Is this a stupid way to hold my crank for building?
 

I held my flywheel up to my engine yoke and two holes lines up perfect. So I ran up the hardware store and got a couple longer bolts, plus a couple spacers to mount it up. Feels solid. The flywheel isn't bottomed flat on the face of the yoke (it's maybe .5mm away) so there is a tiny bit of flex. I don't want to damage my flywheel though. Think this is a stupid way of doing it?

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That crank is heavy. I'm not sure the flywheel was intended to have to support it when bolted in at the edge.

When I did mine, I threaded a few of the old crank-to-flywheel bolts in and the set the flywheel on a table. My approximate order of operations was:

- Install mains in case.
- Install crank in case do Plastigauge fit-up (before rods were on crank).
- Take crank out of case.
- Put crank on flywheel, but flywheel on table (crank goes vertical).
- Clamp flywheel to table to prevent toppling.
- Install rod bearings and rods.

Hope this helps.

Thanks for the sequence. Sounds like you Plastigauge the mains, but not the rods? I've never heard of that before. It's the opposite in Wayne's book. Am I missing something?

I decided the spacers were not helping my setup. So I removed them and cinched the flywheel down so it's now resting flatly against the yoke. I also rotated the whole setup so the weight of the crank is into the yoke instead of away from it. It's solid as a rock.

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Oi, try placing it on the flywheel as a support. :eek: to install the rods for plastigauge work. Maybe on the cleaned floor for leverage.

Sorry - I omitted the plastigauge step on the rods. (I checked clearance on both the rods and the mains with plastigauge.)

It may feel solid, but I still recommend setting that crank vertical (flywheel horizontal on a table).

or at least support the pulley end somehow.

I believe there is a factory tool that holds the crank in the horizontal position but I do not have one. I had a junk engine adapter that came with my stand (probably for V8 engines?) and I drilled the crank/flywheel hole pattern into it to bolt the crank on.

As you can see I drilled one hole incorrectly. So far so good.

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I did try to center the holes around the axis of the tube but the tube diameter lands right on the crank/flywheel bolt circle and didnt work. This is why they are offset on the adapter.

Why not make some V blocks out of some wood or something....

Personally, I would never hang my crank from one end like that without support.

Dump the plasti-gage and buy the tools or pay a machine shop a few bucks to measure and match the bearing to the bores to the journals.

I wouldn't do it, and I'm not the overly cautious type sometimes. ;)

That is a lot of moment weight on there once you start adding bits.

i always just bolt the flywheel on and set it on the bench standing up. which is how cranks are supposed to be stored when not bolted into a block

For reference, here's the factory tool for doing this job, goes into the P313 bench mount clamp just like the yoke can.

http://forums.pelicanparts.com/uploa...1484179102.png

I made my own from some good angle steel and just clamp it in a regular bench vise.

andy

Well, I've been paranoid about warping my flywheel after posting this. So I had my steel shop burn out a "bow tie" which I used as an adapter between the crank and the yoke. Works great. And now my flywheel is resting easy on a shelf.

I'm surprised no one makes something like this. Or maybe they do...

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I wouldn't worry about warping the FW as much as the crank

Wait, what? Warping the crank? Factory has a tool specifically for holding the crank horizontal, Wayne mentions it in his book, countless builders do this. I'm pretty green here, so what am I missing?

I use a junk flywheel and clamp it in a vise. Makes it really easy to assemble and torque the rods. Go for it.

I'd only it do it for the time it takes to install the rods.

I wouldn't store it that way. That's me.

The tolerance for the crank journals are measured in ten-thousandths. Bet you could put a dial indicator on the end of the crank opposite the flange and flex it slightly.

Stomski makes a very nice one that supports the crank at both ends, in either vertical or horizontal position.

https://www.stomskiracing.com/products/911-crankshaft-holder

I'm not going to say if it's right wrong ok or not. It's your crank you do what you want.

But from my experience with machine tools. Specifically with leveling a lathe and taking the twist out of a heavy cast iron lathe bed. You suddenly become aware how "plastic" cast iron and steel really is. It's a real eye opener.

With that being said. I guarantee you that crank is bending in your fixtures under its own weight.

You seem "bent" on mounting this in a cantilevered position. I worry that the jig you fabricated means the crank will sit that way for a period of time, allowing gravity to possibly have an effect on the straightness. As no carrier suggests, set it on a pair of v-blocks or equivalent or mount the flywheeel, then set it vertically on the workbench. A large lazy susan below it will allow full access to measure and inspect. FWIW, when work space was at a premium, I rebuilt an entire engine with it sitting on a lazy susan. However, your crank, but you asked.