Gas vs Diesel

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  • Mark S
    Senior Member
    • Sep 2008
    • 421

    #31
    Jeff,

    Originally posted by jeffgerritsen View Post
    I have a 1976 Pearson 35 with an A4. At 750 hrs on the rebuild, I'm thinking this is a mid time engine, so I'm going through the gas vs diesel repower mental exercise. From what I'm reading on this thread, its thumbs up on staying with the A4 and performing whatever major maintenance is needed, if any. It will sure save me a lot of money staying with the A4.
    We have a 1969 Pearson 35 with an A4 said to be from 1980 rebuilt in the 1990's with probably more hours on it than yours, although the POs' documentation lacks specifics. The problems you and I face with our boats being powered by A4's are two, value and power.

    As to value, the market prefers diesel and when we bought last year we were able to take advantage of that by paying a low purchase price. I figure the cost to go to diesel, were I so inclined, would probably be roughly the same as whatever increase in value we might experience on resale. We aren't selling any time soon, so I'm content to keep the A4 and spend my boat bucks elsewhere.

    As to power, our P35s are probably the most boat the A4 can be expected to push. I'm trying to find ways to increase RPM to get into the A4's real power band which is definitely above the 1500 to 1700 RPM I'm able to reach now. We did quite well downeast this year with the OEM two blade, but I'd feel more comfortable at some higher RPM. To start, I'm going to install an Indigo next spring. What prop do you use?

    Mark S

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    • jeffgerritsen
      Senior Member
      • Dec 2008
      • 37

      #32
      Mark,
      as to the power / value discussion my experience mirror's yours and thanks for your input on that issue.

      Regarding props, yea, 1500 - 1700 is pretty low in the power band. I have the CDI prop and RPM's top out at 1950 - just getting into the usable range of the HP / torque powerband. The opinion and observations I've seen, point to using the Indigo prop as the preferred option.

      I've noticed the need to repack the rudder post and stuffing box. When the boat is hauled out for those, I'm planning on installing the Indigo prop. Reports indicate max rpm in the 2200 - 2400 range - just where you'll need to be to get the most out of the A4.

      We might find at 2200 - 2400 rpm the A4 is well suited for the P-35 application. A bounus we didn't originally expect - I hope!

      Jeff

      Originally posted by Mark S View Post
      Jeff,

      We have a 1969 Pearson 35 with an A4 said to be from 1980 rebuilt in the 1990's with probably more hours on it than yours, although the POs' documentation lacks specifics. The problems you and I face with our boats being powered by A4's are two, value and power.

      As to value, the market prefers diesel and when we bought last year we were able to take advantage of that by paying a low purchase price. I figure the cost to go to diesel, were I so inclined, would probably be roughly the same as whatever increase in value we might experience on resale. We aren't selling any time soon, so I'm content to keep the A4 and spend my boat bucks elsewhere.

      As to power, our P35s are probably the most boat the A4 can be expected to push. I'm trying to find ways to increase RPM to get into the A4's real power band which is definitely above the 1500 to 1700 RPM I'm able to reach now. We did quite well downeast this year with the OEM two blade, but I'd feel more comfortable at some higher RPM. To start, I'm going to install an Indigo next spring. What prop do you use?

      Mark S

      Comment

      • 67c&ccorv
        Afourian MVP
        • Dec 2008
        • 1592

        #33
        I drive diesals for a living...4,400HP diesal locomotives that is, but when it comes to my 1967 C&C Corvette sailboat with the original early model A-4 I will stick with gasoline.

        Comment

        • hgriff25
          Member
          • Nov 2005
          • 1

          #34
          I own a 1969 Cal 2-30 with an Atomic 4 which has been in the vessel for 40 years now with very few problems. I had to switch to premium gas but the extra cost is not a problem. This engine was overhauled once in 1979 by the previous owner. It runs OK but rust around the right engine mounts and oil leaking from the thrust bearing are concerns. A local repairman wants to replace it with a diesel but I am not convinced it is the right choice after reading other user inputs. I will check with Don Moyer. Since I am in Hawaii it is not as easy to get things done. Extra shipping costs installation etc.

          Comment

          • 67c&ccorv
            Afourian MVP
            • Dec 2008
            • 1592

            #35
            Originally posted by hgriff25 View Post
            I own a 1969 Cal 2-30 with an Atomic 4 which has been in the vessel for 40 years now with very few problems. I had to switch to premium gas but the extra cost is not a problem...
            Ok, I'll bite...why is it neccessary for you to use premium fuel in a gasoline powered motor that has a 6.35 to 1 compression ratio?

            Comment

            • jpoe
              Frequent Contributor
              • Sep 2008
              • 6

              #36
              You couldn't payme enough to own a diesel

              You can hear them coming and smell them going...Diesels have higher torque at low RPM than gasoline engines of equal size, they seem to get better fuel economy while they are running. They are completely different animal from gasoline engines because they require very high compression to burn fuel. (A diesel engine operates more like a compressor in that heat of compression ignites the fuel.) That means high potential for breakdown. The worst part is that "we" have been mis-directed to think to the engine as the imortant part of a diesel engine when actually the fuel pump is the major head ache (and expense).

              Have you noticed how many small shops exist only to repair diesel fuel pumps? That is because this expensive little gem has to operate at an even higher pressure than the already extreme pressure in the cylinder to inject fuel in there to burn!

              Want to rebuild your own diesel fuel pump? Good Luck! Pay $20 for a gasoline pump and compare. Rebuild your carbeurator with a $20 kit. Change spark plugs for 75 cents. Gasoline Fumes? Rebuid the above parts and use common sense in maintenance and simply use your exhuast fan as on every boat.

