Hi all, I know that most will want know why would I bother, but I'm seriously considering converting an old FP .40 to diesel operation with a "Davis diesel" head.
 
  I love to try out new things for the sake of doing it, whether it be good or bad it just seems to be food for my withering brain
  The reasoning is that a diesel .40 will swing a 12x6 prop up to around 9000rpm and I figure that it should pull over 650 sq".
  I have quizzed a couple of diesel fanatics on this and they haven't had any experience with the Davis conversion and couldn't offer much in the way of advice other than to run a very small venturi and apparently abc diesels aren't particularly successful. (not stating why?)
 They both stated that the PAW .40 is very strong and will happily pull a .60 size model. Unfortunately the PAW is listed at 120 quid which equates to $301 Aud and is therefore beyond me for the present time.
  I would probably be looking at a 4 stroke if spending this much.
 The Davis conversion works out to be around $70 Aud which is more in my league.
On the Davis website the reviews look good but I don't know of anyone who has used this conversion first hand.
  Has anyone on the forum used large diesels with success? I would love to hear the pro's and cons.
  Thanks in advance, Rob.

Rob I have tryed a Davis diesel conversion on a O S 46 on and R/C plane,
I found that it works like a 4 stroke and has a lot of torque power, does not like to run like a 2 stroke  ( high  R P M )  run it rich and a smaller venturie with a throttle about 3/4 's throttle and it will turn a bigger prop. I had a tail pipe that came out the end of the plane, it seams to like back pressure also.  
I hope this will help you.  Good luck

Did you get my PM?

Rob,
It does not matter whose head you run either will work, the key here is a good piston to liner fit much better than a glow and a beefy conrod. The venturi will probably end up about 1/3 of the size of a glow venturi better ecomony there. Banning the missus from the shed does nothing if she decides to do away with the shed and its contents  Keep the missus happy, or marry your stunt plane.

Scott