IDI Saginaw swap. The Saga begins...

[IDIBronco]

Yesterday, I decided I would finally start on the swap on my bronco. I went over to the parts van I had and rapidly removed all the parts I had thought I would require. The van is a 1983 (have to find build date) with a 300 I6. I have been talking with Jonathan (Ford F834) and he had been kind enough to send me a gas V8 bracket that was thought to work with pump and pulley from my van. I know I have read in several places on forums the gas v8 v belt brackets should interchange with the IDI. The parts came off the van so easy (less than 20 minutes I had it all ready to go) I decided I would try and see how they would go onto the bronco. So I pulled my pump and bracket off and snaked the pressure hose out, and this is where the problems began.

First, I noticed that the van's steering box and the Bronco's box had different threads for the pressure line input into the box. The bronco used a double flare fitting, the van had some kind of an o-ring fitting. After a bit of thought I decided to pull the fitting off the rear of the Saginaw and see if it would swap around with the one that came off the bronco. It looked promising so I decided I would give it a whirl as it would allow me to hook everything up using the bronco's pressure hose to the Saginaw pump until I could source a proper hose to work with the Saginaw's fitting. It took a little tweaking of the bends in the line, but it appeared I would be able to get everything to hook up and lay in a reasonably safe area. Up until this point I had held the pump in position with just the pivot bolt. Next, I attempted to install the belt and see how length and alignment were going to work out. I quickly saw the belt would need to be shorter to work. So I tried to get the adjuster bolt to hold the pump in place close enough to take some measurements for belt length and I found the bolt wouldn't start. I thought at first it was a different thread size and decided to pull the pump out to look more closely at the bracket since I hadn't actually checked to see if the c2 pumps bolt would fit before installing. Once I had the idi and gas v8 bracket side by side it was obvious the bolt was a different size. I found one of the original bolts that mount the C2 pump to the aluminum bracket were the right size and appropriate length. So back in the bronco everything went. Now this time after getting everything snaked back in and up to installing the pivot bolt, the bolt still wouldn't start. My frustration with the project is starting to grow at this point, but I am used to little hurdles with projects. I decided to press on. I made the decision to once again remove the pump to figure out exactly the cause of the problem. I took some time to inspect and compare the mounting hole locations on the c2 bracket and the Saginaw bracket. When holding the brackets up face to face you can overlap the mounting holes. It would appear (in rain and less then perfect lighting conditions) that the 2 mounting holes are not the same spacing between the Saginaw gas V8 bracket and the IDI c2 bracket. Additionally, the gas v8 Saginaw and the 300 I6 Saginaw brackets used the same spacing for the pivot and adjuster holes. The holes are spaced approximately half a hole diameter off. I will hopefully get some accurate measurements of the difference tonight after work, but it appears that some modifications will have to be made in order to get my brackets to work. Having become wet and frustrated, I admitted defeat for the evening. I cleaned up the tools and parts and closed everything up for the night.

I decided to hopefully be able to document what it takes to make this work. If anyone has used the V8 Gas bracket on an IDI please let me know what you did. It is possible that the brackets on the IDI I have in the bronco are unusual. I know a lot of discussion has already taken place on this forum about the IDI Saginaw serpentine swap options, and there is a lot of knowledgeable people here. So I look forward to hearing from anyone with some input.

I hope to hear that I have grossly missed some simple detail and would gladly admit the error I have made, but for the time I do not think the gas v8 bracket will work on the IDI.

[Gary Lewis]

Bummer!

I know nothing about the brackets. In fact, I don't have any of them to measure. But, when you get this all worked out we do need to document it, and that's where I can help.

[IDIBronco]

Bummer!

I know nothing about the brackets. In fact, I don't have any of them to measure. But, when you get this all worked out we do need to document it, and that's where I can help.

Once it is figured out I will gladly work with you to get some properly documenting photos and information.

Note: work delay due to rain. No news tonight.

