Well, here we go again!  Once more we’re confronted with a procedure that has at least one OWT (old wives’ tale) imbedded within it.  Like all OWT’s, this one seems to contain just enough “common sense” to help make it believable.  And it may very well have been done this way in the past – in some military units or in other places.  After all, any one several different methods of a proper “break-in” of the cylinder after it’s replaced certainly possess some amount of validity.  And they might accomplish that particular objective – but very likely at the expense of the other cylinders or the engine itself!

In attempting to obtain a real life procedure that we could both advocate – and – expect to see utilized, we consulted a goodly number of engine overhaul shops while writing this.  These shops are not as numerous as they once were, but the following certainly represents as wide a view of the current practices as is likely to ever be obtained nowadays.      

Stuff yet to write:

Oil grade mineral/AD

Ground run for 45 minutes?  –  I guess that one might see a perceived need to “break-in” a fresh cylinder by running the engine on the ground for a substantial period of time, in one case I’ve even heard of 45 minutes.  While this might satisfy someone’s hope or desire, I’m sure that it’d also “cook” the engine from overheating.  I’ve run overhauled engines in test cells with wooden “test clubs” made especially for that purpose and still have worried about the resultant overheating. 

On the airline we certainly didn’t have the luxury or opportunity to carefully break-in the replacement cylinder in the manner some have recently advocated.  In talking to some of our powerplant engineers and mechanics (all long retired) they say that both the R-1820’s and the R-2800’s 

Oil?  type

R. Sohn   © 2000

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