Re: New Big Block Gran Turismo Kit 200-245cc
Posted: Sat Jan 05, 2013 8:23 am
Interested here also, keep us posted.
Thanks.
Thanks.
The UK's No1 Lambretta & Vespa Scooter Forum.
https://www.scooterotica.org/forum/
The CNC jig has been modified to run both big and small block barrels. Snow has slowed things down alot, there is a tweak to do to the pattern to adjust the mag side transfer port for stock installations which gets started next week. I should start machining the first two cylinders this weekend, then they'll be ready for testing. I expect to run them on the dyno first off to get a basic BHP number with some basic set ups, clubman, JL3, PHBH30 and a Mikuni 34 (if I can work out the jetting). After that they'll go out for some endurance testing before the production order goes in. Rough guess is April time for serial production.yozzer wrote:how`s the new kit going rich, have you started testing yet ?
ExcellentEden wrote:Rich_T wrote:Cast iron.
"Scion Rat"
ive just been playing with anagrams of cast iron and ive decided i like that the best and its rather fitting for my Elbar dont you think?
Scion meaning "of a notable family" or "a brand of vehicles"
ME ME ME ,always thinking big Lc motors When can i have one !!!!Rich_T wrote:The Big Block GT is prototyped from this tooling but this is only to enable the jigs and programs to be constructed. Everything else on the barrel has been proven over the last 10 years with the small block. Sure a few widths and angles are changed but these take advantage of the larger stud spacing and will be advantagous changes. Two port profiles were tested, a bridged design and a trapazoidal design. For reliability the trapazoidal design profile came through however the tooling is designed to run with both if required.
The LC barrel is 272cc on a 60 stroke. This is done for a couple of reasons, firstly to keep the cylinder length down (for foot print and packaging reasons), secondly to keep the piston velocity down and the crank webs small by comparison to CR250 cranks for example. The wide flange releases all the porting constraints. The increase in piston surface area should improve BMEP, the reduction in cylinder wall area is compensated for by very wide ports (no stud problems). It's a work in progress and will be some time away.
The Big Block GT is a matter of single digit weeks away, the LC double digit months at least. If, however, anyone is thinking about a big LC motor I'd be interested to hear from you.