cooling tins

I think they are critical for any shrouded engine that is going to be run for any length of time. A drag race? No, but my opinion is that if you are going to run without the fan or blades, you should un-shroud the engine so air can get to the cooling fins better and provide some cooling while in motion. Someone may come along and say I'm full of it, but air cooled engines are just that... They rely on moving air to cool them and they will overheat if moving air is taken away.

Next time you see some Harley's (or other air cooled motorcycles) traveling the median or shoulder during a traffic jam, keep that in mind. :)
I misunderstood... I was thinking 'fins', but you are asking about the tin shrouds, right? They will provide better cooling for a typical mini than running without them IMO.

Sorry about that, auto correct gets me a lot and I thought that is what happened at first glance.
Hello outlaw, I copy all that and am going to take your advice on
the cooling tins. They are hard to find, I'll have to PM jimkemp for
them. Thanks friend.
A lot will depend on the particular engine, and the application. I'm removing all of that on my street cruiser Tec OHM110 since it's cylinder is upright and the exhaust port is on the side so it gets some cooling. Flatties and slopers may not fare as well, unless turned around and run through a gearbox that reverses the rotation. Or, changing the cam drive from counter-rotating gears to same-spin chain and sprockets like a Honda G-unit so the crank can spin backwards once the flywheel and recoil have been set up for it.


Well-Known Member
The shrouds and fan are definitely needed if you're running gasoline through anything but a dedicated drag engine. Methanol engines on race karts often get the shrouds partly taped-up just so they don't run too cool.

None of these engines were designed to use passive airflow like motorcycles, etc. The fins often face the wrong way and the exhaust port area is not going to get enough air. Most stock configurations direct a lot of forced airflow over that area.