Davis Diesel experiences?

I have used the DDD heads on 3 engines: OS 61 fsr, Fox 74, and ST 90.

I have got them all to run, but am a little disappointed in them. could never get them to turn up like the ads say. I did experimen with the same prop's with a glo head for comparison. The engine always made 200 to 300 rpm lower than glo, but the diesel could run a a cooler temp and give you the ability to run that prop without burnin up( if you needed that). Now mind you, I don't claim to be a diese expert so a learned diesel needle guy might could have eecked out better compression/ mixture setting. It was the best I could get it t run with my experience, and setting compression and air fuel for caramel color exhaust. I was never happy with the transition-- to slow. I did like the idle and restarting traits.

I have used a RJL conversion for the OS 40 fp($20) and like it alot. also decided to try a designed diesel, the PAW 35. IMO, the diese advantage is better with the smaller engines. I have seen some buddie use .15's and under and they are fantastic. I will try the small one next.

Just for the record, the RJL conversion has a 20 fp carb on it. I runs every bit as good as the PAW. I think the small carb has made BIG difference in that conversion. Throttle response is so much bette I don't think it is the brand of head, only a good test bed by luck o the draw-- this engines porting and timing/ carb lend themselves t good diesel operation. I will try some more in the future. They ar expensive enough to be frustrating when you are unhappy with th result. I think that most of those heads run in the $50 range.

Please don't take this as a negative. I just wanted to give you m honest opinion. I will try more. The diesel engines have alot o torque on the low end of the power curve( from idle to 1/2 power). I is amazing. I also think that propping for that power curve is different science, and I need to try a few more to be sure.

They are much quieter in operation. In fact, they sound very cool. They almost sound like a little Harley chugging at idle. The exhaus note is alot softer. The only gripe will be the smell of the fuel. I is very strong.

good luck, turb

-- turbo.gs

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