1990 F350 4x4 7.3 IDI

[THEFERMANATOR]

If you don't like the v-belts, you can do a serp swap.

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With the way the belts are routed on the 7.3l idi, a serp swap would probably be a little tough. They used a double groove pulley on the alternator, 1 groove runs the alternator, then the other groove drives the vacuum pump. You would have to space the vacuum pump forward, then try and come up with a pulley with a serp in the back and a v built onto the front. Otherwise you could run an electric pump for the A/C if you did a hydro boost swap.

 

[n8in8or]

I finished the 3G alternator conversion tonight. It hadn't run for 2 days so it was the first opportunity to do a cold start with BOTH batteries hooked up. It turned over silly fast, yet took a bit to light off so I guess I need to start looking at the glow plug system and check for air intrusion. No biggie, just gotta get after it. As far as the alternator goes, I should have measured voltage with a meter before and after. I do know that it was low enough before that the dash light for low battery would flicker. No more!

 

[Will L.]

That is cranking plenty fast. Clear tube the ip return, and plan on some new glows.

 

[n8in8or]

That is cranking plenty fast. Clear tube the ip return, and plan on some new glows.

I'm leaning towards glows being the problem, but I won't rule anything out until proven. I'll research what the Ford guys do for a rock- solid glowplug system. I like Ferm's idea, so I'll see how that stacks up.

 

[THEFERMANATOR]

Also probably wouldn't be a bad idea to replace the injectors. I know those pencil injectors aren't supposed to do well after 75K miles.

 

[n8in8or]

Also probably wouldn't be a bad idea to replace the injectors. I know those pencil injectors aren't supposed to do well after 75K miles.

Yeah, I will be checking them. The guy claimed they were newer, but as I recall, he claimed the glows were newer as well.....

 

[JayTheCPA]

Nice find. From what I have heard of the 7.3 IDI's around me, they run more quiet than the 6.5.

IIRC, the IDI's are sensitive to the coolant's SCA levels and is the main source of cavitation. When the level goes out of range, it can cause coolant leaks into the cylinder from pitting. Seems that the 7.3 IDI is a good candidate for waterless.

A neighbor used to tow with that motor and as Ferm mentioned, glow plugs and injectors were his top issues. Drove that truck on a trip with him once and do not recall any oddities with brakes or steering. Neighbor drove with the load and I drove with the empty trailer.

 

[n8in8or]

Nice find. From what I have heard of the 7.3 IDI's around me, they run more quiet than the 6.5.

IIRC, the IDI's are sensitive to the coolant's SCA levels and is the main source of cavitation. When the level goes out of range, it can cause coolant leaks into the cylinder from pitting. Seems that the 7.3 IDI is a good candidate for waterless.

A neighbor used to tow with that motor and as Ferm mentioned, glow plugs and injectors were his top issues. Drove that truck on a trip with him once and do not recall any oddities with brakes or steering. Neighbor drove with the load and I drove with the empty trailer.

Thanks for the info, Jay. I will be diving into the glow plugs and injectors tonight to start assessing the situation.

 

[THEFERMANATOR]

The brakes in them stock do leave a bit to be desired. I logged close to 10K miles behind the wheel of a 92 F350 DRW grossing close to 22K, and stock the brakes felt lacking several times. They worked, but the vacuum booster always left me feeling like it needed more assist. If I hit them hard, it would run out of vacuum before the brakes really engaged, so the pedal was easy at the top, then got really hard, then once the vacuum started building back up, the pedal would get softer again. Hydro-boost would have been a HUGE improvement IMHO. I will say putting good pads and shoes on it really helped reduce pedal travel over stock, and helped make the pedal feel firmer at the bottom. But again, the small master cylinder and booster always felt lacking.

 

[n8in8or]

The brakes in them stock do leave a bit to be desired. I logged close to 10K miles behind the wheel of a 92 F350 DRW grossing close to 22K, and stock the brakes felt lacking several times. They worked, but the vacuum booster always left me feeling like it needed more assist. If I hit them hard, it would run out of vacuum before the brakes really engaged, so the pedal was easy at the top, then got really hard, then once the vacuum started building back up, the pedal would get softer again. Hydro-boost would have been a HUGE improvement IMHO. I will say putting good pads and shoes on it really helped reduce pedal travel over stock, and helped make the pedal feel firmer at the bottom. But again, the small master cylinder and booster always felt lacking.

I have plans to go to the junkyard this Saturday and snag a hydroboost off a period F Superduty. I scouted the junkyard today during lunch and found 2 good candidates.

Thanks for the info on the pads and shoes. I will keep that in mind as well.

 

[n8in8or]

Well I found one culprit tonight - I did a quick test with a test light and found 2 completely dead glow plugs. They don't look too old, but they're Autolites which are supposedly bad news. So I have a set of Motorcrafts on order for it. Luckily none of them were swelled up so I was able to remove all 8.

The pic below is the 2 bad ones.

 

[DieselCash]

Awesome project!

 

[n8in8or]

Awesome project!

Thanks! Should be a stout rig some day.

 

[DieselCash]

Thanks! Should be a stout rig some day.

I am borrowing my brothers 1994 Ford F350 with the Turbo 7.3 non-powerjoke. Once I am able, I will make some post on her.

