These days I'm happy if the engines will pull well to 5500 , for the twins at least. Ignorance is bliss and Im sure I happily went higher more than that a few times in the past, unaware of Vincent history , specifically Picador testing.
In any case, above 5500 rpm HP drops off with MK2 cams. That fact is mentioned somewhere in Irving's writings . Not sure about MK1s but most likely that peak bhp point is lower than 5500.
Peak HP may be higher with some of the aftermarket MK2 styled profiles, but really, it's getting pretty risky to spin much above 5500 with that 70 year old stock crank in those 70 year old stock cases. Very late in the day, the factory found out that even new engines came apart quickly with sustained high rpms. I think that testing was at 5800, not 100% on that, need to reread the articles.
The Prince MK5s make peak torque at 5500 and peak BHP at 6500. I would not use those cams in an engine with stock crank and cases. 5500 rpm crank and 6500 rpm cams is not a good match.
I'm just referring to info gleaned on twins, singles seem to handle more revs.
Glen
In any case, above 5500 rpm HP drops off with MK2 cams. That fact is mentioned somewhere in Irving's writings . Not sure about MK1s but most likely that peak bhp point is lower than 5500.
Peak HP may be higher with some of the aftermarket MK2 styled profiles, but really, it's getting pretty risky to spin much above 5500 with that 70 year old stock crank in those 70 year old stock cases. Very late in the day, the factory found out that even new engines came apart quickly with sustained high rpms. I think that testing was at 5800, not 100% on that, need to reread the articles.
The Prince MK5s make peak torque at 5500 and peak BHP at 6500. I would not use those cams in an engine with stock crank and cases. 5500 rpm crank and 6500 rpm cams is not a good match.
I'm just referring to info gleaned on twins, singles seem to handle more revs.
Glen
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