crankshaft services Q...

[hardtimes]

I'm curious about professional crankshaft machining. I suppose that not all machine shops that build A/B engines...have crankshaft grinding/altering/polishing/balancing machines. Of the shops that do have such equipment, are special 'stones' or other specialized equipment needed to handle proper grinding of A/B/BB/C cranks. Could one of you guys that do have the proper equipment and provide such give us an idea of equipment/maybe cost

I realize cost would be specific to what and how much work is needed, but generalized example would enlighten most here, I'm sure.

[Kevin in NJ]

It is complicated...

Here is a link to some comments

Crank grinding

[George Miller]

Model A and B cranks should have a big radius in the end of the crank pins and main bearings. Most shops do not want to put that radius on there grinding wheels. When I use to grind cranks in my Dads shop we had wheels with different radius on them. Then you changed the wheel that was right for the job. We did cars, tractors, trucks, and small engines. So you had a lot of different radius's. With out the right radius your crank will break before its time.

If you change the radius on the wheel every time you grind it would wast a lot of wheel in a hury.

The other thing that does not seem to be happen around this area is dialing in on the flywheel flange. So you are getting flywheels that are running out.

They also seem to be pushing to hard when they are grinding the center main. This causes the center main to run out.

[hardtimes]

Originally Posted by Kevin in NJ

It is complicated...

Here is a link to some comments

Crank grinding

Hey Kevin,
Thanks, that is a very good explanation for any engine owner needing such service. I'm thinking that those 'stones' are several hundred $ ea..no?
Sure adds to what I've been studying lately. Seems like the bottom line for hobbyist (me ) is to do best to do crank bidness with the best !

Question: Does crank owner have to provide A/B etc crank specs to a pro grinder or what required in this area ?

[hardtimes]

Hey George,
As a crank grinder, and doing all types of engines, how do you determine correct radii for that engines crank ?
And, regarding 'flywheel flange'....is the center line of that flange what everything else accuracy is worked from ?

[George Miller]

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Originally Posted by hardtimes

Hey George,
As a crank grinder, and doing all types of engines, how do you determine correct radii for that engines crank ?
And, regarding 'flywheel flange'....is the center line of that flange what everything else accuracy is worked from ?

They are probable using the center in the rear of the crank, or they are indicating from the center main. But who knows for sure what they are doing. Some just do not get it. It is very important to do things right.

We used to have a book with all the specs. You could also check a crank that has never has been ground. We installed a new scat crank and it looked like it had the right radius.

[CarlG]

Speaking of crankshaft services, is there a good place to send a crank to have the counter weights added?

[George Miller]

Originally Posted by hardtimes

Hey George,
As a crank grinder, and doing all types of engines, how do you determine correct radii for that engines crank ?
And, regarding 'flywheel flange'....is the center line of that flange what everything else accuracy is worked from ?

This is not the best way ,but I can do it myself and do it the way I want.

This is the old portable crank grinder we use to grind a rod journal in the car.

[machine girl]

piranios antique auto in texas, look at there web site, a full crankshaft shop, everything done in house.

[tbirdtbird]

better yet Pete's auto machine in Albuquerque

[modelAtony]

Originally Posted by tbirdtbird

better yet Pete's auto machine in Albuquerque

Double yes on Pete's, the son john cosper doe's all the work for the last probaly 7 years. This is a great place to get the 283 chevy pistons also. I like John and his reputation for building. He and his dad were the first to start doing inserts I think. His shop want win a beauty contest but you will love his engines.His engine break in is different , button it all up check for leaks start it run it up to about 1400 rpm baby sit it and let it run 8-10 hrs. BROKE IN AND READY TO RIDE DON'T BABY IT NO MORE. AT this point drive it like you stole it. Jame Rogers also has good reputation for his engines, never had one of his but He is top notch man. have fun modelAtony tony white Lafayette, LA

[J and M Machine]

Originally Posted by hardtimes

Hey Kevin,
Thanks, that is a very good explanation for any engine owner needing such service. I'm thinking that those 'stones' are several hundred $ ea..no?
Sure adds to what I've been studying lately. Seems like the bottom line for hobbyist (me ) is to do best to do crank bidness with the best !

Question: Does crank owner have to provide A/B etc crank specs to a pro grinder or what required in this area ?

Hardtimes: The grinding wheels are 400-700 dollars each Then after arrival at the shop they must be trued and then balanced and then trued again to the crank grinder.
My wheels are 28" in diameter.

Pro grinder should know what specs a crankshaft has when presented to him. I have a book that tells me what crankshafts are to be ground too including radii.

A crank lives and dies by the radius, however most of the cranks we get in Model A and T the radius is long gone.
Basically prior grinder was too lazy to grind a radius on his wheel to do the job properly.

Most often we see Model a and T cranks among others that don't indicate off of the rear crankshaft flange, therefore crank is usually ungrindable due to the amount of out of round caused by this mistake.
http://www.jandm-machine.com/crankshaftGrinding.html

[hardtimes]

Originally Posted by J and M Machine

Hardtimes: The grinding wheels are 400-700 dollars each Then after arrival at the shop they must be trued and then balanced and then trued again to the crank grinder.
My wheels are 28" in diameter.

Pro grinder should know what specs a crankshaft has when presented to him. I have a book that tells me what crankshafts are to be ground too including radii.

A crank lives and dies by the radius, however most of the cranks we get in Model A and T the radius is long gone.
Basically prior grinder was too lazy to grind a radius on his wheel to do the job properly.

Most often we see Model a and T cranks among others that don't indicate off of the rear crankshaft flange, therefore crank is usually ungrindable due to the amount of out of round caused by this mistake.
http://www.jandm-machine.com/crankshaftGrinding.html

Hey J and M,
This is an excellent response/content to my inquiry, thanks ! Sure wish you would have a shop on the Left coast.
Your info explains why this shop guy just charged me $250 to 'shape' one of his stones to cut my C crank/radius ! I saw the stone and it is as you describe..huge. Like someone said do it right first time...or don't do it at all ! I admire that which takes skill and expensive machinery..and which I can not do. Just got short block back home...and hoping that it's 'right' !
Thanks again for you very helpful sharing of expertise/knowledge !!