Best After-Market Internal Balance Forged Crankshaft?

[~JM~]

Trying to determine which of the several forged internal balance Cranks available are the most accurate & best quality. Are there any that are drop in, or do they typically require additional machine work? What are the issues that require attention?

I have yet to decide whether I want to retain stock stroke or increased stroke. Feedback on that aspect is welcome also.

Thank you.

 

[grass doctor]

I asked turbo89 this the other night and it depends on your HP needs

 

[Turbo6inKY]

Trying to determine which of the several forged internal balance Cranks available are the most accurate & best quality. Are there any that are drop in, or do they typically require additional machine work? What are the issues that require attention?

I have yet to decide whether I want to retain stock stroke or increased stroke. Feedback on that aspect is welcome also.

Thank you.

The 4340 forged crank I got from Boost Crew was dead on. All the journals were exactly where they should have been down to the ten thousandth out of the box.

But I did have to put ~$90 worth of Mallory metal in it to get it to balance.

Your mileage, of course, may vary.

Increased stroke? If I were to rewind, I wouldn't do it again. It gives some oomph down low, but I think that could probably be overcome with proper cam and torque converter selection without all the mockup, grinding on the block and all the extra cleaning. I ended up sleeving the oil galley near where it had to be ground to clear the #1 rod, and my first camshaft had to go back to Comp in exchange for a small base circle cam because the standard circle cam interfered with the rods.

 

[grass doctor]

most applications eagle or crower good to 600-800 hp then might want to step it up to winberg or Bryant , and the best of the best is the LA enterprise kryptonite crank , owned by Pankl up to 1500 HP, have read/been told stock crank will hold up to 500 or more but duration of service will be subjective , so that's my 2 cents probably wrong but anyways I am not a racer and very new to the game

 

[NY Twin Turbo]

For a 109?

There are cranks that are available that far exceed the explosion point of a stock block. Not a lot of good to you if you split the envelope your putting it in to. You could spend up to $3600 for a crank and be putting it into a $300 block. Even the right BMS cranks that have been properly prepped have been to 1500 HP.

 

[~JM~]

I should have been more specific. Plan to use 109 or 4.1L Block.

Targeting mid 10 second capability.

Thanks.

 

[No disintegrations]

I should have been more specific. Plan to use 109 or 4.1L Block.

Targeting mid 10 second capability.

Thanks.

The machine shop will need to finish balancing the whole rotating group as part of the build process. ( For internal balance) rod choice and their weight is a factor.

 

[Steve V]

I have used Eagle, GN1, Harolds (which maybe boost crew, Arizona GN, Zimmermans etc) and they all work for 95% of the guys on here.

One thing all Chinese cranks seem to have in common is fat bearing journals. We are talking .0001's here. That is why some turn a new crank .010/.010 . The other option is to use an Hx bearing. Those are extra clearance up to .001, by mixing and matching std and hx you can usually make any crank work without turning it. The rod hx are easy to find the mains are dried up. Found some in New Zealand a while ago from 3800 platform. Expensive to get to USA.

If you turn it your bearing selection goes out the window so the grinder needs to turn it to a size. I have had on job where I dropped off the crank/rods with bearings installed and he turned the crank to the size for .002

 

[captndave737]

I got a GN1 Performance. The journals were spot on and needed very little material removed to balance.