Billet Cranks...

[strikeeagle]

OK, as the latest issue of HRM confirmed to me yesterday, a billet crank is a crank machined from a single hunk of alloy steel. Nothing new here...

Billet cranks have several advantages over cast or forged cranks. For example, stronger, lighter - depending upon application, and so on. And no obvious disadvantages.

Unlike forged cranks, billet cranks don't require "huge, expensive machines and dies with about 3,000 tons of pressure". Again, nothing new here...

What a billet crank does require is "affordable, modern CNC-controlled machining stations", and a program. Once the program is written and refined for, for example, a TR billet crank, it's done, for all time...

So, the problem then becomes fitting TR cranks into the machines' schedules. Nothing else. A billet is a billet. Machines are machines. A program is a program. The necessary investments have been "sunk".

So, to my simple mind, short of greed, TR billet cranks should not be more expensive than any other billet crank. That is, X hours of time to produce Y cranks equals Z dollars per crank...

So, come on boys, give us our cranks!!!

 

[PCS74]

I believe forgings are stronger.

Most "common" billet cranks run between $2k and $3k, buick v6 included.


Chris S

 

[ijames]

So far as I know forged cranks are stronger than billet cranks. Also, it costs a lot of money to get that program done, and they don't charge the first customer the full cost. They spread it over some number of cranks. For the sbc you are right, all the sunk costs have been paid for long ago. For the buick, I don't know.

 

[strikeeagle]

Not according to HRM:

"With big, complex parts like a crank, forging's full theoretical benefits may not be realized because economics dicate compromising the design to accomodate multiple parts from the same tooling. Even though it does interrupt the grain flow, today the trend is to machine high end cranks out of premium billet material; but forging is still preferred for smaller, less complex structures like con-rods."

The article includes a table which shows that forged cranks are "not preferred" for "professional competition", whereas billet cranks are the "best choice".

I know for a fact that high end CNC machines capable of handling large, heavy parts and carrying many tools are VERY expensive. I suppose programming is expensive as well. But again, once you bought the machine, and the programming talent, then to my simple mind a Chevy crank is a Ford crank is a Buick crank - you chop off a hunk of bar stock in a saw, chuck it, push a button, go back to your crossword puzzle, and wait for the beep to beep and the light to light.

Within certain limits, and if you're clever about things, you ought to be able to spread your costs over everything you make...

 

[ijames]

Hmm. I haven't read the article but I guess my first reaction is that a forging is always at least as strong as a billet since you start with a billet to do the forging to shape. I don't see offhand how it could wind up weaker. I agree that the more machining you do on it the more it will resemble a billet. Interesting.

The small, fairly cheap brand machining centers in our shop have a 20 x 40 inch table and with a rotary table totaled about $100,000-125,000 with no tooling. A faster, more rigid unit would be $150,000 or more. Getting some measuring and cutting tools, toolholders, coolant, etc., would add an easy $20,000 before making chips. At a complete guess our machine could rough machine a crank in a day or so, which at our standard outside shop rate would be about $500 just for the machine time. I imagine that there would be another 2-3 hours of tool setup each time you changed crank brands, at least an hour to get a rough crank out and a blank into place, plus some towards the cost of tooling, so maybe a total of $750? Then there's the billet material, which again, working from memory on crank size would be a bar about 10"x10"x24" or 2400 cu.in. or about 700 lbs of 4xxx chrome moly steel. Mild steel is about $0.75/lb and I'm going to use a factor of 3 and guess at least $1500 for the material (that is based on buying one blank at a time; getting the quantity up by 10 would maybe cut that in half and actually measuring a crank would probably show that I'm using too much steel ). After that, you'd have a rough blank ready for finish grinding, and people have posted that Scat and Crower used to get $1500 to 2500 to finish grind a bare Buick Motorsports forging. So that's $750+1500+2000=$4250. Our shop rate pays for the loans on the machines, the tooling, the lights and electricity, and the salaries. If you seriously tried to set up a shop just to do this, you would still have the machine and tooling costs, plus the shop utilities. I haven't touched on programming yet. We are a small shop with one expert machinist/cnc programmer plus some operators, so our programming time will certainly be longer than if you found a dedicated cnc expert, but then you are going to have to pay them a fairly steep consulting rate unless they become a partner. To get a working, debugged program is at least 50 hours, again at between $50 and $100/hr or another $2500-5000 of upfront costs. One option I just thought of is that you can probably find a machine vendor who will do the programming for you as part of the sale. The big advantages there is that they know their machine best and you can roll that cost into the mortgage . Then you need an operator - you really can't just push a button and walk away. You have to set up the tools, monitor the job, check dimensions along the way to keep up with tool wear, clean the chips out of the machine, and all the rest of the overhead stuff. Anyway, you are looking at setting up a shop plus maybe $125-150,000 in investment and/or mortgage payments, plus $4200 a crankshaft minus whatever your capital costs save over our overhead, in very small quantities. You might get your machine time cost down to $300 per crank, and I'm sure that even agreeing to do 10 cranks at a time would get the finishing cost and material cost down by half, or about $2000 a crank which is about $500 less than what I've read that Scat, Crower, or LA Billet charge for a billet V6 crank. Remaining cost savings are going to come from bigger volumes, buying more blanks of a given size and finish grinding more cranks with the same setup, and that gets us back full circle to your comment about Buick cranks not costing any more than the higher volume pieces .

