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my volvo 280 has left hand rotation prop was there a reason for this?-gctid344557

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    my volvo 280 has left hand rotation prop was there a reason for this?-gctid344557

    went to buy new prop, most are right hand rotation should i change? thanks for your answers ,,jerry

    #2
    Gerry nooooooooooooooo do not buy a right hand prop for left hand rotation that is the direction the outdrive turns so you must stay with left hand rotation you MAY change pitch or maybe even prop diameter depending on what kind of performance difference you are trying to achieve but do NOT but a prop with different rotation

    Comment


      #3
      a marine mechanic said just change that little rod there ,and she will spin the other way??

      Comment


        #4
        Jerry, Volvo Penta used the LH more so than the RH, but either works as the drive is prop-shaft-direction-reverseable.

        This makes an easy application for twins.

        Same drives, same engines......... we just reverse the Stbd drive for a RH prop. (it's just a simple linkage arm swap and re-adjustment)

        Now, there is a catch to this, and IMO it may depend on which engine you have.

        First.... a bit of info for FWD gear propulsion:

        LH prop is driven from the transmission's lower driven gear.

        RH prop is driven from the transmission's upper driven gear.

        When we drive from the lower driven gear (LH prop), it creates an up-lift force on the transmission vertical shaft.

        The 280 transmission OEM keeper that "checks" this force, is brass.

        When we drive from the upper driven gear (RH prop), it creates an downward force on the transmission vertical shaft.

        The 280 transmission component that "checks" this force, is an all steel threaded top nut.

        With many hours of use behind the V-8's, and with a LH prop (or Duo Prop), the brass split ring keepers tend to expand.

        [COLOR]"#FF0000" wrote:
        You do not want to let this keeper expand and eventually let go of the shaft! [/COLOR]

        Why am I telling you this???? because if you are V-8 powered running a RH prop, you may want to stay with it.

        If you want to change to a LH prop, and if you've not re-sealed your drive in a while, this would be a good time to check this brass keeper.

        dizzy_wizz wrote:
        Gerry nooooooooooooooo do not buy a right hand prop for left hand rotation that is the direction the outdrive turns so you must stay with left hand rotation you MAY change pitch or maybe even prop diameter depending on what kind of performance difference you are trying to achieve but do NOT but a prop with different rotation
        Dizzy-wizz!

        Intuitively that sounds somewhat correct, in that we do not want to alter an existing gear wear pattern.

        However, with this style transmission and lower gear arrangement, this is a non-issue!

        The only thing that would be altered when switching from a LH to a RH, would be:

        You'd now be driving from the trans upper "driven" gear.

        The trans main drive gear bearing box now has an opposing thrust on it.... and the bearings don't care.

        The lower "driven" gear interior needle bearings go in High Gear! (non-issue... the upper ones were in high gear prior)

        The two large "driven" gear angular contact bearings don't give a hoot. (these are the Sherman Tanks of bearings)

        The lower unit "drive" gear and "driven" gear bearings now have the thrust placed on an opposite side. (non-issue)

        None of this makes a difference with this drive.

        The only catch would be the brass keeper that I mentioned.

        .
        Rick E. Gresham, Oregon
        2850 Bounty Sedan Flybridge model
        Twin 280 HP 5.7's w/ Closed Cooling
        Volvo Penta DuoProp Drives
        Kohler 4 CZ Gen Set

        Comment


          #5
          wow good answer , my boat came with two left hand props ,and i am going to break my new 383 in this spring so your saying stick with the original lefty? thanks jerry

          Comment


            #6
            Bradner... I was editing while you were posting. See new comments.
            Rick E. Gresham, Oregon
            2850 Bounty Sedan Flybridge model
            Twin 280 HP 5.7's w/ Closed Cooling
            Volvo Penta DuoProp Drives
            Kohler 4 CZ Gen Set

            Comment


              #7
              beer- owe ya a cold one,,,

              Comment


                #8
                bradner wrote:
                wow good answer , my boat came with two left hand props , and i am going to break my new 383 in this spring so your saying stick with the original lefty? thanks jerry
                OK, that's new info!

                If you are doing a 383, and using the LH prop, I would strongly encourage you to pull the transmission apart and do several things to it:
                • Check and/or replace the main drive gear bearings (i.e., bearing box bearings)
                • Replace the split ring keeper (I had some specially designed stress-proof steel keepers made if interested)
                • Mildly and very carefully lap the sliding sleeve into each gear cup...... particularly the lower driven gear cup.
                • Check all bearings, etc.




                BTW, I don't recall reading anything about your 383 build, or I completely missed it.

                Any interesting tid bits or tips that would be worthy of a new thread?

                Cost? Parts? Stuff like that!

