7.3 IDI Mild Build going in a 1986 F350 thread

[MasterChiefIDI]

Hey everyone,

Thought I would start a build thread for my 88 7.3 IDI mild build. Only reason I know it is from an 88 is the rod bearings are dated 9/87 ha. As some of you have already seen, the motor is going in my 86 F350 crew to replace the cracked 6.9 that's in it. PO of my truck ran straight water for who know's how long and rusted the block thin. The timing cover was paper thin in some areas! I drove it cracked for almost 4 years (only 20k miles because of the crack) and then head gasket blew. Acquired the 7.3 for $300 loaded from a bricknose so thought that was a pretty good deal.

My goals for my truck is to have a little more get up from a stop and tow my jeep and ski boat occasionally (both under 3000lbs). So not big power but a modest middle of the road build.

Upgrades and parts list ordered/planned:
- R&D 90cc IP
- Stage 2 Turbo kit from CDD w/ T04S 61mm Turbo
- CDD's Gator Head studs
- Water → Air intercooler from Frozen Boost
- Russ's Stock Injectors
- Stock cam
- Hylift-Johnson Lifters
- Comp 910-16 Springs
- Bronze valve stem sleeves with Exhaust seals left off and Viton on Intake
- Flowkooler 1664 Water Pump
- Champion 3-Row Radiator
- Fel-Pro 6.9 Head gaskets and cooling mod
- CDD's CDR delete kit (included w/ the stage 2 kit)
- *Larger exhaust possibly


I will not be using the intercooler or cold air intake from the stage 2 kit as it is designed for Serp belts and not V belts and will sell it once it comes. My V belts have been perfectly fine and already have plans for an E350 sag pump conversion, current AC comp will run you out the cab and already 3G converted alt. I'll have to include details of my sag conversion when I get to it. My AC system is the original and I converted it to R134A. Gets down to 42°F when its 100°+ outside using the Red orifice tube. Does get warm at stop lights though.

Are there any other good 7.3 mods out there I should consider? Or upgrade aftermarket parts?

Very grateful for this forum as I have learned the majority of what I have done so far from here. First steps have been getting the 7.3 on a stand and tearing it down for inspection and machine work. Block is solid with no signs of rusting thin like the 6.9 had. Unfortunately the cylinders are pretty worn with a nice groove to catch your nail on at the top. Also one piston had a broken compression ring. This engine looked like the oil was never changed. Lifters were badly worn but bores in the block checked out within spec.

Backlash and endplay on the timing gears was OK and well in spec too. Crank journals were noticeably worn and material had separated from the bearings so looks like crank will need turning. The cam lobes I think look OK but I will compare to the 6.9 cam once I have it out and choose the better one.

UNFORTUNATELY, I broke a head bolt off 1/2" below the surface in the block.. front most one on the left bank.. Block and crank are at my trusted machine shop for thorough inspection and broken bolt removal. Hoping they can get it out!

A trusted friend of mine specializes in head rebuilds and is doing my heads for me.

Next steps while waiting on parts and machine work will be to start pulling the 6.9 out of the truck!

 

[IDIBOBS]

nice. You will already be able to tow much more then you need but if your going all this way might as well cam it? Pretty cheap low end hp/tq.

 

[Nero]

Looks like you have a good game plan and parts list ready to go, only suggestion I have is unless you already have the injectors, you'll have to source another vendor as Russ isn't around to sell them anymore.

 

[MasterChiefIDI]

nice. You will already be able to tow much more then you need but if your going all this way might as well cam it? Pretty cheap low end hp/tq.

I considered the R&D cam but felt like for my needs, the cam would not be a huge benefit for my part selection and the cost of it and would start getting outside of just a mild build. Felt like if I was building an IDIT block then it would be absolutely worth it to get the most out of that beefy motor.

But maybe my thought process is completely wrong?

 

[MasterChiefIDI]

Looks like you have a good game plan and parts list ready to go, only suggestion I have is unless you already have the injectors, you'll have to source another vendor as Russ isn't around to sell them anymore.

