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Extra High Mount A/C compressor water inlet bracket

30K views 29 replies 13 participants last post by  char1355 
#1 ·
So I am in the very early planning stages to swap the gas V8 in my early 90's Ford pickup to a 4bt Cummins. Something that really excites me about this possible swap is that, from what I read on here, the engine could be an actual bolt in installation using factory Ford and Cummins hardware. That is possible using the Ford 300 inline six cylinder gas mounts that used the rubber isolators (not liquid filled). Then the breadvan 45 degree engine block mounts and dodge rubber isolators. All hashed out many times over and detailed in this helpful thread. Conflicting 300 6 Frame Stand with Ford 4BT Block Mounts Compatibility Issue

The next thing I wanted to figure out was how to maintain all the creature comforts that are available with the current gas V8, namely air conditioning. As is widely known on this site, the stock dodge 6bt setup mounts the A/C compressor way down low on the passenger side of the engine. This would pose two problems in the install in 80's and early 90's Ford pickups. 1) the compressor or lines would get into the engine crossmember and 2) this would not allow the use of the breadvan 45 degree engine block front mounts and 300-6 frame stands for a bolt in install.

To conquer the first problem there is plenty of info around the site about using the "high-mount A/C" water inlet setup seen on early 90's F800 trucks and the freighliner setup which ran 5.9L cummins engines. This bracket raises the A/C compressor above the water inlet and also raises the alternator. There is a good example of this bracket in the following thread. a/c bracket.

While the above "high mount water inlet" would solve the first problem, it would negate the possibility of using the 45 breadvan engine block mounts and Ford 300-6 45 degree frame stands for a bolt in install. This is because this alternative water inlet bracket uses the bottom three front engine block mount bolt holes to hold it to the block. Now, it appears from this post that it is possible to mill down that reinforcing rib going from the water inlet flange to the lower mounting area and still be able to bolt up the bread van 45 degree engine block mounts. Then there is also this post which the author states that he milled down the bottom section of the bracket to still use the 45 degree bread van front mounts.

Both of the above examples solve the first problem and solve the second problem, albeit with modification to the water inlet bracket (possibly detrimental to durability??) I think I have stumbled on a solution that would solve both challenges with no modifications to any brackets or mounting points. I spied a Hyster forklift with an installed QSB6.7 while working on a job site that appeared to have provisions for mounting an A/C compressor in an "extra high" configuration. See the attached photo for explanation. This bracket mounts the alternator in what appears to be the "stock" location and mounts the A/C compressor above it, all on the same bracket. More-over, from what I could tell, this bracket did not utilize the front lower three engine mount holes that will be used by the breadvan 45 degree engine mount plates (see second picture). I was cognizant enough while taking these pictures to grab the ESN from the engine so this bracket part number (and supporting hardware) could be located on Cummins quickserve. This ESN is 22023207. The bracket part number is 5260168. In quickserve, it specifies that this setup accepts a 24Si alternator. I also measured the mounting points for what I suspect is the compressor stand-off's and came up with a top mount spacing of 92mm, bottom mount spacing of 87mm, and vertical mount spacing of 128mm. This mounting corresponds to the compressor mounting mentioned in this post. The only unknown is if this new extra high A/C mount bracket has the same gauge line measurement as does the F800/freightliner brackets for proper belt alignment.

So, any thoughts on this? Think this bracket will work on the 4bt? Anyone have a good way to get a price on this bracket without driving down to the local Cummins dealer?
 

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#2 · (Edited)
... That is possible using the Ford 300 inline six cylinder gas mounts that used the rubber isolators (not liquid filled). Then the breadvan 45 degree engine block mounts and dodge rubber isolators. All hashed out many times over and detailed in this helpful thread. Conflicting 300 6 Frame Stand with Ford 4BT Block Mounts Compatibility Issue
I found that this gave the wrong drive line angles, since the front of the 4BT was riding high in the engine compartment.

If you go to my build thread in my signature below, the details are available. Starting at Post #59, I start to see that something is wrong. At post # 65, DarrenGT gives a summary of problems with using the stock 300 CID (straight 6 cyl) engine stands.

Quick summary: As near as I can figure out, the frame kick-up on the F150 & F250 chassis is different than the frame kick-up on the E350 chassis. When using the Cummins 4BT E350 engine mounts, with Ford 300 engine stands, on the Ford F150/F250 chassis - The center line of the drive line is no longer parallel to the center line of the rear axle pinion.

