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

[Old_Ironsides]

Mag chloride. Liquid rust is what we call it.


Nice job on your build.

ahh... yea that's an accurate name for it...

thanks

 

[Old_Ironsides]

Another update on the truck


I've gotten a few more things done, including making clearance for the starter, getting the clutch in and bolting the drive train together for the last time, and making up a crossmember for the tcase.

For the starter clearance, there was no way I was going to be able to make enough room just by massaging the frame rail just with heat and a hammer, so I ended up having to cut out and re-box a small portion.

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I was able to reuse the piece I took off by cutting off the lip and hammering it flat... helped make it look somewhat less "custom"

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I also decided that while the trans was back out that I would clearance the cross member as there was not much extra space there either.

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This was pretty easy since I just cut and flipped the same piece

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I was pleasantly surprised to find a SMF when I first got the engine. The clutch still looked good so it is going back together as is, with a new pilot bearing and throw out bearing.

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~Transfer case cross member in the next post~

 

[Old_Ironsides]

For the transfer case xmember I didnt get too fancy, and I cant say that I find it very attractive looking, but I had plenty of C-channel around, so that is what I used to make it. Started out with a few plates I found, and worked from there.

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I spent quite a while contemplating what to use for a mount, since I knew that I wanted to work off of the PTO cover (after browsing some other threads featuring 205 xmembers, and seeing that this is where people generally work off of, along with the mounting holes on the opposite side), and finally came up with a pretty simple solution. By some dumb luck, the transmission mount actually lines up with the top and bottom PTO cover bolts, and doing this also makes it easy to get a replacement if I ever need to, being an off the shelf part.

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And this is how it sits at the moment... need to throw some paint on and bolt it in for good, and then I hope to get the cab dropped back on this weekend, if all goes smoothly.

have a good weekend everyone

 

[LCAM-01XA]

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.

Ugh, totally forgot about this, sorry! I did measure it just now tho - there are three pairs of holes, half the time the upper pair ain't used even by GM, just the middle and lower pairs. All the holes are 3-3/8" apart horizontally, the vertical distance between the upper and middle pair of holes is 4" and the distance between the middle and lower pair is 2-1/4", all this is center to center. From the mounting plate's face to the center of the eye in the pushrod for the pedal pin to slip into the distance is 7-1/2". All older C/K hydroboosts mount the same and thus interchange, however the bigger the truck the more powerful the booster and thus ideally you want one off a 454-powered C30, but in reality even a halfton one should make your truck attempt a front wheelie

A suggestion on the transfer case crossmember if you don't mind, actually two - weld some small gusset plates to the front and rear walls of the C-channel where the horizontal beam meets the vertical ones, and maybe weld a plate to the t-case mount so it spreads the load across more than just two 3/8" PTO bolts. Other than that it looks pretty overkill, and overkill is good.

 

[Old_Ironsides]

Ugh, totally forgot about this, sorry! I did measure it just now tho - there are three pairs of holes, half the time the upper pair ain't used even by GM, just the middle and lower pairs. All the holes are 3-3/8" apart horizontally, the vertical distance between the upper and middle pair of holes is 4" and the distance between the middle and lower pair is 2-1/4", all this is center to center. From the mounting plate's face to the center of the eye in the pushrod for the pedal pin to slip into the distance is 7-1/2". All older C/K hydroboosts mount the same and thus interchange, however the bigger the truck the more powerful the booster and thus ideally you want one off a 454-powered C30, but in reality even a halfton one should make your truck attempt a front wheelie

A suggestion on the transfer case crossmember if you don't mind, actually two - weld some small gusset plates to the front and rear walls of the C-channel where the horizontal beam meets the vertical ones, and maybe weld a plate to the t-case mount so it spreads the load across more than just two 3/8" PTO bolts. Other than that it looks pretty overkill, and overkill is good.

Cool, thanks for taking those measurements, i'll have to do some measuring myself now and see if it comes close. As for the tcase support, it does also mount on the other side, but with a mount that came from the factory in 79 instead of off of the cross member I built.

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It shares the same 3 mounting bolts that the left side of my cross member bolts too. I didn't think just that mount was really enough though since it doesn't hold much of the weight being that far off center. My cross member is just a supplement to the factory mount, to more or less "cradle" the case. But i agree that if that other mount wasn't there it would need more support than just the two bolts on the PTO side. Ill keep a close eye on it anyhow once I start driving it to make sure everything seems alright.

