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

[Old_Ironsides]

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.

I never really did research going that route with the motor mounts but that does sound like it could have certainly worked if the mounts cross over like that on the newer trucks. The main reason I approached doing the mounts the way I did was because I am working from the tcase mount forward as far as the placement of the drive train, so i can avoid the added cost of having drive shafts lengthened/shortened. Since i am doing this, any factory motor mounts probably would not have been in the right location to bolt right up. If one were to start by placing the engine and then adjusting for the new location of the trans/ transfer case, then it sounds like factory 460 mounts would probably do the trick.

As for the brakes, I would like to end up doing a hydroboost setup, but I have no experience with them so I certainly need to become more educated before knowing what will work for this project. Any suggestions as to what to look for for a hydroboost/master setup that would be appropriate for a setup like this?

 

[LCAM-01XA]

Well from what I've seen driveshafts are usually not engine-specific, also in case of 4-speed manual transmissions the same transmission is used in everything from Bronco to dually F350 and the shifter always comes out the same exact spot on the floor pan - meaning the transfer case always stays in one place, and it's the length of the engine and possibly transmission bellhousing that vary and thus affect location of motor mount brackets on frame rails. Regardless, I just pulled up some pictures of '70s and '80s/'90s 460 mounts, and they are way different - meaning that even tho IDI+ZF5 in the '80s and '90s uses the same frame brackets as 460+T18/T19/NP435, and 460+T18/T19/NP435 was a perfectly legit factory setup in the '70s, due to the difference between '70s and '80s/'90s 460 mounts the '70s frame brackets probably wouldn't work on an IDI engine... So you're on the right track, and it sure looks like you're doing good progress, keep it up!

Regarding hydroboost, in case of factory IDI trucks the most typical install involves raiding a late-'80s to mid-'90s F-Superduty (essentially a F450) truck and grabbing its brake booster, master cylinder, power steering pump reservoir, and the brake pedal from inside the cab. The brake pedal thing probably won't apply to you as your setup is way different, IMHO you're better off keeping the pedal you have and aligning the hydroboost to that and then varying master cylinder bore to adjust for the different leverage the '79 brake pedal may have compared to the F-Superduty one. Actually if you give me distance from center of foot pad to pedal pivot axis, and then distance from axis of pedal pin (for booster pushrod) to again pedal pivot axis, I can tell you how close to the F-Superduty leverage you'll be, then we can go from there to find you a suitable master cylinder cause the F-Superduty one is simply massive and may end up way too big for your small calipers and wheel cylinders. If you get the F-Superduty hydroboost then you can also use F-Superduty pressure hoses between pump and hydro and then between hydro and steering box (both your steering box and the F-Superduty one should use the same 5/16" O-ring port on the pressure side). Return line from the power steering to pump requires no changes. Return line from hydroboost to pump is just a few feet of 3/8" hose of the same kind you used on the steering box return, preferably of the transmission oil cooler (TOC) variety.

There is another option, and that is the hydroboost of from a late '70s Lincoln Continental TownCar - this one has the same inlet and outlet ports as the F-Superduty one so it can use the same pressure hoses, but its pedal pushrod appears to be a bit longer so it may fit better in your truck (cause I frankly have no idea how far your pedal is from the firewall). Additionally, the original application for this is a huge car with weight and brakes sizes comparable to those of your truck, so this hydroboost and master cylinder pair may be better matched to your needs than the F-Superduty parts. And to top it off there are actually two models of hydroboost units, one has gold (in color) reservoir and the other is silver - one is for cars with skid-control and the other is the regular, idk which is which but at least in theory the silver one should be the one to get as silver (and blue) reservoirs are charged with about 100 more psi of nitrogen than gold ones so in case of emergency you get either one extra brake apply before total loss of assist, or stronger assist during the first 3 brake applies.

Ultimately anything can be made to work well, pretty much depends on what you can get your hands on for cheap. The advantage of using Ford hydroboosts comes in the form of readily available and cheap pressure hose, you can go GM hydroboosts too as they are plentiful and work well but you'll need to have custom pressure hoses made.

