Open Can Motors
 

Are these ok for cars like the b4 and xxx cr where the motor hangs out the back. Eg the lrp and SP v3 6.5t, just worried about using one outside on astro where dust and dirt could get?

Ive been using the Spv3.0 motor's in my B4 and xxx-cr with no problems at all.

outside ?

Yes, outside. On grass and astro.

thanks, that is good to know

If you think about it, all brushed motors were effectively open cans yet they were used everywhere. And brushed motors suffered more from dust and dirt than brushless ones do.
The only difference is you will have to clean the can out from time to time.