What to consider when building a 7.3 IDI?

[MasterChiefIDI]

Hi,

I am brand new to the forum so please let me know if I am not posting in the right place.

I am looking for direction on things to consider and part/vendor recommendations for recommended upgrades to consider for building my 7.3 IDI NA. I do not know very much about building an IDI. I do know how to service a stock unit as I have had my 6.9 for many years and done all the work myself. I have included pictures of my truck w/ 6.9 and my 7.3 I am wanting to build.

I have a 1986 F350 with the 6.9 idi. The block is horribly rusted thin internal from PO running straight water for YEARS. There is a 7" crack above the starter and the head gasket is blown. I picked up a 91 7.3 NA idi that was being parted out. History is unknown but appears to be solid with no pitting in the timing cover. Have not pulled heads yet but will to start deep inspection.

Main goal: not trying to build the absolute best but modest 7.3 IDI. I want more get up from a stop. The NA 6.9 in it now feels too sluggish to get out of its own way. I tow occasionally so want to be able to tow without issue.

Performance items I am researching:
- 7.3 idi NA a good candidate for building?
- Turbo (what stage?)
- IP (what cc's in an IP should I look for?)
- head studs
- cam (is a new cam needed/worth it?)
- lifters (is one brand better over another?)
- Rockers (are stock ones just fine?)
- push rods (is it necessary to replace these for a build if they're all straight?)
- Anything else I need to consider to meet my goal?

Nice things I already have include:
- set of Russ Repair injectors I purchased a few years back now with 20k mi on them
- New valley pan gasket
- Stock IP works perfectly with no leaks (though I think I need more cc's for a turbo?)

Trying not to break the bank but not wanting to cheap out either. Hoping the pistons and cylinders are STD and serviceable and could dingleball and rering.

Really appreciate any guidance.

Douglas

 

[Nero]

If youre looking for a good center of the line between stock and crazy build, its been explained to me the best bang for your buck without upgrading internals are:

-Head studs
-comp spring
-093 turbo or equivalent with wastegate delete
-90cc pump
-Stock or stage 1 injectors
-intercooled
-larger down pipe and exhaust

Its the build I run, and I've been very happy with it. Any more built then you're looking at PSD machined rods and more stuff..

 

[IDIBOBS]

I guess the first question is are you towing? Hauling? What type of weight? Mountain roads or flat? High altitude? Do you have very high temps or very cool temps?

Head job/valve job pay special attention to valve guides they do wear out. New stock lifters and stock rockers seam fine. Head studs, good turbo, cam does work really well if your already tearing into the motor. 3 core radiator, intercooler helps also but to me it’s not worth the price of a kit. A good system can be built for around $500 or less. Stock or stage one ip and injectors but in reality stock system that is tuned right works well. Keel the mechanical fuel pump. Not motor related but gauges to keep an eye on it all. And in the end make sure your trans or clutch is up to the task. Remember more power less longevity and less mpgs you get. Empty I get 22-25mpg and young the 10.5k horse trailer I get 15-18. But I drive slow and easy. I want my truck to last it’s already 35 years old.

 

[u2slow]

For me, the only way to build one is with the turbo pistons and (keystone) rings. That may have a domino-effect of needing the rods and crank also.

 

[IDIBRONCO]

Unless you're going to go big on power, N/A engine internals will hold up fine. Unless you're going big on boost, head studs aren't needed. A good idea, but not a requirement. You can get some pretty decent performance with a fairly stock fuel set up just by adding a turbo. I also recommend an intercooler whenever going with a turbo. Since you're from Mississippi, high altitudes aren't an issue unless you go out of state.
Nice truck, by the way. Bull Nose crew cabs aren't all that common.
Finally, welcome to the Cool Kid's Club!

