Stroker Owners Question

[rd]

Looking to build a 331.

I had decided to go for a forged steel crank vice a cast one, since I want one that will rev safely to 6500 or so if needed. I have all older 28 oz parts in everything.

Several, Eagle, is one, that only offers the forged units in internal balance.

Is a 28 oz forged crank not available, and is there a good reason?

Thanks.

 

[347HO]

There are some steel cranks such as Scat which are more than enough to handle 6500rpm.
Steel Scat will go internal, but the forged Scat will be difficult to get to zero balance... not worth it.
If your goal is only to 6500rpm, 28oz external will be more than sufficient (cost vs value)
It is important you acquire the lightest possible pistons and rods.

When hitting upwards of 7500, you may want to look at going internal and zero balance.

Eagle cranks I've been told are easy to work with, you just have to check it out of the box for runnout, bearing O.D measurement before working on it... but that goes for any part you install.

28oz balance should run you around 300.00 completed.
Zero balance will run from 500.00 to 12000.00 depends on your requirements.

 

[Kumm3]

Zero balance is nice in theory, but its not nice to your wallet.

 

[Grn92LX]

All you need is a scat cast steel crank for that rpm. Go 28oz balance with a good light weight balancer like a romac and get an aluminum flywheel.

 

[95Vert383AOD]

If you get an internal balance crank all you need is to have the weights knocked off the flywheel and have a machine shop check it for neutral balance. And get a ROMAC neutral balance harmonic balancer. Thats what i did on my 383.

Its alot cheaper to buy the Crank already internally balanced than to try having one modified.

The idea behind Internal balancing is that after a certain rpm the counter weight (28oz) starts causing vibration because its no longer effective. That vibration causes unwanted harmonics that can cause main cap walk, premature main bearing wear etc.

You can find an internal balance Romac for just under $300....have the weights knocked off your flywheel and enjoy.

 

[Rick 91GT]

There is some bad info in this thread...

Just because a crank like the Eagle is listed as internal, it still needs to be adjusted to the weight of the rods and pistons. The Eagle Forged cranks are made heavier and typically will go internal with just drilling holes, however I have had them take Mallory to go internal. The SCAT Forged cranks will need mallory to go internal, how many slugs depends on the rods and pistons selected. I can say that the newer style Eagle cranks I have not had the runout issues that the older units were known for.


For what you are looking to do I would go with the SCAT Series 9000 cast crank, it will outlast the stock block and easily go 28oz and save you some money. Spend the extra money on some light weight rods and upgraded bolts. However if you want to go forged, the SCAT or Eagle will easily go 28oz, just keep in mind the Eagle uses a 2.123" rod journal and the SCAT a 2.10" rod journal (important when your considering rod selection). The narrow 1227 bearings required with the Eagles are double the price

347HO- his info is good