ORIGINAL: XJet
....but despite my most concerted efforts I've been unable to wear out a TT46Pro :-)
Bruce,
In normal circumstances, as a sport engine, this is true.
But if put under best effort condition, such as sport Quickie racing, they are just over-stressed and fail (see Vicman's post and I have seen several locally).
It is not the ABN P+L that I have seen peel like in some older OS FX engines, but after a few very high RPM runs, they no longer hand-start and power is down significantly.
This seems to wear the piston down. But I saw two that shattered the metallic bearing cage, causing massive trauma (replaceable in advance with a phenolic/polyamide cage bearing).
Unlike another 'inexpensive' offer from an after-market source that sells his high-speed sets for no less than $36 minus change, [link=http://www.mcintoshcentral.com/rc-bearings/catalog/product_info.php?cPath=81_87_102&products_id=713&osCsid=c0cdae6bd775751c872cc27f372de4d1]Paul of RC-Bearings[/link] offers his set that includes a rear bearing ONLY with this protective, non-metallic cage, for less than $7 + shipping.