stunthanger.com
Building Tips and technical articles. => 1/2 A building. => Topic started by: Paul Smith on February 20, 2025, 08:16:17 AM
-
I saw this item and placed a token bid of $77 which I really didn't expect to pay. It held up until the happy hour sniping an sold for $156.
I have always believed that Cox engines would have been better with a lot intake and less exhaust, like modern OS's.
Maybe the new Cox maker in Canada will take note of this and offer such cylinders to the aftermarket.
-
Have you ever seen any numbers indicating these cylinder made more power than a typical cylinder? These were made quite some time ago, and I've never seen any reports of performance.
-
No I have never gotten a hold on one. As with all things engines, you need to get a hold of one and try it yourself.
The Babe Bee had one intake. The 2-port TD sleeve increased performance to the point that in my neighborhood, which had a lot of 1/2A flyers, every Babe Bee and Golden Bee was upgraded to a Super Bee or Black Widow within three weeks of discovery of the 2-port TD sleeve.
Compared to every other engine I have ever seen, the standard Cox sleeve has way too much exhaust and not near enough intake.
I have a hunch that the 3-intake/1-exhaust sleeve will increase power to the point the bottom end won't take it. Maybe that's why Cox intentionally degraded the top end. But I have good supply of bottom ends, so I could afford a few failures if the sleeves ever hit the market.
-
The most powerful cox TD sleeve was the original #4. It had 2 bypasses and each bypass had 3 flutes. You can get an increase by grinding down the webs between the flutes and smoothing the top of the port. The 3 bypass sleeves don't work as well as you might think because of poor directional control. Not true collision porting. But as with all Cox sleeves, piston fit is king so, ymmv.
MM :)
-
Actually, the most powerful TeeDee .049 cylinder is the one used on the Venom. One extra flute on each main flute opposed to create a swirl flow in the incoming gasses.
🤠
-
Thank you, that was my understanding based on the little information which can be found. The only other comment I've heard was from Paul Gibeault about running a Schnuerle cylinder on a Mouse, not sure if a KK or other homebrew. He said it didn't make more power but was much more fuel effiicient, so much that they were disqualified for not making enough stops.
-
Your theory is consistent with the reality of modern 3/1 engines vs the equal-ported engines of the past. Engines of today, such as the OS FP & LA Series use substantially less fuel than equal-ported engines of the past.
Of course the mouse racer in your example could have won the race by adding less fuel to its tank.
-
I think I recall reading that Gene Hempel(?) either got some Cox .049 cylinders that did not have the ports cut into them yet, or perhaps had some made independently. These were carefully passed around the speed community for the 1/2A speed events. Perhaps Patrick can shed light on this, or perhaps Bill Bischoff? Essentially, those that could, would port them to suit. I suspect various 3-bypass, 1-exhaust geometries were tried. If anyone has more info or can verify this, I'd like to know...
Dave