Is this a Flywheel or a Flexplate?

[dcoy]

To me, it doesn't look like any flywheel I've ever seen. I'm learning all the time, so maybe I'm wrong. The problem is, it is coming out of my FJ60 with a Cummins R2.8 with a manual transmission. The current shop has called it a flexplate but apparently some people can loosely interchange the terms. They believe it may not be up to the task (for obvious reasons) but perhaps they are being a bit too diplomatic. More to the point, did the shop that did the conversion throw a flexplate in where a flywheel was obviously indicated?

 

[thatcabledude]

That’s a flex plate. I assume this truck was never driven after the swap?

 

[dcoy]

That’s a flex plate. I assume this truck was never driven after the swap?

I've been trying to drive it (about 10K miles), but I've been somewhat restrained by sorting various leaks (power steering fluid, A/C, oil, etc) and failed driveshaft/u-joints. This does explain my complaint that I have to give extra throttle when releasing the clutch just to get it off the line. Even added a TDI tuner to help with the R2.8s weird narrow power band but it didn't do anything for the starting issue.

 

[thatcabledude]

I can’t see how that could have possibly came out of your truck then. They must be mistaken.

 

[thatcabledude]

Did they say why that is broken?

 

[dcoy]

I can’t see how that could have possibly came out of your truck then. They must be mistaken.

It did run long enough to break. Perhaps that's a testament to how good a flex plate it was in tolerating an inappropriate application. This is a very unique vehicle amongst a sea of RVs and big rigs at the Cummins shop so I don't know how they would be mistaken.

 

[dcoy]

Did they say why that is broken?

They said it must have been an inappropriately matched or faulty "flex plate" for a diesel platform but that seems to ignore or avoid the fact that there should be a flywheel in there. There was an order for a flywheel in my invoices but I wonder if my engine got swapped for another that was destined for an auto tranny. That's not an excuse, just a partial, possible explanation.

 

[TheBussman]

sometimes flywheels and flex plates are stacked together in certain situations. there are no torque converter bolt holes in it so i think that's whats going on here. its possible that in your application the flexplate only needs to turn the crankshaft for starting. and the flywheel has no starter ring gear teeth on it.

 

[thatcabledude]

sometimes flywheels and flex plates are stacked together in certain situations. there are no torque converter bolt holes in it so i think that's whats going on here. its possible that in your application the flexplate only needs to turn the crankshaft for starting. and the flywheel has no starter ring gear teeth on it.

I was about to say there is no way to bolt a clutch to it (much less a friction surface) then noticed there isn’t a way to bolt a converter to it either.

You must be correct

 

[dcoy]

sometimes flywheels and flex plates are stacked together in certain situations. there are no torque converter bolt holes in it so i think that's whats going on here. its possible that in your application the flexplate only needs to turn the crankshaft for starting. and the flywheel has no starter ring gear teeth on it.

Bingo! Thanks. I'll have to find out why they did it that way. Still, it shouldn't be breaking after almost no mileage.

 

[TheBussman]

looks like there isn't much martial on that flexplate around the bolt holes, i don't know what transmission your running but hopefully there is a flywheel that can also run the starter ring gear or the flywheel your currently running can be machined to accept one.

 

[dcoy]

looks like there isn't much martial on that flexplate around the bolt holes, i don't know what transmission your running but hopefully there is a flywheel that can also run the starter ring gear or the flywheel your currently running can be machined to accept one.

Yes. Those bolt holes appear to be mounts on tabs made of fairly unsubstantial sheet metal. There are gears on the flywheel but I don't know why the starter can't run on it. Perhaps the gear sizes are not compatible?

 

[dcoy]

looks like there isn't much martial on that flexplate around the bolt holes, i don't know what transmission your running but hopefully there is a flywheel that can also run the starter ring gear or the flywheel your currently running can be machined to accept one.

The transmission is an H55F and apparently Axis Industries makes the adapters and maybe the actual flexplate to create the flywheel/flexplate sandwich. Nobody so far can give me a compelling reason why you can't have the starter run on the flywheel. That's just "the way it is". I have yet to find that flexplate on their website or anywhere else. All the flexplates I see appear to be way more solid in the center where the mounting holes are. Awaiting direct communication with Axis Industries.

 

[Skniper]

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