6m/7m cranks

[Justin]

So I've done my share of searching and know that the 6m crank is lighter and not balanced, and the 7m crank is balanced and 5 lbs heavier....

that's nice. Which is better?

I'm picking up a JDM engine and I get to inspect it before I buy it, and I have my choice of however many there are in stock. If i come across one of each, which should I choose???

 

[supra90mkiii]

I don't think either one is "Better", I have a 6m crank in my 1990 engine, cuz i couldn't find another 7m in my area. It works fine. Have a machine shop balance the crank and it should be good. It won't be Fully balanced like the 7m, but it's semi-balanced.

 

[Supra Blues]

I don't think either one is "Better", I have a 6m crank in my 1990 engine, cuz i couldn't find another 7m in my area. It works fine. Have a machine shop balance the crank and it should be good. It won't be Fully balanced like the 7m, but it's semi-balanced.

Also, I think the 6m has a higher rev limit. Its lighter so it will spin eaiser.

You may not even be able to tell a difference. I also have a 6m crank.

 

[Dirgle]

Also, I think the 6m has a higher rev limit. Its lighter so it will spin eaiser.

You may not even be able to tell a difference. I also have a 6m crank.

It should also be noted that the rev limit is implemented by the ECU. So it really depends on what ECU you have what your rev limit will be.

 

[Supra Blues]

It should also be noted that the rev limit is implemented by the ECU. So it really depends on what ECU you have what your rev limit will be.

Oh yes. Thanks.

 

[Idealsupra]

not to mention the 7m can spin high revs NO PROBLEM...just need to build the valvetrain and get it breathing correctly to do so reliably...

frankly either or would work..

 

[Justin]

Cool

Thanks for the help everyone