Fancy compressor

[Vladislav]

The original plan was for the thread to be called "A fancy engine" since I was going to start assembly of a E6 for the R-model. But along figuring on how to free up a big table in the shop I resolved to put together the compressor first since its painted components were taking place on the table for a long while.

 

[Vladislav]

It turned out a bit more attractive about its look when it had before the rebuild. The mechanical part was not perfect too. Cylinders had rusty caves but what seemed more troubleful was one of the connecting rods having cap bolt holes modyfied (drilled through for a bolt with nut). I could live with a repaired rod but it also had a small crack near the repair. What I definitely didn't want was a broken rod in a compressor somewhere in a middle of a highway.

Tried to locate an alu conn rod for Tu-Flo 700 but had almost no luck. Checked out other possibilities and found a NOS compressor locally. Actually that was 700 km from my place but at least in the same country. The compressor had different fittment being a Cummins or Detroit version so I couldn't use it complete nor all of its parts. Good thing the block was found the same so I took it together with pistons and rods avoiding the need of boring the cylinders. Crankshaft was shorter than needed at the drive end so I had to use the original one. Micro caliper shoved minimal to zero wear and that was good. But the size was the 1st repair already so I bought new bearing shells for it. That NOS one was std, of no use there. I also bought a PAI repair set but mostly for gaskets.

[Vladislav]

I have a couple of questions about these compressors though since my one is in fact not completely assembled at the moment.

1st - what is the torque for the conn rod bolts? I measured it when loosened the rods in the new compressor but the bolts had something looking as a thread lock on the threads so unscrew could be harder than the specs. And should I use any Locktight or other thread lock compound there? I know that wouldn't hurt the deal but better to learn what is prescribed by the manufacturer.

And the 2nd. I probably have count the matter but still have a little bit of doubts. I tied to figure out the way the connecting rods oriented. Sure marked all the parts and the old compressor had the rods with the markings (part#) to the drive end (up front). But that NOS one had one rod to the front and another to the rear. And I'm sure nobody opened it before me and the parts were std which meant factory assembly. Also pistons had no arrows pointing any direction for the fittment. So overall it looked like Bendix saw no matter on which way to install pistons and rods. I put them as they were in my original compressor - same way up front. But if anybody may confirm or argue my guess I would like to hear the suggestions. 

[CF-Firefighter]

Vlad,

I don’t know much about the compressors or parts needed. 
 

however I like you, am very mechanical minded and enjoy solving problems others throw away. 
 

this is very interesting to me. Nothing is beyond being taken apart and rebuilt. 
 

Glad to see you find inspiration and ingenuity to work around supply issues we all face in our modern world. 
 

awesome progress my friend. 
 

Taylor

[CF-Firefighter]

Also from a torque standpoint. Find the torque for the grade of a fastener and diameter. 
 

Measure con clearances if you can get them torque to spec for fastener and adjust plus or minus to achieve correct bearing clearance. 
 

if you can get plastigage and play with torque and clarancing might be of help a few percent a either way to get what you need or honing the con rod. 

[Vladislav]

5 hours ago, CF-Firefighter said:

Vlad,

I don’t know much about the compressors or parts needed. 
 

however I like you, am very mechanical minded and enjoy solving problems others throw away. 
 

this is very interesting to me. Nothing is beyond being taken apart and rebuilt. 
 

Glad to see you find inspiration and ingenuity to work around supply issues we all face in our modern world. 
 

awesome progress my friend. 
 

Taylor

Taylor,

Many thanks for the suggestions and kind words! Very appreciated.

The matter with those bolts seems untypical since the rods are aluminium and the threads are cut in their bodies. So I suppose standard torque ratings are for hardware driven into steel/cast iron. The length of the threads in the particular place is longer since alu is softer. I sure blow on water since might just torque by hand feeling. But the spot is crytical and I'm free on time to collect more info.

Measuring the gap or platigageing wouldn't give much adds on since the rod caps are precision milled and in the perfect shape (new). So overtorqueing wouldn't affect the gap. My point the most is to not damage the threads and be sure on no getting loose during the operation. 

Vlad

[Geoff Weeks]

Vlad, here is the 501 manual. I think the 700 series is similar. It has the torque specs you were looking for. No Idea what to do with the one that was modified with bolts and shows sign of cracking? I wouldn't want to trust it. 

TF 501.pdf