 

[n8in8or]

I have a question about brakes that I'm hoping that at least @THEFERMANATOR can weigh in on.

So the truck was converted to dual rear wheels. To do this they added wheel spacers. Not the ideal method in my opinion. I happen to have a true dually rear axle out of a 94 Dodge 3500 that is a Dana 80. I'm thinking about swapping that axle in the truck. The Dana 80 has 3.54 gears and have yet to confirm the gears in the F350 currently. My question is regarding how the brakes will work as a system.

I will be swapping in the hydroboost and mastercylinder from an F Super Duty into the F350. This will give me a master cylinder bore of 1-5/16" instead of 1-1/8". The Dodge had a 1-1/8" master cylinder bore.

If I do the Dana 80 swap, my wheel cylinders will stay 1-1/16", but if the F350 was a true dually it would have actually had 1-3/16" wheel cylinders.

Also, if I do the Dana 80 swap, my brake shoes go from 12" x 3" to 13" x 3.56". Fi the F350 was a true dually it would have actually had 12.13" x 3.5".

So, if I do all of the swaps that I'm thinking here, am I going to have a messed up braking system or will it work together ok? Should I have larger wheel cylinders? Will the larger brake shoes offset the smaller wheel cylinders? Should I plumb an adjustable brake proportioning valve in the rear brakes? Any thoughts would be appreciated by anyone with experience as I know some of you have played the brake game before. Thanks.

 

[JayTheCPA]

I have a question about brakes . . . So the truck was converted to dual rear wheels.

Do some homework here to make sure the end result is solid. Had seen some litigation where dually rigs (commonly OE configurations) were on the wrong side of suits where the focus was under-powered rear brakes which resulted in collisions (commonly while towing).

 

[n8in8or]

Do some homework here to make sure the end result is solid. Had seen some litigation where dually rigs (commonly OE configurations) were on the wrong side of suits where the focus was under-powered rear brakes which resulted in collisions (commonly while towing).

Thanks for the tip, Jay, will do!

 

[n8in8or]

I did a little homework last night. I found that the F350 has 3.55 gears, so the Dana 80 is a direct bolt-in in that regard, but that's about it..... The spring perches are too narrow and the shock brackets are in the wrong configuration - those are both fixable with a grinder and a welder, so that's not the end of the world. The wheel spacing is correct and that one could have been a deal breaker. So this axle is still a possibility, I'm just not sure if I want to spend that time on it right now. I might try to find a Ford dually axle locally that would just bolt right in. We'll see. The Dana 80 would be sweet though...the 4" axle tubes and the size of the pumpkin just look STOUT, and that's what this truck is supposed to be all about.

 

[THEFERMANATOR]

My question is does your FORD have the speed sensor in the rear axle? If it does, it may not work with the one in the DODGE AXLE. As to the DODGE axle, you have a WIDE variety of wheel cylinders you can swap into it as any of the wheel cyclinders used in 2500/3500 GM trucks will work as DODGE used GM brakes in those years. So you can choose between a 1", 1 1/16", or 1 3/16" wheel cylinder in the rear. I know most everybody who had a mid 90's DODGE complained about the brakes, and a common upgrade was to swap in a set of GM DRW wheel cylinders because DODGE used 1 1/16" wheel cylinders in the duallys while GM used 1 3/16" wheel cylinders. I just looked, the DODGE was listed as a 1 1/4" not 1 1/8" master cylinder. The larger master cylinder piston is just going to reduce pedal travel, but it will actually decrease the amount of braking as it will take more pedal effort to get the same pressure. But that is where the hydro-boost comes in as it can apply more assist to compensate. Knowing how much larger the front brakes were on the FORD than the DODGE, I would put the 1 3/16" wheel cylinders in with the hydro-boost. IF it's too much rear braking, then it's not that expensive to swap in a set of smaller wheel cylinders.

 

[n8in8or]

My question is does your FORD have the speed sensor in the rear axle? If it does, it may not work with the one in the DODGE AXLE. As to the DODGE axle, you have a WIDE variety of wheel cylinders you can swap into it as any of the wheel cyclinders used in 2500/3500 GM trucks will work as DODGE used GM brakes in those years. So you can choose between a 1", 1 1/16", or 1 3/16" wheel cylinder in the rear. I know most everybody who had a mid 90's DODGE complained about the brakes, and a common upgrade was to swap in a set of GM DRW wheel cylinders because DODGE used 1 1/16" wheel cylinders in the duallys while GM used 1 3/16" wheel cylinders. I just looked, the DODGE was listed as a 1 1/4" not 1 1/8" master cylinder. The larger master cylinder piston is just going to reduce pedal travel, but it will actually decrease the amount of braking as it will take more pedal effort to get the same pressure. But that is where the hydro-boost comes in as it can apply more assist to compensate. Knowing how much larger the front brakes were on the FORD than the DODGE, I would put the 1 3/16" wheel cylinders in with the hydro-boost. IF it's too much rear braking, then it's not that expensive to swap in a set of smaller wheel cylinders.

Thanks for looking into this Ferm, that is very helpful. My Ford is still cable drive off of the transfer case, so I won't have a speedo issue - that's a good thought though.