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DonE DonE is offline
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Join Date: Mar 2004
Location: Brooks, GA
Posts: 1,211
Off topic - P-51 Valve Train

Sorry about being off topic, but I thought those of you who do your own valve adjustments might find the below pictures of a P-51 Merlin (I am a member of the ground crew and sometimes get to fly it) engine valve train interesting. The adjustment procedure is nearly identical to the 930 motor - loosen the lock nut, insert feeler gauge (.010), adjust elephant foot, tighten lock nut.

This is a shot of one side of the V12 Merlin. You can just see the exhaust stacks to the right. Each stack handles one cylinder and two valves - it's the ultimate Zork tube.

This is a shot of the top of one cylinder - 4 valves per cylinder. Check out the cam lobes and the "rockers" - otherwise known as Merlin fingers. A complete set for this V12 is $17,000. The black "X" on each finger means the adjustment is complete. Oh, and each plug is $100.

This is a shot of the cam drive. As you can see, a shaft comes up from the crank where the cam gear forms a type of ring and pinion. Timing the cams after a complete teardown is not too difficult, but the process of safety wiring everything is very time consuming. This is 1940's engine technology at its best - over 1700 cu in, twin plug, 4 valves per cylinder, 6.0:1 CR, water and oil cooled, dual stage supercharger and over 1,700 shp.

The engine is going through a 100 hour inspection after a very successful P-51 ride campaign at Oshkosh this year.

Enjoy - I do...

Last edited by DonE; 08-16-2009 at 02:58 PM..
Old 08-16-2009, 02:55 PM
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