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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> How thin can you go on the cylinder sleeve?
Post Info TOPIC: How thin can you go on the cylinder sleeve?
TTRfan


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How thin can you go on the cylinder sleeve?
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I visited the Yeovilton Fleet Air Arm Museum yesterday in the company of TTR Steve and other similar but greyer old reprobates biggrin

I have had discussions in the past about how thin you can go on cylinder sleeves before they would go "wavy" or otherwise distort in use.

There were quite a few sectioned aero engines in various places in the museum which showed the thickness of their cylinder walls and have copied them below. 

I was surprised how thin the walls were but I guess that a small increase in thickness on a multi-cylindered radial aero engine would add unwanted weight so they are kept as thin as possible without prejudicing reliability.

It makes me wonder if there is an option for a further rebore once the current "maximum" of 263cc has been reached on the TTR sleeve ....

Brian

Radial aero engine cylinder sleeve thickness 1.jpg

Radial aero engine cylinder sleeve thickness 2.jpg

Radial aero engine cylinder sleeve thickness 3.jpg

 



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Cubber


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MELLING

      CLICKY are professional sleeve manufacturers who say:-

"Melling Cylinder Sleeves offers liners with a broad range of bore diameters, starting as small as 2” up to a very large 8.50” bore, and finished lengths ranging from 1/8” up to 24”. Sleeves are available in 3/32” and 1/8” wall for bore diameters up to 5-1/8”. Bore diameters larger than 5-1/8” are stocked only with 1/8” wall thickness. Melling Cylinder Sleeves also offers 1/16” and 2mm wall thickness’ for limited applications."

Your TTR may well qualify as a "limited application".  wink

Martyn

 

 



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petenz


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I know the sleave in the GM speedway motors are quite thin..

what is the OD of a TTR sleave ?? .... might do a piston search just to see whats out there...



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mossproof


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TTR250 sleeve o/d 78mm, i/d 73mm (originally)
TTR325 sleeve o/d 86.3mm (on mine), i/d 82mm
TTR350 (currently being installed...!) o/d 91mm, i/d 86mm off the shelf from Westwood Cylinder Liners.

I think a lot depends on the strength of the barrel casting and side loading from the throw of the crank.



-- Edited by mossproof on Sunday 17th of December 2017 09:10:02 AM

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Kaos


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Currently being installed , eh!!...biggrin. 

Tell us more.   Oh the suspense.

 

I'd be happy to test one in Australian conditions...



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mossproof


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When I've got some pics I'll post the latest update in the 350 thread. Machining was nearly finished on the first 2 prototype barrels last week. Just 6-8 week wait for pistons from Mr Wossner (maybe more as Christmas gets in the way a bit!) and the bores can be honed and the bits of motor I've got lying all over the workshop can be put back together! The highs and lows of waiting for various tradesmen to do their bit have been killing me!

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