Adding engine driven A/C to a 2001 Thomas Saf T Liner MVP-ER

[david.dgeorge07]

I’m just starting work on adding road A/C to my bus using a donor system from another bus. I already have two 1 ton mini splits which are great when parked but not very effective while driving.

Would you guys be interested in a thread that documents what I learn along the way, what it costs and how it turns out?

If so I’ll get things started. I’m also hopeful that I can get advice along the way. I know enough to be dangerous basically.

[o1marc]

Learn something new everyday, why stop now? Bring it on. We need to get together soon.

[Tarheel Travelers]

Dave, I’ll definitely be up for that!!! I’m trying to add an engine driven a/c to my C2 but that seems to be a bridge that not too many people cross.

[david.dgeorge07]

Ok, so this all started when TeacherJoe posted that he had a system that he wasn't planning to use. That was a few months ago, but I finally found time to drive from TN to CT to pick the stuff up.

It was a pretty long haul and I put just shy of 2000 miles on my Jeep to get the stuff.

I'll go more specifically through what I picked up, but here are a couple of pictures from when I was loading up.

He had two complete systems and gave me everything related, with the exception of one compressor which he left mounted so he could add dash air to his bus.

I've goat a lot to figure you, such as where I can actually mount the evaporator without it taking up an enormous amount of usable space, but I have some ideas.

When I get a chance my next post will be to look through all the components that I actually have and figure out what they are.

[cadillackid]

im always interested in A/C related threads.. there is one thing I'd change already though and that would be the evaporator... while i know its expensive, if useable space is a real concern, MCC, and ACC are both making Header panel mount evaporators.. (or did you mount a minisplit already in your front header panel?)


the header panel mount evaporators recess into that otherwise useless space above the windshield and only stick out a little.. I got to drive a brand new Bluebird bus with one up front.. was nice n cool in Texas heat..

[Brad_SwiftFur]

Originally Posted by cadillackid

im always interested in A/C related threads.. there is one thing I'd change already though and that would be the evaporator... while i know its expensive, if useable space is a real concern, MCC, and ACC are both making Header panel mount evaporators.. (or did you mount a minisplit already in your front header panel?)


the header panel mount evaporators recess into that otherwise useless space above the windshield and only stick out a little.. I got to drive a brand new Bluebird bus with one up front.. was nice n cool in Texas heat..

I am interested in a header mount evap ... Estimated cost?

[cadillackid]

Brad the inwall evaporator is right around a grand brand new, that’s for a 50-60k btu.
I can check with my AC contacts for exact pricing if you are more serious about it.
Bus AC brand new isn’t cheap, these dual factory systems in busses that people throw away cost 10k new, of course the street value is near zero for them used. I bid on a broken bus the other day where the DT360 needs inframed but it has dual working AC, I was going to snag the ac and scrap the bus. One of my collector friends wanted it as it’s a Wayne so I backed off. I think the bus sold for 1100. But of course it had the usual ugly evaporators.
You can also custom build dash air into your existing driver enclosures like I did on my DEV bus. That won’t cool a whole busbut for someone like David it’s an option where he still runs his mini splits to cool the family and he has dash air for him driving

[cadillackid]

I haven’t seen David’s dashboard but Thomas did make an evaporator at one time that mounted behind the heater core .. at least for the busses that have the whole row of square dash vents across the front . I thought it was for the MVP ER model.

[Brad_SwiftFur]

Mine's a T444E powered IH 3800 Bluebird. I believe the engine has a nice convenient place ready for a compressor. I'll poke around the boneyards in my area since I'm not into spending 2K on an AC system if I can get used stuff cheaper. Since this is a short bus but I need cooling for more than just myself, I figure I'll want a minimum of 50K BTU cooling (Of course more is better).


Should I go for a skirt mount, roof mount condenser? What about one in front of the radiator off of a straight-truck?

[cadillackid]

The single 444e bracket is pretty easy to come by. You need the bracket idler and bolt on pulley. My RedByrd has a transair 45k system on it and after I rebuilt it and put bigger motors in the Evan it cools decent up front while people in the back freeze. I wish my evap was up front.. I’m considering buying a header unit for the front then using the current rear unit in my other bus.
Christopher

[Meathead]

David, we have the same bus except for the length.
This is how my AC looks.

[david.dgeorge07]

Originally Posted by Meathead

David, we have the same bus except for the length.
This is how my AC looks.Attachment 33710
Attachment 33711
Attachment 33712

Cool! Does it work? It looks like you have two compressors. I may ask you for more info as I get deeper in if that’s ok!

[Meathead]

They are great. I’ll keep both this summer but I may not need both long term. They were sized for at least 22 windows, poor insulation, 66 ppl, and the door opening every few blocks. None of this will be the case for me.

[cadillackid]

thats an extra big A/C system... looks like its got 2 TM-21 series compressors which are the big boys... its likely a 150,000 BTU total system.. probably gets cold quick in there..



I used the new Sanden Enhanced HD7 compressor which mounts on a standard ear mount like a car compressor.. (david the HD7 looks similar to the Jeep compressor)..


its output is really nice... better than the regular HD7.. you could easily drive a 50-60k BTU system with it..



another in-wall evaporator option.. I can get more info on some of this stuff too..



Evaporator IWS55 - 50 001 441


I use proAir stuff in my DEV bus.. they have different options for buying an oipen chassis device and building your own which is how I did that bus..


repurposed the driver heat-only console into a heat / cool unit..

