Converting a 1973 1310 from gas to diesel


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Post Wed Nov 13, 2019 10:38 pm

Converting a 1973 1310 from gas to diesel

Hi all,
I need some advice and answers to some questions that I believe y'all can help me with.
First of all what I have to work with:
1973 IHC 1310 Travelette (1 ton crewcab), 4x4, 5 speed Overdrive, Dual wheel, Power-lok front and rear axles, 392 ci (6.4 L)V-8, Dual Exhaust, A/C (factory). It’s a darn fine truck and she runs real good, however it is almost cost prohibitive to drive at 5mpg and no it don’t matter empty truck or loaded to the hilt in 4 low climbing a mountain.
Now what I’m thinking about:
Converting it to diesel. Thinking of using a 7.3L Power Stroke, as it’s basically an IH T-444E engine and I would like to keep it as much IH as possible.
First thing, what do you think of the idea?
The biggest problems I see are motor/transmission mounts, transmission to transfer case connection. There are of course the problems of connecting all the other things; throttle, radiator, heating/ac, fuel tanks (which need to be replaced anyway), shift linkage, etcetera.
What I don’t know is if the motor will fit, what if any, modifications need to be done to the engine compartment? Will I lose any steering or suspension travel?
What am I missing? What advice can you give me?
I live in southeast Idaho, does anyone know who would/could do this kind of work and about what it costs (if I provide the motor, transmission and new fuel tanks)?
Thanks all for the assistance.
James
winchester86@live.com

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Post Wed Nov 13, 2019 10:50 pm

Re: Converting a 1973 1310 from gas to diesel

First, there are more experienced folks than me by far. Engine, what is the weight of your original, compare to the 7.3, measure the dimensions. Ok, I realize you want to "keep" it as original as possible, but what about a Body swap? Upgraded components but old style charm? There are a few of us in Idaho, and more in the surrounding areas. give it time for responses.

Golden Jubilee
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Post Thu Nov 14, 2019 12:42 am

Re: Converting a 1973 1310 from gas to diesel

I did the silly , keep-it-all-original thing with my R120. I installed an IH/Ford 6.9 V8 Diesel. This was a very difficult install, mostly because of the size of the really big 6.9L.
After all of the difficulties were behind me and the installation, I had an Old IHC R120 that sounded fantastic, got very good fuel economy. The top speed with a Gear Vendors Overdrive was about 90mph.
The power was rather feeble at 140hp and less than 400 pound/feet of torque.
The second situation you will run into is the 1300 plus pounds the 6.9/7.3 idi engines weigh.
To try and preserve the frame, I had to move the shock absorber frame mounts to directly under the engine mounts. To try and keep some kind of civilized ride quality, rather than installing heavier leaf springs, I used an air spring system with Holland-Neway levelling valves.
These old 6.9 and 7.3 idi engines are obsolete and I was told they are not allowed in California as of a few years ago. Parts are all but obsolete. The later Power Stroke is the turbo version of the 7.3.(aka444) This is a serious engine that can make some real power. Once again the parts are becoming more difficult to find. This is a really old engine. Then there is the weight issue of 1400 plus pounds.
While I like the Power Stroke 7.3, a buyer must be sure the previous owner has kept up the service 100%. One or two missed oil changes will guarantee and early death of the HEUI direct injection system.
This HEUI system is very complicated and difficult to explain. There are much better descriptions of how it works on the internet. Make Google your best friend.
Repairing a HEUI injection system used to start at $10,000 and go up if more than the main high pressure pump was worn out. Missing an oil change could damage the oilpump.
The development of the HEUI system was a joint venture of Caterpillar and Navistar.
I would strongly advise installing a Cummins 5.9 liter inline 6. For s simpler install up to start and run, one of the earlier 12 valve Cummins is a good choice. With reasonable care a Cummins 5.9/12 valve will last a million miles.
The Cummins is lighter, smaller and gives more power on less fuel. The Cummins 5.9 has lots of aftermarket adapters and lots of available transplant information. The Power Stroke is on its way out. It is way too expensive to fix.
And another important thing. Those engines leak oil. The gaskets come in a tube. I got an warning ticket from the environmental police for a small leak on some cobblestones. The "R" was off the road the next week.
Attachments
R120 in 1991 (2).jpg
I built the custom canopy.
CUMMINS COFFEE1.jpg
CUMMINS COFFEE 2.jpg
CUMMINS 24 VALVE BRINGING IT HOME.jpg
cummins 24 valve.jpg
this Cummins if for an IHC "R" install.
Cummins Package.jpg
6.9 worn out and in an R120.jpg
after 225,000 miles
I would rather have tools I do not need than to need tools I do not have
Thinking risks being controversial and possibly being offensive

