rpm limit with MI16 crank

[andy0075 9 1 Cars]

Hello,

 

i have a MI16 race engine with steel liners (Westwood), steel conrods, solid lifter,....

 

The only original thing left in the engine is the MI16 crank.

 

Question : what is the rpm limit with this crank?

 

Actually my limiter is set to 8300rpm

 

Andi

[JeffR 51]

I ran my old 1.9 Mi to 8300 rpm. Std crank, shot peened rods, ARP bolts and solid lifters for nearly 10 years.

All internals were balanced though.

[mrmut 0]

xu10j4r-rfy Mi 16 to 8500 rpm. Std crank, std rods ,  std light flywheel , std bolts and solid lifters home made, valve sprig 

[opticaltrigger 52]

On 1/9/2020 at 4:33 PM, andy0075 said:

Question : what is the rpm limit with this crank?

 

Hi Andreas.

The crank's not really the issue here.

When balanced properly, the crankshaft itself as an independent component should effectively spin on it's own axis without any imbalance present whatsoever. That is,,, up to the limitations of the balancing machines maximum speed and sensitivity. Therefore, it's rpm limit is only limited by it's own structural integrity. And that's extremely high indeed. 

 

The problem comes when you start to hang heavy rods and pistons on it. The rpm limit is much more relative to your conrods, there length, and in particular the bolts in them, than it is to your crankshaft. If you wanted to you could work out the momentary weight of your piston / rod assembly at TDC, at 8500 rpm, It's horrific.......

In Drag racing, where possible we like an aluminium rod..... It's allot less mass but it's reliable service life is very low.

 

All the best,

O.T.

 

[andy0075 9 1 Cars]

Hi,

 

thanks for the answers.

 

@opticaltrigger

I have 85mm Wössner pistons and steel rods with ARP2000 bolts (~1997ccm), KingRacing bearings,

billet steel lightweight flywheel,....

 

Andi

Edited January 16, 2020 by andy0075