Two piece crankshaft !!!

[JEHall]

New to the forum so hello all. I thought I would share a picture of the crankshaft out of my turbo engine. It's is a reman I purchased for the turbo setup but now I think I would like to fix this engine. I have a 1992 F–Superduty that needs an engine so hopefully I can fix this one. The crank was a regrind that appears to have been built up by welding on the rod journals. The heat markings are apparent on all 4 of the rod throws. The crank was also stamped 20 mains and 10 rods and the bearings were the same 10 and 20 under. Me thinks when they built up the crank they took some of the temper out of the crank and made it susceptible to fatigue causing it to give up the gohst. Now I am in need of a usable crank and one usable turbo rod. These turbo rods seem to be as rare as hen's teeth I couldn't find any on eBay or from a parts store. The dealer may have some but I'm sure there mighty proud of it and would want an arm and a leg. Turns out the balancer is split at the keyway slot as well. Don't know what caused that but I need a balancer to. If anyone has these parts they would like to sell please let me know. I am in central Virginia near c–ville.

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[no mufflers]

I had a balancer that was cracked at the key way also.

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[manimal]

WOW, thats just crazy... I use to see that in GM 6.2/6.5's all the time. Did it vibrate more than normal? Ive seen cranks break clean at the journal and throw, but that one looks like it may have had a crack in it BEFORE it was welded.

 

[FarmerFrank]

What about using a NA rotating assembly since the turbo stuff is so hard to find?


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[JEHall]

I don't know if it vibrated as I bought it that way. I would guess it did though. The guy I got it from said it made noise so he put a single mass clutch kit in it thinking the dual mass was bad. The crazy thing is that he ran the truck like that for a while and it didn't come apart. From what I can tell the rod had both halves of the crank captured wich kept it going until the cap finally split. Tuff motors.

The reason I want fix this engine is it came with a new clutch kit and the bigger wrist pins pull more heat off of the pistons. The pistons are like new as well. As clean as this motor is on the inside and cross hatch still in the bore I'm guessing it had less than a 100k on the reman. I guess I'll keep hunting for a rod. Should be able to pickup a crank pretty easy and there is a balancer on eBay right now.

Here's a pick of my SD tow rig to be. I may be able to salvage the crank out of the engine that's in it now but not sure. There's a nice 3" crease pushed out on the side of the pan so I don't know what I got until I pull it out and down.

Hope everyone still has all their fingers after the fourth.......Jim.

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[snicklas]

Aren't the cranks the same, turbo or N/A? I thought the only difference was rod/wrist pins, harmonic balancer (dampner) and a different balance on the flywheel/flexplate. I don't think there's any difference in the crank itself. The only "special" thing you may be looking for is that one rod......

 

[hesutton]

Wow! That's pretty rare. As far as I know, this is only the third crank failure I've seen on these IDI's.

Heath

 

[sjwelds]

So the flywheel balance is different because of the rods/wrist pins, not because of the crank being weighted differently?

 

[snicklas]

So the flywheel balance is different because of the rods/wrist pins, not because of the crank being weighted differently?

Yes, the harmonic balancer and flywheel/flexplate are where the different balance is. The larger wrist pins are a bit heavier, so making the balance different.

 

[FORDF250HDXLT]

The cranks are for sure different guys.

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That's a great looking F-super duty/F450!
You wont be able to rob her crank because I'm pretty sure all the F450's came with M codes (8th digit in vin = n/a engines) I say this,just simply because I've yet to run across a factory turbo optioned f-sd before.I'v looked at a lot of for sale adds cus I love these trucks.

 

[Macrobb]

Or just build it as a NA motor, more or less. Don't worry about the smaller wrist pin, I don't hear about wrist pin failures even under heavy boost.
The oil jets are where the heat from the piston goes; a little bit of liquid oil will take away a lot of heat. This is why you can boost these engines without long-term issues, vs, say, a Perkins 4.108 which has no oil jets and will wear out quickly when you add a turbo.

You could also check into a set of modified Powerstroke rods for even greater strength - R&D IDI Performance makes a set, but they aren't cheap.
You'll also have to have whatever crank you use balanced if you go that route.

 

[icanfixall]

Well that's special isn't it. My bet is the crank grind radius was incorrect causing a stress point. So it broke easily. I built my na engine with turbo rods.I personally balanced each piston to between 1/4 and 1/3 gram difference across all 8 pistons.Then I gave every rotating piece to the balancer guy and he drilled and added weights to the crank. So I have a set of turbo rods on an na crank.Can't feel the engine running either but you can hear it. Balancing an na crank works but if you can do try to locate a turbo crank. That way you can just install it and run it. Balancing not required. Ford does sell the turbo rods as does International Navistar. Let the phone shop for you.

 

[JEHall]

Thanks for all the comments and advice y'all have given. I didn't realize that the 93-94 superduty trucks were not offered with turbo option. Ford was probably worried about having to warranty transmissions on those trucks and decided not to.

I have wanted a superduty for a while and when this one came up on craigslist I jumped on it. I gave 1400 for the truck and it came with a broken motor and a family of mice. The guy i got it from said the mice came free. I thought i got a deal on it until the first hot day I went to work on it. The smell will flat out knock yo down. Let me tell ya I was ready to load it up and take it back to the guy I bought it from. I thought I could get by with pulling the seat and carpet and giving them a good powerwashing but the mice have set up shop in the duct work. Im gonna have to swap out the dash and ducting to make it tolerable. The carpet cleaned up nice and I have a set of caiptains chairs/center console out of a gasser parts truck to swap in. I should be able to use the dash out of the as well if I swap the harness. Its allot of work but its the only way. Dam mice.

I like the idea of balancing the crankshaft to turbo rods and pistons. I would assume then you would use the standard 0 balance flywheel and balancer.I'm pretty sure that the na mill is internally balanced and that the flywheel and balancer are not weighted. Engine builders mag has a good article on rebuilding the 6.9/7.3/ps7.3 and the progression of improvements . In this article the author states that all cranks from 6.9-7.3 idit are the same forging.However the picture that Fordf250hdxlt posted of the two crankshafts sure look different to me. The counter weight on the one on the left looks smaller and has been drilled also. They both show discoloration on the rod throws. Is that factory or have they been built up by some welding or spray process that put allot of heat in that area of the crank. I saw a post a while back about another broken 7.3 crank that broke at the same 5/6 rod journal that mine did. It to was a reman and also has discoloration in the rod throws. Ive polished up a couple gasser cranks when replacing bearing and don't recall seeing heat markings on them. In that string someone also commented on the radius being ground wrong. I guess it could be a combination off things.

The turbo setup i bought is a factory rig off of a 94 dually,that's complete, including the squashed down pipe. I plan to open up the exhaust housing on the turbo to 3" and use a factory 6.0 exhaust system. The 6.0 down pipe has a 3.5" flange that necks down to 3" pipe so with a little adjustment it should work. Its stainless as well so that's a bonus. An inter cooler add is on the radar but that gonna be down the road a bit as there is allot of stuff to do before i get to that.

Jim


http://www.enginebuildermag.com/2006/07/rebuilding-the-international-6-97-3l-powerstroke-engine/

 

[icanfixall]

My non turbo crank was balanced to fit the turbo rods. So was the auto flex plate and the crank damper.