Knife edge, Bull nose, lightened crank?

Posted By: racer_amx

Knife edge, Bull nose, lightened crank? - 06/27/08 02:13 PM

Anyone done any of these or a combination on a steel big block crank? If so did you see any improvements?
How much weight can be removed from a big block crank?
Thoughts?

Posted By: torkrules

Re: Knife edge, Bull nose, lightened crank? - 06/27/08 07:10 PM

Quote:

Anyone done any of these or a combination on a steel big block crank? If so did you see any improvements?
How much weight can be removed from a big block crank?
Thoughts?

If you get into this you will need to lighten the pistons and upper part of the rods to keep everything in balance, or you will need to install a pile of mallory metal to make up for the material removed during bull nose/knife edging.

Posted By: Neil

Re: Knife edge, Bull nose, lightened crank? - 06/27/08 08:41 PM

My brother did it to a steel oldsmobile 330 crank. Took a stupid amount of work to do it. Days worth of heavy grinding followed by days worth of sanding to smooth everything out.

The crank grinder who does his balancing told him not to take too much material off the crank as it can make it difficult to rebalance.

Posted By: racer_amx

Re: Knife edge, Bull nose, lightened crank? - 06/28/08 10:43 AM

Quote:

If you get into this you will need to lighten the pistons and upper part of the rods to keep everything in balance, or you will need to install a pile of mallory metal to make up for the material removed during bull nose/knife edging.

Most definately, if I decided to do this I would be getting lighter pistons rods, ect...

Quote:

"My brother did it to a steel oldsmobile 330 crank. Took a stupid amount of work to do it. Days worth of heavy grinding followed by days worth of sanding to smooth everything out.

The crank grinder who does his balancing told him not to take too much material off the crank as it can make it difficult to rebalance."

Did your brother see any gains? Was he happy with the crank? Did he think it was worth it in the end?

I am hoping to hear from someone who has done this to a Big block mopar, but the only info I can find all seems to be on 4 cylinder forums, I take it this is not a common thing to do to v8's

Knife edge cranks

Posted By: Neil

Re: Knife edge, Bull nose, lightened crank? - 06/28/08 12:56 PM

The engine is still being built so he hasn't run it yet. I imagine the cost of the labor to do it keeps most people away V8 or not. Steel cranks are made out of some tough material and it takes a long time to cut and reshape it.

Posted By: 451Mopar

Re: Knife edge, Bull nose, lightened crank? - 06/28/08 05:28 PM

I think Crower Cams and Equipment do alot of these cranks, but almost all are Chevys.
The crank I got from 440-Source looked pretty smooth. I'll have to take a few pics.

Posted By: racincuda

Re: Knife edge, Bull nose, lightened crank? - 06/28/08 05:56 PM

Actually it is more common now on 440's but dont remember how much weighht they take off, kinda remember something like 4 to 6 lbs, dun with a lathe not a grinder. You may want to consider adding a oil shedding coating if you are going to the expense of knife edging and profiling.
Find a good crank grinder, somebody who can do everything you want in house.

Posted By: RobR

Re: Knife edge, Bull nose, lightened crank? - 06/28/08 06:46 PM

The cost to re balance with heavy metal far exceeds the perf benefits for the average guy.