What crank to grab?

[Hardwire666]

Ok so after months and months of searching I can't seem to get my hands on a decent 258 4cwt crank. Plus since there is a good chance of buying one that's toast I have decided to go with either a Scat, Hesco or 505. I'm looking for advice from those who have experience with these cranks as I'm unsure what one really is the best to get.

Thanks in advance.

P.s. I'll be reusing my stock 6.125 rods with BT pistons in my 4.7 build.

[CandyCaneXj]

505 is a crook, liar, and extremely disorganized. Plus the 3.895 cranks he sells are scat cranks. Might as well just buy from jegs and get the free shipping. I have one which I didnt get to use yet but the machinist that offset ground it for me said it looked good. And it only weighs 47 pounds.

[Hardwire666]

sweet thanks for the info! Scat it is!

[CandyCaneXj]

I don't know why scat's website says it weighs 56lbs Anyone else weigh one??

[Cheromaniac]

A 4cwt 258 crank weighs 46lb, a stock 8cwt 4.0L crank weighs 55lb, and a 12cwt 258 crank weighs 66lb.

[CandyCaneXj]

It's definitely the 4 weight scat sells. My scale must be a pound off.

[IH 392]

Any particular reason you want a 4cw crank?, I would, and did, go with the 12 cw crank.

[jsawduste]

Any particular reason you want a 4cw crank?, I would, and did, go with the 12 cw crank.

Because the OP thinks it will spool up faster ?

[IH 392]

Any particular reason you want a 4cw crank?, I would, and did, go with the 12 cw crank.

Because the OP thinks it will spool up faster ?

Like to see PROVEN evidence of this?, plus the greater mass of the 12 cw will run SMOTHER! and wheel at low speeds better, and will also have improved clutch engagement.

[jsawduste]

Any particular reason you want a 4cw crank?, I would, and did, go with the 12 cw crank.

Because the OP thinks it will spool up faster ?

Like to see PROVEN evidence of this?, plus the greater mass of the 12 cw will run SMOTHER! and wheel at low speeds better, and will also have improved clutch engagement.

You took my comment out of context.

The extra mass of the cwt is located so close to the centerline of the crank itself that the added weight does very little in regards to the spool rate.

What the added weight DOES do is help to absorb the harmonics generated by the reciprocating asm. Moving the resonate frequency to a higher RPM.

[CandyCaneXj]

If the extra weight is so important in shifting a manual then does that mean you can't offroad in a 4 cylinder or v8 manual jeep or because the crank is too light? Most of the time you are moving you are not shifting so I see no reason not to go with the lighter one. Some form of energy has to be wasted to spin the exta pounds around. And I cant believe the 12 weight would help that much if the crank is already balanced.

[Cheromaniac]

The extra mass of the cwt is located so close to the centerline of the crank itself that the added weight does very little in regards to the spool rate.
What the added weight DOES do is help to absorb the harmonics generated by the reciprocating assembly. Moving the resonant frequency to a higher RPM.

What he said.

the greater mass of the 12 cw will run SMOOTHER! and wheel at low speeds better, and will also have improved clutch engagement

The extra weight on the 12cwt crank merely adds more rotational inertia so once the crank is spinning, it takes longer to slow down. That helps you rockcrawl at low rpm 'cause the engine's less likely to stall.
A lighter crank is better if you race down a dragstrip or on a short road course where you frequently change gear and you want the rpm to drop quickly to enable better clutch engagement. For the same reason you'd also opt for a lighter flywheel.

[Hardwire666]

The extra mass of the cwt is located so close to the centerline of the crank itself that the added weight does very little in regards to the spool rate.
What the added weight DOES do is help to absorb the harmonics generated by the reciprocating assembly. Moving the resonant frequency to a higher RPM.

What he said.

the greater mass of the 12 cw will run SMOOTHER! and wheel at low speeds better, and will also have improved clutch engagement

The extra weight on the 12cwt crank merely adds more rotational inertia so once the crank is spinning, it takes longer to slow down. That helps you rockcrawl at low rpm 'cause the engine's less likely to stall.
A lighter crank is better if you race down a dragstrip or on a short road course where you frequently change gear and you want the rpm to drop quickly to enable better clutch engagement. For the same reason you'd also opt for a lighter flywheel.

Thats exactly why I want a 4cwt. Besides the fact finding a 258 crank for a reasonable prive is almost impossible. And if im gonna pay I want new.

[IH 392]

So this engine will be used for road racing?, and you don't mind that you'll have to rev it up to get it rolling?, personally I don't care for the smell of clutch smoke?

[Hardwire666]

Not even for real racing, though i might hit the track here and there. I'm building it just because. Everyone around centeral florida goes for 3"+ and 32's. Im doing something different. And even though I'm not going full race I still want it to perform when I mash the gas a bit. And considering im auto not manual I don't have to worry about burning clutch. While I was considering an ax swap its just not wirth it.

Im not really building a race car im just having fun. If I wanted a race car I'd be looking for something to drop an LS into.