Rebuild on 7.3 idi

[jaluhn83]

I'd go cam over studs on a 7.3. Studs are good on the 6.9 with the smaller bolts, but on the 7.3 I don't think you need them. Cam gives a nice boost to low end, and even without a turbo it wouldn't hurt. I can't speak to Justin's cam though, I'm using the one from Russ (TYP4).

Stellite is a chrome/cobalt alloy that is very hard and used as a coating on the valve face. The valve itself is still some steel alloy. This adds wear resistance to the sealing surface. Inconel is a nickle/chromome alloy high good corrosion, temperature and wear resistance. Again, it's probably a coating or the head is made of it and welded to a steel stem.

At the end of the day, it really isn't that critical - use what valves you can get and you should be fine. I'd be more concerned with having good quality than stelite/inconel or whatever.

 

[BryantMarwitz]

Alright so I have to engine mostly apart just decided on who to use as a machinist. I'm trying to put together a parts list what head studs do you guys use? Also should I replace the hpop?

 

[BryantMarwitz]

I'd go cam over studs on a 7.3. Studs are good on the 6.9 with the smaller bolts, but on the 7.3 I don't think you need them. Cam gives a nice boost to low end, and even without a turbo it wouldn't hurt. I can't speak to Justin's cam though, I'm using the one from Russ (TYP4).

Stellite is a chrome/cobalt alloy that is very hard and used as a coating on the valve face. The valve itself is still some steel alloy. This adds wear resistance to the sealing surface. Inconel is a nickle/chromome alloy high good corrosion, temperature and wear resistance. Again, it's probably a coating or the head is made of it and welded to a steel stem.

At the end of the day, it really isn't that critical - use what valves you can get and you should be fine. I'd be more concerned with having good quality than stelite/inconel or whatever.

Yeah I wouldn't replace them but they are somewhat worn and rusted I wouldn't use them again so I'm getting headstuds. The budget on this rebuild is about 3k

 

[Thewespaul]

Call sinister diesel and ask for the hpop reseal kit for your idi. Make sure and tell them it’s an 88-94 7.3 so they get the right kit

 

[79jasper]

Alright so I have to engine mostly apart just decided on who to use as a machinist. I'm trying to put together a parts list what head studs do you guys use? Also should I replace the hpop?

You don't have a hpop...........................

Sent from my SM-G892A using Tapatalk

 

[BryantMarwitz]

Ahh well I'm a newbie it does h

You don't have a hpop...........................

Sent from my SM-G892A using Tapatalk

Ahh I am a newbie it does have an oil pump though. Is that something I should replace?

 

[Thewespaul]

Just having some fun don’t worry man, the oil pumps on these trucks are extremely stout and rarely fail, as long as yours is smooth and has no corrosion the original pump is better than anything you can buy

 

[79jasper]

Just having some fun don’t worry man, the oil pumps on these trucks are extremely stout and rarely fail, as long as yours is smooth and has no corrosion the original pump is better than anything you can buy

He wouldn't have known any better. Lol
Sinister probably would have sold him a hpop gasket. Lol

Sent from my SM-G892A using Tapatalk

 

[Fision]

I am in the same situation as the OP: using 2-4qts/100miles. Assuming nothing is obviously wrong, How much does a machinist need to be involved? No doubt there’s room for opinion in this question, so perhaps some ranking of what YOU consider the necessity. I will suggest the system of 1-5: 1 being low necessity but “gold standard build”; 5 being “you’re an idiot if you don’t”.
Also, is there some IDI specific info that a competent machinist wouldn’t know?
Or IDI specific info that a couple shade tree mechanics doing a rebuild would benefit from?
Thanks again for all the info y’all put on here!

 

[Macrobb]

In my case, I had one engine that did that - ran good, would always start(with good glow plugs), but drank oil - quart every 50-100 miles.
Turns out, it had .020" of bore wear at the top.
Had to be bored .030" to actually clean up.
As a cautionary tale, make absolutely sure of the head valve recession specs if you have someone who isn't an IDI shop do the work. You need to make sure there is enough clearance piston to valve, especially if they deck the block and/or heads. Stock, there is only .030" of clearance between the piston chasing the valve up... that's pretty tight.
If they get it wrong, your valves can hit the pistons. Now, it's an IDI with valves square to the bore, so it won't instantly break anything..lt'll just destroy the valve guides in short order.

 

[nelstomlinson]

I have several IDIs that will go through a gallon in 200 miles, or more. All are good starters and good runners. All have serious blow by, so I suspect that the bores are worn like Macrobb's.

I am also very interested in hearing answers to Fision's question - what are the things that should (and maybe shouldn't) be done in a rebuild? I've done a couple rebuilds, many years ago, and probably didn't do them right. A list of musts, maybes and don'ts sounds like a great starting point.

Fision, are you in the Interior?

 

[Fision]

Thanks macrobb for the clearance reminder! Question on boring the 7.3: any way to tell if the walls are too thin? Cavitation is already a concern, especially with an engine with 200k and an unknown history.

 

[Fision]

Fision, are you in the Interior?

No, south-central, near Wasilla. I know y’all love it up there, but I think you’re crazy! 100 degrees in the summer, 50-60 below in the winter, and it’s flat! Y’all are crazy! Somehow it’s probably a good kind of crazy, but it’s still crazy...

 

[nelstomlinson]

I spent 13 years on the coast, and it never stopped raining. It's dry up here.

 

[IDIBRONCO]

Thanks macrobb for the clearance reminder! Question on boring the 7.3: any way to tell if the walls are too thin? Cavitation is already a concern, especially with an engine with 200k and an unknown history.

I know that they can be bored .030, but when I was in the business, the machine shop that we used wouldn't go over .020 because they felt that was too thin. If a block didn't clean up at .020, it was sleeved back to standard.