I have an off the wall question. I want to convert my 74 f 350 two wheel drive to a diesel. I have a 7.3 out of a 90 f250 lined up. I have a fly wheel and bell housing but I was wanting to know if any one had done a swap like this and knew what motor mounts I needed of if there is some kind of adapter of modifacation required. Any help is aprecated

 

It will be a fairly large custom job.

Make sure you do some measurements to see if the 7.3l will fit under the hood of the 74.

Clearances of the 7.3l in the 83'-94' trucks are pretty tight. The rocker covers are right up to the firewall.

Pretty much everything you touch will have to be custom made.

Will get expensive, make sure the 74 chassis is worth it.
What tranny are you considering, Lots of electronics on the automatics in the 1990. The 5 speed OD standard ZF5 tranny would be alot less trouble.

 

i ws going to use a standard trans becase that is whats in it

 

Good, the manual tranny will make the job a lot easier.

You still got an uphill battle so; some things to consider:

1.0 Fuel Tanks: Need return line and fuel selector valve for the diesels.

2.0 Engine Mounts: already discussed.

3.0 Two Batteries: Diesel needs two batteries, have you got room in the 74?

4.0 Clutch: Proably needs a lot of custom fitting to get from the pedal to the fork.

5.0 Front Suspension: The 7.3l diesel is a lot heavier than any gasser (1,000-1,100 lbs)

6.0 Steering Box/shaft: The 7.3l diesel is pretty tight on the drivers side exhaust manifold, make sure it fits.

7.0 Frame width: The newer truck frames are wider. Watch out for starter and oil cooler access.

8.0 Drive shafts: will have to be cut, watch your drive line alignment.

9.0 Tranny cross member: Most certainly will be a custom job.

10. Dash. Best to replace the entire dash with the diesel dash as most if not all the stuff on the 74 dash will not work with the diesel.

11, General wiring. Lots of work required there, Good news is the diesel engine is relatively low complexity electrically.

12, Radiator: The diesel radiators are quite large, will take some cutting, etcc. to make it fit the 74.

13, Exhaust: Probably need to run a new custom exhaust.

As a said, it will be a big job and each item above can take one or several days of work to resolve, not to mention the cost.

If the above does not discourage you, then go for it and be prepared to deal with more issues as they arise.


Seb.....

 

i just read yor post I am a diesel mechanic on bid trucks you listed a lot of things that have nothing to do with putting the motor in. for example trany crossmember and drive shaft I an planing on keeping th 4 speed that is in the truckso thats not an issue the clutch fork isnt eather I can use the same fork as what my 86 has. the dash all I need is a glow plug, wait to start, and water in fuel the rest stays the same. frame is the same width so that isnt an issue, the truck allready has duel battreys.

ALL IM WORRIED ABOUT IS THE MOTOR MOUNTS I know some one has done this swap before becase thats where I got the idea

 

You could remove the engine towers from a diesel equipped pickup and modify them to fit your 74. Or fab up your own custom towers. I would set it up to use standard 7.3 mounts. Once you get the engne situated where you want it in the chassis, then figure out where your towers will mount. Depending on your clearance to the firewall, hood and radiator, you may need to relocate the transmission to best suit your needs. I think that your main concern will be that the 74 is a rear steer pickup which may make the clearance tight at the LR.

What is on an IDI that would require you to change the dash if you swapped it into an earlier chassis? That makes no sense to me.


Jason

 

No towers on the diesels, they mount straight to the frame. Check my gallery for pics, the oval shape in the 460 frame is where the diesel bolts to.
I think what he refers to is as already mentioned, the glow plug light and water in fuel light. Glow plugs can be set up to run amnual, and if you need an indicatorlight, one can be set up, and water in fuel, well, it can be done, or you can set it up with an add on prefilter/water separator. Look for an 80's GM 6.2 and snag the base and prefilter, they work quite nicely, bolt right to the firewall. user name Scot has done both a 6.9 and Cummins swap into the older frames. Scot's Gallery

 

I guess calling them towers is a stretch, I'm referring to the mount plates that bolt to the crossmember. I was thinking about taking these plates to build off of to attach to the early frame. Or cut out the entire late model crossmember out and grafting it into the frame (either the whole thing, or just the engine mounting area of the crossmember.

Instead of changing an entire dash just for a couple lights, just get some small LED or standard bulb indicators to put into the early dash.

Jason

 

Looking at what Scot did, he made towers for his swap, so for the early frame, it looks to be an accurate name, but that's the thing, they will have to be built, noone makes such in a production format. Other than that, as far as mounts go, shouldn't be a big deal. I have the 460 towers from the 92 if you would want them for reworking to your app...

 

thanks for the info guys that is exactly what I needed to know

 

The transmission that is behind a gas motor will not bolt up to a diesel.

 

It should as long as he is using a 6.9 bellhousing.

Jason

 

i have a 6.9 bellhousing sitting here in my shop and a flywheel

 

That will work.

The wiring you will have to do on a 7.3 engine will not be that hard since it has the new style glow plug controller.
The ignition wire to the coil will go to the fuel shut off solenoid.
That same wire will also run to the ignition terminal on the glow plug relay/controller on the 7.3 engine.



As far as the sending units go, I would use mechanical gauges that actually give readings than mean something anyway.

If you want pitures of the motor mount pads on an 86 that had a 6.9 in it, mine is out of the truck right now so it would be easy to get a picture for you.

 

yea if you dont mind could you send me some pics or post them here , thanks