 

[onetonjohn]

Are you guys doing machine work when you go though these motors? When I did my ranger it was like 4K at the machine shop for parts and labor, and that was V6 10 years ago. Are these bottom ends bullet proof such that you aren't line boring and turning the crank? What about boring cylinders? The 7.3 doesn't have a lot of meat on it to start. Are you planing the head mating surface to ensure it's flat? Cam bearings? And the heads what are you doing there?

Curious. I want a motor that will last forever. For project little foot, I just did the heads, but didn't touch the bottom end. It has 10 over pistons in 6.9, so I figured it was done recently (well at least once before). I hope skipping machine work for the bottom end doesn't come back to bite me in the ass.

I'm thinking for the $500 dollar price listed above, we're maybe new main and rod bearings (checking surfaces are still good - can visual inspection tell, or do you get wear you can measure?), new rings and gaskets. New oil pump? New gaskets and seal it up? I don't know how far you need to go to get reliability, and were you can skimp.

BTW: Love that 86 crew cab. Need one of those to add to the fleet.

 

[Nero]

I did not do anything with my bottom end. Original rods, crank, cams, bearings, ect. All I did was take heads off.

 

[KansasIDI]

I’m gonna throw out some names on complete new or refurbished turbo kits

Big power and big money = R&D

Good power and not so much money = Classic Diesel Design’s refurbished 093 ATS kits

Good power and big money = Banks

Good power and not so much money = Hypermax

All but Banks have intercooler kits, and I believe all have exhaust systems available.

I personally have all of Hypermax’s bolt on upgrades on my 91 F-Superduty. This truck is extremely heavy, it’s a service truck, but it moves around quite well.

My 94 will be getting a modified 093 ATS kit, but may receive the Hypermax intercooler and exhaust. Currently rebuilding and upgrading its E4OD myself.

Or maybe I should go a different route, one that’s long, lean, loud and overrated… just kidding.

 

[MasterChiefIDI]

Thank y'all for all the replies and compliments on my truck. It is a joy to drive. Yes I am in MS where the truck spends most of its life so only around 300ft elevation. I tow a single axle ski boat in the summer (3300lbs) and will pull a 16' car hauler flat trailer on occasion.

I have a C6 in it right now that I will use while I build an E4OD to replace it and a 91 king pin dana 60 I plan to swap in after engine build.

I have a FOMO 7.3 service manual and plan to check all lower components for serviceability.

Working on a list from what I am hearing:
- Definitely a turbo w/ waste gate delete (thank you for the list @KasasIDI)
- Definitely add an intercooler (it seems this is a challenge in the bullnose platform)
- Definitely new injectors (got those)
- Get new valve springs
- maybe, maybe not bigger IP
- maybe, maybe not head studs
- Stock lifters and rockers seem to be fine
- new cam might be beneficial?

Questions:
- am I better off sourcing a 7.3 IDIT or would my NA 7.3 candidate build nicely for what I am wanting?
- can a turbo be added after the engine is in the truck?
- are there any guides on installing a intercooler on a bullnose specifically?

I am thinking I will give Justin or Wes a call to see what the recommend for IP and turbo combos.
This has been very helpful getting my thoughts together on what to aim for. Thank you!

Douglas

 

[THSIM9]

Welcome to the forum, you have an awesome truck by the way.

There are some great suggestions above. If you have the tools and knowledge to verify that your bottom end is in spec I wouldn’t spend the money to have it machined. If anything is out of spec you will obviously want to get that corrected before adding new parts.

I would not replace push rods unless they are out of spec. That being said they are not that expensive, I had to replace mine in my recent build because I had a bent pushrod. Same goes for rockers. I think lifters are also pretty robust in these engines and as long as everything looks/measures correctly you should be fine.

I like studs as an insurance policy for any turbo, but as mentioned above they are not necessary for mild boost levels that you will get with a 093, banks, or hyper max kit.

CDD and R&D are the best bets for pump work. I went with a 110 CC pump, stage 1 injectors, stage 2 turbo/IC setup from CDD and so far I am very happy.