 

[LCAM-01XA]

Ah yes, I had a blonde moment and forgot about the factory side mount of the case - you should be good then, what you got will work fine. Are you planning on twin-sticking the 205, or does it shift decent enough to leave it factory?

 

[dirtbiker]

Good progress, it's coming along nicely. Are those the drive shafts from the 79 or the donor rig? Just curious which you ended up using, I don't recall seeing it mentioned anywhere in here.

 

[Old_Ironsides]

Ah yes, I had a blonde moment and forgot about the factory side mount of the case - you should be good then, what you got will work fine. Are you planning on twin-sticking the 205, or does it shift decent enough to leave it factory?

It still shifts quite nicely in its current setup. I'll probably leave it this way for the time being just for simplicity sake, but if I ever get really ambitious down the road its always a possibility. They are pretty cool twin sticked, even though I'm not sure it would be all that practical for what I am ever going to do with this truck. I guess if shifting it does become a problem that would be a good reason to do it though.

 

[Old_Ironsides]

Good progress, it's coming along nicely. Are those the drive shafts from the 79 or the donor rig? Just curious which you ended up using, I don't recall seeing it mentioned anywhere in here.

Thank you. And I haven't talked much about drive shafts, but those are the originals from the 79. The joints I am sure are a little under sized for the job (being 1310's I believe) so that's just another thing I have to keep an eye on. Last thing I want to do is bust a joint and ruin a drive shaft, but I think if I don't get too wild with it and leave it N/A they should hold up alright. Service life may be a little shorter than normal with the joints, but I can live with that.

 

[LCAM-01XA]

Well you don't necessarily have to swap or mod shift rails when you twin-stick it, you can keep the factory rails in their factory form - you just have to make sure you rear axle is in the range you want before shifting the front axle in the same range. The rails swap/mod is what allows you to turn just the front axle while rear is in neutral, if you don't want/need that power flow option you just swap the shifters - a good solution to shift linkage that's so loose you can't tell if she's in 2H or 4H, which is sorta what I'm working with

And yeah your U-joints are likely 1310s, one of these days I gotta try and see if a NP208 yoke will fit the NP205 - if it does that's a cheap 1330 upgrade, can even be had in CV (double-cardan) style off a Bronco NP208. I'll let you know what I find out soon.

 

[dirtbiker]

Thank you. And I haven't talked much about drive shafts, but those are the originals from the 79. The joints I am sure are a little under sized for the job (being 1310's I believe) so that's just another thing I have to keep an eye on. Last thing I want to do is bust a joint and ruin a drive shaft, but I think if I don't get too wild with it and leave it N/A they should hold up alright. Service life may be a little shorter than normal with the joints, but I can live with that.

Yeah, that's what it looked like to me. I had the driveshafts from my donor rig shortened but I forget exactly what I did for joints. I believe that I used whatever was on them already except just replaced them. They fit in the 9" and d44 yokes just fine, so it shouldn't be a big deal for you to swap your joints out. They might even be 1310's, it's just been awhile since I did the shafts. In any case, you're right and you'll be fine as long as you aren't being too wild. I don't beat on my truck, but I do get on it sometimes and the drivelines and everything are holding up just fine.

 

[Old_Ironsides]

Well you don't necessarily have to swap or mod shift rails when you twin-stick it, you can keep the factory rails in their factory form - you just have to make sure you rear axle is in the range you want before shifting the front axle in the same range. The rails swap/mod is what allows you to turn just the front axle while rear is in neutral, if you don't want/need that power flow option you just swap the shifters - a good solution to shift linkage that's so loose you can't tell if she's in 2H or 4H, which is sorta what I'm working with

And yeah your U-joints are likely 1310s, one of these days I gotta try and see if a NP208 yoke will fit the NP205 - if it does that's a cheap 1330 upgrade, can even be had in CV (double-cardan) style off a Bronco NP208. I'll let you know what I find out soon.

Oh ok, I gotcha.. yea I was thinking the full blown twin stick conversion. Even without doing the full modifications that would be much better than a shifter thats so loose you dont know where you are lol.

And if that does work swapping yolks that sounds like it would be a nice easy upgrade. I am pretty ignorant to u-joint specs though, so I really don't have much concept on how much stronger a 1330 is.. is there a significant difference between them? Either way I think the 1310s should hold up to what I am going to put them through for the time being.