Thank you! I purchased the injectors a few years back. Was sorry to hear he passed away

 

[IDIBRONCO]

If you're going with a stage 2 turbo, it might push more air than a 90cc pump will fuel. You could probably step up to a 110cc pump if you wanted to. With a stock cam, I don't see a need for the Comp 910 springs. It's not the N/A block that's the weak link, it's the rods. You can build a N/A block up like you can a Turbo block.

 

[Overloaded-dadbod]

I considered the R&D cam but felt like for my needs, the cam would not be a huge benefit for my part selection and the cost of it and would start getting outside of just a mild build. Felt like if I was building an IDIT block then it would be absolutely worth it to get the most out of that beefy motor.

But maybe my thought process is completely wrong?

I do have a russrepair type4 cam sitting in my garage. I mistakenly bought both (over a year apart and found the other on the shelf while rebuilding) willing to sell n ship.

 

[FrozenMerc]

I agree with IDI Bronco. The pump is likely to be undersized and the limiting factor with that turbo and intercooler setup. 110cc is likely a better match.

 

[IDIBRONCO]

The pump is likely to be undersized and the limiting factor with that turbo and intercooler setup. 110cc is likely a better match.

I did forget to mention that he won't have to worry about EGTs with the 90cc pump.

 

[MasterChiefIDI]

110 probably would be a better fit.. I've already ordered the 90cc from Justin. I could upgrade the pump later if I feel the need.

 

[MasterChiefIDI]

Been working hard. Pulled the bed off and 6.9 out all in 8 hrs. That was moving pretty quick and a luckily having every needed tool to do it on hand. Pulled bed to replacing sending units, pickup tubes, fill necks, and install Spectra 38 Gallon rear fuel tank. Also needed new bed bolts and pads as bed was moving around on frame. Dennis carpenter sells OE style replacements bolt sets.

Fun fact, you CAN remove the entire AC system as an assembly with out draining. My air blows Ice cold after an extensive R134A conversion and wanted to try removing whole so I wouldn't have to expose the system to the atmosphere after evacuation.

This 6.9 ran very well before pulling. The amount of oil that was in the radiator makes me think the oil cooler fractured and dumped into the cooling system, not a head gasket failure as I originally thought. Tear down will tell.

Replacement 7.3 is at the machine shop getting checked out. Hoping to get it back soon for assembly! Going to degrease, pressure wash, and put down a little paint in the meantime. To give me as much clearance as possible for the turbo downpipe, I opted to replace the body mounts with a quality set of S&B Silicone Mounts. I am also considering biasing the engine and transmission forward and the cab rearward to help with clearance too while I am here. Trying not to bend anymore than just my trans tunnel seam for clearance. Hate to taker a hammer to it.

 

[MasterChiefIDI]

Also purchased the front half of a 1990 F350 w/ a Dana 60 king pin. Buying the frame with it is definitely the way to go as there are several brackets I will be transferring. Started tearing it down for cleaning, inspection, and reconditioning.

Purchased Sky's Off Road RSK 2WD to 4WD Kit that uses 99-03 Super duty Springs for easy install and some modest lift. Going to see how it goes! I purchased their End Link extensions so I can retain the factory sway bar. Dream Truck is coming along.

 

[CodyRisner]

I do have a russrepair type4 cam sitting in my garage. I mistakenly bought both (over a year apart and found the other on the shelf while rebuilding) willing to sell n ship.

I would be interested in buying it.

 

[Overloaded-dadbod]

Also purchased the front half of a 1990 F350 w/ a Dana 60 king pin. Buying the frame with it is definitely the way to go as there are several brackets I will be transferring. Started tearing it down for cleaning, inspection, and reconditioning.

Purchased Sky's Off Road RSK 2WD to 4WD Kit that uses 99-03 Super duty Springs for easy install and some modest lift. Going to see how it goes! I purchased their End Link extensions so I can retain the factory sway bar. Dream Truck is coming along.

Which code springs are you gonna use?

 

[TahoeTom]

If the 6.9 crank is good it would be a better option than turning down the 7.3 one