 

[Old_Ironsides]

Well from what I've seen driveshafts are usually not engine-specific, also in case of 4-speed manual transmissions the same transmission is used in everything from Bronco to dually F350 and the shifter always comes out the same exact spot on the floor pan - meaning the transfer case always stays in one place, and it's the length of the engine and possibly transmission bellhousing that vary and thus affect location of motor mount brackets on frame rails. Regardless, I just pulled up some pictures of '70s and '80s/'90s 460 mounts, and they are way different - meaning that even tho IDI+ZF5 in the '80s and '90s uses the same frame brackets as 460+T18/T19/NP435, and 460+T18/T19/NP435 was a perfectly legit factory setup in the '70s, due to the difference between '70s and '80s/'90s 460 mounts the '70s frame brackets probably wouldn't work on an IDI engine... So you're on the right track, and it sure looks like you're doing good progress, keep it up!

Regarding hydroboost, in case of factory IDI trucks the most typical install involves raiding a late-'80s to mid-'90s F-Superduty (essentially a F450) truck and grabbing its brake booster, master cylinder, power steering pump reservoir, and the brake pedal from inside the cab. The brake pedal thing probably won't apply to you as your setup is way different, IMHO you're better off keeping the pedal you have and aligning the hydroboost to that and then varying master cylinder bore to adjust for the different leverage the '79 brake pedal may have compared to the F-Superduty one. Actually if you give me distance from center of foot pad to pedal pivot axis, and then distance from axis of pedal pin (for booster pushrod) to again pedal pivot axis, I can tell you how close to the F-Superduty leverage you'll be, then we can go from there to find you a suitable master cylinder cause the F-Superduty one is simply massive and may end up way too big for your small calipers and wheel cylinders. If you get the F-Superduty hydroboost then you can also use F-Superduty pressure hoses between pump and hydro and then between hydro and steering box (both your steering box and the F-Superduty one should use the same 5/16" O-ring port on the pressure side). Return line from the power steering to pump requires no changes. Return line from hydroboost to pump is just a few feet of 3/8" hose of the same kind you used on the steering box return, preferably of the transmission oil cooler (TOC) variety.

There is another option, and that is the hydroboost of from a late '70s Lincoln Continental TownCar - this one has the same inlet and outlet ports as the F-Superduty one so it can use the same pressure hoses, but its pedal pushrod appears to be a bit longer so it may fit better in your truck (cause I frankly have no idea how far your pedal is from the firewall). Additionally, the original application for this is a huge car with weight and brakes sizes comparable to those of your truck, so this hydroboost and master cylinder pair may be better matched to your needs than the F-Superduty parts. And to top it off there are actually two models of hydroboost units, one has gold (in color) reservoir and the other is silver - one is for cars with skid-control and the other is the regular, idk which is which but at least in theory the silver one should be the one to get as silver (and blue) reservoirs are charged with about 100 more psi of nitrogen than gold ones so in case of emergency you get either one extra brake apply before total loss of assist, or stronger assist during the first 3 brake applies.

Ultimately anything can be made to work well, pretty much depends on what you can get your hands on for cheap. The advantage of using Ford hydroboosts comes in the form of readily available and cheap pressure hose, you can go GM hydroboosts too as they are plentiful and work well but you'll need to have custom pressure hoses made.

Lots of good info there, thank you! I will have to get some measurements later in the week here and get back to you. From what you are saying though one from a continental sounds like it may be the most viable option, as far as keeping the brake system more or less proportioned. My current master cylinder has a 1 inch bore, just for reference. I just took a look on napa at the continental booster and it looks almost identical in regards to the mounting pad and the push rod. Napa is getting right around $200 for just the booster including the core charge though, so i'll have to keep my eyes open for a used one somewhere, I'm sure I can find one cheaper than that. Hydroboost is definitely going to be the way to go when I can come up with the components though... the brakes on this truck in stock form were in no way anything to write home about.. and they certainly aren't going to improve with a diesel hanging over the front.

Also, you mentioned a reservoir for the power steering pump, is this just one that is run in addition to the standard style PS pump with the built in reservoir, or would this setup require a different PS pump all together?

 

[LCAM-01XA]

Aye, I looked up your brake master cyl size before I suggested the Conti setup, you run 1" bore and the Conti is 1-1/8" so close enough. If anything you'll get a wee bit higher pedal when brakes start applying which may actually make it feel a bit more controllable.