                .
                Rick E. Gresham, Oregon
                2850 Bounty Sedan Flybridge model
                Twin 280 HP 5.7's w/ Closed Cooling
                Volvo Penta DuoProp Drives
                Kohler 4 CZ Gen Set

                Comment


                  #9
                  ok so here is my engine ,started with a 1976 high nickel 4 bolt main block . machined the decks bored cylinders 40 thousand kieth black forged DEEP DISH MARINE pistons , forged pro comp rods swinging on a forged scat 400 crank . new stock oil pump, new pan ,arp bolts, crane cam, part number 100052 grind number 272 h10 all balanced ,heads 1977 corvette ported polished ,planed new seats, guides , ford umbrella seals, manley stainless valves screw in studs new springs seat load 122 open load 309 pounds.edelbrock performer intake, new marine quadrajet carb, kn marine air cleaner, new pertronix billet distributor with marine advance springs. new manifolds and y pipe ,comp cams high zinc break in oil broke in the cam ,now gets instant revs and sounds like a good ole nova from the seventies. she gets wet this spring been a long haul.. jerry

                  Attached files [img]/media/kunena/attachments/vb/647297=23857-4083.jpg[/img] [img]/media/kunena/attachments/vb/647297=23856-4089.jpg[/img] [img]/media/kunena/attachments/vb/647297=23902-IMG_2391.jpg[/img]

                  Comment


                    #10
                    Mmmmmm, love the smell of a new 383. She looks nice! How hard was it to find the 77' vett heads? They are getting scarce around here.

                    Not to poo poo anything you have done, but you may want to replace the front / back intake manifold gaskets with silicon fill. With an aluminum intake those rubber gaskets can pull out over time - just a suggestion, not telling you how to build an engine - you really know your stuff!

                    Very nice!

                    Comment


                      #11
                      those heads are around jeff ,they just need dremel time to clean them up ,, and yea those intake seals are glued with aviation glue top and bottom there a bitch to scrape off ,jerry

                      Comment


                        #12
                        Just for fun, I looked these up.

                        I show a casting number for this cylinder head as per "H" here.

                        Apparently these fall into the heavy casting catagory, which is ideal for Marine.

                        (see the thread in the BOC Vault on SBC cylinder head casting numbers to avoid)

                        The H listed are the 64cc chambers w/ a straight wedge.

                        This means that ideally the piston dish volume should accommodate the smaller chamber, and the wedge should infuence the piston deck shape if the goal is to create a good squish or quench.

                        Later hi-perf or "fuelie" heads, some 186 ('69 & later) & all 492 have accessory bolt holes;

                        1.94/1.50 or 2.02/1.60 valves; 64cc chambers; '70 LT1/Z28 use 492; avail as PN3987376

                        Source.

                        http://www.fastnuf.com/Headguide.html

                        3987376 ÔÇö Cast Iron High-Performance Head (Large Valve)

                        This cylinder head (casting P/N 3991492) was originally installed on special

                        high-performance small-blocks such as the 302ci Z-28 and 350ci LT-1. It is

                        popularly known as the "fuel injection" head because it shares many features

                        with previous high-performance Corvette heads. This head has straight

                        spark plugs, 3/8" screw-in studs, pushrod guideplates, and heat riser

                        passages. The 64cc combustion chambers are machined for 2.02" intake

                        valves and 1.60" exhausts. Seats are not heat-treated.

                        Source pdf page 49.

                        http://www.s-series.org/htm/tech/GMP...ts/046-050.pdf
                        Rick E. Gresham, Oregon
                        2850 Bounty Sedan Flybridge model
                        Twin 280 HP 5.7's w/ Closed Cooling
                        Volvo Penta DuoProp Drives
                        Kohler 4 CZ Gen Set

                        Comment


                          #13
                          When I did my 383 I had to use 1 - #993 head and 1 - #487 head.

                          The vette heads are non existent here, and I could not find a matching 993 head, but the 487 (pre Mexico) head has the exact chamber design as the 993, just a little different exterior bolt pattern, of which did not matter as all my stuff re bolted back up.

                          Comment


                            #14
                            well this is it, 0 deck .planed heads 400 crank bored 40 thou had to use DISHED kieth black forged slugs , came out to 8.8 to 1 comp.

                            Attached files [img]/media/kunena/attachments/vb/648006=23901-IMG_2391.jpg[/img]

                            Comment


                              #15
                              That is nice that you had the budget for the KB forged pistons. Forged will be very stout. But dang it..... I sure wish we'd a had a BOC discussion prior to that full dish piston.

                              Keith Black's forged D-dish or Keith Black's hypereutectic D-dish would have given you a quench/squish area.... and your C/R could have been increased a bit (via the dish volume).

                              (example only to show the D shape)



                              Or similar to this with the Vortec heads.



                              No problem.... it will work! Just be conservative on your ignition TA, and you'll do OK.
                              Rick E. Gresham, Oregon
                              2850 Bounty Sedan Flybridge model
                              Twin 280 HP 5.7's w/ Closed Cooling
                              Volvo Penta DuoProp Drives
                              Kohler 4 CZ Gen Set

                              Comment

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