Hi, I’m really looking for information from those of you more knowledgable than myself. I have an item that I believe is an ashtray made out of a Merlin Piston. But this is an assumption, can any of you confirm my theory and tell me any more about it. Also, there is a number marked in it, what would this be? 315RP55. Thanks, Sarah
By: Scouse - 4th February 2008 at 23:37
My 1967/8 Janes lists the Gipsy Queen as having 120mm bore, light alloy forged pistons with two compression and one oil control piston rings. Looks like your piston has indeed got three rings.
By: Arabella-Cox - 4th February 2008 at 19:54
Many thanks for all your help, as requested, here are some more photos! Sarah
By: Papa Lima - 4th February 2008 at 16:18
My 1964-5 Janes lists some Continental horizontally opposed engines made under licence by Rolls Royce, but the bore sizes are either too small or too large.
By: RPSmith - 4th February 2008 at 13:55
Rolls Royce produced Lycoming (American) horizontally-opposed (flat 4 & flat 6 ??) engines in the 60’s and 70’s I think.
Roger Smith.
By: Creaking Door - 4th February 2008 at 10:32
Apparently de Havilland aero-engines were absorbed into Rolls-Royce (via Bristol Siddeley) so that would provide a route for this piston to have come into your grandfather’s possession.
Rolls-Royce were certainly marketing the Gipsy Queen 70 (120mm diameter pistons) in the late sixties.
The identifying part numbers tend to be near the skirt on most pistons and unfortunately the skirt was cut away when this piston was made into as ashtray.
The piston only seems to have grooves for two rings which is unusually few. If you post a few more photos I’m sure somebody will be able to confirm its identity.
By: Creaking Door - 4th February 2008 at 08:41
The de Havilland ‘Gipsy Major’ (1932-1948) piston had a diameter of 118mm (all Merlin pistons have a diameter of 137mm).
Rolls-Royce did produce some smaller air-cooled six-cylinder ‘boxer’ aero-engines post war but I can’t remember what they were called (or even if they were an original Rolls-Royce design or just produced under licence).
As far as I know de Havilland aero-engines was never absorbed into Rolls-Royce.
By: Arabella-Cox - 4th February 2008 at 07:36
Hi, thanks for your response, the diameter is 118mm. My grandfather worked for Rolls Royce and one of his main roles for many years was training apprentices. Does this sit with your theory? Sarah
By: Creaking Door - 3rd February 2008 at 23:23
I hope you will not be too disappointed if I tell you it definitely isn’t a Merlin piston.
It is forged (as opposed to cast) so it is high quality and the marking ‘315RP55’ (stamped under the crown?) looks like a number to identify the batch of alloy this and other pistons were made from (again a sign of high quality).
It would be useful if you could say what diameter the piston is, to within 2mm will do, and any more photos you have would help.
As a guess I’d say it was probably a de Havilland ‘Gipsy’ piston.
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February 3, 2008 at 9:59 pm