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  • #46
    Re: Priming the oil pump through the relief valve?

    Originally posted by drude View Post
    Hi Garry and all,

    It will take a lot of oil as you say and some pressure as well.

    That's because the path is up hill to the front of the engine and to get oil up the hill and back to the pump you have to contend with oil losses from the main bearings, can bearings and rod bearings.

    My point is that simply removing the plunger and squirting an oil can in there is not going to do it.

    BTW this is an interesting discussion.

    No intention to insult or offend anyone but I suspect that the discussion is ripe with misunderstanding, lack of knowledge, mistaken cause and effect, poorly defined terms, sloppy language, multiple scenarios that are being confused as one and all that kind of stuff. Well for not intending to offend I probably covered all of us!

    But the bottom line for me is that you guys that are having these problems you should consider whether an engine that can't self start its own oil pressure is in a condition for safe operation. That is part of the definition of airworthy. I see engines that sit for months and then start up with good oil pressure, no messing around, that's how it is supposed to be. I don't think that an engine that has to have its oil system doctored up to get initial oil pressure is in a condition for safe operation and would not pass it for annual.

    Regardless of all that please consider getting it fixed. A $800 oil pump will be cheaper than a stopped engine and the results it can bring.

    I say $800 because ; gears/kit- $400, shop work on cavity $325, misc- $75

    Dave
    the a65 oil pump issues have been around a long, long... long time. Before jumping off the deep end making expensive repairs we might want to ask how many if any failures have actually occurred in whole or in part due to oil prime loss issues. I could be off the mark but I'm thinking none. Loss of prime on these engines is not necessarily an indication of excessive wear. the oil pump is not a good design to start with and the distance from the pump to the oil in the tank is relatively far (more head to deal with). The is no seal on the pump cover and a tiny leak here is all that is required for the pump to drain back into the oil tank (because air can leak in past the cover).

    These motors will run quite happily and safely through to overhaul complete with loss of prime, but all the normal indicators remain valid, investigate low oil pressure, check the screen regularly for signs of trouble, oil analysis if you need more comfort.
    Scott
    CF-CLR Blog: http://c-fclr.blogspot.ca/

    Comment


    • #47
      Re: Priming the oil pump through the relief valve?

      Originally posted by Scott View Post
      the a65 oil pump issues have been around a long, long... long time. Before jumping off the deep end making expensive repairs we might want to ask how many if any failures have actually occurred in whole or in part due to oil prime loss issues. I could be off the mark but I'm thinking none. Loss of prime on these engines is not necessarily an indication of excessive wear. the oil pump is not a good design to start with and the distance from the pump to the oil in the tank is relatively far (more head to deal with). The is no seal on the pump cover and a tiny leak here is all that is required for the pump to drain back into the oil tank (because air can leak in past the cover).

      These motors will run quite happily and safely through to overhaul complete with loss of prime, but all the normal indicators remain valid, investigate low oil pressure, check the screen regularly for signs of trouble, oil analysis if you need more comfort.

      LOL

      poppycock

      What greater sign of trouble do you need to see other than no oil pressure on start up.

      A65 pumps are the same design as all small Continentals thru O200 with lift requirements similar to many internal combustion engines.

      Dave

      Comment


      • #48
        Re: Priming the oil pump through the relief valve?

        well for a start those engines use different materials

        perhaps you can tell us about a failure, engine stoppage, rough running engine, lost oil pressure in flight, anything negative that has occurred because of lost prime after being parked. If the problem more than just an inconvienience, surely there must be examples of problems, even an AD?
        Scott
        CF-CLR Blog: http://c-fclr.blogspot.ca/

        Comment


        • #49
          Re: Priming the oil pump through the relief valve?

          Perhaps then if it is merely an inconvenience you and others can tell us how you inform potential buyers about the process and methods that you use to over come it?

          Do you leave the engine sit for a few days and make sure the pump is dry so that you get an actual demonstration when they come to see the plane during the sale?

          How is it done?
          Last edited by Guest; 08-06-2014, 19:38.

          Comment


          • #50
            Re: Priming the oil pump through the relief valve?

            The longer they sit, the more likely they will loose prime. I stop the engine if I'm not getting pressure in 10 or 15 seconds (an ETERNITY when you are sitting looking at the gauge!). The last time I hadn't run the engine in YEARS and didn't try to start it first. I took the plugs out, sprayed a little oil in the cylinders and pulled the prop through by hand to get a "bump" on the pressure gauge. When I didn't, I primed through the pressure relief hole and got pressure (don't know why, but we have some theories after the discussion here I will be testing). When my plane was parked with the fuselage level I never had a problem.
            I WOULD NOT worry too much if I didn't get immediate pressure on starting. I also know I have NEVER waited my 10 second limit before I got pressure of panicked and shut her off.

            Hank

            Of course I would usually rather tinker with the plane than fly her. Got to change that.

            Comment


            • #51
              Re: Priming the oil pump through the relief valve?