 

[NJTurbo]

Originally posted by ijames
Hmm. I haven't read the article but I guess my first reaction is that a forging is always at least as strong as a billet since you start with a billet to do the forging to shape. I don't see offhand how it could wind up weaker. I agree that the more machining you do on it the more it will resemble a billet. Interesting.

The small, fairly cheap brand machining centers in our shop have a 20 x 40 inch table and with a rotary table totaled about $100,000-125,000 with no tooling. A faster, more rigid unit would be $150,000 or more. Getting some measuring and cutting tools, toolholders, coolant, etc., would add an easy $20,000 before making chips. At a complete guess our machine could rough machine a crank in a day or so, which at our standard outside shop rate would be about $500 just for the machine time. I imagine that there would be another 2-3 hours of tool setup each time you changed crank brands, at least an hour to get a rough crank out and a blank into place, plus some towards the cost of tooling, so maybe a total of $750? Then there's the billet material, which again, working from memory on crank size would be a bar about 10"x10"x24" or 2400 cu.in. or about 700 lbs of 4xxx chrome moly steel. Mild steel is about $0.75/lb and I'm going to use a factor of 3 and guess at least $1500 for the material (that is based on buying one blank at a time; getting the quantity up by 10 would maybe cut that in half and actually measuring a crank would probably show that I'm using too much steel ). After that, you'd have a rough blank ready for finish grinding, and people have posted that Scat and Crower used to get $1500 to 2500 to finish grind a bare Buick Motorsports forging. So that's $750+1500+2000=$4250. Our shop rate pays for the loans on the machines, the tooling, the lights and electricity, and the salaries. If you seriously tried to set up a shop just to do this, you would still have the machine and tooling costs, plus the shop utilities. I haven't touched on programming yet. We are a small shop with one expert machinist/cnc programmer plus some operators, so our programming time will certainly be longer than if you found a dedicated cnc expert, but then you are going to have to pay them a fairly steep consulting rate unless they become a partner. To get a working, debugged program is at least 50 hours, again at between $50 and $100/hr or another $2500-5000 of upfront costs. One option I just thought of is that you can probably find a machine vendor who will do the programming for you as part of the sale. The big advantages there is that they know their machine best and you can roll that cost into the mortgage . Then you need an operator - you really can't just push a button and walk away. You have to set up the tools, monitor the job, check dimensions along the way to keep up with tool wear, clean the chips out of the machine, and all the rest of the overhead stuff. Anyway, you are looking at setting up a shop plus maybe $125-150,000 in investment and/or mortgage payments, plus $4200 a crankshaft minus whatever your capital costs save over our overhead, in very small quantities. You might get your machine time cost down to $300 per crank, and I'm sure that even agreeing to do 10 cranks at a time would get the finishing cost and material cost down by half, or about $2000 a crank which is about $500 less than what I've read that Scat, Crower, or LA Billet charge for a billet V6 crank. Remaining cost savings are going to come from bigger volumes, buying more blanks of a given size and finish grinding more cranks with the same setup, and that gets us back full circle to your comment about Buick cranks not costing any more than the higher volume pieces .

Thank God you are not bulding nuclear weapons, you would be very dangerous.

 

[Buicksx2]

Carl,

Great post and pretty much dead on, plus throw in the fact most Buick guys would want a group purchase on it, shipped tomorrow or else they wouldn't buy it. That pretty much explains why Scat amd Molex want 2 grand payable upfront and there is a 6 month wait. So unless Scat and Molex should feel "honored" to do it for the Buick crowd you won't get one out of them unless you pay em up front and are willing to wait. It's their bat and ball and tooling machines and time so gotta play by their rules.

Just my 2 cents.

 

[Jeff Rand]

On my billet crank order could you make the rod journals the same size as a Chevy rod?
Thanks,
Jeff

 

[JoyOf6]

I plan to order a Scat billet V6 this year through the machine shop I use. They called "whatshisname" @ Scat, and told me $2250 and 14 weeks. All the billets are expensive. That's all I can add...

Art

 

[turbodave231]

I had Moldex turn 2 raw forgings. They charged $1000 each to turn a raw forging into a nice crank. They told me that to buy the same cranks from billet would be $2100 each.

I gotta assume the extra $1100 is for the billet and the extra lathe time to turn that cylinder of metal into something that looks like a crank. I spent some time in their shop. No high dollar CNC machine centers that I saw. Looks like they make them the old fashion way.

You'd have a hard time convincing me that a forging is weaker than a billet. But try to find a Buick billet these days. Now only if Mike at TA could buy the old dies that Buick used to forge their supply..........cranks could be bought a whole lot more reasonable.

For whatever its worth...

Dave

 

[EightSecV6]

In 1994, I bought a brand new forged crank from Moldex, the total including balencing was $1450....shoulda bought a couple!

