RCU Forums - View Single Post - O.S. .46 AX - bad rear bearing - metal shards... (replaced and running)
Old 04-02-2008, 02:51 PM
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XJet
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Default RE: O.S. .46 AX - bad rear bearing - metal shards... (pic heavy)

Just a tip if you ever find yourself with an engine that has a lightly scored piston or bore.

Mix up a batch of fuel with 25%-30% castor oil.

Run the engine on that fuel and run it *very* lean for a couple of tanks.

Don't let it get so hot that it seizes -- keep the runs fairly short but hot.

You can then switch back to your regular fuel (so long as it also contains at least 2-3% castor).

I've done this a couple of times in the past and what happens is that the castor will form very hard varnish that fills the gouges on both the piston and the bore, promoting a better seal.

There are engines still running (good as new) in our club today after being "rescued" from piston/bore damage in this way.

It may not work every time but it's a *whole* lot cheaper than a new P/L set and there's really nothing to lose by trying it.