R Type Piston Rings (std)

Al Coutts · Posted: Tue Jun 11, 2019 11:17 am Post subject: R Type Piston Rings (std)

Hi - none of the usual suspects have any standard rings available.

Does anyone have any leads?

Does snyone know the bore, depth of the rings and ring thicknesses?

All suggestions gratefully received!

Thanks,

Al

Christopher Carnley · Posted: Tue Jun 11, 2019 1:11 pm Post subject:

Did you contact F W Thornton in Shrewsbury?

John Murch · Posted: Tue Jun 11, 2019 1:14 pm Post subject:

http://rrtechnical.info/mkvi/wshoplate/2.pdf

Scroll down to page 7, is this what you need?

Stephen Blakey · Posted: Tue Jun 11, 2019 2:04 pm Post subject:

To answer your question, the bore is 3 5/8" which is 92.075mm. Don't know the ring thickness but could measure a few this evening if that would help.
Hopefully you can find a set of the shelf. Was there a 3 5/8" military engine? I've a feeling they have jumped straight to 3 3/4?
As a bit of a last resort, DLA engines of, ahem, Athens, sell piston rings by the mm. You could spend a lot of time navigating through their thousands of listings and may then end up have to machine out the grooves. On the plus side this would freshen them up and restore the clearance. Christopher put me on to these people.

https://www.ebay.co.uk/itm/Piston-Rings-90-74-92-08-mm-3-572-3-625-in/400324531487?hash=item5d3533951f:m:mqH-so0cHMgBb_V9BYUQs1Q

John, It's interesting that on the page you refer to, someone has written on the shell bearing OD's. I wonder if said person was hoping to find a set of shells from another engine to avoid spending a zillion pounds on a set individually hand-made by Belgian nuns?

Christopher Carnley · Posted: Tue Jun 11, 2019 4:42 pm Post subject:

All those "Greek" piston rings are made made in Turin.

Your piston ring grooves will be worn and bell mouthed.

Christopher Carnley · Posted: Tue Jun 11, 2019 4:42 pm Post subject:

All those "Greek" piston rings are made made in Turin.

Your piston ring grooves will be worn and bell mouthed.

Al Coutts · Posted: Tue Jun 11, 2019 8:38 pm Post subject:

Thank you all, again!

I've had a discussion with Thorntons - they are based very close to my parents and they can't help.

When I add it all up, a set of replacement pistons c/w rings and gudgeon pins from T&G, is not a million miles from re-grooving the existing pistons and cobbling together a set from various suppliers.

I did find the same piston/ring/pin set in the US for a LOT less and do have a house-guest next month from Boston, Ma. Unfortunately, he's travelling mil-air and despite his exalted rank will not be able to bring them over!

Norman Geeson · Joined: 20 Mar 2012 Posts: 2

You should find a number of the different 4.2 ltr. Jaguar rings will do the job.

Al Coutts · Posted: Wed Jun 12, 2019 9:26 pm Post subject:

Thank you Norman - decision not yet made, so will look into that.

Love your website, by the way - it's inspired me to take on an R Type rebuild!