remove my name from list please --- "mail@xxxxxxxxxxxx" <List@xxxxxxxxxxxx> wrote: > Topics covered in this issue include: > > 1: Rolled fillet cranks > by "Bruce Hevner" > <scramblr@xxxxxxxxxxx> > 2: nitriding by the pound from KustomKemps > by lynn peterson > <kustomkemps@xxxxxxxxx> > > > -------------------------------------------------------------------------- > 1 Message:0001 > 1 > -------------------------------------------------------------------------- > > Message-Id: > <3rr0ks$it15k9@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> > From: "Bruce Hevner" <scramblr@xxxxxxxxxxx> > To: "AMC AMC" <mail@xxxxxxxxxxxx> > Subject: Rolled fillet cranks > Date: Sat, 19 Feb 2005 22:25:55 -0500 > > >Another question is of fillet rolling - something > >done to the Turbo Buick Grand National Crankshafts > >to ward off cracks forming. As I understand - > these > >filletts are rolled under high pressure during > manufacturer - > >is it possible to do this to welded up cranks and > >cast crankshafts alike ? > Rolling the fillets is not done to prevent cracking > although it does kinda > have that effect. It's done to increase the strength > of the journal by > effectively increasing and smoothing the radius of > the area where the > journal meets the crank itself AND compressing the > metal at that point to > make it stronger. We have been told to NEVER grind a > rolled radius crank > enough to remove (or even TOUCH) the radius. I > believe the number given was > a 20% reduction in strength. This means most of > these type cranks will only > grind .010 or .020 at most. > There are MANY OE cranks besides the Buick that use > this. The later model > Chebby cranks are rolled on the rear main only. I > race a lot of Toyota 20r > series motors. The rods are rolled on all these > motors from the factory. > I have not seen this done in person but the > pictures of the process I have > seen involve a LARGE hydraulic press with narrow > steel wheels rolling the > journals of the crank. Not something the average > shop could afford much less > an individual. > We looked at having the cranks cryogenically > treated to increase strength > but it was pretty costly so we never had it done. > That is a REAL good indicator of quality in a crank > grind. Forget the > finish (look at it second),,, look at the fillets > first!! Look at the > fillets on a custom crank like COLA. They are large > and smooth,,, > BEAUTIFUL!! Sometimes it is necessary to trim the > edge of the bearing to > clear the radius on these cranks. > If the crank grinder is lazy or they don't own a > radius dresser for their > machine, the radius will end up with a square > corner. Do NOT accept a job > like this!! It's a stress riser that INVITES > cracks!!. The radius MUST be > blended as perfectly as possible into the cheek of > the crank. I have > magnafluxed cranks where the crack was on the SIDE > of the radius. The radius > withstood the pressure but it was transferred to the > mating line of the > radius to the crank. Strange pressures are at work > here!! > But hey,,, that's just me!! > Bruce Hevner > > > > > -------------------------------------------------------------------------- > 2 Message:0002 > 2 > -------------------------------------------------------------------------- > > Message-ID: > <20050220060055.36478.qmail@xxxxxxxxxxxxxxxxxxxxxxx> > Date: Sat, 19 Feb 2005 22:00:55 -0800 (PST) > From: lynn peterson <kustomkemps@xxxxxxxxx> > Subject: nitriding by the pound from KustomKemps > To: mail@xxxxxxxxxxxx > > Well, I'm glad to see that I have generated some > chatter accross the ether. Some people think that > nitriding is super expensive, but it is not. In > fact, > we nitride BY THE POUND, with a 100lb. minimum. > Therefore, the more cranks we have in a run, the > cheaper it is. Example: if you sent a crank from > Ohio > to the shop in Portland, Or, and did not have a UPS > account, it would run about $170 to ship the crank > both ways. (We prefer Forward Air) This is more than > $100 over the cost of the nitriding. Except for one > engine, all the motors we build run offset ground 2" > SBC journals with a couple of 1.88" NASCAR size > thrown > in. The possibility exists that we could have a > crank > that is harder in one area than another. We feel > that > any crank that might be cut beyond the factory > hardness level will be better for the process. (does > anyone know what depth the AMC cranks were hardened > to > from the factory?_ > > L. Peterson > > Kustom Kemps > > > > __________________________________ > Do you Yahoo!? > Meet the all-new My Yahoo! - Try it today! > http://my.yahoo.com > > > > > End of digest for 20 Feb 2005, hour 0:00 > **************************************** > > > > > __________________________________ Do you Yahoo!? Yahoo! Mail - Helps protect you from nasty viruses. http://promotions.yahoo.com/new_mail