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D-mod engine's ?

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  • D-mod engine's ?

    I am contemplating building a D-Mod engine for a hydro and am interested in anyone's advice on which is the best equipment to source and what to build and what to buy? I understand the four cyl Mercury power heads of 40 or 44 ci are the preferred choice ? Are the standard utility fishing motors I may find suitable donors for this endeaver ? What would I expect to spend in total to build a reasonably competitive engine? What is the best gearfoot to run in this class and what do they cost ? I know it's a lot of questions but Im just keen to get something to ponder and hopefully build this winter.

  • #2
    The Merc 44s from the center of plug to the newer offselt plug versions are desired!

    You have asked a question about Merc 40 cube 4s like the Merc 55Hs and Merc 44s from Merc 400, 450, 500 classic right to Anniversary Special 500s through to Merc and Mariner 44X racing engines. All these engine blocks be they 40 cube or 44 are much beloved block basis of racing engines for class D Modified or as their original in cases stock outboard racing engines as in the 55H or the 44Xs. I would not advocate taking a wonderful stock racer like the 55H or the 44Xs and converting them into a Modified outboard. You would have others as well as collectors wanting to string you up from the nearest tree!

    Thing is that the cost or price of a Merc 40 or 44 Modified is that they are only worth the sum of their parts and there are those that would trade you up to 2 already built modified D Mercs for one completer Merc 55H or the 44Xs outright.

    Right now the Mercury 40 cube 4 cylinder engines have a gigantic piston problem. The pistons are not being produced by Merc anymore nor is there a reasonable aftermarket maker, so the 40 cube engines are governed by their piston life as getting stock or oversizes in .015 or .030 are next to nil. What I am getting at is that the Merc 44s are plenty and so are their parts.

    These engines turn up completer here and elsewhere very reasonably and like all racing engines its the buyer be ware and the buyer should overhaul to know what has been purchased and then overhaul. Assuming your spinning the wrench it can be quite economical to quite pricey but the first place to start is to get a MODIFIED OUTBOARD RACING HANDBOOK that several racers of honorable record on this board and other boards can point you to, read it and go from there. From your post here I can see people coming at you to help out and may even offer you one already built and the buy and sell here will even find you some of the componets like exhausts, blocks, gearcases, tower housings etc. so have a good look and do a lot of yakking before buying.

    I love the Merc engines, to me there is nothing like their sound be they a stock, modified or alky in preparation and everyone here I am sure will give you tons of their wisdom and experience to come into the D-Modified Merc group that hangs around here. See something, feel free to email them and ask more. There is a lot of free and good advice that will help you compete when its all said and done. Your are amongst a friendly group here that would also welcome you to a race site and to compete well on a racecourse. Welcome!


    • #3
      Living where you do a 44 is the only motor you want. Also due to where you live you should try to find Steve Bensen. He's out your way somewhere. He can help you as well as anyone and he may be close enough to you that you don't have to do everything via e-mail and telephone.

      I'll try to give you some places to start.....

      Start with a mid 70's or newer Merc 500. Those are easy enough to find and cheap enough to buy. Take it apart (oh boy..... I hope you have done this before. Didn't think of that.) and send the block to someone and have it bored and ported. (I don't know if Bensen still has all the equipment to do that or not.)

      A couple of people from other parts of the country for boring and porting: Jim Ruck (no e-mail address or web site - I have his phone number somewhere) or Phil McDaniels (rpms@sccoast.net).

      Dudley Malone (no web site - I have his phone number also) used to bore and port. I don't know if he still does or not.

      You'll need a set of stacks. Dudley sells Bayer stacks. Parker stacks are sold by (can't remeber his name right now! sorry about that). Hustler stacks and towers are sold by Snider (his son is a member here).

      Steve Roskowski (he's a member here) does all sorts of stuff. He builds an ignition system, a tower, and does some machine work. Talented guy. Also very busy. In addition to the motor stuff he does he builds boats. (And he has a regular job too!)

      Lower units: Try Steve Litzell (Konny) or Rick Montoya (Yamato).

      Dave Scott is the one stop shop. He builds motors, boats, lower units (Mercury), etc., etc., etc..... He's a member here also.

      Lee Tietze is a member here and he builds parts such as hardware for rigging your boat, towers, exhaust systems for some motors, and no telling what else. (He's working on a lower unit, but it isn't ready yet.)

      You have come to the right place for help building a 44 mod.

      OMC FE/SE powerhead parts for sale. Kurcz ported block, Mod 50 pistons and cylinder head, exhaust, etc.


      • #4
        Don't forget about Sid Bass. Sid does machine work and also builds the Bass Machines lower unit that is very popular under the D-mod, and FE motors. And they hold up great, and parts are available from them.

        If you need his contact information, let me know and I'll dig it up for you.

        Sattler Racing R-15
        350cc Pro Alcohol Hydro
        TEAM VRP
        The Original "Lunatic Fringe"

        Spokane Appraiser


        • #5
          44 D-mod

          Hey Glen,

          What you want to build is a non magneto 44XS mod. the only drawback to this is finding the flywheel. The flywheel can be accomplished by purchasing a SST-120 (V6) racing flywheel from a source - Scream and Fly or Ebay they are on there quite a bit. Then using a hub from a stock fishing 50HP flywheel from the mid 80's.

          These are the newest of the blocks for 44 up to 1992. the blocks after 1992 were oil injected and the ports were moved on the exhaust side by .050. The cranks in these later blocks are longer on the bottom to support the oil pump drive gear. The 44xs powerhead does not use a distributor and is not belt driven robbing useful horsepower

          The 44xs powerhead does not use a distributor and is not belt driven robbing useful horsepower. David's suggestion of the mid 70's block will work as well but you will need to run a magneto and finding Merc Mag parts that are any good are pretty rare as well. Points espescially - I will only use Merc NOS points in any mag I build, the springs on the aftermarkets are very weak and tend to flutter at higher RPM if not dwelled and setup properly.