Russ

p.s. This swap is <slowly> being completed. Life had other plans for a while... ;)
 
#4 · (Edited)
Thanks for the info Russ! So if I am understanding you right, the front of the engine is riding higher than it should be? Resulting essentially in the angle of the ujoint at the trans or transfer case being less than the angle at the rear axle? I would think that if you measured the new angle of the powertrain, you could add leaf spring shims to compensate the rear axle, no?

I'd say that part has possibilities. I believe the water inlet mounting area is the same on the B series engines and the CR units which is the QSB 6.7.
Great info, thanks!

The one thing I see in the photo is the 4 mounting pads at the top seem to be spaced too far apart for most ac compressors. Of course you could make a steel mounting plate to attach the compressor to the bracket.
Very good concern and I realize that the mounting points look "off". Possibly the angle the picture was taken or the snow tricking your eyes. If you read the bottom of the 5th paragraph of the original post though, you will see that I measured the mounting points. To reiterate, the spacing between the top two standoffs is 92mm, the spacing between the bottom two standoffs is 87mm, and the spacing between the top set of standoffs and the bottom is 128mm. This corresponds (according to this thread) with the mounting points used on the freightliner/F800 compressors, which are SD7H15 style and specific Sanden part number of 4474. So....the only unknown at this point is whether the gauge line (distance between front mounting points to pulley midpoint) is 49mm on this new bracket as it is on the Freightliner/F800 brackets.

Diameter (A): 119
Gauge Line (B): 49.00
Dimension C: 92.00
Dimension D: 87.00
Dimension E: 128.00
 

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#3 · (Edited)
I'd say that part has possibilities. I believe the water inlet mounting area is the same on the B series engines and the CR units which is the QSB 6.7. The one thing I see in the photo is the 4 mounting pads at the top seem to be spaced too far apart for most ac compressors. Of course you could make a steel mounting plate to attach the compressor to the bracket. There is a similar bracket for the QSB4.5 but it had only 1 mounting pad instead of the 4. Not sure what it was about. Might want to sit down when you ask Cummins for the price. I'd guess in the $200 plus range. The other option is to mount the ac on the driver's side next to the #1 valve cover. Freightliner and Case Tractors had this option. That one isn't cheap either. What you see in the photo below is about $700. A custom fabricator could do something far cheaper.
 

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#5 ·
Cool. One more option. But...will it fit under the hood? Probably sits as high as the ac mount above the injection pump.
 
#6 ·
Bet your right. Don't think it will be an issue in a Ford F-series package though. Are there other instances where you would be using the front engine mount locations (and need this bracket) in a smaller engine bay? Seems like most smaller truck installs usually include some form of custom mounts anyways.
 
#7 ·
I agree with russ that the engine sits too high in the engine bay with the 300 mounts. Also, my truck is a 1995 f150, and my frame standoffs were behind the cross member, but the engine stands are almost centered on the cross member. It was easier in the long run to just fab motor mounts with the engine in place. The AC mount does look promising though, and an F150 definitely has the hood clearance for it.
 
#8 ·
The bracket in your picture will NOT fit the older 2 valve B series engines. The upper portion of that bracket is 100% specific to the commonrail cylinder head design. That bracket would be about an inch off from being able to fit the 2V head design. It is too close to the head. Another significant downside to the Cummins bracket is it's REALLY tall. It hangs the top of an AC compressor quite a ways above the top of the valve cover(s) where it would be in the hood in many conversions.

I'm almost finished with an accessory mounting system for the older B series engines that will solve a lot of issues for the conversion guys. It was partially inspired by the bracket in this thread, but doesn't have any of it's shortcomings. The system we are manufacturing is designed to accomodate all common 8 groove pulley alternators and AC compressors including all the Ford 4G, 5G, 6G, FS10 and Dodge Denso and Sanden pieces. In addition the system includes a universal upper waterneck that can point in any direction and support multiple different hose diameters. The lower water connection is also configurable for different hose diameters.

The part number I have for that bracket from Cummins is 5260171. You will need a lot more than the bracket to make it work even on a commonrail engine as it only fits specific industrial alternators and AC compressors.
 
