Author Topic: TS Vave seat grinding and piston pins  (Read 396 times)

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Offline SunbeamS7

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TS Vave seat grinding and piston pins
« on: 16 Dec 2022 at 20:16 »
I need to cut valve seats in my TS and i note that modern engines/valves typically use 3 different degree cutters. Just wondering if someone would be kind enough to clarify if such is needed on my TS, or i can  just use the singular 45 degree cutter?
I'm using new valves via LDMCC.

Additionally, I am also installing new J&P pistons and i note various opinions on the forum regarding using "buttons" to retain piston pin vs circlips. I had wondered if the buttons were preferred as they allow piston pin to move/get oil and seemingly the circlips don"t?
I had wondered about ensuring that the piston pin does have some side to side play in it and then use the circlip retainers.

Thoughts appreciated,
Regards
bryan


Offline graeme

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Re: TS Vave seat grinding and piston pins
« Reply #1 on: 23 Dec 2022 at 05:13 »
Hi Bryan

Buttons are used to prevent the danger of circlips popping out of the pistons, and wrecking the cylinder bore. The gudgeon pins on the 2 3/4hp are such a small diameter, that the little circlips don't have much spring tension.
Buttons made from tufnol seem to be a popular choice.

Cheers, Graeme

Offline douglas1947

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Re: TS Vave seat grinding and piston pins
« Reply #2 on: 23 Dec 2022 at 07:37 »
Hi Bryan,

you use the 45 (modern cutters are sometoimes 46) if the seat bfor the valve is worn  / burnt.
The other cutters, 60 inside and 15 outside are used to correct the valve seat to the valve dia.

Michael

Offline SunbeamS7

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Re: TS Vave seat grinding and piston pins
« Reply #3 on: 26 Dec 2022 at 20:04 »
Thanks for getting back to me and clarifying the use of buttons/valve seat cutters, greatly appreciated. Its always good to know the "why" behind something !
Regards
bryan

 

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