Regarding the pump, the IDI one is a two-piece design - you have an aluminum housing that holds the working parts, and a plastic reservoir that slips onto that from the back side to hold the fluid. The plastic tank is sealed to the aluminum housing via a big o-ring, and the only thing preventing it from sliding off is the big fitting that the pressure hose bolts into. There are two reservoirs available for this pump, the regular kind that has only one return port (on the bottom) used by the steering box, and then there is the F-Superduty reservoir that looks nearly identical but has a second return port (on the top side) for the hydroboost line to hook up to. The two reservoirs interchange, all you have to do is remove the pressure port fitting (there's a spring-loaded valve behind it, it rarely attempts a flight but still it's good to be aware of its presence), slide old reservoir off, slide new one on, and reinstall the fitting. Supposedly from the factory the actual pumps are also different, with the F-Superduty pushing a bit higher pressure, but replacement pumps are all the same, so there's no real reason to swap the pump itself unless you really wanna do more work than it's probably worth the effort. That's why I said to just grab the F-Superduty reservoir, it's usually cheaper than a whole pump with pulley and brackets. Or you can grab a new reservoir alone from the dealership, IIRC someone on here did just that not too long ago.

If you can't find an F-Suprduty truck to rob for parts, but you do find a Continental, you can use its power steering pump too. That one is different model, it's made by Saginaw and looks nothing like most Ford pumps, but very much like most GM pumps - it's more friendly to line pressure modifications and there are many aftermarket reservoirs and fittings available for it. Ford actually did use this pump on IDI engines, but only in Econoline vans and only with V-belts. For ease of installation use the Conti pump and its mounting bracket, extra benefit is you can run the Conti pressure hoses too and all will match. Minor mods will be required (some grinding on the pump bracket and bending the hoses due to their ridiculous length) but it's no big deal. In case you're wondering I'm speaking from experience for the most part, I run the Conti pump and reservoir and mounting bracket on my IDI, just the hose is GM cause my hydroboost came from a GM truck. I have the bug to try a Ford hydroboost cause it's rumored to be stronger than the GM stuff, but I'll still be keeping my Saginaw pump, just switch it over to Conti pressure hose to match the Ford hydro (likely a hose for a Conti with Skid Control cause it's like half the length of the normal Conti hose).

 

[Old_Ironsides]

Aye, I looked up your brake master cyl size before I suggested the Conti setup, you run 1" bore and the Conti is 1-1/8" so close enough. If anything you'll get a wee bit higher pedal when brakes start applying which may actually make it feel a bit more controllable.

Regarding the pump, the IDI one is a two-piece design - you have an aluminum housing that holds the working parts, and a plastic reservoir that slips onto that from the back side to hold the fluid. The plastic tank is sealed to the aluminum housing via a big o-ring, and the only thing preventing it from sliding off is the big fitting that the pressure hose bolts into. There are two reservoirs available for this pump, the regular kind that has only one return port (on the bottom) used by the steering box, and then there is the F-Superduty reservoir that looks nearly identical but has a second return port (on the top side) for the hydroboost line to hook up to. The two reservoirs interchange, all you have to do is remove the pressure port fitting (there's a spring-loaded valve behind it, it rarely attempts a flight but still it's good to be aware of its presence), slide old reservoir off, slide new one on, and reinstall the fitting. Supposedly from the factory the actual pumps are also different, with the F-Superduty pushing a bit higher pressure, but replacement pumps are all the same, so there's no real reason to swap the pump itself unless you really wanna do more work than it's probably worth the effort. That's why I said to just grab the F-Superduty reservoir, it's usually cheaper than a whole pump with pulley and brackets. Or you can grab a new reservoir alone from the dealership, IIRC someone on here did just that not too long ago.

If you can't find an F-Suprduty truck to rob for parts, but you do find a Continental, you can use its power steering pump too. That one is different model, it's made by Saginaw and looks nothing like most Ford pumps, but very much like most GM pumps - it's more friendly to line pressure modifications and there are many aftermarket reservoirs and fittings available for it. Ford actually did use this pump on IDI engines, but only in Econoline vans and only with V-belts. For ease of installation use the Conti pump and its mounting bracket, extra benefit is you can run the Conti pressure hoses too and all will match. Minor mods will be required (some grinding on the pump bracket and bending the hoses due to their ridiculous length) but it's no big deal. In case you're wondering I'm speaking from experience for the most part, I run the Conti pump and reservoir and mounting bracket on my IDI, just the hose is GM cause my hydroboost came from a GM truck. I have the bug to try a Ford hydroboost cause it's rumored to be stronger than the GM stuff, but I'll still be keeping my Saginaw pump, just switch it over to Conti pressure hose to match the Ford hydro (likely a hose for a Conti with Skid Control cause it's like half the length of the normal Conti hose).

