1992 F450 rebuild 7.3L idi

92obsidi

Registered User
Joined
Dec 28, 2025
Posts
25
Reaction score
12
Location
Birmingham, Alabama
Just started to rebuild a single cab 2wd 1992 F-450 (super duty) cab & chasis with a 7.3L idi and a ZF5 transmission. I plan on turning it into a welding rig/daily driver. I just pulled the motor and tore it down to the block, and everything looks great for having 250k miles, very little wear. I would like to bore the cylinders 0.010" over, rebuild and turbo it. It's N/A right now.
Does anyone have any suggestions or tips?
 

franklin2

Full Access Member
Joined
Feb 24, 2009
Posts
5,650
Reaction score
1,913
Location
Va
They complain that the 7.3 has thin cylinder walls from the factory. And you want to bore it? Does it really need it? Try not to bore it if it doesn't need it.
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
4,158
Reaction score
4,710
Location
OR
If the hone marks look good and you don't have abnornal wear, just put it back together with head studs and it'll do just fine.
 

Clb

Another old truck
Supporting Member
Joined
Mar 1, 2013
Posts
6,905
Reaction score
3,288
Location
nannyfornia
Hit the stickies, hit the tech 101 stuff and don't move to quickly to punch it out.
Get a set of fsm's so you have the correct specifications for the eng.
Navistar made the bunder under the hood...
 

92obsidi

Registered User
Joined
Dec 28, 2025
Posts
25
Reaction score
12
Location
Birmingham, Alabama
They complain that the 7.3 has thin cylinder walls from the factory. And you want to bore it? Does it really need it? Try not to bore it if it doesn't need it.
They say that, but you can bore them 0.020", 0.030", up to 0.040" over. 0.010" is nothing really, just enough to freshen everything up. Plus, like I said I'm going to put a turbo on it, so I'd like to go with stronger internals.
 

92obsidi

Registered User
Joined
Dec 28, 2025
Posts
25
Reaction score
12
Location
Birmingham, Alabama
If the hone marks look good and you don't have abnornal wear, just put it back together with head studs and it'll do just fine.
I'm taking it to the machine shop in the morning. I've already found a rebuild kit with forged pistons and connecting rods.
Why not run better internals if i have the money?
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
14,972
Reaction score
14,070
Location
edmond, ks
Does anyone make +.010 pistons? I haven't seen any. Other than that, it sounds like you're on the right track so far. One more thing, these are a high nickel block so whoever does the bore work will need to be aware of that ahead of time.
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
4,158
Reaction score
4,710
Location
OR
I think I remember seeing Mahle offers .010 over.

I'm taking it to the machine shop in the morning. I've already found a rebuild kit with forged pistons and connecting rods.
Why not run better internals if i have the money?

What exactly do you mean by "forged" internals on these? Most would say an "ideal" build is PSD rods machined to fit turbo pistons and you'll have a sound bottom end. For top end, if you are going turbo, comp springs. Nothing really left to upgrade unless you put a lumpy cam in.

I would advise educate yourself on what good internals are, so the shop doesn't give you a run for your money.

Just to throw it out there, I kept my bottom end 100% n/a block (na pistons, rods and rings) and did head studs with comp springs. I run a wastegate deleted 093 turbo intercooled, and can push 18-19psi of boost easy. EGT's climb a little fast, but as long as EGT's are kept in mind it is a good build.

Going "forged internals" does not mean you can ignore your EGT's.
 

92obsidi

Registered User
Joined
Dec 28, 2025
Posts
25
Reaction score
12
Location
Birmingham, Alabama
I think I remember seeing Mahle offers .010 over.



What exactly do you mean by "forged" internals on these? Most would say an "ideal" build is PSD rods machined to fit turbo pistons and you'll have a sound bottom end. For top end, if you are going turbo, comp springs. Nothing really left to upgrade unless you put a lumpy cam in.

I would advise educate yourself on what good internals are, so the shop doesn't give you a run for your money.

Just to throw it out there, I kept my bottom end 100% n/a block (na pistons, rods and rings) and did head studs with comp springs. I run a wastegate deleted 093 turbo intercooled, and can push 18-19psi of boost easy. EGT's climb a little fast, but as long as EGT's are kept in mind it is a good build.

