Briggs & Stratton OHV Plastic Engine No Compression

[GearHead36]

My oil is better than your racing oil.

I don't recall, but I doubt we had racing oil. This was the early 80's, and we were changing it every race day. Probably should have changed it every heat.

 

[RevB]

You DO understand the concept of racing engines, right? High lift cams, bigger valves and valve springs, ported intake & exhausts. Steel cranks. I think the rods were aluminum. Not sure about the pistons. There were 3 classes. Stock, stock appearing, and modified. Stock is stock, except you could remove the governor, use bigger jets in the carbs, and any exhaust. Modified was, anything goes within the confines of an OEM block and OEM head. The carbs, intakes, and exhaust flowed WAY more than stock. We burned WAY more methanol than a stock engine on gas would. I think I read somewhere where the stock engines were burning about 2.5 times compared to gas. Modified was considerably more. If the stock engines were producing, say, 6.5-7HP, then the modified engines were probably in the range of 20-25.

The engines DID run cool at anything less than full throttle. I ran a few road courses, and for the last few races, I had a temp gauge. The engine would run very cool until the green flag, then I'd watch it climb every time I was on the throttle. When I'd lift, going into a corner, it would cool quickly. It would do this every lap, every turn. Also, every lap the temp would be 5°-10° hotter than the lap before. I got concerned a few times when I saw 400 at the end of a heat.

As for lubrication being washed away, you're probably not wrong. Engines were good for about one season, and we were running I/C engines with steel sleeves. I changed oil after every race, and it was always very thin. There was lots of blowby. Didn't much matter, though. Every season, the parts manufacturers would come out with a better, faster engine kit (cam, crank, piston, etc). If you didn't build a new engine with these new parts, you'd be left behind. That's when I discovered that, while cheaper than car racing, kart racing was still a very expensive hobby, and I got out.

You just repeated everything I said...

 

[GearHead36]

You just repeated everything I said...

But then you go on to refute my claims of "way more power".