Engine back in frame, five bolts in front, two hefty bolts in back.
Looking at the massive amount of aluminum in that block makes it easier to understand why those ran so hot(!). It must be hard for the air to do its job with that shape.
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Folks..
The Square Fours were notorious for overheating..especially in hot weather and ridden for long distances. I wrangled with that problem for several years..when I had my '58 Mark II which was supposed to be 'state-of-the-art' for Ariel Square Fours. As you can all probably appreciate..it is very difficult to air-cool the two rear cylinders when the hot air from the front cylinders is essentially blowing directly back on the rear two.
Some of the remedies we had back in the late 50's..early 60's..were to: simply stop and let the engine cool down a bit..the go on with your ride
[an obviously impractical drag LOL]. Another popular remedy @ the time was to paint the cylinders black [rather than leaving them the natural aluminum color] which was reportedly more effective in dissipating the heat from the entire cylinder block. I didn't ever try that remedy myself..but reportedly it worked well enough @ keeping the two rear cylinders cool enough..so that it wasn't necessary to stop due to overheating.
And lastly here..I just wanted to say that it wasn't always necessary to stop to let the engine cool..which depended largely on the ambient temperature outside..on the days you were riding. I lived in So. Cal @ the time..and the summers' could get pretty hot [103-110F]. If it were me today..I'd probably paint the cylinders black..
Hope this was helpful Ichi