Alright, thanks for the clarification on the pump. Yea I'll have to just see what maybe pops up, and I'll have a better idea once I have the body back on with everything else in place as to what kind of room I really have to play with. The only possibility I have come up with so far is a GM hydroboost setup out of a 78 c10 350 diesel, so this may be the way I go when I get to that point.

 

[Old_Ironsides]

Here's another update on my progress.

First off, I got in some parts I ordered from Bronco Graveyard, including springs, C-bushing kit, and body mounts. I decided to go with 4 inch springs, and if they end up being a little too much in the front I will do something to pick the back of the truck up a little bit.

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I wanted to replace all of the front end bushings before painting the frame so that I didnt have to chew up the new paint after the fact pulling the radius arms and whatnot apart. The c bushings were definitely at the end of their life....

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And here are the pictures of my frame primed and painted. All I did to clean it up was to spend a good deal of time with the pressure washer, running purple power through it. Beyond that there was no scale on the frame, and I only had to do a little scrapping to take off what was left for original undercoating and paint.

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After this I finished up my motor mount towers, adding another plate to each for support and burning them in all the way. They also got a treatment of paint, and here they are bolted up to the frame.

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At this point I was pretty much ready to drop the engine/trans/tcase in the frame to see how thing were all lining up. Before this though I needed to notch the ZF so it would accept the 205. This was quite a bit easier than I was anticipating, and it really did not take much to get things to fit. I started by making a cardboard template based off of the tailhousing on the C6, locating off of the dowel pin and one bolt. I transferred this to the ZF and made a scribe line with an awl.

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Now it was time to grab the sawzall and start cutting. My greatest word of advice to anyone doing this themselves is to cut a little inside of where you need to get to. The sawzall will not leave a very nice cut, and a die grinder with carbide bit or something of that nature is needed to finish up with, so having a little extra material to work with is not a bad thing.

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That is as much as I could get at with the sawzall, and the rest I just used the die grinder for. One other piece of advice is to smooth out all sharp edges afterwards, since cracks have a tendency to start at sharp edges. I know this is a practice on engine blocks, and with the extra stress being put on the ZF's tail housing, it cant hurt.

~Continued in next post~

 

[Old_Ironsides]

Continuation:

Here is the ZF finished up and bolted to the 205.

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Now I dropped everything back into the frame rails for the moment of truth, whether or not the transfer case was going to fall right up on its mount, which I have been working off of to locate the drive train.... It was right on the money, and I couldn't be happier about how everything lines up.

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One hiccup I did run into however is with clearance for the starter... To this point I have neglected to trial fit the starter, and while the issue is not huge, the solenoid is hitting the corner of my motor mount tower, and the top bolt which also secures the shock tower.

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The solution to this is going to be to cut the corner off of my tower to start with, and hopefully this will create sufficient clearance. If not, then i will have to heat and bend in on the corner of the boxed section of the frame where it is hitting, but this is a last resort as I really dont want to have to do this.

This is as far as I am at the moment, and next, after resolving my starter issue, is going to be to put the fuel tank back in, run fuel lines, and to start playing with the exhaust. Upon trying a while ago, the front driveshaft is going to try to occupy the same space as the IDI's y pipe when it is back together.

and I almost forgot... happy new year everyone!

Edit:
I should also add that a t case cross member is also on the list of things to do coming up, since from what I understand this is an absolute must when hanging a 205 off the back of a ZF to prevent eventually cracking the tail housing.

 

[racer30]

Nice work....You have a nice project going... Looks real Good.

 

[Old_Ironsides]

Nice work....You have a nice project going... Looks real Good.

Thank you!


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[LCAM-01XA]

Great work so far! Quick question, are the C-bushings degreed for caster or not? I had 4" lift on a truck like yours and IIRC it ended up needing a few extra degrees from the C's cause of how the radius arms turned down and twisted the entire axle into zero caster situation, now I know you won't have 4" lift with the diesel on top of them coils but even with a bit of lift you may benefit from some 2 degrees more caster. Actually looking at JBG's site they say 4* is needed for lift of 1-3", I bet that's right where you'll end up after all is said and done.

Oh, and I saw you mentioned a C30 hydroboost as a possibility for your brakes, I got one of them laying around - I'll measure it up for you tomorrow so you can figure out what it will take to make one work.

 

[opusd2]

Those GM Hydroboosts work very well. The one in my 84 6.2L M1009 Military Blazer stops the 37" Goodyear MT Hummer tires like they were nothing, and the 82 6.2L C10 4x4 Suburban will stop it like it was a 78 Chevette. People remember those Chevettes, right? I have often thought about upgrading a couple of my 70s truck projects with them.

