Posted By: moparrulzzz
Question on turning a crank... - 10/07/09 12:22 AM
I am taking my crank(forged) in tomorrow to be magged and turned. I know it will need turned as the rod journals (not the mains) have rust on them.
What is the most I should let them machine?
There is no damage from a spun bearing or anything like that so I am guessing it should be no more than .010, but ya never know.
I also read somewhere to have them champher the oil holes, shall I tell them to do this as well?
Sorry if this is trivial but I am pulling the trigger on my 1st build. (440)
Posted By: MoparforLife
Re: Question on turning a crank... - 10/07/09 12:32 AM
Go as little as it will clean at. .030 won't hurt it and bearings are still available at that size. Mains can be cut to 383/400 size so go figure.
Posted By: Neil
Re: Question on turning a crank... - 10/07/09 12:36 AM
Most shops chamfer the oil holes without asking, but it wouldn't hurt to bring it up.
Posted By: RapidRobert
Re: Question on turning a crank... - 10/07/09 12:53 AM
I'd install your rod/main bearings & mike them & give that dimention to the crank grinder so he he can grind the exact clearances that you are after.
Posted By: moparrulzzz
Re: Question on turning a crank... - 10/07/09 12:55 AM
Thnx for the tips guys. I will tell them no more than what is needed to clean them up and call me if it needs more than .030(which I doubt) and I will tell them to chamfer the oil holes!!..THNX!!
Chuck
Posted By: Dodgem
Re: Question on turning a crank... - 10/07/09 12:28 PM
That's right on the bearings wait till they measure it. They don't always champer holes and polish so make sure they are going to do it! What is the intended use??
Posted By: moparrulzzz
Re: Question on turning a crank... - 10/07/09 01:15 PM
Building a 450-500 HP 440. Street use only. doubt it will see 6500 RPM's.
I can post more specifics later if needed. On my way to work.
The crank is still in the garage till I get more specifics..
Posted By: therocks
Re: Question on turning a crank... - 10/08/09 11:59 AM
Had mine turned they polished it chamfered the holes and balanced the assembley.I did change pistons also.They also blueprinted and clearanced mine.Its a street motor but built for race.Rocky
Posted By: MoparforLife
Re: Question on turning a crank... - 10/08/09 03:21 PM
We like to stay at .0015 and no more than .002 on boththe rods and mains in the engines for street ans strip. No problems and have always used a HV pump.