Well, I about fell out of my chair. I found the right displacement a/c compressor I needed to run the a/c in the bus. Found it on the famous auction site. Problem being is that it has a v-belt clutch, and I have the serpentine belt setup. I called to see how much the new clutch was. It was only $480, and that's just the clutch. The clutch only, and nothing but the clutch. I called another company and they would sell it to me cheap for about $468. It's a special compressor used on buses and emergency vehicles. It's not very popular, but just the right size that I need.

I called bracketry systems in Texas, they didn't have a bracket for this compressor on this engine.

So now I'm toying around with ideas on hooking up this baby. I begin this story like I do with all invention storys I have when buying parts at the local supply house. "What I using it for, is not what it was designed for."

Either of the following ideas I've come up with, so tell me all the short comings I'm not seeing here.

1. Have a seperate small engine to drive the compressor (gasoline side shaft) I thought, well, hey, stick an extra alternator on there for a belt tentioner too, why not?

I would have to build kinda like a "surf fishing platform" on the back of the bus to mount all this fun stuff. I could let the small engine run, charge the batteries, run the a/c without accumulating long idle times on the diesel engine.

2. Come up with some way to mount a pulley on the front of one of the serpentine belt pulleys already there. This way the engine could drive it still without another engine.

Only thing I don't like about this idea is messing around with the serpentine belt. If something were to go wrong, I lose my whole serpentine setup, which would be a bit more precious than the a/c running. Stopping this rig without the hydroboost, I'd be sweatin' bullets even if the a/c was running.

I'm flipping the coin here, and looking for some input.

You need a genset which you can put a drive pulley on and maybe an alternator. Some large over the road trucks do this to save fuel. They typically use a Kubota engine to run ac , alternator, and water from the main engine. The water from the engine is to keep the engine preheated in the winter when the main rig is parked. Also the cab can be heated in the normal manner as well.
Here's one: http://www.etrucker.com/apps/news/article.asp?id=21598

Idle Hawk Genset

Aux Generators’ new Idle Hawk genset provides a wide range of features not available on previous models, including air conditioning and heating at 70 degrees, battery charging, 110V-AC and 12V-DC for all comfort and convenience needs, auto mode which cycles engine off/on to main battery charge and unit rollouts (without disconnection) for quick simple 360-degree service access.

The Idle Hawk’s 9.6 horsepower Kubota diesel engine consumes less than one-tenth of a gallon per hour, the company said. Aux reduced the number of moving parts on the Idle Hawk to reduce breakdowns and installation and service time. Aux offers a financing/lease option.

Aux Generators Inc.
(877) 843-5289
www.auxgenerators.com

knkreb, how big is that compressor, looked at 1 yrs ago and was 5ton carrier unit with 3 v-belt drive. thermal-king makes refrigeration units for box trailers, used to have dual compressor units 1 on trailer and another compressor mounted on engine, valves would switch dis/suction to operating compressor. dont think electric drive would work. have you looked at the aftermarket a/c mfg's for components. if it is small auto compressor might use 10 hp diesel engine to drive, need good airflow around it though. i would use tubine as much as possible in system, seems refrigerant and oils work thru hose's, stainless would be best(more durable, copper would need to be secured to prevent vibration breakage) best

The compressor is a TM31-HD. It's 313 cc displacement, which is double the size of the GM HT6 at around 160cc. It's ready to go for r134a. I had orginally looked into spliting up the front and rear a/c systems, which would have been the best plan to work out because parts are already available and ready to go for that application. But this compressor was only $39.00 new in box. $2100 new retail. couldn't pass it up. It would be worth figuring out how best to use it.

There are alot of Amish around here that we do work for. They use little Honda's to drive a Blissfield CG or sometimes a Thermoking for their refrigeration uses. I figure I'll just use a few of their ideas, just not the buggy.

Most automotive compressors are over-driven - have you considered your LOSSES vs gains?

Losses as in HP requirements? According to the BTU/HP chart, the HP requirement starts around 7 and moves up to the 13-15HP range. I wouldn't be using the upper range because it would be too much capacity for the system (not enought capacity with evaps & not a large enough condensor, just opposite of what I have now.) Right now I have too much in the evap's and condensor departments, and not enough compressor. Well, I shouldn't say that . . . if I held the pedal to the floor for about 72 minutes, it would drop the temperature to a comfortable 70° range . . . of course the engine would be in pieces by this point.

