3 replies to this topic

[jason russell]

Model:Austin Mini Advantage
Year: 1987
Description of problem (please be as in depth as possible):
While cleaning up the Pistons out of my engine I have managed to Snap one of the compression rings. They are the flat top pressed gudgen pin type with 2 compression and 1 oil ring. They are standard sized pistons.

Ive searched High and Low on Mini Spares and Mini Sport but theres so many choices how do I know which ones I need? Also im unsure if you buy a piston ring kit for all 4 or just the 1. Surely at about £50 a set its for 4?

If anyone could provide me with a link to the correct ones it would be greatley apreciated

This is my first topic so I apoligize in advance if I've made a mistake or not supplied sufficient information

Regards
Jason

Edited by jason russell, 22 November 2010 - 05:53 PM.

[Cooperman]

£50 is for a full set for all 4 pistons.
You must match the rings to your pistons. To do this you need the piston part number which is stamped into the top of the piston. The rig slots are not the same for all pistons even though they may be for the 998. The ring slot width and depth will be what's important. You also need to know whether the bores/pistons are standard size or if the engine has previously been re-bored. Loook at the top of the pistons and after the baswic piston number there will either be no further stamped numbers, or numbers giving the oversize, e.g. +0.020", which would indicate that it hasw been re-bored to plus 20 thou. Your new rings must be for the correct bore size or over-bore size.
If in doubt, call F.W. Thornton Ltd., who are in Shrewsbury, give them the piston part number and oversize (if oversized) and they will supply the correct rings.

[jason russell]

Thanks for the super fast reply!
I know my my pistons have
21964 G8 stamped on the top. There not oversized so its never been rebored.
Could you help me with the measurments I need to make please? Am I right in thinking I need to measure the height and width of the compression rings? And all 3 parts of the oil ring?

Thanks again
Jason

[Cooperman]

To measure yourself you really must have a Digital Vernier Caliper. You measure the height of each ring groove in turn then the depth of the groove rom the outside surface of the piston to the base of the groove. Make sure you have cleaned out the DGS (dirt, grit & s***) from the grooves before measuring.
Then phone FW Thornton, give them the piston number and, if they need it, the groove dimensions. With a debit or credit you will have your new rings within about 48 hours.
Don't forget to thoroughly hone/glaze-bust the bores before re-fitting and use a good ring-clamp to avoid breaking those nice new rings.