Build Thread:: 1979 f150 7.3 IDI Conversion (Old Ironsides)

[Old_Ironsides]

Keep in mind the wheel bearings are smaller for the 5 bolt D44, but I still don't think you'll have problems. Some of those old gas engines were pigs, not weighing much less than a 6.9, and tons of Dana 44s survived.

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ahh.. alright. When I did the brakes a while back I reused the bearings since they didn't look too bad, but there were two I believe that were cheap Chinese ones which didn't thrill me too much. I should probably put a new set of good timken or national bearings on the list of things to do before too long.

 

[racer30]

Hey look into a smaller diameter booster...Its a Hot Rod Modification a lot of guys do when they put bigger Engines into tight Engine bays.

 

[Old_Ironsides]

Here's what I have done the past few days.

Got the transmission mounted up in its new location, and surprisingly I have not had much for clearance issues yet. One thing I did have to do with the new mount though is to make up spacers to go between the mount and the transmission, since the old mount was one inch taller. I used a piece of 1/2 plate that i had hanging around to make the spacers out of, which luckily enough already had holes drilled that were pretty close to where they needed to be and only required a little massaging with the die grinder to make them work

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all bolted up under the truck

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Next I hoisted up the IDI and did the first trial fit. It went in, but just barley..

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Just from putting a tape measure on it quick, it doesn't look like the mechanical fan is going to be staying when everything is said and done, since the IDI is sitting 3-4 inches further forward than the 351 was.

After this quick fit so I could start visualizing what to make for motor mount towers, I pulled the engine back out and called it a night. Today, I dragged some old plate steel out of the snow and started cutting up pieces for the frame side of the towers.

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Then I just finish-welded both pieces and they are ready to bolt on to the frame

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And this is as far as I got today. I am going to weld off of these plates so I dont have to weld directly to the frame. These towers certainly aren't going to look factory, but they should be plenty fucntional. I hope to get them finished up in the next few days. The hardest part is going to be figuring out just where the engine needs to be; mainly how high up off the mounts it needs to sit. My thought is to get it set down as low as possible, but I also want to leave ample clearance for the front axle, especially since there is already going to be clearance issues with the oil filter.

 

[Old_Ironsides]

Hey look into a smaller diameter booster...Its a Hot Rod Modification a lot of guys do when they put bigger Engines into tight Engine bays.

That thought has crossed my mind. I actually still have the parts truck (a 1987) that that I got the c6 out of when i fist got the '79, and I believe the booster in that has a smaller diameter.. ill have to check it out, since with the setup I have now things are so tight I wouldnt even be able to pull the drives side valve cover off the IDI without first pulling the booster lol...

 

[oregon96psd]

*** is sprouting out of the drivers side head on the idi, looks like a piece of black pipe with a tee in it and a hose going to the water pump....

 

[Old_Ironsides]

*** is sprouting out of the drivers side head on the idi, looks like a piece of black pipe with a tee in it and a hose going to the water pump....

Couldn't tell you... I wasn't quite sure if it looked all that factory when I saw it either.

 

[BDOGONE]

Might research E350 springs. Heavier coil not taller. Easy junkyard find.

Flea bay has 2" coil spacers listed but that might not be the best plan.

Keep up the good work!




Sent by wing, prayer & ATT

 

[77f250diesel]

I used the 2" Skyjacker coils on mine and they support the added weight just fine. I think I've got abt. 10-12 years on mine and the D44 is still holding up.
If you end up with clearance issues between the pumpkin and oil filter just use a remote mount, Summit has them, pretty sure their Perma Cool.

 

[Old_Ironsides]

Here's another update on what I have been doing on the truck

I finished up building the motor mount towers, just using the original top plates that came bolted to the 7.3, and more flat plate cut to fit.

A heavy piece of wire works well for finding angles when doing something like this. (I'm using an old piece of brazing wire which the flux has fallen off of)

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here's a picture I took after I had the engine back out of the towers tacked up. I am going to add more bracing and support to them when I finish burning them in.