          Then the rest of the P/H is as David say find a reputable boring facility and have the block blueprinted and ported. I myself do not cut the intake ports - Never have - Never will. I would use Jim Ruck for the maching. No guess work you tell him what you want to run I.E. porting for D-mod and he will do the rest and send it back to you ready to assemble. There are few other things Steve Roskowski can help you out with the crankshaft. Find a reputable balancing facility (outboard crankshaft) out your way can do a excellent job with the Flywheel and the crank as an assembly.

          I would use Wiseco pistons in this engine they are forged instead of cast and are a little more forgiving at high temps. There are a few tricks here as well that you need to do. They are heavy - I'll put it that way.

          The block will need some massaging in certain places internally to help direct fuel/air flow etc...

          Lower Unit there are plenty to use. I myself an swithcing to a 302 yamato with a nose cone installed for next year or a Konny/Rossi. The mercury which I have run for ever will go back onto my 44XS. The 302 yamato is cheap at 120LB from the Mike Ward in the UK He will have more stock in 4 or so weeks. With the 44Xs units being so rare I am opting to use the less expensive lower unit on my mod next year. A lot of people will maybe suggest the 302 lower unit is not strong enough we have one living under a 50HP modded e-rude up here and handle the torque just fine. You can reach Mike Ward from this web-site the link is on the left as the Yamato UK.

          Then find a mid-section I am looking into recasting an obrien mid - section to a 44xs height mainly because I run all my boats at 44xs height and do not want to cut the transoms down to fit the 8" - 10" mid section height.
          I know sid bass has a couple housings that you could get but I think you need to run there gearboot under them as well I think this is a 2K investment alone with no clamps. There are rumours of another mid being cast in the mid-west but I have heard nothing more yet. Steve roskowski also has a mid if he chimes in here he could post a pic or two. his ignition is also a way to go distributorless it is self contained and you do not need the flywheel I mentioned about I think you just need a rope plate bolted to a hub. The cost between making a 44XS flywheel and running a roskowski igntion is minimal. The nice thing with making a 44XS flywheel is you will most likely wind up with a ring gear and you can run electric start.

          Finally - If you have not built one of this find someone out there to help you assemble it for the first time. The last thing you want is the frustration of a reed cage pin loosening up on you and chattering the reed cage and finally destroying itself internally. OH YA despite what you may hear You only need to shim at .012 to .014 in a Merc NO MORE. If you have a away to apply pressure to both end caps when assembling to mimic having the crank case install then .012 will do. Always check it again with a dial indicator once you have the crankcase installed. I use three bond 1104 motorcycle crankcase sealant between the crankcase sealant. it never gets totally hard and it make a real good seal. Put it on even and thin it is meessssy stuff. Use SKF 6206 -C3 end cap bearings NEW and National double lip seals they are softer rubber and do not cut into the crank as some others do. Pay attention to the way you remove the seals in the bottom bearing carrier and press the new one's in the same way. leaving a little space between the two seals.

          I hope this helps and is not too confusing. If you are interested I am building two mod powerheads and a complete for some guys around here and I have all the stuff in stock to build you a complete P/H including blocks and cranks. you can e-mail directly if your interested and I can give you a quote on a P/H.


          Dave Scott
          Aim Marine Inc.
          613-831-1246 8-5 Mon-Fri
          Ottawa, Canada
          DS(M)H - 20CE


          • #6
            D-Mod engines

            I just saw your post and replies. I do have an ignition working and will do the final test of Generation two in a couple of weeks. Once I do that they will be into production and available. I do make towers for 10" transoms and do porting, crank bevelling and miscellaneous machine work. I'd just look for a Merc 500 and start gettting it apart to see what you have. I'd recommend having Ruck bore it for new pistons and start fresh.

            Have you raced before or is this a total start up venture? You might want to get some rides in somone's rig before you start dropping money into it. Where are you located? You might try to find some used equipment just to get started. I may not be the greatest salesman for what I do, but I always recommend trying it out first to be sure you like it. I don't know of anyone who decided not to race after this, but you never know, a DMH is quite a handful for a first ride!


            • #7
              D-mods motors question

              Hey every one, is the Merc the only motor you can run or can you run the johnson or evinrude. If the motor is a 40 power head. this might be a stupied question.
              I have the need for speed but not
              the bank account.

              7-P pro,mod,soAPBA,DVORA,TRORA


              • #8
                Eligible D-Mod motors

                In APBA the only motors legal in D-Mod are the 40 and 44 cube Mercs. In NBRA and (I think) AOF the 40 and 44 are in separate classes as APBA used to be years ago when we had D and E classes. The Johnsons and Evinrudes of roughly that displacement are Formula E class motors.

                These are not entry level classes. You are required to be at least 18 years old to run them, however, a person with no experience would find these classes a bit intimidating. Just think in terms of running 80+ mph into a corner alongside 4 or 5 other guys and having no brakes if someone gets in your way. I have run D hydros since 1960 and I am still impressed with their performance.


                • #9
                  I have 2 mod d towers and a konig 12 to 15 lower unit that i am willing to part with for the right price. My email is l.w.reynolds@icloud.com if you are interested in pictures


                  • ZUL8TR
                    ZUL8TR commented
                    Editing a comment
                    Original Post is 2005 wonder where Glen Wesanko is with his mod project today? Try a PM to glen