M39 series LDS 465-1A to Mack ENDT 673 repower

[AMGeneral]

Well,I have FINALLY gotten around to starting this thread that I had promised I would start on 2 years ago!!

What I intend to cover is the necessary parts to change/replace when doing a powerplant change on a M39 series 5 ton truck,as well as the proper procedure of same.

The object of my personal repower is a 1967 Kaiser/Jeep M51A2 5 ton dump that I aquired from SS member Papabear several years ago in trade for the M553 GOER.

Although my truck is a 5 ton dump,this will cover a powerplant conversion on any common M39 series 5 ton.

First off,you will need a Mack engine and overdrive transmission from another 673 powered 5 ton truck as well as the complete throttle linkage from the same truck,from the link passing through the floor that attaches to the "gas" pedal all the way to the link going to the injection pump.

You will also need the complete air intake piping from the air cleaner to the turbo inlet,all of this is Mack specific.

Also,if it is possible,remove the fuel supply and return lines from the donor truck as well as the main air line from the compressor to the "wet" or lower air tank,these are also specificly curved or made for the Mack powered trucks.

If you are pulling the Mack from the donor truck yourself,notice that the right had frame rail upper flange is cut out to clear the accessory drive on the 673 Mack,measure and make a pattern of this because you will have to do it on the truck that you are repowering as well.

In the following days,I will cover in pictures as well as measurments where to place all the necessary parts.

 

[AMGeneral]

A few pictures of the throttle linkage,first of the multifuel then the Mack specific linkage.

 

[Artisan]

Sub'd! Keep the pics coming!

 

[vtdeucedriver]

A few pictures of the throttle linkage,first of the multifuel then the Mack specific linkage.

Same linkage for the gas set up....................correct? Sure looks the same.

 

[5ton beachbuggy]

I put the mack in a M246 gasser and used the stock throttle linkage.

 

[AMGeneral]

Same linkage for the gas set up....................correct? Sure looks the same.

Yes,It has the same common components,the Mack just uses 1 further link and another bellcrank for the final step to the injection pump.

 

[AMGeneral]

Well folks,I promised a daily update of the progress so far,so here is today's update.

Today I installed the fuel supply and return lines in the places suited for the Mack engine.
Since the injection pump is on the right side of the engine,it is necessary to route the lines along the crossmember just below the front of the cab as shown in the first couple pictures below.

After that is done unfortunately it is necessary to trim the upper flange of the right hand frame rail to clear the accessory drive of the Mack.

Take your template you made from the donor truck,or measure it out and cut it with your choice of grinder,torch,plasma cutter etc,as shown in the pictures below.

If you do not have a truck to make a template from,measure 1/4 inch back from the right hand grill upper support where it is rivited to the frame( see pictures) and cut a 1 1/2 inch deep x 36 inch long rectangle out of the upper flange.

This will give sufficient clerance for the accessory drive and fuel and air lines.

After you are done cutting,clean it up with a angle grinder if you wish,check you work aera for anything that will hang or obstruct the engine install, then ease the engine into place.

NOTE!!

Some multifuel powered trucks have an extra support at the rear of the radiator support,you will need to remove this before installing the Mack!!!

Updates to follow,stay tuned.

 

[topo]

Where do the heater hoses come off the Mack engine ? It looks like one of them comes around the rear of the engine .

 

[vtdeucedriver]

Which truck is the donor engine coming from? Not that it matters as you have so many. I would really like to have a Mack Tractor. I cant wait to get back out there behind my yard queen.

 

[AMGeneral]

Where do the heater hoses come off the Mack engine ? It looks like one of them comes around the rear of the engine .

Actually topo,that is one of the power steering lines that come around the rear of the engine,honestly,I could not tell you where the water lines hook up,I've never seen a Mack powered truck with a heater.

 

[AMGeneral]

Which truck is the donor engine coming from? Not that it matters as you have so many. I would really like to have a Mack Tractor. I cant wait to get back out there behind my yard queen.

This engine came from a VERY rusted out M543A1 chassis I got in a trade deal with Blythewood Joe,early engine,big turbo,18 stud heads and the smaller head studs,(9/16 vs 5/8 ).

 

[vtdeucedriver]

Actually topo,that is one of the power steering lines that come around the rear of the engine,honestly,I could not tell you where the water lines hook up,I've never seen a Mack powered truck with a heater.

Want pics???????? I got one on mine and its coming off ASAP and getting sold as trucks in Vietnam did not have heaters.

 

[vtdeucedriver]

Here ya go of the heater install.

 

[AMGeneral]

What do you have in mind for the heater Jeff?

 

[Squirt-Truck]

AM, you have indicated that the engine is coming from an A1, based on the picture is seems that is was built as an A1. It does not have the gasser bulkhead. Does the Mack linkage differ for the older bulkhead configuration (converted truck) or is it long enough to work anyway?

 

[AMGeneral]

AM, you have indicated that the engine is coming from an A1, based on the picture is seems that is was built as an A1. It does not have the gasser bulkhead. Does the Mack linkage differ for the older bulkhead configuration (converted truck) or is it long enough to work anyway?

Mark,

I have seen both types used on Mack powered trucks,the linkage installed on this truck came from a factory Mack powered truck,I will check the M52 gasser tomorrow and see which linkage it has and compare lengths across the firewall.

The dump itself is a factory multifuel(A2) engined truck.

 

[AMGeneral]

Well,nothing much to tell today,too rainy and nasty to work outside much,I got the fuel return and supply lines hooked up,as well as the secondary fuel filter canister cleaned and a new filter element installed.

 

[AMGeneral]

Update,

I removed the pto driveshaft for the dump mechanisim and cleaned/lubricated it. I also installed the short driveshaft from the trans to the transfer and greased all the fittings associated with the dump linkage.

 

[AMGeneral]

Update,

I got quite a lot accomplished this weekend,I removed both front fenders to gain easier access to the engine bay for further work.

Also I,
Replaced all the power steering hoses to adapt to the new style Ross power steering.
Swapped out the radiator for a better one I had in stock.
Hooked up the throttle linkage,and starter cables to facilitate first start.
Checked over the fuel system and primed it up,then found I had a pin hole in the fuel tank.
Replaced all the oil feed lines to the injection pump.
Installed the alternator and replaced all the belts and coolant hoses.

After about 3 engine rotations the Mack fired and ran great,all pressures and temps seemed to be in the proper range.

After about 5 minutes of warm up,I tested the clutch and trans for proper operation,as well as the dump mechanisim,everything worked correctly.

Next update will have to wait till next Sunday,no work this week.

 

[73m819]

Boy it is hard to read run on sentences at the punctuations, sorta like text talk