MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MG Y Type - Oil Ring Replacement

In the process of replacing the pistons and rings on my MG YT the new oil ring broke on the last piston!
The engine is the standard 1 1/4 Liter XPAG as found on the MG TC, TD, etc.
The oil ring type is a "double beveled" oil ring (see photo) and were supplied with the new pistons.
The pistons were bought from Moss but their replacement ring sets are of a different configeration.
Does anyone have a source of this type of oil ring as per the photo?

E. Geissler

What size bore is it ? All my rings I fitted to my YT where sized in the bore as they come a little bit too big, I have a few spares.
Bob Wood

Bob,
The bore size is 67 mm and the pistions are stamped .060"
E. Geissler

Hi I have not got .060 rings spare, sorry. Modern pistons only have oil rings above the pin. My engine was rebored so the lower ring is no fitted to the piston but the ring groove is left empty It is not smoking, It is important to check the Ring gap (sizing) as it will the damage engine..
Bob Wood

That's odd. 0.060" = 1.524mm.
So the bore size should be 66.5 + 1.524 = 68.024mm.
Are the pistons a very tight fit?
R WILSON

No, Not at all.
I checked with a local MG mechanic who has serviced my MG ZB and he said to just use the oil rings supplied and move on with the restoration. The oil ring is not a chritical as the compression rings and it should work fine.
Which is what my wife said and I will do.
Thanks for your help.
Ed
E. Geissler

Well. I don’t know how 68mm pistons fit in 67mm bores. Anyway, I have found a set of used +0.060” piston rings, with four oil control rings in the design you want – but only seven compression rings (or whatever they are called). They haven’t done many miles because I changed all the rings for a later set with a better design of oil control ring (when I changed the rings I broke one of the original compression rings).
If you are still looking for a ring, I can send you the whole set FOC – see (poor quality) scan. Let me know, my local Post Office says that airmail takes 6 days.


R WILSON

I have to admit that my photo does not show the rings at their best, but the top and bottom faces of the oil control rings are flat – there are no steps.
The engine did not smoke or consume oil before I changed the rings.
R WILSON

Thanks for the offer R. Wilson but I have already installed the new rings as recommended by my mechanic and have moved on with the rebuild.

Thanks again,
Mind as you go

Ed
E. Geissler

From memory the XPAG piston as originally specified has two oil control rings, one above and one below the gudgeon pin. You could run the engine with one ring installed and one missing, but oil consumption will be affected. Ed, let us know what you find after start up - fingers crossed!

(I used to work for the components maker AE who owned Hepworth and Grandage, the piston manufacturer for Nuffield engines. The cast oil rings such as you show here were always prone to breakage - later designs were multi-part spring steel and a good deal more durable and handle-able.)
Tim Griggs

This thread was discussed between 23/08/2024 and 12/09/2024

MG MG Y Type index

This thread is from the archives. Join the live MG MG Y Type BBS now