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#846 - Cummins Swap
Author: andy1canada (Show all albums)

Howdy Folks!

Going to give this another try as my first attempt didn't go so well on the 'Diner-conversion' thread (Will update/edit that soon).

Started my Cummins swap by pulling off the bumper; only took better part of an hour. That sucker is HEAVY! Better part of a 100 lbs I bet. Will be looking to knock substantial weight off that baby while still retaining a 5000 lb towing standard.

This will take a while as it will unfold as time and resources permit, so please be patient.

More pics and hopefully some videos (FMC-TV) to follow.

Show Newest Photos First | Show Oldest Photos First234 Photos - Page : [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]

The bolt holes are more or less in a straight line on 4 1/4" centers. My laser came in handy for aligning the holes (which are also the centerline of the air-springs and the 3ft long mounting arms) which all had to position correctly (plumb) beneath the upper spring mount on the chassis. As is shown in the pics following, the 6" dia. circular 1/4" upper spring mount disc needs to be offset from the chassis beam enough to allow access to the mounting bolts and air-line hardware.

Forgive me my Cummin's brethren for I have sinned...all I had handy was some 'Caterpillar yellow' rust paint!

To figure what I thought could be right place to weld the upper spring mount I decided to use the point on the chassis frame where the radius from the center of the torsion bar tube (center of rotation) out to the center of the air spring disk. Then it was a simple matter to transfer that distance up onto the chassis.

Scored all the fittings & 20 ft of 1/4" airline for under $40 bucks. Ready to install and test for leaks.

Again, the spring mount arms are quite a patchwork assembly and need not be; it's what I had on hand. I'm asking this design to provide up to 1000/lbs of additional lift to the rear of my coach. Applying this amount of lift at a point on the chassis 3-ft behind the torsion bar tubes should hopefully help mitigate the extra 400 lbs the Cummins brings to the party. If there are any strength issues (ie. flexing/bending) in service, I'll change out the arms for some 3"x3" heavy box channel. One thing I think I got right with this design is the ease of removal of the assembly for repair and/or access to the shocks and wheel hub assemblies.

Ready to plumb in the air-lines.

To get me up and running I decided to go the easy route on the air-control. Simple schrader-valves mounted in the engine house (pass side) just ahead of the access door. Easy access.

Will be adding a trick 'dual' needle pressure gauge in the proximity of these fill valves so I can see at a glance where the pressure is at. Will wait till I do the final clean-up of the firewall as there's likely more stuff to get rid of as the 12-valve's ancillary equipment necessary to run it is little more than a battery, a keyed starter circuit, fuel shut down solenoid and the heater grid for cold starts.
Show Newest Photos First | Show Oldest Photos First234 Photos - Page : [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]

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