Golden Jubilee
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Location: Canada's left Coast

Post Thu Nov 14, 2019 1:07 am

Re: Converting a 1973 1310 from gas to diesel

A body swap is a terrible idea. A body swap is something that very few persons can do successfully. None of the problems are avoided. In fact, a body swap bring a ton of grief with it.
The 6.9 and the 7.3 are 37.375" wide. This changes everything. I had to "dog-house" the cab firewall back, 6 inches, to accommodate the width of the engine.
After the engine was in and running there was about 3/8" clearance left and right and to the back. I had to have $1000 custom radiator built.
The engine needed a fresh air intake system. I tool air for the engine in on the right side of the radiator. The "R" has a 5 inch square hole on each side of the radiator..
I designed an air dam for under the truck. This lowered the under-hood pressure at highway speed. I have a manometer.
The automatic transmission had to be cooled separate from the engine. The ATF cooler was mounted under the box.
Attachments
R120 6.9.jpg
fresh air intake
ATF oil cooler.jpg
transmission oil cooler
I would rather have tools I do not need than to need tools I do not have
Thinking risks being controversial and possibly being offensive

Pile of Parts
Pile of Parts

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Post Thu Nov 14, 2019 2:14 am

Re: Converting a 1973 1310 from gas to diesel

How often are you really driving this truck? What are doing with it? Do you really need a diesel? If so would find a newer one in your price range & enjoy the old truck the way it came from factory.

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Post Thu Nov 14, 2019 3:00 pm

Re: Converting a 1973 1310 from gas to diesel

I have had this truck since 1997, put about 500 to 700 mile a year on it so mpg wasn't a big deal, but as of last spring it has become our full-time towing rig. So due to the mpg we only took one trip of about 65 miles.
I could maybe come up with enough to pay for the swap ($12,000.00 +/- ??) but $30,000.00 minimum for a good 1 ton crew cab truck is more than I can handle. If I was going to get a newer truck I would prefer gas, they are about impossible to find.
I think the engine compartment on my '73 is quite a bit bigger than an R would be.
I'm not in a big hury, if I decide to do this it will be in smaller stages so I can afford it.
Thanks for the help so .
James

Golden Jubilee
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Location: Canada's left Coast

Post Thu Nov 14, 2019 3:23 pm

Re: Converting a 1973 1310 from gas to diesel

When I did my R120 it was 1990. I did all of the work. This included the engine, transmission, transfer case and Dana 60 axles. I spent $26,000. I would expect to pay twice that amount to have a good shop do the work.
A good used 12 valve Cummins are often under $4000. If you can do the work yourself, $10,000 and a year of your time is reasonable. Your truck has everything but the Cummins engine. It is all of the little things that add to the final cost
I would rather have tools I do not need than to need tools I do not have
Thinking risks being controversial and possibly being offensive

Rookie
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Post Thu Nov 14, 2019 11:02 pm

Re: Converting a 1973 1310 from gas to diesel

1449360468553.jpg


if I did this right there should be a picture of said truck

Rusty Driver
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Post Fri Nov 15, 2019 4:46 am

Re: Converting a 1973 1310 from gas to diesel

I did a little math, which has some assumptions involved, so take that for what it's worth. Assuming $3/gal gas vs. $4/g diesel, and 5mpg gas vs 20mpg diesel, you get about 40c/mi difference fuel cost. The project minimum guesstimate of $10K means you have 25,000 miles to tow before breaking even. A guesstimate of project cost of $25K means you won't get your money back until 62,500 miles of towing.

The heart wants what the heart wants, IF you want a diesel-powered 1973 IH truck, go for it. Most of us know it isn't about economy.

IF I could take a cool-looking old IH truck like yours and upgrade it to modern diesel technology while increasing performance and reliability, I'll take that old truck every day over a worn-out newer one.

Golden Jubilee
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Location: Lyman, IA

Post Fri Nov 15, 2019 9:06 am

Re: Converting a 1973 1310 from gas to diesel

I got 6-7 mpg out of my 6.9 powered service truck. About the same with my L10 powered semi. 20 mpg is not realistic for that truck towing or carrying a heavy load.
Like the previous poster stated, monetarily it doesn't make sense, if you need to justify it, seek another justification.
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