Going "forged internals" does not mean you can ignore your EGT's.
I mean exactly what I said forged connecting rods & pistons. R&D idi performance makes a set. But if you think I'll be fine with just a regular 0.010" rebuild kit, I might go that route. I wasn't planning on running an intercooler. I was planning on buying the CDD non-intercooled turbo kit with the upgraded 61mm turbo.
 

92obsidi

Registered User
Joined
Dec 28, 2025
Posts
25
Reaction score
12
Location
Birmingham, Alabama
I think I remember seeing Mahle offers .010 over.



What exactly do you mean by "forged" internals on these? Most would say an "ideal" build is PSD rods machined to fit turbo pistons and you'll have a sound bottom end. For top end, if you are going turbo, comp springs. Nothing really left to upgrade unless you put a lumpy cam in.

I would advise educate yourself on what good internals are, so the shop doesn't give you a run for your money.

Just to throw it out there, I kept my bottom end 100% n/a block (na pistons, rods and rings) and did head studs with comp springs. I run a wastegate deleted 093 turbo intercooled, and can push 18-19psi of boost easy. EGT's climb a little fast, but as long as EGT's are kept in mind it is a good build.

Going "forged internals" does not mean you can ignore your EGT's.
And I haven't said one thing about EGT's. Nor did I imply that forged internals had anything to do with them. So I'm not sure why you even brought that up
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
4,158
Reaction score
4,710
Location
OR
I brought it up because EGT's are the killers of these engines, cracking and melting pistons by those who run them too hard.

If you're going with that turbo kit, you could really benifit from an intercooler. I ran CDD's stock 093 kit for a year without a cooler, then put one on and saw EGT's drop by about 200f. In my opinion, it is a bit backwards to do upgraded internals without doing a cooler.

Either way you go, if you wanted to 'go big or go home' build, definitely get head studs, comp springs, wastegate delete, 3" down pipe and 3 or 4 inch exhaust. The more she can breathe the better.
 

ttman4

Last Nite's Dream..
Supporting Member
Joined
Oct 31, 2005
Posts
1,317
Reaction score
868
Location
Hi in the Cascades, Nearly- Redmond,Oregon
And I haven't said one thing about EGT's. Nor did I imply that forged internals had anything to do with them. So I'm not sure why you even brought that up
Easy @92obsidi , slow down, @Nero is just trying to help, for real!
EGT's got my '94 Factory IDIT engine in my '90 CCLB Dually, (that & an off brand ((not Motorcraft)) thermostat) .....2 low popping cylinders.
 
Last edited:

Indadesert

Registered User
Joined
Dec 24, 2025
Posts
48
Reaction score
22
Location
California
Spending money on these motors with out an intercooler doesn’t make since to me either. Especially since one can be put together for less the $300
 

Clb

Another old truck
Supporting Member
Joined
Mar 1, 2013
Posts
6,905
Reaction score
3,288
Location
nannyfornia
You "Do Want" an I.c.
It's probably different for flatlanders, but still it's probably a good idea.
 

92obsidi

Registered User
Joined
Dec 28, 2025
Posts
25
Reaction score
12
Location
Birmingham, Alabama
I
I brought it up because EGT's are the killers of these engines, cracking and melting pistons by those who run them too hard.

If you're going with that turbo kit, you could really benifit from an intercooler. I ran CDD's stock 093 kit for a year without a cooler, then put one on and saw EGT's drop by about 200f. In my opinion, it is a bit backwards to do upgraded internals without doing a cooler.

Either way you go, if you wanted to 'go big or go home' build, definitely get head studs, comp springs, wastegate delete, 3" down pipe and 3 or 4 inch exhaust. The more she can breathe the better.
I've never had anything with a turbo. So im still learning A LOT.
Honestly now after I've talked to some people on here. I'm thinking about leaving the stock internals, except for the cam, to save some money and spend it on an intercooler.
I'm nit trying to go crazy with it. It's going to be a welding rig/daily driver. So I'll have 2k-3k on the bed at most times plus pulling a trailer with steel. I just want to have enough ass to pull all of that around no problem cruising 70-75 mph. Thank you for the suggestions.
Do you think I should buy new stock internals or go with the ones that were in it?
 

Forum statistics

Threads
92,927
Posts
1,155,060
Members
26,417
Latest member
jfryguy

Members online

Top