#10 ·
The bracket in your picture will NOT fit the older 2 valve B series engines. The upper portion of that bracket is 100% specific to the commonrail cylinder head design. That bracket would be about an inch off from being able to fit the 2V head design. It is too close to the head.
Darn! There goes my cheerios! Could you possibly elaborate some more on this? I understand the 2V head has the thermostat pointed to the off drivers side of the head and the 4V has it pointed strait up. So you are saying that the cast-in thermostat housing of the 4V head is not as large as the bolt on upper water flange on the 2V head, therefor this new bracket wouldn't sit flush over the upper water outlet? If I look at this picture though (borrowed from this thread) it looks like the mounting point for the lower alternator mount in this instance would be the mounting point for the upper two bolts in this new bracket. Can you explain in what way this new bracket wouldn't match up with the water outlet pictured below? Would the holes not line up vertically or horizontally, or would there be interference? You seem like you've already been down this path, have any other threads you could link to or pictures of interferences?



Another significant downside to the Cummins bracket is it's REALLY tall. It hangs the top of an AC compressor quite a ways above the top of the valve cover(s) where it would be in the hood in many conversions.
How would this bracket put the A/C compressor any higher than the alternator in many of the "high-mount" setups posted on this site? Reference the picture above. That alternator and bracket sure looks higher than the valve cover. No argument intended, just looking for data.

I'm almost finished with an accessory mounting system for the older B series engines that will solve a lot of issues for the conversion guys. It was partially inspired by the bracket in this thread, but doesn't have any of it's shortcomings.
Great news! Have any pictures or more specific description of what you are working on? Are you selling anything yet? Have a website? What are some of the shortcomings of this bracket, other than it likely not fitting a 2V head? Thanks!

The part number I have for that bracket from Cummins is 5260171.
You reckon cummins would have only put one part number on that bracket? In looking on the parts list in QuickServe for the ESN I listed above (22023207), Cummins lists two part numbers for that water inlet bracket: 5260169 and 5260168 which are both close to your 5260171. Wonder if your number is a later revision? Do you have an ESN to go along with your 5260171?

You will need a lot more than the bracket to make it work even on a commonrail engine as it only fits specific industrial alternators and AC compressors.
Understood you will need more than just the bracket, but this thread was pertaining specifically to that bracket. Also, did you read my first post all the way through? What do you consider an "industrial alternator and AC compressor"? I've already mentioned twice that the mount pads for the A/C compressor on this bracket are the standard dimensions for Sanden SD7H15 compressors. Also, QuickServe mentions this bracket fits a 24si alternator.

Thanks for any other info you can provide!
 
#11 ·
The picture in your post above is the Ford/freightliner bracket. I have used these in a couple swaps and wouldn't use that path again. Especially on a 4BT where front mounts are required. The bracket in your original post is nothing like the Ford/freightliner mid mount.

The part number I listed was cast in the bracket I had which was recent production. A 24SI alternator with an 8 groove pulley is not a pickup application. The connection locations for the AC compressor you choose is a very important factor you may be underestimating, especially true for the ford/freightliner setup. The downsides to the bracket in your original post are- It hangs the AC compressor way above the top of the engine, it will only fit the commonrail head design engines. The bolt pattern and spacing is completely different from the 2V style engines. Most 2V style upper waternecks are not conducive to the AC compressor being right there.

There will be pictures and information on our website when the parts are ready in a few weeks. This has been a concept of mine for years, we've machined dozens of application specific Cummins accessory mount systems to get around the problems associated with the EXPENSIVE and not so versatile Cummins offerings. The thing that makes our kit so appealing compared to anything else is the combination of alternator and AC flexibility, compactness and completely universal water connections. You can point the upper neck at any compound angle you want, it rotates 360 in one axis and 90 in another and you can choose between 1.5 or 1.75" upper connections and 1.75 or 2" lower connections.
 
#13 ·
As I stated above, the commonrail high mount AC bracket does not fit the 2V head design because it is atleast an inch too close to the head for the 2V waterneck to fit. The bolt pattern in the commonrail head is similiar to the bolt pattern in the industrial 2V engine waternecks, but it isn't the same and it's shifted up or down some (don't recall exact vertical difference right now).

I think replacement parts sourcing is a very important consideration when doing a diesel conversion. If you use an alternator or AC compressor from an industrial/medium duty application the cost is going to be much more than a pickup version of the same part and availability may not be as good.
 
#15 ·
I fabbed an aluminum plate and some aluminum brackets that ended up being very similar to that F800 bracket, but the compressor and alternator are closer together and the alternator sits much lower:





The compressor is an ear-mount Seltec,and the outer ears are used for support brackets for the alternator. The only problem with this arrangement (which I didn't realize at the time) is that the Seltec compressors are NOT meant to be mounted with the ports more than 45° from vertical, as it can cause oiling issues. Sanden compressors can be mounted 90° from vertical, so they would be the logical alternative.

