B.S.Binder - Do not listen to the "hype" about the DV550. I would tend to bet that most of the people that put them down have never seen the inside of one! There are a few things that you will need to address to make it competitive: 1. Injection system: The two hole nozzles (as part of the MANN combustion chamber system) do not lend themselves very well to "high speed" operation. It actually was a mis-application of the MANN system, which was noted for being a relatively quiet diesel with good lugging ability. A combustion process that is keen to lugging is not a good choice for a comparatively short stroke (V8) diesel. You should look at having the nozzles or tips modified to a minimum six hole configuration and a "fast delivery" cam made for the pump. The pistons should also be changed to the typical "cone inside a Ricardo cup" type to maximize the effects of the new injection scheme. 2. Crankshaft: The crankshaft should be taken to a reputable, knowledgeable crank man in your area. He should be able to tell you some of the deficiencies of the crank. Areas I would check would be the rod journal fillets (check for cracks), also ask if he has heard of breaking the noses off of these pieces. Depending on how far you wanted to go, I would have the rod journals welded up (maybe stroked while I was at it) and then re-ground with LARGER radii in the rod fillets. A large radius would be 0.250in and should provide tremendous strength increases over the stock radii. The rods and perhaps bearings would then have to be chamfered (clearanced)to fit back onto the journal. I would take the stock rods and have them hardened to Rockwell 28 to 30 on the C scale, or preferably have custom 4340 rods made to fit the new crank (with the bigger radii). If you have rods made, you might be able to find a bearing of the proper dimensions such that they do not have to be machined. The custom rods wil also allow you to use a slightly smaller rod diameter, which would help clear any additional stroke. 3. The block: Should be line bored and line honed to ensure an absolute straight crank line. The decks should then be surfaced off of this new centerline, as well as any overboring that you have done. O-ringing of this block may be necessary, as the head stud pattern does not ensure the best clamp load distribution. 4. Call the guy that Eugene referred you to! Anyone who has built one would be able to provide you with insightfull information, provided that he is willing! Regards, Goldsburg
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