crankshaft reconditioning Q...

[hardtimes]

Anyone (engine builders, etc.) polish/restore A/B cranks that you use and if so, how
Is there any tips/info to share regarding how to determine whether crank is straight ?

[BRENT in 10-uh-C]

As with anything, better quality results generally require better quality tools. If you can accurate support the crankshaft in a lathe using centers, you then can use an indicator to measure run-out.

As for restoring a crankshaft, it is likely the least profitable operation performed in a machine shop. This is why most shops either don't do it at all, -or don't do it well. I found my crank grinder for a deal, but even after restoring it myself, I'd bet I have $10k in it. Many used crank machines will cost over $50k. It generally takes about 2 hours of labor to restore a crank. Not all of that time is spend grinding. You also have cleaning, testing, straightening, prepping, and packaging involved. Prices for a reground crank are basically the same today as they were back in 1980. If a shop charges $125 for a crank job, but has 2 hours in it, and their hourly shop rate is $90 an hour, you can see why there are so many crappy crank jobs turned out.

[BILL WILLIAMSON]

I watched as a Man polished a crank for me, on a machine that rotated the crank, between centers. His machine used a LOOOONG band of Crocus Cloth, revolving at a high speed. He had to hand raise & lower it, as the crank throws passed by. The mains were EASY. It was a very QUICK job. He also dial indicated the center main.
Wish I knew the BRAND of the machine??? He said it also worked for polishing CAMSHAFTS.
OH, found a VULCAN machine on E-Bay---ONLY $4,500.00!!!!
Bill W.

[Kurt in NJ]

As Brent says--in a lathe, measure all surfaces, also on V-blocks on a surface plate, measure stroke, index of journals

From the Ford blueprint--
with the shaft mounted on the end bearings the ccenter bearing must not runout over .002 indicator, and the timing gear shoulder, and the flywheel pilot(rear flange) must not runout more than .001 indicator reading
the pins and bearings must not be out of round more than .00025
the pins and bearings must not taper more than .0005 in the length of the bearing surface
The face of the flywheel flange must be within .0005 at the rim
The axis of the crank pins must be paraell to axis of the main bearings within .001 in 6 inches
stroke and index must be within .005

many times I have seen polishing used as a crutch to cover up bad grinding

if you just want to polish up a journal some for your own use take a strip of fine (320 or so) and some oil and shoeshine---you can use shorter strip of emory cloth by tieing string to the ends

[CarlG]

Turn the clock back -- I was about 9 years old, helping my dad "polish" the rod journals on a Model A. Engine in the car with the pan off. He held long strips of crocus cloth around the journals while I pressed the starter pedal up in the cab.

[hardtimes]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by CarlG

Turn the clock back -- I was about 9 years old, helping my dad "polish" the rod journals on a Model A. Engine in the car with the pan off. He held long strips of crocus cloth around the journals while I pressed the starter pedal up in the cab.

Ha, cool story !

I've a nos C crank with cosmoline or whatever is on crank. Intend to employ this C crank into Tods new alum block B bottom.

Wiped it clean and the surfaces are a little discolored. Don't like that so thinking that 600 grit will remove any discoloration and still leave with standard measurements. Also, just wondering is tiny dark spots are worth the effort, as no pits, etc that can be picked up with finger nail. Maybe tooo picky, eh

[hardtimes]

Originally Posted by forever4

Rich
How about 2000 grit?
600 is pretty severe IMO.
I don't see a little staining being a problem. JMHO

Hey Vince,
Thanks for your input ! Honestly, I have never seen 2000 grit, but if I can locate where to purchase it, that sounds great advice
Or maybe I'll look it over a lot closer (mag glass) to ensure that it has no flaws. My eyes are not young, and my cvs glasses aren't the best. It does mike out very well ! I am familiar with a poor mans version of polishing tools, i.e.- flat shoe string , WD40 and wet sand paper.

All good info to consider/use. Thanks to all for that.

[40 Deluxe]

Originally Posted by hardtimes

Ha, cool story !

I've a nos C crank with cosmoline or whatever is on crank. Intend to employ this C crank into Tods new alum block B bottom.

Wiped it clean and the surfaces are a little discolored. Don't like that so thinking that 600 grit will remove any discoloration and still leave with standard measurements. Also, just wondering is tiny dark spots are worth the effort, as no pits, etc that can be picked up with finger nail. Maybe tooo picky, eh

I think 600 is way too coarse. Use crocus cloth. It will put a mirror finish on that crank.

[rogeroadster]

Originally Posted by hardtimes

Ha, cool story !

I've a nos C crank with cosmoline or whatever is on crank. Intend to employ this C crank into Tods new alum block B bottom.

Wiped it clean and the surfaces are a little discolored. Don't like that so thinking that 600 grit will remove any discoloration and still leave with standard measurements. Also, just wondering is tiny dark spots are worth the effort, as no pits, etc that can be picked up with finger nail. Maybe tooo picky, eh

Richard -

email me your address (again) and I'll mail you a couple sheets of crocus cloth.

[hardtimes]

Originally Posted by rogeroadster

Richard -

email me your address (again) and I'll mail you a couple sheets of crocus cloth.

Hey roger,
YOU are an great example of some of the best people on the Ford Barn and of people that a guy can meet in this hobby/life !
Must be ESP , as I've been going to contact you as I have a couple of things to talk with you about. For example, how is that beautiful T roadster and CRAGAR banger engine coming along ? Seems unfair that one person (YOU) can have so much talent while others (me) skimp by

[Mikeinnj]

Originally Posted by hardtimes

Hey Vince,
Thanks for your input ! Honestly, I have never seen 2000 grit, but if I can locate where to purchase it, that sounds great advice
Or maybe I'll look it over a lot closer (mag glass) to ensure that it has no flaws. My eyes are not young, and my cvs glasses aren't the best. It does mike out very well ! I am familiar with a poor mans version of polishing tools, i.e.- flat shoe string , WD40 and wet sand paper.

All good info to consider/use. Thanks to all for that.

Any auto body shop or supplier will have a range of wet n' dry papers up to 2000 grit. Be sure to remove all the grit...

[rogeroadster]

Originally Posted by hardtimes

Hey roger,
YOU are an great example of some of the best people on the Ford Barn and of people that a guy can meet in this hobby/life !
Must be ESP , as I've been going to contact you as I have a couple of things to talk with you about. For example, how is that beautiful T roadster and CRAGAR banger engine coming along ? Seems unfair that one person (YOU) can have so much talent while others (me) skimp by

Richard -

I'll drop the crocus cloth in the mail tomorrow and respond to your pm later tonight. And not to hijack your thread but since you did ask, here's a pic of the roadster, which like all projects, is making slow progress.

[hardtimes]

Originally Posted by rogeroadster

Richard -

I'll drop the crocus cloth in the mail tomorrow and respond to your pm later tonight. And not to hijack your thread but since you did ask, here's a pic of the roadster, which like all projects, is making slow progress.

Looking good !
I especially like that one off water pump and custom intake/exhaust work !!