jan 12, 2013 5:48 pm

The intercoolers, exhaust, and intake manifolds are indeed cast iron.

The odd part of this compressor is that the cylinders have to be pulled to remove the pistons and connecting rods. There is no "pan" That also means that common hose clamps have to be used as ring compressors when assembling it.

There is nothing cheap about Devilbiss compressor parts. Go look for a rebuild kit for one.

This particular compressor was run low on oil and one crankshaft journal was badly scored and worn. I had to have that crankshaft journal spray welded and ground.

You can be assured that I will be keep close tabs on the compressor oil level. I might even put a sight glass on it.

It is rated at 20,000 hours meaning that as long as I maintain the oil in it, it will outlast my son.
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Re: Devilbiss 423 compressor done.

Postby Richard-TX » Thu Jan 24, 2013 11:20 pm

I got the compressor up the stairs and is ready to be mounted, plumbed, and wired tomorrow. It took two of us to lift that beast up one stair at a time. For now I an going to drive it with a 5 hp 1ph motor.

Scott should be stopping by to take pictures. I will post links when I can.

I will have to fashion a belt guard later. Maybe next weekend. My arms are sore from the 260 lb tank.
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