That is the main problem with R-134 - needs tremendous refrigerant flow thru the system and air flow thru the condenser to achieve similar cooling as R-12.
Won't cool at idle, freeze you out at rpm.

Smaller displacement compressors and more over-drive to get the btu-handling capacity up, right?

Over-drive as in pulley speed at the compressor turning faster than the crank? Yes, agreed, that would be better.

I currently have a Transicold CM2 skirt mounted condenser rated at 57,000 BTU/H IMACA. The EM14 rear evaporator is rated at about 26,000 BTU/H IMACA, and the in-dash system is rated at 12-15,000 BTU/H. I installed a liquid receiver to keep the condenser in latent heat exchange mode, rather than raising the head pressure with liquid backing up into precious coil space.

Even turning the current OEM stock compressor has just enough capacity to drive the rear evap under real world conditions. On paper, if you had the engine at it's max govenored RPM, you may reach the rating point that appears on the spec sheet.

Commonly these buses are set up with TWO seperate compressors, one for the front in dash system, and one for the back system. Both of the commonly used compressors total up to the displacement of this one compressor that's coming.

Still couldn't beat the price. It's worth making it work.

Here's a link for the compressor. I didn't get it from this website, but it at least had the information available for it. Click on the link for part numbers and all the important information about it comes up.

http://www.mkjltd.com/seltec/tm31hd/tm31hd.htm#

Looks like that mounting plate could be modified to fit the new-style engine bracket on your '97, and the pulley could be modified, as well, but you'll need some hands-on for dimensional comparison.

Remove the serpentine belt, unbolt your comp and lift it away from the engine, ref hoses attached and sealed.

Also, iirc, were some Frigidaire A-6's available with serpentine-belt sheaves

I'm gonna call a rebuilder today if I get a chance and see if I might be able to work out something with the sheave.

I'm a little squeemish on attempting to make my own bracket. Don't want to mess up the serpentine belt setup. Transicold won't give me the time of day, and the dealer isn't much help either. I'm gonna see if I can get through to Transaire, or one of them too. Somebody has had to put one of these compressors on a school bus with a 6.5 under it before. They have put a 6.5 on full size school bus have they not?

Dunno about that - most large buses had Navstar, Cummins, or Cat sixes. Fords had Cummins.

But - never hurts to ask.

That appears to be a 'universal' mounting plate bolted to the new comp.
Check out the mounting assembly, where the comp mounts to the bracket on your engine - it's a very simple saddle arrangement.
I think it would be an easy modification, as the '97-up saddle bracket is essentially a flat interface to the comp, so aligning the sheave centerline should be the only adjustment.


Hit the boneyards with your new comp for a comparo with what's on any of the oem makes - anything, GM, Ford, Chrysler, Toyota, Hyundai, etc.
Likely you'll find a match in several versions, as the clutch\sheave assy is usually a 'purchased' assembly, not made by the comp manufacturer.

Also try the truck-only yards, for possibly identical parts, brackets, sheaves.

It is not as difficult as it may seem, but getting the correct belt may be the problem.
The belts are sized for the projected loading per application - length is easy, the load dictates the required width.

Having a junk '97 6.5 comp on hand will give you a better idea of what is necessary.

Well, hit a brick wall on two accounts today. Called Trans/Aire. They said that that compressor will not physically fit into the spot where the OEM was. Entirely possible, haven't measured, but certainly believable. This guy was from the install dept too, so he should know.

Call rebuilder, pulley and clutch one assembley, at the tune of $320+. I think some creativity could bypass this budgetary shortfall somehow. Might be resorting back to second small engine to drive this baby.

Wonder if there is a hydrolic power take off that could be driven by the serpentine belt to drive the compressor in another location?

There are many reasons, usually, when they tell you that, but mainly because they do not know how to make it fit, which requires selling you something.

OEM is a 4-post saddle-type arrangement - that comp flat-mounts to a flat plate, fwics.

Hit the boneyards with your new comp for some really comprehensive show and tell.

W-O-W ! ! ! I really like these new site features....................

Speaking of site features, have you gone to chat yet?

Nah - this isp gives too much trouble - repeated hang-ups, drops the carrier, etc

They claim it's my modem(s) and\or my telephone line, but I see the hang-up\disconnect command come in. My modems are external, so it's is easy to catch them.

I almost forgotten what dialup is like. Had DSL for a while now, and would hate to back.