Originally Posted by
Dave, FormerDairyFarmer
I don't run Diesels over 10,000 rpm, to do so seems to defeat the economy. If that .40 were my engine I'd run a 12x6. My LA .46 turns a Graupner 12x7 at 9,450, the .40 should turn a 12x6 in the 9,700 rom range. Here is my LA .46 doing that very thing.
I agree with Dave. Even though I'm pretty new at the diesel "thing", I try to shoot for around 10k. My beat up compact case Fox .40 with a gouged piston turns an 11x7 MAS at about 9,600rpm or so, seen here:
http://youtu.be/NvqJdzuadYk It turns a 12x6 at 7,600rpm, but keep in mind this is a .25 sized case .40. It was never supposed to be dieseled due to a weaker rod. I have an ABC compact .40 Fox that might get some diesel abuse when I get around to it. The head is a Davis unit for a K&B .40 which is why the head fins are askew. I would think a normal larger case .40 to do a fair bit better as Dave suggests.