New Big Block Gran Turismo Kit 200-245cc

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oktc123
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Sat Jan 05, 2013 8:23 am

Interested here also, keep us posted.

Thanks.

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mawso
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Mon Jan 07, 2013 12:49 am

Is a full cast barrel preferable to a sleeved alloy barrel, along lines of Rapidos? Just asking as others had questioned why iron over plated, but nothing about sleeves. I run cast iron and am happy with it, was just curious re' alloy sleeved barrels as they would seem to offer improved cooling?

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Rich_T
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Mon Jan 07, 2013 7:32 pm

To do a nice production sleeve job you need a 5 axis CNC (expensive) and either re-work an existing liner or spin cast a new one (very expensive!). You are still left with the thermal distortion issues too. The rapido, as many know, has a cast in place liner. This is also expensive, nearly twice as much tooling. Additionally, as a few have found out, if the stud breaks the cast iron it is tapped into a repair is well...not exactly straight forward.

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mawso
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Mon Jan 07, 2013 10:58 pm

Thanks Rich, appreciate you taking time to answer, I wasn't trying to pick holes, just wondered what the reasons were why sleeved wasn't the way to go. I've no problem with cast Iron. Cheers.

yozzer
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Tue Jan 22, 2013 7:16 pm

how`s the new kit going rich, have you started testing yet ?

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Rich_T
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Tue Jan 22, 2013 10:13 pm

yozzer wrote:how`s the new kit going rich, have you started testing yet ?
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.

swizz
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Wed Jan 23, 2013 5:55 pm

cast iron or ally, any is good for me as long as its steel lined,,,,coatings are crap for any engine thats actually being used daily, especially with no air filter,,i know someones going to say..i had my TS 5 years and it dont need plating, well it probably does, even when not worn off it expands,, i do 4-5 back tyres a year and nicasil etc would cost me a fortune,,new rings (ten quid) and re-bore every few years (15 quid) i can afford,, 90 quid every six months for re-plating i cant afford, and any ways people are getting better results from steel over plating for tuned engines..plus "my" home tuning dont like plating's, it chips and cracks to easily around ports..(from my experience it does any ways) 37 years of lambretta's and plating sucks.. them casts look great by the way..

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Rich_T
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Wed Jan 23, 2013 8:04 pm

Cast iron.

jimmers
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Wed Jan 23, 2013 8:24 pm

Eden 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? 8-)


Scion meaning "of a notable family" or "a brand of vehicles"
Excellent :D

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TED CRUD
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Tue Feb 05, 2013 8:25 pm

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.
ME ME ME ,always thinking big Lc motors :D When can i have one !!!!
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