First post here. About a month ago I bought a '94 F-350 Ext cab 2WD XLT with the 460 and E4OD/4.10 gears to pull our 5er toyhauler. The truck had 121K miles on it and had been sitting for a few years while the deceased owners kids fought over who got what. The price seemed reasonable.

On the way home from buying it the Fuel Pressure Regulator went out. No big deal, so I replaced it. I gave it a fresh tune up with new plugs, cap/rotor and 9mm Ford Racing wires, air filter, new injectors and she ran like a top. I also fixed a rear wheel seal and put synthetic in the rear axle. When I changed the fluid it was a chocolatey brown color.

We bought the truck specifically to make a trip for a reunion. The truck pulled the trailer fine on the trip down. After a few days of running the truck around unloaded we were coming up a steep grade and the truck started vibrating badly. My first thought was a blown tire, but when we pulled off the rear axle was smoking badly from the pinion bearing.

I was able to locate a rear axle near where we staying and bought it. When we got the axle to camp we figured out real fast that it was from a Cab&Chassis truck and was not going to bolt in. My buddies talked me into just swapping the pinion and differentials... which we did. We did not have the greatest selection of tools in camp so it was a hack job at best. However, when I test drove it for the next few days everything seemed fine unloaded.

The day we left for home we hooked up the 5er and headed for home. I stopped about 15 miles from the start and checked the temperature of the rear axle at the snout and it was 230F. My buddies powerstroke rear axle measured about 175 with a similar load. He chalked it up to break in- we let it cool for 20 minutes and headed on.

As we drove it seemed like it took more throttle as the rear end got hotter. Hard to prove and even harder to 'feel' when pulling a load that heavy. Our next stop was another 25 miles or so and again the axle was over 220 F. I took the opportunity to dump all my tanks and all water to lighten up the load as we were heading for an 8000 foot pass to make it home. I checked the fluid level and all was good.

The next leg was a long steady climb with a few steeper hills thrown in. I noticed that my temperature was running higher and towards the 'L' on normal. It would go down when I hit a stretch where it could shift up into overdrive. When we came to the first steep hill I got a bit of a run at it and kept my eye on the temp- it was around the 'A' as we approached the incline.

I could tell right away that we weren't going to be able to maintain full throttle, so I started to back out of it to try and keep it cool. There was no place to pull over until the top of the hill, so I finished the climb in first gear at about 25 MPH> by now the temp gauge was pegged. We pulled out and I left the truck running, but I guess the damage was done. Oil had begun to leak out of the drivers side valve cover. We spent the next 10 hours adding oil and driving a few miles to get to the next city. It was Sunday evening and no parts stores were open. We both needed to be to work the next morning so we continued on painfully stopping to add oil as it was needed leaving a trail of smoke as we went.

That was about a week ago. When I got the time Saturday I repaired the valve cover gasket,changed the oil and filters. I found the air filter completely oil soaked. After a short test drive the oil on the exhaust burned off and all seemed well. I found another rear axle about 35 miles from home, so I took the truck to pick it up. Again, all seemed well on the trip up, but as I headed home the truck began to smoke badly again. When I stopped to check the oil it was already below the dipstick!!

I added 3 quarts and drove it home. I could see smoke intermittently as it danced in the lights of passing traffic. The next day I pulled the PCV valve and checked it- it works just like it should. My conclusion now is that I wiped out a cylinder or two during the overheat. I now have a truck that needs a rear end and a new motor.

Last summer I pulled the drivetrain out of a 1992 IDI diesel. It has a good ZF5 to go behind it. It also has a nearly new turbo.

Should I rebuild the 460 ($$) or swap in the IDI that I have, knowing that it will also cost a few dollars to make that happen??

The truck is pretty clean, but if I would be better off cutting my losses I can take hearing that too... Thanks for reading this long post. Any advice will be appreciated.

 

Since you already have the IDI, AND its a turbo with a zf5 speed, I would certainly drop that in to replace the 460. That way you don't have to spend so much on a rebuild for the 460. The sterling 10.25 rear end is very easy to find to replace your bad one with. I think you'd be happier with the performance with the diesel over the 460 anyway.

 

For pulling its hard to beat a diesel. I would say that if you do a fair amount of pulling and working with your truck, and you plan on keeping it for awhile, diesel is the way to go.

 

Thanks for the input guys! I was leaning towards diesel, but I just ran across a 460 replacement motor for $350 that the guy swears is good. Going to check it out after work.
I would prefer the diesel, but I am not sure I will keep this truck long enough to recoupe the cost.
I have also considered a 12 valve swap. Again, $$$ than I can spend right now.

 

Idi, ZF5, in the long run its worth it. My vote is to swap.

 

Called the DMV. They have no issue with a conversion as long as I fill out a statement describing the swap and pay $10 for a diesel title.

 

Where do you live, and do you have any kind of emissions equipment checks? It is illegal to go back model years on engine swaps, and may cause an issue during inspection.

Also keep in mind going to a 7.3 IDI Turbo, you're going to loose ~10 lb-ft of torque and nearly 40HP.

 

but gain about 10mpg.

unless he upgrades his turbo down pipe,then he'll be close enough performance wise that it's about a wash.whatever running empty pep the 460 will have over the idi is all washed away with fuel mileage gains anyway,plus it sounds like hes using it strictly for towing only.so the old school easy diesel swap is a good way to go,even if that $350 460 was free,it wouldn't be worth putting in if you have 7.3/zf5 combo sitting there already.

 

Great points. In our area they recently took out all the opacity/dyno roller machines and dropped testing on all pre-OBD2 stuff. So there is not even a visual inspection on the older trucks. The enforcement mechanism is a local 'smoking vehicle' hotline where snooty patooties can call and complain.

The motor came out of a '92, but I have some '94 valve covers with the CDR and 1994 sticker. I don't see how they could not allow it in this '94, but government never ceases to amaze. I can't really even be sure that the motor is a '92 because it was a reman that someone put in just before it was t-boned. Good SCA's and clean oil so I payed the $300 he was asking for it. The ZF5 came from the same truck for another $150. I don't have as much confidence in it as the truck was fairly high in miles. The dual mass flywheel was coming apart when I seperated them.

 

That is the big one there- gas mileage. The other one is I sure hate working on this truck with all emissions stuff on it. Changing the valve cover on the drivers side was a joke due to the EGR pipe and the A/C stuff making it near impossible to remove.

My old IDI had an ATS turbo and I was always happy with it. I generally got 15-17 mpg unloaded and 9-11 loaded. The last trip on the 460 it was 5-6 going down and closer to 3 coming home with all the issues. The IDI blew a headgasket, so I really need to factor in a set of ARP studs before I go to all the work to put it in. It will never be easier to do than now.