grinding a crankshaft in a engine lathe

[George Miller]

Here is how I grind my own crankshafts. Takes longer, but I can get them the way I want.

[DaWizard]

Is it me, or are the pictures unviewable?

[Mitch]

They did not show for me either

[Dennis]

They might be an incorrect file type.

[CarlG]

Don't work for me either.

[George Miller]

they showed up on mine

[George Miller]

image_5223.jpgimage_5222.jpg Try again

[George Miller]

Did you get them this time

[DaWizard]

Yes George, nice setup, could you do a video of that working?

I know, all they want is more more, and more. Never satisfied.

[George Miller]

could I do a video not me i do not know how. But maybe I could get my Son to do one. The grinder goes up and down as you grind the rods.

[Dennis]

I see them now.

[tbirdtbird]

Wish I had the equipment. Better yet, the skill to use it.
George, I can see how you can machine the main journals, but unlike a crank machine, I don't get how you are able to do the rod journals

[George Miller]

This is a grinder that I used in my Dads garage to grind rod journals while the engine was in the car. I did this when I was a Teen. We lived in northern Mich. Lots of people came up there on vacation in the summer from the big cites.

The plymouths 6 were bad about burning out a rod bearing when they had not had there oil changed when it was time.I would grind the rod journal in the car. Then they could get back home.

We also had a regular crank grinder so I have a lot of experience grinding cranks.

Any that I had done in recent years are not careful to get the flywheel flange running with in .0005 like it should be. Plus they force grinding the center main and cause it to run out. Model A crank is flimsy so you have to be careful.

It does not show to good but there is two rails and a center guide that the grinder rides on. It goes up and down as the crank turns. You can adjust it to get the tapper out.

[Kevin in NJ]

So how do you assure that the grinding is on the center you want?

That is I believe this machine only makes things round based on the distance from the grinding wheel to the V. So if I understand it correct then the grinder will make the center offset on any uneven wear. So the center main wears 180 out from the end mains and so this could end up with your centerlines offset.

You also can not correct for previous bad grinds. If someone ground off center (which happens more then you might think) then it will only make the surface round on that new center.

Are my assumptions correct or am I missing something?

[George Miller]

As far as being on center, just indicate the crank in on the lathe.

Well it was not meant to do mains, but it works fine for me. You just feed the stone in with the cross feed on the lathe. You take the tapper out with the adjust meant on the grinder. You do not use the vee for the mains, just the rods. But yes you are at there mercy of the one before you on the rods.

Yes you can correct cranks that were ground off, that is why I do my own.
Yes it would be easier with a big crankgrinder but I use what I have.

[Dennis]

George I always measure my piston protrusion when assembling. What would you say should be maximum allowable, and maximum difference?

[George Miller]

Dennis It depends on a lot of things. Like what kind of head you are using. Best to measure how far it can go in the head with out hitting. The head gasket is going to compress and the pistons will come up higher when it is hot and run fast.

I do not like them coming up above the block, but it happens on the A.

[George Miller]

The engine we used for the Hillclimb last year the crank was ground on the lathe. We had a rev limiter set at 4500 rpms for our last runs. I took the engine apart after the the hill climb the crank and bearings and my home made rods were fine.
That was with 6 guys driving up the hill 2 hours of practices, and two climbs each for the final. Plus it was a good two mile run back to the bottom of the hill. I can not say the same for clutch.