7.3 idi in farmall M

560farmer · Oct 4, 2017

I have a farmall M with a stuck engine and me and a couple buddies have an idea of putting a 7.3 idi in her. Ik and heard the horror stories of these rear ends and plan on beefing it up if need be just a little play toy. My questions are how big a clutch do I need and how am I gonna make my input shafts? Should I use the 7.3 idi fly wheel or the farmall m? Any other info would be great!!

Sprint 6 · Oct 4, 2017

Rear end will probably be fine, a 7.3 IDI can't pull a greasy string from a cat's butt. They stand up to V8's at the hotrod antique pulls, those engines are making more horses in one cylinder than an IDI does in 8. I would use the IDI and a C6 auto in front of the M trans, easier to adapt and three more speeds. Engine and trans length might be an issue. Radiator is going to be a problem, too. Indirect engines need a large radiator.

oliverkid · Oct 4, 2017

There's a couple videos on YouTube of a guy that did a really clean job of putting a 7.3 in a super m.

560farmer · Oct 4, 2017

How would I do my input shafts?

9598Farmallred · Oct 4, 2017

did this 25 years ago with a chevy 6.2 with banks package, we made the M adaptor plate fit the chevy and made the Farmall flywheel fit the 6.2 so still uses the same farmall clutch and input shaft, also use the M radiator with elec. fan only problem ever have is not with tractor was with the 6.2 , this tractor is still going today, although it is on its second 6.2. it was a close fit with 6.2 although was able to keep frame & hood stock so 7.3 probably need some serious modification. Good luck. Andrew

jr1983 · Oct 5, 2017

That rear end I not gonna hold up to an idi. I always heard this crap about an idi being a turd but I've ran one for years with no power issues and opinions aside you're talking 210 HP. No farmall m rear end gonna hold that.

ptfarmer · Oct 5, 2017

Farmall M with a 7.3 idi
https://www.youtube.com/watch?v=5u2x_v0qy5I

560farmer · Oct 5, 2017

How did u hook engine to tranny input shaft thanks

ptfarmer · Oct 5, 2017

I have never done the swap, but from the way it looks it shouldn't be too hard. A adaptor plate for the engine to transmission, adapting a M flywheel to the 7.3, and I think the frame rails had to be reworked some. Someone who is a good machinist/fabricator should be capable to do it. I've also seen M's with Chevy V8's, 71 series Detroit Diesels, Cummins Diesel, and I'm sure there is more out there with different engines.

rustyfarmall · Oct 5, 2017

The rear end will hold up just fine as long as you are not trying to do more than what the M was originally designed to do. That M was built to handle a plow with 3, 14" bottoms. If you try to pull a plow with 5 or 6 bottoms, you WILL have problems.

jr1983 · Oct 5, 2017

An IDI 73 is governed out at 4500 RPM. If I was going to do it and this is just my opinion I would slap a turbo on it turn it down to 3000. At 3000 rpm the factory in clutch should hold up just fine I would think. I'm sure there's more knowledgeable Farm all people that will chime in here. All of that said I would find a flywheel for a 84 to 1987 6.9 diesel.That flywheel should be small enough to fit in the bell housing of them and is a single plane so you should be able to have a machine shop drill it to accept a stock in clutch.

DR. EVIL · Oct 5, 2017

A stock 7.3 IDI is 185 hp, non-intercooled 7.3 PowerStroke is 210 or 215 depending on if you believe IH or Ford. Sticker on the valve cover on my '96 PSD put on by Navistar says 215 hp, Ford said 210.

An M in good mechanical shape should take anything a 7.3 IDI can throw at it.

ptfarmer · Oct 5, 2017

(quoted from post at 06:37:44 10/05/17)
The rear end will hold up just fine as long as you are not trying to do more than what the M was originally designed to do. That M was built to handle a plow with 3, 14" bottoms. If you try to pull a plow with 5 or 6 bottoms, you WILL have problems.

Like getting the tractor stuck in the ruts made from the tires, if you can do that you shouldn't be on a tractor anyways.

wilson ind · Oct 5, 2017

Lost me on what is idi engine??

ptfarmer · Oct 5, 2017

(quoted from post at 07:48:09 10/05/17) Lost me on what is idi engine??

Its the International/Ford 7.3L diesel which became the 7.3 power stroke.

dhermesc · Oct 5, 2017

IDI is InDirect Injection diesel engine. An IDI has the fuel injected ahead of the intake valve, while the "power stroke" is a DI or Direct Injection engine where the fuel in injected directly into the cylinder. And IDI also means the injector can be replaced in half hour while the DI needs all day. While both engines are 7.3 displacement they share the block (maybe?) and that's about it. The crank, pistons, heads, and pretty much everything else is different between the two engines.

You can just about rebuild the older IDI 7.3 for about the same cost as replacing the injectors in the Powerstroke 7.3 when you include labor.

wilson ind · Oct 5, 2017

Thank you that us most helpful, in understanding the terminology.

Fritz Maurer · Oct 5, 2017

Huh? Injected ahead of the intake valve?

jr1983 · Oct 6, 2017

So lets go with your numbers. You're trying to tell me a tractor drive train built for 38 HP in a stock m is gonna hold up to 185? The closest HP in the farmall line was the 1566 at 174 Hp and if you didn't flip the gears in those you'd take out the ring and pinion. An m is a decent tractor but the trans / rear end aren't the strongest thing out there and if you load it at all with an idi you are going to shred the ring gear.

jr1983 · Oct 6, 2017

HP numbers came from tractor data

rustyfarmall · Oct 6, 2017

(quoted from post at 05:25:18 10/06/17) So lets go with your numbers. You're trying to tell me a tractor drive train built for 38 HP in a stock m is gonna hold up to 185? The closest HP in the farmall line was the 1566 at 174 Hp and if you didn't flip the gears in those you'd take out the ring and pinion. An m is a decent tractor but the trans / rear end aren't the strongest thing out there and if you load it at all with an idi you are going to shred the ring gear.

ANY engine makes only the horsepower required to get the job done.

7.3 idi in farmall M

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