I have direct experience that the hard working valve-gear on the 500 can debilitate the engine through wear, and obviously there is plenty of scope for ancillary components to deteriorate over time. But now I am looking at my third stripped-down engine which appears to have no significant crankshaft or bore wear.
I could have expected that from the first, 499cc engine, which I knew had done only 32,000 miles. The second 650cc engine was an unknown quantity which looked OK internally, so was re-assembled with new rings, shells etc. and without any measurements being taken. This third 594cc engine, with no history, has negligible wear after measurement so can be safely rebuilt without expensive machining.
It seems that these engines are unburstable. Does anyone have experience of real bad 'uns?
Over to you Toshi.

Hi Peter

I wonder sometimes with the heat that they give off and the high rev operation. But my 594cc is performing well, (there I've said it now), I have this 650cc engine and gearbox that was given to me, it is in quite a state, but as I cut it out of a dune buggy that had sat in all weathers for some time, clearly it has had a hard life. When I get into stripping it down I'll look at the internals and let you know what she's like. If there is any room for hope, the plan is a rebuild, nice winter project for me.

Cheers
Hugh Jarce (aka Gary)

Did you say Toshi or Touche' ?
If all of the engine components are as the designer intended and correctly assembled then you have a chance of having a long life provided the car is serviced properly and with the correct parts. You will sometimes get mechanical failures if an original part is not quite up to scratch but most problems happen with engines that have been neglected, abused, not put together properly or over stressed by tuning. I have come across a few disasters like main bearings so worn they welded to the crankshaft, timing chain fitted the wrong way round, all manner of bodges and improvised parts, excessive use of sealants, things under tightened, over tightened, sheared off, stripped threads etc etc. I think that if you have a good reliable engine then you should look after it as that little two cylinder engine can run like clockwork and go on for many miles. There are some stunning stories about mileages covered and I do know of a 594cc car that was running well at over 100,000 miles with only regular servicing. Example of how not to do it. A different 2 cylinder air cooled 425ccs motor assembled by a mate who did not quite have the "touch" 100 miles from the Greek boarder in the former Jugoslavia the engine literally fell out in the middle of nowhere but we got the motor home !

Toshi 975 said:

Did you say Toshi or Touche' ?

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The reference to you young man, was simply because I think that you have been actively involved with the oily bits of 500's for longer than most people and I can tell that your knowledge is drawn from experience.
I have read before that the 594 is supposedly the toughest of all and I'm intriqued to get it going even though I really don't need a change of engine.
I wouldn't mind a quieter gearbox though.:bang:

I rebuilt my engine at the 110,000 KM mark. The only things I had to replace were the barrels, a broken valve spring, and an extremely worm camshaft. Everything else I replaced was just for piece of mind.

When I did the engine swap on my 2nd 500 (the car we moved to Edinburgh in) I changed engines at 90,000 plus purely because I had built up another engine.