I bought a Callies racemaster crank from a good friend. One of the rod bearings spun and needed fixing.

The crank was taken to a reputable shop near me since I knew this place has a good outsourcing machine shop doing this type of work for them.

I basically told them that strength was what I wanted to retain in this crankshaft. The shop said that would be no problem. We discussed keeping the 2.100" rod pin size, and I *thought* we had agreed upon that.

The crank just came back and the rod journals were taken down to 2.000". Although I was scared at first, I called Callies to see what they had to say. They told me that tuning the rod journals down to 2.000" from 2.100" would take all the power I wanted to throw at it if I had the crank heat-treated after machining (which I did). That was a relief to hear.

I know they make plenty of good forged rods with a 2.000" big end, so that is not a concern.

Just wondering if anyone has had any experience with crank machining like this, and if the strength will be ok (900+hp).

I trust what Callies said, but just want to get a couple other "expert" opinions before I put it in my new shortblock.

All work was performed by Moldex Tool Co. in Dearborn Heights, MI....which apparently does work for Winston Cup team and other high end motorsports divisions.

Thanks, Jason

 

I would not worry about it at all if Moldex did it. They do alot of high end work for Cup teams, Katech etc... In fact they made the V-16 crank for the Cadillac 16 show car with a 1000hp, 1000ft lbs motor.

Either there was a miscomunication between someone or the crank was beat up enough that it had to go to 2.000". Normally you are looking a a few hundreths smaller not a full tenth.

The same process is needed on offset grinding of cranks too. You actually grind them, not turn them. Two completely different processes. They probably cut thru the case and so had to put a new case on the crank, the only bad thing is that the new case hardening probably makes the stuff the wasn't reground (counterweights etc..) thicker which could be a good or bad thing.

Either way Moldex is someone to trust on all of this. 900hp is minimal for them, especially something that's not going between 5000-9000 for it's entire duty cycle.

I don't think you are going to find a good forged 2.000" journal forged rod to take 900hp, maybe a billet one. For forged stuff you are looking at Eagle, Howards or Lunati and that stuff is only reated to 750 HP with L19 ARP's in them. They should hold up, but at the same time you are going beyond their design limit. It would be a good idea to get new ones then because most used 2.000" rods have been really beat on.

My crank guy out in Binghamton had a Scat Lightweight there last time I visted him that he ground down to 2.000" rod journals and that thing was running fine in a 8 sec bracket car.

OTOH, Winston Cup guys run smaller journal (1.880) cranks at high revs all day long, not just on short bursts and it's not really the HP but the RPM that breaks the crank, so I would feel really comfortable with someone like Moldex doing the work.

Bret (with a little help from the old guy)

 

Thanks Bret (and John)

That give some additional encouragement. Those Winston Cup cranks are not ground down to 1.880" are they? I thought they were cast with the smaller rod pins.

As far as rods, I know that Scat and Oliver both offer some very nice rods in a 2.000" big end diameter. I will definatly buy new. I dont really want to go billet, but I may have to.

Thanks, Jason

 

I had to check with him on the case thickness stuff, not my bad of tea normally.

Those guys use a billet crank, so it's all ground and tunred on a big CNC lathe. They would be down in the Mistubishi and BMW journal sizes, but I think they are rules limited on that now to stick with the Honda size.

Either way a 2.000-1.880 journal size is most likely going to be made of the same forging a 2.100 is.

Scat does have some H beams but the Olivers are a much better bet. They make everything in 2.000" pins. If you are throwing boost at it you might as well stick with the 5.700" ones and keep a big piston in there.

Bret

 

Right on....yeah your dad is a *wealth* of information (to put it mildly)!

I figured it was the same forging, I guess I just didnt understand how much material was actually "there".

5.7" rods are the plan, as I already have some -31cc dished pistons setup for 3.75" stroke, 5.7" rod.

Any good deals on Oliver rods from you Bret? How are the regular "forged" rods from them (ie. the non-blingers)?

In any case, I may have to go with the billets.
Thanks bro
Jason

 

FWIW, crank forgings are generally oversize enough to accommodate various strokes and main journal sizes. This is from GMPP and explains a lot.

http://www.gmpartsdirect.com/perform...CATID=883.html

Billet cranks can be anything you want, of course.

I agree that Moldex, while not cheap, is a good place to have your crank modified.

 

you said that the nascar motors are running a small diameter right? does it really surprise you too much? those motors are all business, and smaller diamter journals have reduced friction. hidden hp secrets