998 Ring Change
| Quote: Posted by J. Hill Hi All, I need to do a fairly urgent ring change in the other half's 998. It's got to be done over the weekend, as it's got to be taken to work on the Monday. Now, In the past with other FWD cars, I have whipped the sump off, whipped the head off, and pushed the pistons up, done the business, and put it all back together again, thus saving pulling the block out. Is this method possible with the Mini? bearing in mind the gearbox is somewhere down there.... Please advise!! Cheers, James
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Sorry James, but the unique design of the mini dictates that the main engine to subframe mounts are on the gearbox, in order to remove the gearbox which is also the integral sump, the engine has to come out.
Removing an engine is a bit easier (read as lighter) if you first remove the head and manifolds, alternator, starter...but it's only benefficial if you're moving the engine by hand and not using a crane or hoist.
I tried to learn the engine-out wiggle in order to disengage the driveshafts but I've got two left feet and just undo the top and bottom ball joints on the suspension on either side and withdraw the driveshafts from the diff before moving the engine. After that there's only a couple of cables and it'll come straight out.
Then the gearbox has to come off the bottom, so the flywheel and transfer casing has to come off too, you might need a flywheel puller there.
As a precaution why not order the gearbox main bearing...on such a high mileage car the ball bearings could have lost the cage they run in on the main shaft bearing and if that went in 1000miles time you would have a horrible taste in your mouth.
As for the pistons it's difficult to say exactly which ring set to use, but your choice is restricted pretty much to 4-ring or 3-ring sets, and assuming it's original then you need just size 'std'. I think Minispares do a return service, but if you don't want to pay for the 2-way postage you ought to be able to source rings from a local piston/bearing supplier which can be found in your Yeloow pages, if you can't drop in to Minispares in person.
The other thing you need is a cylinder hone, although new rings will seal on un-honed cylinders they won't actually 'bed' in. A coarse bore is required to prepare the new ring for it's final fit, the most abrasive aspect of the hone wears off within 20 miles or so, but if you just fit new rings to smooth glazed cylinders you're not doing as well by the engine as you could do.
If you have a lcoal Partco/Brown Brothers depot you might be interested to know that sometimes they keep 'specialist' tools for occasional use by their garage customers, torque wrenches, pulley pullers and cylinder hones are common...but you might find them more willing to help if you buy something from them first and offer a full deposit for the tool...They're not obliged to offer any service of this sort though, I only found out by chance but the guys in my local branch are only interested in being helpful.
If you lived nearby (Edinburgh) you'ld be welcome to come and pick up a spare 40,000 mile 998 block with pistons, which might make a changeout quicker to do, and then you could pass your old block on to someone else....it's a shame nobody has a universal shared surplus parts depot !
Chris
Posted: Jun 29, 2006 06:05 PM