[Ford F834]

Andrew, I am sorry for the problem. I don’t understand how the same bracket can drop in place of the C2 aluminum one on my I-6 but not on the IDI. I need to look into it. I’m Facebook friends with an IDI guy who is running Saginaw on his V belt IDI. That’s who I got pics from, and it looks likes one of Craig’s pics illustrates exactly what you are talking about. I’m betting he will have an answer. Stay tuned...

[IDIBronco]

Andrew, I am sorry for the problem. I don’t understand how the same bracket can drop in place of the C2 aluminum one on my I-6 but not on the IDI. I need to look into it. I’m Facebook friends with an IDI guy who is running Saginaw on his V belt IDI. That’s who I got pics from, and it looks likes one of Craig’s pics illustrates exactly what you are talking about. I’m betting he will have an answer. Stay tuned...

I think I figured out a decent solution. I should be back together and have more information tomorrow.

I am planning on running the 300 bracket with some modification. It needs spacers front and rear to align the pulley front to back. And the pivot hole needs to move 1/4" to work.

Hopefully, plenty of pictures tomorrow.

Notes:

C2 pump bracket pivot to adjuster mount holes are 3.25 inch center to center

Saginaw 300 and the bracket I got from Jonathan are both 3 inches center to center

The 300 Saginaw bracket has different rear offset compared to the one Johnathan sent.

 

[IDIBronco]

I think I figured out a decent solution. I should be back together and have more information tomorrow.

I am planning on running the 300 bracket with some modification. It needs spacers front and rear to align the pulley front to back. And the pivot hole needs to move 1/4" to work.

Hopefully, plenty of pictures tomorrow.

Notes:

C2 pump bracket pivot to adjuster mount holes are 3.25 inch center to center

Saginaw 300 and the bracket I got from Jonathan are both 3 inches center to center

The 300 Saginaw bracket has different rear offset compared to the one Johnathan sent.

The bracket starting point

First attempt to adjust the location of a hole. I removed the welded nut from the back of the bracket and drilled a new hole. This looked promising to work, but the issue was the long pivot bolt to the head couldn't be installed as there was just enough interference with the pulley that you couldn't get the bolt installed. So back to the shop to figure out a different approach.

My next thought was just to locate the hole just off the location of the original hole to space the pump back out close to the original location. I outline in blue the location approximately. So I went ahead and commited to this location and decided to remove the steel to install a 1 inch O.D. 1/2 inch I.D. tube to use as the mount. I made the tube 4 9/16" long to match my original c2 bracket. I found with the 300 i6 saginaw bracket the pump needed to be shimmed back towards the head 3/8" to align belt properly. So I mounted the tube with 3/8" in front of the bracket and made another piece of tube 3/8 thick to go in front of the adjuster hole.

I got the pump all assembeled and installed. Started up the bronco and the belt is a bit loose fully adjusted so tomorrow I am picking up a belt 2 inches shorter, and I ordered a new pressure hose from a 1986 ford van (gates 359470) that I think should work and come in tomorrow by 2 at the local parts store.

Once I get the new belt installed and ensure the hose is right I will take everything apart one more time to paint the bracket. I will take good installed pictures then and try to write up a how I made it work document with dimensions and what I used for parts.

I think I may go ahead and add a couple of triangular gussets from the tube to the bracket for more angular support then the little welds on the front and back, but I am not sure they are really needed.

 

[Gary Lewis]

The bracket starting point

First attempt to adjust the location of a hole. I removed the welded nut from the back of the bracket and drilled a new hole. This looked promising to work, but the issue was the long pivot bolt to the head couldn't be installed as there was just enough interference with the pulley that you couldn't get the bolt installed. So back to the shop to figure out a different approach.

