1994 F350 7.3 idi needs an engine

So not sure if anyone has attempted this specifically. I was directed here form the diesel guys over on Reddit.

Have a feb/94 F350 7.3 idi turbo diesel, automatic (blue tag photo). Dad say the block is no good. So we found a 92 F250 7.3 idi (non turbo) manual trans (black tag photo). We’re just planing to take the block from the 250 and throw it in the 350 bolt on our turbo and let it rip.

Reddit recommended we take the flywheel as well off the donor. Is this all I need to consider. Do y’all think this will work?

I see Navistar used the same 7.3 idi from like 86-94 and just in 93-94 added on a turbo option. So I figure it’ll work. Let me know. We’re gonna pull the engine this week I think.

I don’t have a lot of information on this but when I was looking up fly wheels for our 93 na idi zf5 it had different fly wheel options. And I was also told it had to do with the crank balance on the na vs turbo engines. Not exactly sure if that’s true but that’s what I’ve been told. I’d take the fly wheel and get it resurfaced.

I'm assuming you're keeping the auto trans? If so, you'll have to order the proper flexplate for the N/A 7.3. Turbo and N/A engines are balanced differently based on the connecting rod differences and should not be interchanged.

Here is some info on the Factory Turbo IDI Engine.


Another link to "Know your IDI History"


This will bone you up on the correct info instead of the false
info floating around on the internet and old "Wives Tales".
We can`t have too much correct info.

What is wrong with the Turbo Block?


Goat

Steven66 said:

I'm assuming you're keeping the auto trans? If so, you'll have to order the proper flexplate for the N/A 7.3. Turbo and N/A engines are balanced differently based on the connecting rod differences and should not be interchanged.

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So, bad idea? I do want to keep it auto. I was told by several, just so long as I keep all the moving parts it should be almost plug and play. But from what your saying, I’m thinking I need to change internals?

You need the NA flexplate for the NA engine. Even if you swap the turbo over.

I don't know how you plan to use this truck, but the pistons, rings, wrist-pins, & rods of the NA aren't as robust to deal with cylinder pressures of turbocharging. If I intended to work the truck hard, this NA engine would be a stopgap measure while I rebuilt the factory turbo engine.

Steven66 said:

I'm assuming you're keeping the auto trans? If so, you'll have to order the proper flexplate for the N/A 7.3. Turbo and N/A engines are balanced differently based on the connecting rod differences and should not be interchanged.

Click to expand...

Tell me about the flex plate. Am I ordering one for an automatic 92? Since the 92 the donor engine is coming from is a standard?

u2slow said:

You need the NA flexplate for the NA engine. Even if you swap the turbo over.

I don't know how you plan to use this truck, but the pistons, rings, wrist-pins, & rods of the NA aren't as robust to deal with cylinder pressures of turbocharging. If I intended to work the truck hard, this NA engine would be a stopgap measure while I rebuilt the factory turbo engine.

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I plan to use it for a daily driver with occasional brush hauling or transporting building material from Home Depot for the house. Maybe hauling a small RV from time to time. Nothing serious l, I think. Also since it’s not 4x4 I can’t take it off road.

Do I pull the flex plate off the standard 92 or order a new one?

Dabbling Madman said:

Tell me about the flex plate. Am I ordering one for an automatic 92? Since the 92 the donor engine is coming from is a standard?

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Just order a flexplate for a truck with the M vin code. If the 92 is a standard, there is no flexplate to remove since it has a flywheel. You'll have to order one new. As long as the flexplate specifies for vin code M trucks or says N/A specifically, you're good. And while it's true that the connecting rods are more robust, some key group members have noted piston issues with factory turbo trucks due to the stock piston design being bored out more for a bigger wrist pin. Now, it doesn't matter if it's a factory turbo engine or N/A engine with a turbo setup swapped onto it, both will work just fine in any normal case. You can work both hard and they will do the work just fine. Both have problems if you push them too far, which is easily avoidable if you run an EGT gauge and don't do stupid things.

Edit: One more thing, be sure to save the flexplate spacer and washer from the turbo truck. It's a large washer that all of the flexplate bolts go through, as well as a huge chunk of steel that spaces the flexplate off of the crank. Without it, the torque converter will disengage from the pump if you try and bolt it to the flexplate.

At stock or a little bit above stock power levels, the N/A engine will be fine.

The 92 block should be alright if you use all of the other parts from the turbo engine. Rods, piston pins and pistons are different weights, so the flywheel or flexplate must match the rotating mass. While you have it apart, you will thank yourself if you have everything balanced, too.

Knuckledragger said:

The 92 block should be alright if you use all of the other parts from the turbo engine. Rods, piston pins and pistons are different weights, so the flywheel or flexplate must match the rotating mass. While you have it apart, you will thank yourself if you have everything balanced, too.

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I know the fist post says "the block", but I took it as he's going to put the entire N/A engine in the Turbo truck with the turbo on it.

IDIBRONCO said:

I know the fist post says "the block", but I took it as he's going to put the entire N/A engine in the Turbo truck with the turbo on it.

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I was not sure, since only the block was the problem and he said he was going to use the "block" from the 250. Probably meant the entire engine. If that is the case, I would love to buy his rods, crank, flexplate and harmonic balancer.

Dabbling Madman said:

We’re just planing to take the block from the 250 and throw it in the 350 bolt on our turbo and let it rip.

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Dabbling Madman: Please confirm that you are just doing a complete engine swap as your “taking the block from the 250” verbiage suggests you are swapping the internals.

Second, what’s the diagnosis on current “bad block” engine?

Lastly, if you fill out your signature with the details on your truck, it will help other members in answering your questions by knowing a little more about what year/model/etc you are working on.

Again, welcome aboard and good luck on what it sounds like should be a pretty straightforward engine swap.