OE Metro Turbo piston rings
Turbo Mini Forums

I have a set of Hepolite 20831 pistons which I understand are OE for the Metro Turbo.
I have ordered and received from FW Thornton a set of AE rings to suit - standard size. The compression rings are fine but the original oil control ring was 3 piece and 3.5mm wide. The oil control ring now supplied is one piece (which is not a problem in itself) but it is only 3.00mm wide.
Thorntons say they cannot find any 1275 piston with 3.5 oil rings but have offered an MG Midget ring set which has the right size compression rings and a 4.0mm oil ring.
Before I set to and machine the pistons to accept the 4.00mm rings, has anyone any helpful comments or observations to make, please ?

if you buy pistons fro ae they have the rings already fitted, maybe worth sending what you got back, and getting a set of ae pistons,

i know from experience it's not worth taking the risk, or even machining until your 100% that everything is correct.

otherwise it can end in tears and cost you lots of money.

The Hepolite pistons have the AE symbol and an AE reference on them. They are not new, but came from an MT engine.

What are the old oil cont rings like? If they are OK I'd be tempted to consider reusing them along with the new compression rings.

This is a common problem will all suppliers of ring packs, they seem to think the Metro Turbo pistons use the same ring pack as the non turbo, Not so, As you have found out, the oil ring is 4mm. They are the same ring pack as the Cooper S 19230 three ring pistons, as far as I am aware, the MG Midget also. They are difficault to find, so if you do end up haveing problems, you may have to buy Total seal rings Like I did.

can i assume that the two thin scrapers are all one thickness, and that the extre0.5mm is amde up with the spring, therefore cannot you find some suitale springs ,machining the grooves is doable but if you get it wrong the jobs fucked,

carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

I dont want to use the old oil rings as the problem was a bit of oil consumption and I am pretty sure its nothing to do with valve guides/valves as they are all new.
Not sure if I have made myself clear, Sprocket - the "original" oil rings on these pistons are 3.5mm and the Midget ones that I have been offered are 4mm.The ones supplied by Thorntons, in AE original packing, are 3mm.
I think that I can back myself to machine the grooves to take 4mm rings,but was hoping that I wouldn,t have to,as its a PITA to set up four pistons separately just to whistle 0.5 mm out of the groove.
Thanks to everyone for their comments.

Oh, BTW, I searched first and tried to see if I could get Totalseal rings, but they dont seem to list them ATM for A series 1275

http://www.totalseal.com/SearchByApplication.aspx

Austin Rover, and away you go

3.5mm or 1/8" is suspiciously odd ball!

Edited by Sprocket on 12th Jun, 2009.

can't find 3.5mm/1/8 oil cont ring from the link. have you a part number that's very interesting, since I had to machine the groove, and already have lost two set of pistons.

Given the above comment by Fab, it appears that I am not the only one to have 3.5mm oil rings.It certainly appears to be a rare specification.

I shall machine and fit the 4mm rings in due course, but the engine is not being rebuilt until the end of the summer as I am enjoying driving the car too much.

I will let you know how well it worked in due course.

Fab, are you suggesting that you "lost" the pistons because you had to machine the oil control groove ?. I cannot see why that should be the case.

i know this game, the wound sping things the bit that cocks it all up, im poor and resoursefull and used a half moon diamond file on the ringland to give clearance for the spring, you dont need to take much out ( 1-1.5mm) and if you look at new 8.4cr pistons at minispares thayve lost a lot of metal hear anyway, hope this helps

, didn't lost the piston this way.
In fact this is a good idea, seing the time I'm allowing to looking for parts under my house I should invent "part" finder .
Sure , you know the situation:
You're looking for a 1275gt pignon in your juggle parts stock, can't find it, you 're phoning friends to know if they have one, finally you're lucky and collect one, or not and buy one.
Then two weeks later you're looking for this nice barbecue grill that you carrefully store last year....still can't find the grill but did find the carrefully stocked 1275 gt input pignon...
yersterday I needed a spare wheel for a friend, guess was seat just behind to stock of wheels the barb grill!

20831 3.5mm oil control isn't a rare spec, I found about 50% of my pistons had them.

Edited by fab on 13th Jun, 2009.