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I also got the throttle pedal and clutch pedal/master cylinder all set up.

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For the clutch, I started by cutting the cross shaft that the pedal mounts to, and then cutting a piece of the bushing off of the brake pedal. Then I found a heavy piece of steel that already had 4 holes in it that i could build off of, and used some more flat plate.

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This is the brake pedal, and what I cut off is the bushing to the right

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~Continued in next post~

 

[Old_Ironsides]

After finding a spot where the clutch pedal seemed to fit well, I mounted it through the firewall, and then determined where the master cylinder needed to be placed.

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As I have seen in other's threads, next was to re-enforce the firewall to limit the amount of flex that happens when actuating the clutch. I chose to approach this by making a stiffening plate:

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I welded 8 bolts through the plate, and will use large washers inside the cab to secure the plate to the firewall

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next... I decided that if there is ever going to be a time to clean up and coat the frame with something, it is now.. so I pulled the cab and bed off of the frame, and pressure washed it thoroughly to get ready to prime/paint. The other reason I wanted to pull the body off is just for the ease putting the drive train back in, running fuel lines, making a tcase crossmember, etc...

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And that's where I am at right now. This week I plan on getting frame all painted up, but first just have to do a little welding on the cab mounts where they rotted where the bushings were.

 

[riotwarrior]

Looking good, coming along quite nice!

Keep up the good work!

 

[racer30]

Nice Job on the fab work...Everything looks very stout...Now that you have it all apart for cleaning and paint/coating you will have a nice old Ford Truck. Cheap to insure, Tough enough to do anything you need...

 

[Eli]

You're really making me miss my '78 F150 4X4! I wonder if the guy I sold it to still has it...

Eli

 

[LCAM-01XA]

*** is sprouting out of the drivers side head on the idi, looks like a piece of black pipe with a tee in it and a hose going to the water pump....

It alters the coolant flow. You know how on the passenger side you have hot coolant exiting the head, running thru the heater core, and returning to the water pump? Well this is pretty much the same setup, minus the heater core. And the T-ee is there because this is the port the overheat temperature switch is installed in from the factory, the switch now resides in said T-ee. Overall idk if such setup is actually helpful or not to an IDI engine. In theory it allows more coolant to bypass the thermostat and return to the water pump for recirculation. Maybe this was done so the engine retains more heat during cold winter driving, the logic being that factory radiators tend to overcool (hence the need for grille covers) in low temperatures and thus if more coolant is recirculated in the engine itself and less is redirected thru the radiator then the thermostat will have an easier job maintaining proper operating temperatures?

Ironsides, I got a possibly silly question for you - did you ever consider using factory big-block engine mounts for your model year? The reason for asking is because IIRC the frame brackets in the factory IDI trucks are stamped "7.5/7.3" meaning they are used for both IDIs and 460s. Following that logic wouldn't it be possible to use '70s frame brackets and drop the IDI mounts on top of them? Or are the '70s and the '80-up 460 motor mounts way different, and thus frame brackets made to work with one don't come even close to fitting the other? Just wondering...

Regarding the brake booster, do yourself a favor and lose the vacuum booster and go hydro now while you have easy access to the firewall. Halfton '70s trucks have quite pathetic brakes IMHO when rolling on anything 33" or larger, even upgrading to the dual diaphragm F350 booster for the respective year is not that big of an improvement. Heck, factory IDIs run much larger brakes, and people still find them lacking in the braking department. So kill several birds with one shot and do the hydroboost from the get-go, you will solve your interference issue with the valve cover (hydroboost can be installed upside-down which moves its reserve canister towards the fender, hot-rod folks do it all the time) and you will make up for the smaller wheel brakes with the increased line pressure. Plus you won't need to run vacuum pump, unless your truck has factory A/C or cruise.

 

[Old_Ironsides]

Looking good, coming along quite nice!

Keep up the good work!

Thank you!