On Tuesday 18 April 2017 18:03:32 andy pugh wrote: > On 18 April 2017 at 22:11, Marshland Engineering > > <[email protected]> wrote: > > 2 Stroke motors have been doing this since the 1960. > > Very, very few of them. Most disc valves have been put on the end of > the crank, and multi-cylinder ones have tended to use reed valves, > which are entirely passive.
Or in the relatively massive center web of a 2 cylinder inline, deflector head engine. In the 1930's Johnson made a 2 cylinder 10 hp 2 stroke, unfortunately with deflector head pistons so it was all done at around 7 grand. The clearances around the wide center of the crank probably were not sufficient to deny its touching the bronze bushing in the center of the crank when wound up tight as the one I had, was a Pacific Marine Bilge pump, so the crank was horizontal. I liked the looks of it, so I bored out the intake and fitted a single bowl carter carb with a 1.125" throat to replace the 5/8" throat Bing it came with, then threw away the flywheel and magneto because I didn't trust all that potential shrapnel with a 20 gauge piece of sheet metal between it and my back after I had made a swing mount for it and hung it on the axle of my Gopher GoKart. Both the flywheel and the magneto were replaced with a Bendix button magnet magneto that was probably good for 20,000+ revs. Needle bearing mains on each end of the crank, and I never saw a conrod big end like those, it was totally machined as one piece, the rod bolts drill and fitted, then it was broken off to separate the rod cap, with the breakage resembling cast iron, and the grain of the steel when bolted back together was so well matched that you could not find the break with a strong magnifying glass. And you could actually buy, from the local outboard engine shop, oversized replacement needle rollers and the bronze cage they ran in if it wore too loose. It took about 2000 revs to develop enough power to call it running so I always had some volunteers to pick up the back end and run about 10 feet before setting it back down to start it. It was up to around 3500 revs in another 15 feet, and throwing up a roostertail of dirt from the track until it was 4 stroking at around 7500 revs. At 13.5 cid, I had to run in class C, so I rigged it so I could run booze and castor oil, or gas and Castrol. A 2.5 gallon tank on each side, one for fuel, one for water, which was circulated thru an old Nash heater core under the steering wheel hoop took care of the cooling for long enough I was out of booze. Thats one piece of certified 135 mph giddyup I still wish I had. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
