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compressor rebuild

ashman

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A few months back I managed to get my hands on a Le Roi Dresser 2 stage, series 600 air compressor with a 120gal tank for $150. It had a 10hp 3 phase motor that I couldn't use, so I sold that for $100. I bought a single phase 7.5hp motor to replace it for $475, so all told I was into the compressor $525 and it ran great. :woot: Awesome!

Unfortunately in the process of replacing the motor, I got distracted and forgot to check the oil... it was bone dry. :( It actually lasted a few hours of run time before I smoked a rod bearing, but eventually it did and now I need to rebuild it.

Luckily I found a company that was able to supply me a good pdf (attached) with all of the parts list and they are willing to sell me just what I need and not make me buy a full rebuild kit.

Today I started the tear down.
Case with heads and pistons removed:
20191112_180641.jpg

Massive heads:
20191112_181623.jpg

smoked bearing:
20191112_174547.jpg

Second stage piston and cylinder show some scaring:
20191112_181203.jpg

20191112_181231.jpg

Not great in the first stage cylinder either:
20191112_181245.jpg

The rod journal looks fine. Piston rings look good still. I think I'm going to try and hone the cylinders a bit, but otherwise just plan on replacing the main bearings and head gaskets and slap it back together.

Any thoughts?
 

Attachments

  • Leroi_600_3AVC.pdf
    1.7 MB · Views: 1
make sure the pulley size now matches the 2.5hp less package . my IR unit was a 10 hp and i swapped it to a 5hp for my needs and got the correct pulley .
 
make sure the pulley size now matches the 2.5hp less package . my IR unit was a 10 hp and i swapped it to a 5hp for my needs and got the correct pulley .
I talked to the guy that sells and repairs these compressors about that. He said that the 10hp motor was oversized for this compressor, so the 7.5hp should be fine. He said to keep an eye on it at start up and if it labors to start, change the pulley size, otherwise it's good to go. Until I smoked the bearing it would start up pretty easy, so I think I'm ok.
 
Just figured I'd update with the results of the rebuild. I ran into problems with the low pressure piston rings while rebuilding it. I wanted to find a ring compressor that would come apart after I used it so that I could put the cylinder on from the top, but I couldn't find one big enough. The piston is 6" wide. I tried making my own, but ended up bending one of the oil rings in the process. :(

In the end, I took the head off of the cylinder and put the piston in from the top. I was able to leave the rod connected to the crank and just pull the wrist pin. Luckily I was able to push the piston down in the cylinder far enough to reconnect the wrist pin without popping the rings out the bottom.

As far as the bent piston ring goes, I just left it out. After discussing the situation with a few guys that build compressors, it turns out that most (including later versions of mine) only have 1 oil ring. Since mine had 2, they said I'd be just fine leaving the bent one off and running just the one oiling ring.

I got it all put together and so far, so good. :waytogo:
 
Was there no access to the crank end of the rod from the bottom of the main casting?
 
They make hose clamps 6" and larger...used them before instead of a ring compressor when nothing else was available!..
 
They make hose clamps 6" and larger...used them before instead of a ring compressor when nothing else was available!..
That's what I tried to use, but the cylinder had some things hanging down on the bottom that caught the winding part on the hose clamp and pushed it down. That's how I managed to bend one of the rings. :(
 
How did the hone job turn out? I assume you polished the crank? I know it’s too late now but I would be concerned about the skirts and any cylinder taper or out of round conditions as well.
 
How did the hone job turn out? I assume you polished the crank? I know it’s too late now but I would be concerned about the skirts and any cylinder taper or out of round conditions as well.
I talked to several compressor guys and basically, if there was any taper, or out of round issues the only solution was to replace the cylinders and that was too expensive to even consider. They all told me though that compressors are very forgiving and that I should just put it back together and run it, so that's what I did. Hoping for the best.
 
Coming from the guys in the biz, I’d say you’re good!
 

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