[Thomas]

Yes, the procedure remains the same. I can't tell you something about stellite tipped valves. Better ask G&S. I prefer leaving the material and design as introduced by the works and I see no disadvantage with a cap because it works as it should. But again, no idea about stellite tipped valves.

[MarkO]

Hello again Thomas

Thanks for the article. I have a pair of old guides that I refurbished with bronze liners. I will not use them but will instead will make another new set out of correct C.I material and this time I will heat treat them!

I will also follow the practice laid out in your article about rocker and pushrod geometry. The 95L uses hairsprings rather than coils, but the procedure is basically the same.

What is your opinion on using stellite tipped valves without lash caps?

Kind regards

Mark

[Thomas]

Very well, Mark! Attached is another article which deals with the guide material because in the first article I talk about bronce guides. Don't use such material. It must be cast iron.
Thomas

[MarkO]

Hi Thomas!

Thanks so much for your comprehensive reply - and the attached docs which I am sure will be invaluable.

I contacted G&S first thing this morning - they seem to be the go-to specialist for valves.

With reference to the C.I spec, I think that is the same grade that I used. I did not perform the heat treatment though - so my fault that the guide had such a short life. I will probably need to do the inlet valve guide too.

I will let you know how I get on.

Thanks once again and Kind regards

Mark

[Thomas]

Hi Mark,

I bought the nitrided valves for my 1937 Model 9 from G&S valves. Attached are respective drawings for the valve. The measures are different to your specs. However, that is common for Sunbeams and G&S can make them specifically according to your needs (talk to Andrew Grenside). I had the same problem with the strike angle but you have some freedom for dealing with the valve and push rod lengths. For this I've once written a short article for the Beaming journal. It is attached.

For the guides you need grade 2.50 SG cast iron. Chris Odling said that you need to heat tread it to a dull red (not a bright cherry red) and quench it in water. One should drop it into a water column for even hardening. There are guides available in the club shop, though.

Cheers, Thomas

[MarkO]

Hello all
Can anyone help me find a new exhaust valve for my Model 95L?
The head diameter of the one that came out is 1.625" head dia, stem 0.373 (3/8") and the length is 4.125"
The first question is - is that the correct length? I ask because after 1000 miles, the guide is so badly worn that is a wonder the bike ran at all. It was last used in anger at the 2023 Bo-Peep regularity event in Sussex and it did quite well.
I am querying the length because I am concerned that the rocker strike angle might be incorrect. I machined the guides out of a grade of cast iron that came recommended for valve guides. The inlet guide seems fine.
I have looked at the valves in the club shop but all are shorter in length. The nearest are those listed for the Model 80.
If anyone can help I would be most grateful. I am retiring this year and I am hoping to campaign the bike more often!
Rgds
Mark