 

[LikeMy6]

I just recieved my Billet Crank from Scat that I ordered way back in March of '02 "14 weeks" dont count on it! more like 6 to 9 months. They(Scat) offer 2 different Billets. 1 is their standard finish billet($1900) and the other is their "Pro Comp" style($2150) it comes w/t knife-edged Counter weights, plus a few other tricks.The crank looks very nice, but they kinda went overkill on the Fillets, as they measure 1/4" wide! each. When ordering you must make sure that you specify all dimentions that you need to be different from the production crank. like crank pin width. or you are going to get just that,a narrow pin. And when it comes to customer service SCAT SUCKS!! thats for REAL! They will NEVER return your calls and if you decide to change any aspect of your crank once youve placed the order too bad. They claimed to me that a Billet Crank is about 15% stronger than a forging, and that the Top Fuel teams use Billets exclusively. They say its in the grain structure.

So they say.

HTH

Frank

 

[turbobuick]

Billet Cranks

I ordered a billet 3.625 narrow journal from Crankshaft specialties about 9 months ago, its suppose to be here today. I'll let everyone know how it turns out, I got the crank done at a pretty decent price $1500. I got a discount from the $1850 he normally charges since I had some other crank work done. My machinist knows them and says they do nice work but they are not the fastest group to deal with.

You don't want to use a SBC rod journal size on a Buick even fire crank it weakens the journal due to the split journal design.

My machinist (Dale Francis) was an ASA engine builder involved with the Buick engine program from the beginning. He said the forgings broke or cracked frequently before they went to billet. He said it was rare to tear an engine down, to be freshened, and not find the crank damaged when using a forging. He said all billets are not the same either, depending on materials etc. He personally liked LA Billet and Kryptonite.
Chris Lyons

 

[JoyOf6]

Chris,

I thought LA Billet made the billet "Kryptonite" cranks. Is there another distinction you're making? I have time to choose a manufacturer even if it takes a year to deliver, so all input is welcome.

Art

 

[turbobuick]

Art,
I think your right about that. Its my understanding that they won't make Buick V6 cranks anymore.

Crank showed up. Very nice piece. We'll see how it measures up but from the manlte piece perspective its certianly pretty to look at Art I e-mailed you a pic. Maybe you can figure out how to post here for others to see.
Chris Lyons

 

[JoyOf6]

Originally posted by turbobuick
Crank showed up. Very nice piece. We'll see how it measures up but from the manlte piece perspective its certianly pretty to look at Art I e-mailed you a pic. Maybe you can figure out how to post here for others to see.
Chris Lyons

Please take it up to ~8000 rpm ASAP and let me know how it works out, okay?

Here's a link to a pic of your crank
www.geocities.com/joyof6/Crank

Art

 

[LikeMy6]

Hey Chris what was the shipping weight of your crank? just curios.
looks really nice.

Frank

 

[odell4o8]

I have a new never been used 3.625 kings billet crank its about 6 to 8 years old . it has to have mallory added to end counter weights to balance cost 300 and it has to have the pilot bearing hole opened up .1000 so the torque convertor will fit, another 80 bucks, my crank has knife edge counter weights same as the one above, i paid 2000 for it. i have a 3.590 billet that i got 4 years ago paid 1600 for it, i have never had any trouble with the 3.590 crank, i have a forged 008 3.625 in my motor in the car and a forged 3.590 that i have had for 6 years, it was used when i got it, it needs turned .010 on the rods, i will put it in a spare block that i have, i collect old buick stuff, just adding 2%

 

[S2V6RACER]

Re: Billet Cranks

Originally posted by turbobuick

You don't want to use a SBC rod journal size on a Buick even fire crank it weakens the journal due to the split journal design.

I have a billet crank with the chevy 2.100" rod journals. I also thought it would compromise the strength of the crank, but after looking at the thing for a while, you are only talking about a total of .125 of material off. Now based that billet is 15% stronger than a forged crank, that means taking 15% off a journal of 2.25" means that you can take about .337 off to be equal, the chevy journal only has about 5.6% less material than the Buick rod journal, but I know it is stronger than a stock iron crank, and that has been proven in over 800 HP applications. Depending on the target power level you are shooting for, I think that the Chevy rod billet crank would make a decent alternative. I am open to opposition, and if there is evidence of failures of these units I am all ears.

 

[PCS74]

Re: Billet Cranks

Originally posted by turbobuick
...My machinist (Dale Francis) was an ASA engine builder involved with the Buick engine program from the beginning. He said the forgings broke or cracked frequently before they went to billet. He said it was rare to tear an engine down, to be freshened, and not find the crank damaged when using a forging. He said all billets are not the same either, depending on materials etc. He personally liked LA Billet and Kryptonite.

Chris Lyons

Interesting. Can you ask him if they ever investigated why the forgings were being damaged? I would *guess* it was some manufacturing defect with the forgings. Please let us know.

LA Enterprises is very high quality. Their Kryptonite cranks are made from en30b. I believe Crower can/will also make cranks from this material.

Chris S