O.S. 21XZ-M Speed Inboard Marine Engine

[Tim_Duggan]

Looking for any feedback on the O.S. 21XZ-M Speed 3.5cc Inboard Marine Engine

Anyone run one yet - thoughts?

 

[RaceMechaniX]

I have run the older 21 VZ-M with good results. Looks like they just took the on-road VZR motor an changed the head and carb. It will likely still need some shim removal and timing increase. Otherwise not bad motors, but for the cost you can buy a nice NR motor.

 

[Tim_Duggan]

Thanks Tyler,

I won't be going away from NR's any time soon but was curious about the coating used on the "speed" version's crank and wristpin and whether it works well or is marketing hype.

Tim

 

[NITROSNIFER]

The Speed versions also have a balaced crank. And yes the coating does help. I've ran them both in a rigger the Speed revs better even though the numbers are the same. Or it could just be the ceramic bearings.

 

[ALLAN YUEN]

It is very good but replace piston/sleeve and bearing kit most expensive good luck!

 

[Tim_Duggan]

It is very good but replace piston/sleeve and bearing kit most expensive good luck!

Still cheaper than NR 35+!

 

[Tim_Duggan]

The Speed versions also have a balaced crank. And yes the coating does help. I've ran them both in a rigger the Speed revs better even though the numbers are the same. Or it could just be the ceramic bearings.

Thanks Kevin,

Does it pull decent prop pitch in a rigger?

Tim

 

[NITROSNIFER]

I was pulling Mark Sholund 1450/1455 and also a full blade 1450 with it. Was a little tricky to get the right pipe combo but she hauled when you found it.