Definitely look into electronic fuel pumps and read all the threads here to get the most current information on good vs bad options. I went with the CDD E-fuel kit for one stop shopping but you can definitely build an E-fuel setup cheaper if you piece it together yourself.

Good luck, and I hope to see a build thread so we can all follow along!

 

[FrozenMerc]

Questions:
- am I better off sourcing a 7.3 IDIT or would my NA 7.3 candidate build nicely for what I am wanting?
- can a turbo be added after the engine is in the truck?
- are there any guides on installing a intercooler on a bullnose specifically?


Douglas

For a mild performer (stage 1, 90 cc pump), an N/A base/core motor will be fine.

Yes, a turbo can be added after the engine is in the truck, but it is a royal pain in the ass (stomach). Much easier to do it out of the truck. I have seen me do it both ways, and I can pull the motor faster than I can lay my fat ass across the radiator and on top of the engine and try to wiggle the small bolts out (or into) the back of the turbo that are tucked under the cowl.

For the build level you describe, I would not hassle with the intercooler in a bullnose. Lots of fab work to make it all come together. If that is your bag, then go for it, but I would not do it unless you are considering a much more aggressive engine build (Stage 2, 110+ cc pump, cam, compression drop, etc.)

 

[u2slow]

I'll vouch for the factory turbo business being difficult to re&re. BTDT.

I'm in no rush to build one of these, so I had time on my side to eventually find a complete TiDi. If I hadn't found one, I wouldn't be bothering with Ford V8 diesels at all. JMHO.

 

[IDIBRONCO]

Questions:
- am I better off sourcing a 7.3 IDIT or would my NA 7.3 candidate build nicely for what I am wanting?
- can a turbo be added after the engine is in the truck?
- are there any guides on installing a intercooler on a bullnose specifically?

I am thinking I will give Justin or Wes a call to see what the recommend for IP and turbo combos.

Yes a turbo can be added when the engine's in the truck. I can't vouch to the difficulty compared to installing a turbo and engine into the truck at the same time since I've always removed and installed the engines and turbo separately. It is more difficult to install an air to air intercooler in a Bull Nose truck, but you don't have to use one of those. You can use an air to water intercooler. Those might be more expensive, but it would certainly be easier to install. A N/A/Turbo engine depends on what power level you're wanting to have. If you want a mild (but still highly effective) increase in power, a N/A bottom end will do just fine. If you want a huge increase, then you'll need to go with Turbo parts. All you'd really need is the rods since they're the weak link in the N/A engines. You'd then need to have all of your rotating parts balanced so that you won't have excessive vibrations. Before you call Wes or Justin, you want to have a good idea on what you're wanting to do. From your above answers, I'd second what Frozen Merc said and say that you probably won't need to go with a pump that's bigger than 90cc.
Just to cut down on possible confusion, I always capitalize the words Factory and Turbo when I refer to the engines and parts that were optional as new from Ford in 1993 and 1994. I do that to separate them from aftermarket parts that were added to N/A engines. I've seen people claim that they have a IDIT powered truck and they have an aftermarket turbo on it. Those are NOT the same as IDIT trucks.

 

[The_Josh_Bear]

+1 water-to-air CAC for a bull nose. Charge air cooling is the second best mod I've done, right after the turbo(mine is air to air, but I've never read about anyone regretting the water to air)
I personally am shocked at the performance gains I got from it, I would not have believed it without the experience.

 

[KansasIDI]

If you go Hypermax, they are not wastegated, and they offer an air to air cooler for the bullnose, with their turbo kit. Instructions cover install for all 83-94 trucks.

Hypermax - Product Display

If you go with an 093, Hypermax also has an intercooler for that setup as well. Ron at Hypermax told me it should work in any 83-94 truck with light modifications to the core support and back of the grille (except 92-94, the grille sits farther away). The instructions are for factory turbo trucks, but it’s the same intercooler core, so it fits a bullnose.

Hypermax - Product Display