Could you Sleeve down an old crusty 7.3 to run 6.9 pistons???

[Wrenchmonkey316]

I’m curious if you could possibly do a swap from a 7.3 piston down to a 6.9 and swap to the normal 6.9 gaskets and everything still all line up? Do the heads need to be swapped? Or anything else? Is it possible? Difficult? Easy? Has anyone heard of it being done? Thank you. All of your input is appreciated.

 

[Kdo58]

R&d resleeve the 7.3 block for 6.9 pistons

 

[Cant Write]

Would that cure cavitation concerns and give you the larger head bolts...win win?

I don’t know about journal sizes between crank/rod and rod/piston but I’m sure it’s surmountable.

I’m already punching above my pay grade.

 

[Jesus Freak]

I do get paranoid about cavitation, because I have a cavitated block (not in my truck of course). I'm sure that's a legit option though. Maybe make the new holes 4.030" to give it a little extra.

 

[FrozenMerc]

No reason you can't do it, and there are lots of good reasons to do it for an all out build like R&D's. The biggest hurdle will be coming up with a sleeve. I doubt there are readily available aftermarket sleeve's with the right wall thickness, so you will likely have to modify something or machine custom sleeves. Don't forget to rebalance the crank for the lighter 6.9 pistons.

 

[Booyah45828]

I'd be more concerned with finding pistons. Somewhere I read that 6.9 pistons are no longer made and will be obsolete, any truth?

 

[Wrenchmonkey316]

Ok, the piston swap just went too far for me to want to attempt it. Another thought. Is it expensive to get a shop to put the regular 7.3 repair sleeves in all 8 on a crusty old 7.3 during the rebuild ? as an upgrade to help prevent some issues down the road.

 

[FrozenMerc]

Not that I am aware of. 6.9 pistons should still be available. If not, custom pistons are very doable and have gotten much, much cheaper over the years do to the advances in CNC technology. The advantage to going the custom route is you can spec pin height, compression ratio, ring groove geometry, etc. and really dial them in for the application.

My experience has been $80 to $125 per hole to install, fit, and machine a dry sleeve. Your best bet is to call some local shops and ask for pricing.

 

[Booyah45828]

No reason you can't do it, and there are lots of good reasons to do it for an all out build like R&D's. The biggest hurdle will be coming up with a sleeve. I doubt there are readily available aftermarket sleeve's with the right wall thickness, so you will likely have to modify something or machine custom sleeves. Don't forget to rebalance the crank for the lighter 6.9 pistons.

Found it on facebook.

According to justin anderson (r&d), 6.9 pistons have been obsoleted by mahle, and uem.

Custom pistons are made frequently, but they're typically made off an existing forging/casting. As far as billet pistons are concerned, I don't think those are exactly affordable. Likely have more in pistons then most have in a truck.

 

[Wrenchmonkey316]

I like the 7.3 sleeve route better for myself, it’s cool the 6.9s will work but I want to try to keep it cheap n easy.

I’ve seen used running 7.3s with a 1 yr warranty for $2500. I’ve seen rebuild kits for around $1500. I’m not understanding the price I saw for a remand 7.3 idi at $10000.

 

[FrozenMerc]

Mahle may have discontinued 6.9 pistons, but you should be able to still get them from Speed-Pro or Silv-O-Lite.

What was the content level on the reman 7.3 IDI? If it includes fuel, $10K is a pretty good price. The remanufacturer I work for sells 6.7 Fords and DirtyMax long blocks (no fuel or turbo) for around $7K to $8K to wholesale distributors. How much they are marked up from that point for final sale to the end user, I can not say. However, you can rest assured that a large percentage of the cost is going to distributors, and not the remanufacturer. Remanufacturing a 40 year old platform such as the IDI is expensive and difficult. Core is getting rarer and in worse condition, often it will take 3 or 4 core engines to yield enough material for one good engine, and new replacement parts are getting harder and harder to find. That is why we won't touch the older IDI stuff. The oldest engines we reman today are 1st Gen HEUI DT466's, which came out in '94 and even those are falling off quickly. We had to reman a mechanical DT466 last year for a warranty claim. It took 4 core engines to yield enough parts to fully rebuild the damaged warranty unit. Needless to say, we lost our ass on that one.

 

[Booyah45828]

According to justin anderson (r&d), 6.9 pistons have been obsoleted by mahle, and uem.

Mahle may have discontinued 6.9 pistons, but you should be able to still get them from Speed-Pro or Silv-O-Lite.

silvolite is made by uem.

TRW(sealed power/speed pro) hasn't shown stock for awhile now. Anything you find is NOS. If you've got a source for them, buy them up and set yourself up as a little niche reseller.

 

[Wrenchmonkey316]

Mahle may have discontinued 6.9 pistons, but you should be able to still get them from Speed-Pro or Silv-O-Lite.

What was the content level on the reman 7.3 IDI? If it includes fuel, $10K is a pretty good price. The remanufacturer I work for sells 6.7 Fords and DirtyMax long blocks (no fuel or turbo) for around $7K to $8K to wholesale distributors. How much they are marked up from that point for final sale to the end user, I can not say. However, you can rest assured that a large percentage of the cost is going to distributors, and not the remanufacturer. Remanufacturing a 40 year old platform such as the IDI is expensive and difficult. Core is getting rarer and in worse condition, often it will take 3 or 4 core engines to yield enough material for one good engine, and new replacement parts are getting harder and harder to find. That is why we won't touch the older IDI stuff. The oldest engines we reman today are 1st Gen HEUI DT466's, which came out in '94 and even those are falling off quickly. We had to reman a mechanical DT466 last year for a warranty claim. It took 4 core engines to yield enough parts to fully rebuild the damaged warranty unit. Needless to say, we lost our ass on that one.

Sad crying emoji..

I didn’t realize how hard parts are to find for old idi’s. When I rebuilt a high mileage Subaru ti or whatever it’s called that had a bad head gasket I didn’t really need to get “xtra” parts, mostly just machining cost and the master rebuild kit cost. Do the major components in these old idi’s usually have damage or excessive wear?

 

[Wrenchmonkey316]

Seems like the best option for a rebuild right now is to get a 100-250k used with 1 year warranty for $2500-$3000 and rebuild that unit before installation. So, maybe $5000 for a fresh engine with some luck?

 

[tbowker]

So, maybe $5000 for a fresh engine with some luck?

I bought a 7.3 remand engine from Jasper for $8k last year. Has a 2 year unlimited mile warranty. I figured it was pricey but the warranty sealed the deal for me.