New Hampshire CMP Barn 2011- 2012 HUP Overhaul

[Phil Waterman]

Detergent or Non-Detergent Oil that is the question? Well from looks of this engine it is hard to say, this engine has been running straight 30 weight non-detergent oil for 66 years, without the sludge buildup that all the oil commercials say should be there. As mentioned before as far as I know this engine has never been fully apart in all that time. Of course given the amount of oil leakage that has developed over the last few years maybe all the sludge has been leaking out.

But I don’t think so I suspect that the true answer is that if you change to oil regularly and drain the oil when it is actually hot that there is very little left behind. The only place with anything you might call sludge or deposits was on the inside of the front valve train cover, which has some light crusting which may be the result of this likely being the coolest area of the engine.

The large military style filter probably is also responsible for keeping the oil clean. On Beauty my Pat 13 C60S which had the oil filter mounted hidden in the frame rail the filter had sludge but the engine was clear of sludge. On that engine I suspect that the oil got changed but the filter didn’t.

Before disassembling the engine I did some testing of how long it took for the engine to actually reach a uniform temperature, where water temp, bottom of the oil pan, oil filter and the oil pan above the level of the oil all reach the same temperature, as you can see at no load it takes a long time to get the engine fully up to temperature.

Cheers Phil