04-03-2017 11:10 AM
The basic reason for choosing the 1000 hour interval for estabilshing the baseline for valve recession is that Cat determined a certain amount of time is necessary to allow the new parts to "seat" or evenly mate. This is because the process of valve and seat surfacing is a grinding process and not a machining process. This grinding process leaves a more uneven initial surfaces on the valve face and seat face and the 1000 hours allows these minute high spots to wear in. An interval that is longer will begin to allow the valve face and seat face to begin wearing and reducing the life left as part of the 0,070" Cat allows before planning a top end repair.
This 1000 hour interval for establishing the baseline has been Cat's recommended interval for many years and has served the purpose to establish a valid starting point for measuring valve recession. If you were to run the engine to the normal 2,000 hour interval, you would run the risk of losing some of the 0.070" operating interval until top end overhaul as indicated above. This is a negative reason for not going beyond the 1,000 hour interval. I don't know of any positive reason for going beyond the 1,000 hour interval.
04-03-2017 12:05 AM - edited 04-03-2017 12:07 AM
Got a G3608 A3 that's just come back from a complete overhaul, and per the CAT manual there should be a 1000 hour valve recession baseline check completed.
Has anyone ever extended this to align with a normal 2000 hour scheduled service? What's the potential implications of stretching this recession baseline?
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