I am looking for a new piston, the current bore size is 70.34 mm so a plus 0.040" piston at 71 mm would be ideal. The pistons for the earlier Model 8's have a smaller gudgeon pin at 5/8" so the later piston cannot be used without modification.
In the event that others are making a similar quest I have investigated the possibility of having a new piston made, the minimum order quantity is two pistons at an approximate cost of £300.00 per piston. If any one is interested in taking up this option let me know soon as I will need to move quickly else the price may well change!
Pease let me know soon if you can help,
Many thanks,
Tom.
Hi Tom!
That's a high price. Just for information: I once got a piston for my BSA C11 from JP Pistons in Australia for a reasonable price: https://www.norndaautomotive.com.au/jp-pistons.html
Another option might be JE Pistons in the US. They have an interesting order form: http://www.jepistons.com/PDFs/OrderInfo/JE-custompistons-orderform.pdf
Cheers, Thomas
Hi Thomas,
Thanks for the link I'll se what JP can do. I have had JE make pistons for me a few years ago, this time I went through a third party as I am very busy with other projects which is why the price is so high I guess. I'll have to get the ball rolling with a manufacturer soon if an old stock piston cannot be found as the summer will be on us soon.
Best regards,
Tom.
Good day All,
To conclude this story I had two pistons made by JP in Australia it took them four to five week from the point where we agreed size and specification to when they were ready for dispatch. I had them ten days after that. I sent them a pattern but requested an oil ring in place of the third plain ring which they did. All other dimensions / weights were as original with the exception that the new parts were the next two over sizes up.
I would consider this is an easy route to piston replacement compared to finding a piston that is nearly right and then machining it till it fits and accepting any compromises that have to made to be able to use it.
Photo attached for your information.
Regards,
Tom.
Very nice Tom..
If I need a piston for the 9A then that's where I'll get them from.
John