And the Hydroboost brakes off of a 5.7L diesel powered car are amazing as well. Still run them on my 82 Pontiac Grand Prix that the 327 from my mom's old rusted out Chevelle went into. Converted a regular Saginaw to accept the second return line due to the way it mounts so close to the exhaust. I wouldn't hesitate to use one of those units on a vehicle not too heavy, though they were on Toronados.

But has anyone tried an electric assisted master cylinder like off of a C60 truck? I used to drive one when I first started delivering fuel, and I can remember that gas drinking 366 dying on an incline and the buzzing of the electric assist kicking in to hold the truck as I had to restart it. I honestly wouldn't mind one of these, or a 2 speed rear on the old Ford of mine

 

[opusd2]

But I didn't mention, I LOVE all the progress info and pictures. It keeps bugging me about a couple of different vehicles I have that would be great diesel recipients. But since it's hard enough to keep my 86 going at the moment, I'll worry about the bigger projects later.

Oh and those radius arm bushings make a BIG difference in handling. My 73 F100 has bushings that look like mush and the steering really shows it. My 79 Bronco has rough bushings too, but the difference isn't as bad. Still I would love to do both vehicles, but the bolts holding the radius arm halves together on the 73 scare me. They don't look like they will come out well and the thread on the end looks spotty. But the truck did spend many years cruising through the crap in the barnyard on the farm. So that really makes the rust a lot more aggressive.

 

[Old_Ironsides]

Great work so far! Quick question, are the C-bushings degreed for caster or not? I had 4" lift on a truck like yours and IIRC it ended up needing a few extra degrees from the C's cause of how the radius arms turned down and twisted the entire axle into zero caster situation, now I know you won't have 4" lift with the diesel on top of them coils but even with a bit of lift you may benefit from some 2 degrees more caster. Actually looking at JBG's site they say 4* is needed for lift of 1-3", I bet that's right where you'll end up after all is said and done.

Oh, and I saw you mentioned a C30 hydroboost as a possibility for your brakes, I got one of them laying around - I'll measure it up for you tomorrow so you can figure out what it will take to make one work.

Yes, the c's are degrees for caster, and the ones I put in it are the 4 degree ones, which should work out alright when it is all said and done.

As for the hydroboost I have a lead on, it is actually from a c10, not a c30, but I don't know if the mounting between the two is different or not. I'm sure they are different boosters though. If you know that they mount similarly then some rough measurements wouldn't hurt if you have the time to take some.


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[Old_Ironsides]

But I didn't mention, I LOVE all the progress info and pictures. It keeps bugging me about a couple of different vehicles I have that would be great diesel recipients. But since it's hard enough to keep my 86 going at the moment, I'll worry about the bigger projects later.

Oh and those radius arm bushings make a BIG difference in handling. My 73 F100 has bushings that look like mush and the steering really shows it. My 79 Bronco has rough bushings too, but the difference isn't as bad. Still I would love to do both vehicles, but the bolts holding the radius arm halves together on the 73 scare me. They don't look like they will come out well and the thread on the end looks spotty. But the truck did spend many years cruising through the crap in the barnyard on the farm. So that really makes the rust a lot more aggressive.

Thank you! Yea with the new bushings it should clean up the handling a bit more, although surprisingly it was not that bad before. And I know what you mean by the noise the electric booster makes, I drive a IH 4700 for work that has juice brakes, and whenever there is no hydraulic pressure to the booster with the engine off the electric backup kicks on when you hit the pedal. An electric setup would probably work on a pickup, the only thing I would be concerned about is relying on it all the time, since they are really only intended for backup use.

I know the rust routine, fun is...The bolts in my radius arms didn't look too good before I took them out, but they ended up backing out alright after letting them soak in PB blaster for a while. The only thing that saved the underside of this truck is the fact that it was taken off the road before CT decided it was a good idea to start spraying calcium or magnesium or whatever it is they are putting down now in the winter.


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[trackspeeder]

I know the rust routine, fun is...The bolts in my radius arms didn't look too good before I took them out, but they ended up backing out alright after letting them soak in PB blaster for a while. The only thing that saved the underside of this truck is the fact that it was taken off the road before CT decided it was a good idea to start spraying calcium or magnesium or whatever it is they are putting down now in the winter.


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Mag chloride. Liquid rust is what we call it.


Nice job on your build.