My next thought was just to locate the hole just off the location of the original hole to space the pump back out close to the original location. I outline in blue the location approximately. So I went ahead and commited to this location and decided to remove the steel to install a 1 inch O.D. 1/2 inch I.D. tube to use as the mount. I made the tube 4 9/16" long to match my original c2 bracket. I found with the 300 i6 saginaw bracket the pump needed to be shimmed back towards the head 3/8" to align belt properly. So I mounted the tube with 3/8" in front of the bracket and made another piece of tube 3/8 thick to go in front of the adjuster hole.

I got the pump all assembeled and installed. Started up the bronco and the belt is a bit loose fully adjusted so tomorrow I am picking up a belt 2 inches shorter, and I ordered a new pressure hose from a 1986 ford van (gates 359470) that I think should work and come in tomorrow by 2 at the local parts store.

Once I get the new belt installed and ensure the hose is right I will take everything apart one more time to paint the bracket. I will take good installed pictures then and try to write up a how I made it work document with dimensions and what I used for parts.

I think I may go ahead and add a couple of triangular gussets from the tube to the bracket for more angular support then the little welds on the front and back, but I am not sure they are really needed.

It is really looking good! And I think the triangular gussets would be a help.

Can't wait for the finished pics and writeup.

[Ford F834]

The bracket starting point

First attempt to adjust the location of a hole. I removed the welded nut from the back of the bracket and drilled a new hole. This looked promising to work, but the issue was the long pivot bolt to the head couldn't be installed as there was just enough interference with the pulley that you couldn't get the bolt installed. So back to the shop to figure out a different approach.

My next thought was just to locate the hole just off the location of the original hole to space the pump back out close to the original location. I outline in blue the location approximately. So I went ahead and commited to this location and decided to remove the steel to install a 1 inch O.D. 1/2 inch I.D. tube to use as the mount. I made the tube 4 9/16" long to match my original c2 bracket. I found with the 300 i6 saginaw bracket the pump needed to be shimmed back towards the head 3/8" to align belt properly. So I mounted the tube with 3/8" in front of the bracket and made another piece of tube 3/8 thick to go in front of the adjuster hole.

I got the pump all assembeled and installed. Started up the bronco and the belt is a bit loose fully adjusted so tomorrow I am picking up a belt 2 inches shorter, and I ordered a new pressure hose from a 1986 ford van (gates 359470) that I think should work and come in tomorrow by 2 at the local parts store.

Once I get the new belt installed and ensure the hose is right I will take everything apart one more time to paint the bracket. I will take good installed pictures then and try to write up a how I made it work document with dimensions and what I used for parts.

I think I may go ahead and add a couple of triangular gussets from the tube to the bracket for more angular support then the little welds on the front and back, but I am not sure they are really needed.

So I’ve been messaging with Craig Montague today... who is an advocate of the V belt system as well as extremely knowledgeable of the IDI. He sent me pictures of the Saginaw differences and boy did I have it all screwed up. I did have the correct pump bracket engineering number... and the part I sent you, Andrew, is the right pump bracket for the IDI (D8TA-3A732-BA). It shares this part with the 1978 and up 302 gas V8. Craig pointed out that the IDI ones had the engineering number stamped “upside down” relative to the installed position, and the gas ones have it stamped right side up for whatever reason... but either part will work.

The engine webbing support bracket is IDI van specific. Craig says his does not have an engineering number stamped on it. If trying to identify, measure the distance from the mounting hole to the adjustment pivot. It should be 3”. The Thompson / C2 pump is 3.25”.

The IDI also has a specific Saginaw pulley E3UC-AB. It has a different diameter and offset than the gas engine pulleys. It requires a belt for a 1983 Econoline with the 6.9 diesel. So much for “easy”... you pretty much need a complete IDI van donor 😔

My one nagging question is whether the pump bracket on my straight six might have a different distance between the pivot and the adjuster bolt. It dropped right in where the C2 came out... I wedged my phone in there and got a shot of the engineering number. It’s diffierent. It is -GB instead of -BA. I don’t have the time to mess with it, and I can’t take my water hauler out of service, but I’m wondering if that bracket might replace the C2 bracket without a special engine bracket.