[Sleddgracer]

150,000 BTU total system`- you could almost use that as a reefer van - lol

[cadillackid]

Originally Posted by Sleddgracer

150,000 BTU total system`- you could almost use that as a reefer van - lol

at least reefer vans have insulation... someone I know / knew (havent talked to him for awhile). is/was converting a Reefer straight truck... sans the reefer as it in itself is a terrible air-conditioner..





but you figure an uninsulated bus with all that glass and stuff with 50+ people.. and its expected to be cooled down quickly .. they put crazy big air conditioners in them..



coaches and city busses use a 2 or 4 cylinder V-style compressor..



whats omteresting is believe it or not one of the best (and still available) compressors is the old GM-frigidaire A-6.. the ones you used to find on all the 60s and 70s classic cars.. big long thing.. HUGE capacity in those.. they are just a total PITA to mount because of their length.. so everyone has gone to sankyo / sanden style..



Genuine sanden-built compressors last nearly forever when properly cared for..



the chinese ones dont always fair so well... they often dont make the charted capacities or the clutches fail in high load situations..



Internally Nuking a compressor is a TOTAL PITA... just read about ford and the black death FS-10 compressors..


-Christopher

[Sleddgracer]

Originally Posted by cadillackid

at least reefer vans have insulation... someone I know / knew (havent talked to him for awhile). is/was converting a Reefer straight truck... sans the reefer as it in itself is a terrible air-conditioner..





but you figure an uninsulated bus with all that glass and stuff with 50+ people.. and its expected to be cooled down quickly .. they put crazy big air conditioners in them..



coaches and city busses use a 2 or 4 cylinder V-style compressor..



whats omteresting is believe it or not one of the best (and still available) compressors is the old GM-frigidaire A-6.. the ones you used to find on all the 60s and 70s classic cars.. big long thing.. HUGE capacity in those.. they are just a total PITA to mount because of their length.. so everyone has gone to sankyo / sanden style..



Genuine sanden-built compressors last nearly forever when properly cared for..



the chinese ones dont always fair so well... they often dont make the charted capacities or the clutches fail in high load situations..



Internally Nuking a compressor is a TOTAL PITA... just read about ford and the black death FS-10 compressors..


-Christopher

you always have such informative posts - it`s very much appreciated - a lot of stuff on this forum is totally new to me - it`s nice to get information from someone that could have written the book

[david.dgeorge07]

Originally Posted by cadillackid

at least reefer vans have insulation... someone I know / knew (havent talked to him for awhile). is/was converting a Reefer straight truck... sans the reefer as it in itself is a terrible air-conditioner..





but you figure an uninsulated bus with all that glass and stuff with 50+ people.. and its expected to be cooled down quickly .. they put crazy big air conditioners in them..



coaches and city busses use a 2 or 4 cylinder V-style compressor..



whats omteresting is believe it or not one of the best (and still available) compressors is the old GM-frigidaire A-6.. the ones you used to find on all the 60s and 70s classic cars.. big long thing.. HUGE capacity in those.. they are just a total PITA to mount because of their length.. so everyone has gone to sankyo / sanden style..



Genuine sanden-built compressors last nearly forever when properly cared for..



the chinese ones dont always fair so well... they often dont make the charted capacities or the clutches fail in high load situations..



Internally Nuking a compressor is a TOTAL PITA... just read about ford and the black death FS-10 compressors..


-Christopher

So much good info!!!

As I unpack the components I got it seems like evaporators are a good place to start.

I anticipate that the evaporator choice and placement will be one of the most difficult and compromise laden parts of the project. There just isn’t a lot of space to tuck them into. I already have a mini split on my front bulkhead.

Here’s what I got though.









Two units of the same design. Both carrier. I didn’t show all parts of each. You get the idea.

One is big, like 3+ feet long. The other is pretty small, like 2 feet.

They both draw air in the back and push it out the front via squirrel cage blowers.

Don’t know BTU yet. If the size of these is any indication though relative to the evaporator in my Jeep, there is a lot of cooling even in the smaller unit.

They are R-134a systems which is good. That refrigerant is available everywhere inexpensively to normal people.

Right after taking these shots I covered and protected the ports. Hopefully there isn’t too much foreign material inside.

[cadillackid]

the EM-6 you posted is a 30,000 BTU capacity evaporator...


I attached my carrier bus A/C manual to the post.. hopefully folks can read it..


on page 1-2 is a list of total system part numbers,.. they are listed with the quantity of evaporators in parenthesis and the model number so you can deduce the capacity...



if you put that small EM-6 at one side of the bus and either ducted it to the driver area or place it up high where it coulkd blow out. that would go long way towards keeping you cool...



I used the carrier blower motors in my TransAIR system because those little buggers move air and can handle being ducted and make enough air pressure ... you MAY have to devise a drain pan as i think on those the plastic shrouds also act as the drain pan..
-Christopher

[david.dgeorge07]

Having a tough time finding specs on these specific units, but it looks like they are likely 45-60 BTU/H for the bigger one and 30-45 BTU/H for the smaller one.

One place I might put one is in the sofa. Could allow air in at the foot level and blow it up through the seats. That should keep the passengers cool!

Also considering putting the whole unit under the skirt and building an airflow box. It would blow air up through the floor like a central A/C in a house! That would be a lot of work but could be pretty slick!