Beware: I had issues with belt squeaking and shaving rubber dust on the compressor. It turned out that the accessory bracket mounting surface on the upper water neck was NOT perpendicular to the front face of the engine! The compressor and alternator sat cocked at a slight angle which caused the belt to ride on one edge instead of flat and even. It was not visually noticeable until I recently put the bracket back on after resealing the engine. Something looked a bit off, so I threw a square on it and lo and behold it was quite a bit off. I had to machine the spacer between the plate and water neck at a matching but opposite angle to compensate. It's square to teh block face now and should fix the issues.

Also FWIW, I may end up running a Seltec TM-21 compressor if I can get the outlets to clear the oil filter housing. Second option is a Seltec TM-16. The TM-15 I had on there never moved enough gas at idle and low speed due to the smallish crank pulley on the Cummins (only 6-3/4" OD vs 8" OD for a Chevy 6.0 gas engine crank pulley), so the AC worked like crap at low speed and idle during the summertime. A 16 will be better than the 15, but the 21 will easily match the performance of the stock R-4 compressor on the 350 TBI gas motor (which had an 8" crank pulley) that my truck originally had. The 21 is a direct mount, however, so I would have to modify my brackets. The 16 is available ear mount, but it may not clear the oil filter housing with the ports in the proper vertical position. More experimentation is needed...
 
#17 · (Edited)
I fabbed an aluminum plate and some aluminum brackets that ended up being very similar to that F800 bracket, but the compressor and alternator are closer together and the alternator sits much lower:

Max, that is almost exactly what I had planned for my alternator position with my Ford acc mount. I am thinking of keeping my alternator mounted to the water outlet and running a brace up from one of the compressor mounting bolts. Did you have any issues with belt squeal with that amount of wrap? I think you and I must have the same engine since I see you have a forward shutdown solenoid as well. I haven't seen many setup this way yet.
 
#21 ·
Hey I recently completed a 6BT swap in my 97 C3500 Dually. I used the industrial a/c bracket which accepted my factory 6bt a/c compressor. My 6Bt was from a 94 Dodge 2500 truck. I have a belt alignment issue with the a/c compressor on this bracket with the harmonic balance. It is almost 3 grooves off, 1/4 inch. There is no adjustment to the bracket, and my new a/c compressor matches the one I took off. Anyone else have this issue? I have attached some pictures of what I have. The a/c compressor pulley sits too far rearward, toward the firewall.

I used the original a/c bracket, cut the top and bottom off it, and put it on top of the new a/c bracket so my radiator hose nipple would come out horizontal. The bracket I got from Cummins, part# 3930888

Engine Auto part Vehicle Automotive engine part Carburetor

Auto part Engine Automotive engine part Carburetor Fuel line

Material property Magenta Label
 
#22 ·
So I found my answer after some SEARCHING lol. I guess the ''gauge line'' is the distance from bolt hole center line to the center rib on the pulley. The stock 94 dodge a/c compressor is about 44.45mm best I can tell. I found another post showing the compressor for this bracket needs to be 49.0 mm. This would move it up to about where it needs to be, about .180 forward of its current location.
 
#25 ·
Hey J Mack --- I notice the your mount locates the Cummins tensioner diffrently than my Jonesey's plate. Mine has another plate for the tensioner that extends out quite a ways. Did you mod yours to that configuration or did it come that way. I like the tucked in arrangement much better.

Also notice you have a fluid dampener. Have you run it yet? If so, how do you like it?

Thanks
 
#26 ·
#28 ·
Thanks J Mack --- but I still don't get how you mounted the Gates. The plate I got from Jonesey's came with an extended tensioner mount as seen in the pic below. Did your come in a different configuration?
Looks like you either have an earlier or later version of the mount then mine. Not sure if Jonesey’s is still in business or if they just changed owners but diesel adapters made the Jonesey’s mount and you can see it here http://dieseladapters.com/images/77b692c685c0acd7c1d2293407e1af17.jpg


I would contact them and try to find out what you have.

http://dieseladapters.com/Quick_Mount_Cummins_AC.html
 
#29 ·
Made some mods to my accessory brackets. Here's what it looks like now:



There's more than 180° wrap on all pulleys in this setup. I had to move the tensioner below the compressor and add an idler pulley between the compressor and alternator. Also required was a different lower water neck, as the original one interfered with the new belt routing and tensioner.
 
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