 

[IDIBronco]

So I’ve been messaging with Craig Montague today... who is an advocate of the V belt system as well as extremely knowledgeable of the IDI. He sent me pictures of the Saginaw differences and boy did I have it all screwed up. I did have the correct pump bracket engineering number... and the part I sent you, Andrew, is the right pump bracket for the IDI (D8TA-3A732-BA). It shares this part with the 1978 and up 302 gas V8. Craig pointed out that the IDI ones had the engineering number stamped “upside down” relative to the installed position, and the gas ones have it stamped right side up for whatever reason... but either part will work.

The engine webbing support bracket is IDI van specific. Craig says his does not have an engineering number stamped on it. If trying to identify, measure the distance from the mounting hole to the adjustment pivot. It should be 3”. The Thompson / C2 pump is 3.25”.

The IDI also has a specific Saginaw pulley E3UC-AB. It has a different diameter and offset than the gas engine pulleys. It requires a belt for a 1983 Econoline with the 6.9 diesel. So much for “easy”... you pretty much need a complete IDI van donor 😔

My one nagging question is whether the pump bracket on my straight six might have a different distance between the pivot and the adjuster bolt. It dropped right in where the C2 came out... I wedged my phone in there and got a shot of the engineering number. It’s diffierent. It is -GB instead of -BA. I don’t have the time to mess with it, and I can’t take my water hauler out of service, but I’m wondering if that bracket might replace the C2 bracket without a special engine bracket.

An absolute treasure trove of hard to find information there.

I know it is very unlikely I will ever turn up a diesel idi van to get parts from. I am pleased with how the bracket is turning out. It looks like I will have good clearance all around and alignment is all sorted out. Hopefully I can get good pictures tomorrow.

Jonathan, I have been looking at this picture and I suspect now the c2 pump 300 bracket must be a different spacing than the v8 gas/idi brackets. It must use the same 3" spacing between,the adjuster and pivot the Saginaw brackets use.

I may be mistaken, but the idi pulley in the picture looks like a double v groove. I wonder how the belt routing was on the van if that is the case. I sure would enjoy finding an old idi van to add to my collection to just study how the accessory drive is set up.

[Ford F834]

An absolute treasure trove of hard to find information there.

I know it is very unlikely I will ever turn up a diesel idi van to get parts from. I am pleased with how the bracket is turning out. It looks like I will have good clearance all around and alignment is all sorted out. Hopefully I can get good pictures tomorrow.

Jonathan, I have been looking at this picture and I suspect now the c2 pump 300 bracket must be a different spacing than the v8 gas/idi brackets. It must use the same 3" spacing between,the adjuster and pivot the Saginaw brackets use.

I may be mistaken, but the idi pulley in the picture looks like a double v groove. I wonder how the belt routing was on the van if that is the case. I sure would enjoy finding an old idi van to add to my collection to just study how the accessory drive is set up.

The sad part is, I passed up an idi van thinking that I didn’t need anything from it. Damn 🤦‍♂️. I want to try to go back to see if it’s still there but I doubt it. That was last fall. I moved and it’s a far drive now just to take a peek.

I didn’t notice it at first, but you are right. The pulley looks like a double V. I have a double V Saginaw pulley from a 1986 GMC 6.2 diesel truck, but the front groove is smaller in diameter. I might be able to substitute it if it’s just an idler for the AC... but I have no idea how it will line up. Best thing would be to find a van, or press forward with engineering the serpentine bracket.

On the 300 it’s really tight to get in there to measure in place. But I stuck a tape in there just out of curiosity and it looks to me like it’s 3.25”. I so the -GB bracket might be a useful one if it does direct swap with the C2 aluminum one. Not to muddy the waters even worse, but Craig mentioned that he thought there may be more than one aluminum C2 bracket also... with perhaps a 3” spacing on some applications.