bendix air compressor ???

robertglines1 · November 24, 2015, 02:38:24 AM

The transplant engine I used (2000ye 60 series 12/7) came out of a truck. 550 air compressor. Not enough in stop and go traffic w/air clutch assist. 750 tru-flo (16.5 cfm -107813 is what prevost used. There is a a transit update that is 32 cfm. What is best route and least complicated change out?? Any one have a 750 or the 990 air compressors?? I have no air leaks. The 550 build quick and recovers quick but in stop and creep and creep it is marginal. Sort of a rambling post but is where I'm in my thought process also. Other possibility is to add a belt driven additional air compressor.?? Bob

luvrbus · November 24, 2015, 02:59:29 AM

Another option is more tanks, the fuel pump drive on the rear of the compressor is the kicker I have both for you but with no fuel pump drive.My DL has a 550 on the 60 series it does fine it never drops below 100 psi in traffic

TomC · November 24, 2015, 03:05:43 AM

Automatic

robertglines1 · November 24, 2015, 06:16:01 AM

I could easily add another wet tank. That is why I throw things out here. I have added a air assist to the clutch for the eaton 10 spd auto shift. Maybe I'm being to cautious as it has yet to drop below 90psi. The fuel pump drive seems to be big factor. Bob

niles500 · November 24, 2015, 06:40:05 AM

Bob, have you tried just dialing up the psi? FWIW

chessie4905 · November 24, 2015, 06:43:28 AM

What size chamber are you using to assist clutch? Is it consuming more air than needed to perform the task. The one I had in the 4104 never used much. It probably only had about a 3 inch piston. Easiest would be to just add another tank or two.

robertglines1 · November 24, 2015, 01:08:21 PM

3 inch piston on assist cyl(new) Most of air system is newly rebuilt and leak down is 36 + hrs on aux side. Service side holds for up to a week depending on temp outside. I have extra tanks laying around and will tap into wet tank to preserve the brake integrity. Bob

Oonrahnjay · November 25, 2015, 03:15:34 AM

Bob, the Bendix literature indicates that the Tru-Flo 750 should fit but I'd worry too about the drive connection (it would probably be OK but I'd want to check for sure). Have you thought of a separate aux tank for the clutch only with a one-way valve between the brake systems and that aux tank? That way, when the system was charged all the way, you'd get air in the brakes that was used only for the brakes; if the clutch is used so often that its pressure falls, it will not bring down the brake system. If air is used from the brake system for braking, it would be recharged as soon as the pressure in the clutch tank exceeds the brake system -- and since the compressor is basically only feeding the clutch system, it should fill quickly and then get full air back to the brakes. I'm sure that there's also a good use for a pressure-protection valve in the system, too, but I haven't drawn out a system to figure out where it is, how it would work, and what kind of override you'd need.
But the extra capacity of the clutch tank would be a big benefit to you without the expense of changing the compressor.

luvrbus · November 25, 2015, 03:33:14 AM

I never could find but 2 compressors that would work on a non EGR series 60 with the fuel pump drive on the rear of the compressor

Oonrahnjay · November 25, 2015, 03:39:11 AM

Quote from: luvrbus on November 25, 2015, 03:33:14 AMI never could find but 2 compressors that would work on a non EGR series 60 with the fuel pump drive on the rear of the compressor

Yeah, the Bendix sales literature makes it seem like "pick what you want, they all fit" but I was guessing that real life wasn't like that. Further confirmation that more tank capacity is the way to go.

luvrbus · November 25, 2015, 03:48:24 AM

They make a 750 for the non EGR engine the problem I ran into was Bendix wanted 1200 bucks for a rebuilt 750 without the 750 core and wouldn't take the 550 as a core,then you needed a different gear because of the tooth count.There is only 3cfm difference between the 550 and the 750 it wasn't enough for me to pay the difference

The way the Bendix guy explained it to me was a 550 will produce the same CFM @ 115 psi as a 750 produces @ 120 psi

Oonrahnjay · November 25, 2015, 05:34:03 AM

Quote from: luvrbus on November 25, 2015, 03:48:24 AM
They make a 750 for the non EGR engine the problem I ran into was Bendix wanted 1200 bucks for a rebuilt 750 without the 750 core and wouldn't take the 550 as a core,then you needed a different gear because of the tooth count.There is only 3cfm difference between the 550 and the 750 it wasn't enough for me to pay the difference
The way the Bendix guy explained it to me was a 550 will produce the same CFM @ 115 psi as a 750 produces @ 120 psi

I was wondering about the core value and I guessed that that would be the way that they work it. It sounds like a 550 is a good compressor - works better than its rating would indicate. And $1200 is a lot of money for a rebuild.

luvrbus · November 25, 2015, 06:03:00 AM

The 550 made plenty of air for 18 wheeler with air bags and brakes on the truck and trailers should be plenty for a bus you would think

robertglines1 · November 25, 2015, 07:36:06 AM

I was probably over thinking it. We have been caught in a lot of stop and go traffic lately. Hasn't dropped below 90 but was hoping it was simple change. Extra tank is easy as i have a fitting for rear shop air that is plug and play. Bob