 

[Old_Ironsides]

Yeah, that's what it looked like to me. I had the driveshafts from my donor rig shortened but I forget exactly what I did for joints. I believe that I used whatever was on them already except just replaced them. They fit in the 9" and d44 yokes just fine, so it shouldn't be a big deal for you to swap your joints out. They might even be 1310's, it's just been awhile since I did the shafts. In any case, you're right and you'll be fine as long as you aren't being too wild. I don't beat on my truck, but I do get on it sometimes and the drivelines and everything are holding up just fine.

That's good that you haven't been having any problems with them, I'm guessing yours must be similar to what I have if they still fit your old yolks fine. Also considering that the idi is right in the same league as the 460 power wise (based on specs for a late 70's 460), they should be good i'd think. 351 to 460 is a common enough swap, and I haven't heard of anyone having drive line issues with the 460's.

 

[Old_Ironsides]

Here's another update on what I've been up to.

I have gotten the cab and nose back on the truck, and it is really starting to come together quite nicely. It definitely sits quite a bit taller than it did before.. By the time everything is back on the front end It will be sitting just about level, although its hard to tell without the bed on yet.

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Once this was on, I felt like starting with modifying the doghouse and getting the shifter set up. I was originally planning on finding or making my own shifter that fit the look of the truck better, but the original zf shifter proved to fit just fine, clearing the dash, and clearing the tcase shifter after bending the tcase shifter slightly out of the way.

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Oh yea... and my new found starter clearance should also work out just fine

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Next step: fitting a 6.9 radiator where it was never supposed to be. I did get the 7.3 radiator with the engine, though it was never going to work in this setup since the frame is too narrow for it to sit down in between, and it is so tall it would be above the core support by about 6-7 inches, making closing the hood a problem. The 6.9 radiator is one that we had hanging around here, that once upon a time came out of a 84 250 my dad used to have.

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I started by roughly cutting out what was going to have to be removed from the inner fenders, and then it was just a matter of repeatedly trying the rad until i go it to sit down in there. Once I had the clearance, I moved on to making mounting brackets. Took me a while to finally come up with something that would work, and turns out all I needed was some flat stock, bent into shape.

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The brackets are welded to the core support on the bottom since it is boxed and would have been difficult to bolt to. On the brackets, there are bolts welded on the bottom for the radiator to rest on, and then bolts welded on the top tabs as well, for the radiator to fall into. I am very happy how this setup works, since it is still very easy to install and remove the radiator.

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The problem I knew i was already going to face was not having enough clearance for the mechanical fan. I don't even have the clearance for electric fans on the engine side, so it will be getting two pusher fans mounted to the front of the radiator.

My initial hope was to use the particular radiator that we had, though that plan changed pretty quickly. It has some serious what I believe to be calcium buildup inside of it, and even after trying to loosen it up with boiling water, it is still not much better. On top of that, many of the tubes are also closed up solid, since when it was full of hot water, running my hand over the outside showed that about 1/3 of the outer tubes were not even getting warm. I could have brought it to a radiator shop and had them clean it out, but I found a replacement on amazon, a spectra, for 300 shipped. By the time I took this radiator to a shop, and they would probably have to dismantle it to "rod" the core, I would have likely been close to that cost anyway. I really want to make sure that I am not introducing any new contaminants into the cooling system, since when I looked at the coolant when this idi was still in the donor truck, the coolant and inside of the radiator were immaculate.

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~Continued in next post~

 

[Old_Ironsides]

~Continuation~

Heres another shot from inside the old radiator

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One more problem I ran into was with the lower radiator hose. The way i have the radiator mounted, with the bottom kicked towards the engine slightly to clear the core support mounts, everything is so tight that an original hose was not going to work. To fix this, I took some 2 inch pipe I found, and made myself a 90 degree elbow.

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The pieces of hose I used to connect everything together came from a single lower hose, so replacement will still be easy enough.

Moving onto mounting a second battery tray, I first had to reinforce the inner fender where i had cut out. This started with a piece of angle with a tab welded to it.

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Wet paint in that picture makes it look kind of strange, but the angle is welded to the inner fender and just bolted to the core support.

For the second battery tray, I used one off of the 87 parts truck I have. All that I had to do was drill holes, and it fit quite well.

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Finally, I started playing with some electrical and started with the glow plugs, to see if I needed to get some coming. there were two burnt out ones, and thankfully the PO believed in beru's... came out no problem. The second one was making me nervous, but working it in and out and spraying with PB finally brought it out. Was just carbon holding it up, not a deformed tip.

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And that's about where I am at at the moment. The new radiator and other parts including the fans should be here today, so I will be able to get things put together for good here soon. Should be ready for the first start up before too awful long.