              So, save a few bucks on fuel consumption? Diesel costs more per gallon. Then after a few short years of messing with critters in the fuel and spend $1000 bucks to replace / Rebuild fuel pump, engine.... No way. Give me a 30 year old A 4 in any case. If I were to purchase a new 50 footer I would want an A4 change out and sell the diesle to someone who is too lazy to think it out.

              Comment

              • Mo
                Afourian MVP
                • Jun 2007
                • 4519

                #37
                Well, I like my diesels. My truck and car are both diesel. My boat has an atomic 4 in it and I have my spare in my garage. No matter what you have it has to be looked after. I have towed home 3 diesel powered boats this year due to fuel problems and 1 that had water back up and damage the valves (yanmar) Catalina 30. Had a fuel problem myself but the engine didn't quit...I didn't have all my horsies, but a few stayed up and running and we made it to our destination.

                The biggest problem that I see with diesels is that most underpower their boat. I can walk away from most of them as soon a chop or wind comes up. Not because the diesels are bad....they put 20 hp in a boat that need 40 hp. This happens fequently.

                I know enough about engines to be comfrotable with my Atomic 4 and if I had to take her out in a bit of weather tonight to get one of the boys I know those horsies will get up and at it. That's TRUST!
                Mo

                "Odyssey"
                1976 C&C 30 MKI

                The pessimist complains about the wind.
                The optimist expects it to change.
                The realist adjusts the sails.
                ...Sir William Arthur Ward.

                Comment

                • ArtJ
                  • Sep 2009
                  • 2183

                  #38
                  It may well be true that they under power Diesel boats, but my understanding
                  is that a lesser horsepower diesel is supposed to be the equivalent of
                  a larger horsepower gasoline engine. Something to do with the stroke etc. Perhaps some of engine experts here can add more to this.


                  Regards

                  Art

                  Comment

                  • Laker
                    Senior Member
                    • Sep 2010
                    • 458

                    #39
                    "Some of the sailors mentioned that the Atomic 4 was not a good engine."

                    Good thing that we are connected only by the internet rather than standing together in a bar...!
                    1966 Columbia 34 SABINA

                    Comment

                    • hanleyclifford
                      Afourian MVP
                      • Mar 2010
                      • 7004

                      #40
                      No shake, rattle, or roll

                      Destiny came with a tired early A4 and I got a lot of free advice about "drop-in" diesel conversions. But driving the Crosby launches around and listening to the deck hatches coupled with advice from other wooden boat owners put me off the idea. I don't know if it's really true but they claimed a diesel can shake fasteners loose and might have to have soft engine mounts which can complicate drive line alignment. Besides, I was already a gasoline engine mechanic. What really nailed it for me was helping the distraught captains of million dollar yachts standing off Edgartown harbor ferry jug after jug of useless diesel ashore so they could pay someone to dispose of it.

                      Comment

                      • ArtJ
                        • Sep 2009
                        • 2183

                        #41
                        Hanley
                        Just curious, where is your home port?

                        Art

                        Comment

                        • hanleyclifford
                          Afourian MVP
                          • Mar 2010
                          • 7004

                          #42
                          Edgartown, Martha's Vineyard

                          Comment

                          • ArtJ
                            • Sep 2009
                            • 2183

                            #43
                            Hanley

                            I used to keep my boat in Mattapoisett. I loved going to MV and anchoring
                            in Katama Bay, aside from the occasional idiot, power and sail included,
                            who anchored poorly in the entrance and dragged anchor, it was a
                            great place. Then the "environmentalists " got the town to permanently
                            close anchoring in there due to potential pollution, even though a pump
                            out boat patrolled and was used by nearly everyone. Since then,
                            you have to either pay several months ahead whether you actually use a downtown
                            mooring or not.( If you don't show, they leave it vacant.)

                            That leaves only mooring and anchoring outside the harbor with the
                            heavy chop from Vineyard sound and steamships heading for "amity".

                            Don't know if this policy has changed a little, I would hope so. It was
                            my favorite destination. I am sure people wouldn't have minded paying
                            a landing fee to support the services.

                            Regards

                            Art

                            Comment

                            • Mo
                              Afourian MVP
                              • Jun 2007
                              • 4519

                              #44
                              Most people like what they have, because that is what they know. Diesels are larger in comparison to their gas counter part. Some boats that require a 30hp don't have the room to install it without ripping the boat apart. They settle for the smaller engine...and my atomic 4 will keep up with a 15-20hp diesel no problem...when it gets rough I punch through...they don't. I know this because my friends (2) have diesels in C&C 30's also. They all scoffed at the A4 initially. After a few cruises, and a couple of tows, these guy are are pretty quiet about how good their diesels are.
                              Mo

                              "Odyssey"
                              1976 C&C 30 MKI

                              The pessimist complains about the wind.
                              The optimist expects it to change.
                              The realist adjusts the sails.
                              ...Sir William Arthur Ward.

                              Comment

                              • rigspelt
                                Afourian MVP
                                • May 2008
                                • 1252

                                #45
                                Sold on the Atomic 4 gas engine.

                                Always thought I had to have diesel in a sailboat, and always associated diesel odour in boats with "the sea", but our latest boat came with an A4 three years ago, and I'm a convert now, at least for our day trip/coastal cruising lifestyle. Clean, reliable, simple, cheap, safe (if kept shipshape).
                                1974 C&C 27

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