              Originally posted by Hank Jarrett View Post
              The longer they sit, the more likely they will loose prime. I stop the engine if I'm not getting pressure in 10 or 15 seconds (an ETERNITY when you are sitting looking at the gauge!). The last time I hadn't run the engine in YEARS and didn't try to start it first. I took the plugs out, sprayed a little oil in the cylinders and pulled the prop through by hand to get a "bump" on the pressure gauge. When I didn't, I primed through the pressure relief hole and got pressure (don't know why, but we have some theories after the discussion here I will be testing). When my plane was parked with the fuselage level I never had a problem.
              I WOULD NOT worry too much if I didn't get immediate pressure on starting. I also know I have NEVER waited my 10 second limit before I got pressure of panicked and shut her off.

              Hank

              Of course I would usually rather tinker with the plane than fly her. Got to change that.

              Hi Hank,

              Are we discussing 1) persistent behavior of no oil pressure on start up unless some doctoring is done or 2)starting an engine that has been in long term storage?

              I thought it was #1 please correct me if I am wrong about that.

              BTW - I have tractors and planes that sit 4-6 months and then start with oil pressure right away.
              Last edited by Guest; 08-06-2014, 08:35. Reason: corrected type meant #1

              Comment


              • #52
                Re: Priming the oil pump through the relief valve?

                Originally posted by Hank Jarrett View Post
                The longer they sit, the more likely they will loose prime. I stop the engine if I'm not getting pressure in 10 or 15 seconds (an ETERNITY when you are sitting looking at the gauge!). The last time I hadn't run the engine in YEARS and didn't try to start it first. I took the plugs out, sprayed a little oil in the cylinders and pulled the prop through by hand to get a "bump" on the pressure gauge. When I didn't, I primed through the pressure relief hole and got pressure (don't know why, but we have some theories after the discussion here I will be testing). When my plane was parked with the fuselage level I never had a problem.
                I WOULD NOT worry too much if I didn't get immediate pressure on starting. I also know I have NEVER waited my 10 second limit before I got pressure of panicked and shut her off.

                Hank

                Of course I would usually rather tinker with the plane than fly her. Got to change that.
                Just an FYI but my Continental A65 manual says give it 30 seconds.

                I have had that manual for a long time so there is some chance that the number has been revised.

                Perhaps the owner of a later manual could check.

                Dave

                Comment


                • #53
                  Re: Priming the oil pump through the relief valve?

                  Originally posted by Scott View Post
                  the oil pump is not a good design to start with
                  The picture below is of a Continental IO-550C oil pump that I removed this morning. As everyone can see it looks remarkably similar to the A65 oil pump pictures that I posted a couple of days ago. Yes the pump gears are much larger. The IO-550 produces 300hp at 2700 rpm vs the A65's 65hp at 2300 rpm. The IO-550C is a current production engine so Continental must think it is a pretty good design, having stuck with it for 75 years. All of the engines that I've worked on that were losing prime also had oil pressure problems....in cruise the pressure ran on the low side of normal and at idle it was pretty much zero. I consider an engine that reguarly looses prime to be not airworthy. Continental's specs for oil pressure for an A65 is max 35, normal 30 to 35 and idle 10psi minimum. I wouldn't try to start an engine that has been sitting idle for a couple of months or more without pre-oiling it using a pressure pot or wobble pump to actually get the oil pressure up to 30psi and then pulling the prop thru with that 30 psi oil pressure.

                  Bottom line is that I err on the side of safety to protect my customers and to protect my A&P and IA certificates.

                  Last edited by Garry Crookham; 08-06-2014, 10:04. Reason: addition

                  Comment


                  • #54
                    Re: Priming the oil pump through the relief valve?

                    Originally posted by Garry Crookham View Post
                    The picture below is of a Continental IO-550C oil pump that I removed this morning. As everyone can see it looks remarkably similar to the A65 oil pump pictures that I posted a couple of days ago. Yes the pump gears are much larger. The IO-550 produces 300hp at 2700 rpm vs the A65's 65hp at 2300 rpm. The IO-550C is a current production engine so Continental must think it is a pretty good design, having stuck with it for 75 years. All of the engines that I've worked on that were losing prime also had oil pressure problems....in cruise the pressure ran on the low side of normal and at idle it was pretty much zero. I consider an engine that reguarly looses prime to be not airworthy. Continental's specs for oil pressure for an A65 is max 35, normal 30 to 35 and idle 10psi minimum. I wouldn't try to start an engine that has been sitting idle for a couple of months or more without pre-oiling it using a pressure pot or wobble pump to actually get the oil pressure up to 30psi and then pulling the prop thru with that 30 psi oil pressure.

                    Bottom line is that I err on the side of safety to protect my customers and to protect my A&P and IA certificates.

                    Thanks Garry,

                    That is good advice. I should start doing that on the airplane but not so easy on a tractor.

                    Dave

                    Comment


                    • #55
                      Re: Priming the oil pump through the relief valve?

                      Originally posted by Hank Jarrett View Post
                      The longer they sit, the more likely they will loose prime. I stop the engine if I'm not getting pressure in 10 or 15 seconds (an ETERNITY when you are sitting looking at the gauge!). The last time I hadn't run the engine in YEARS and didn't try to start it first. I took the plugs out, sprayed a little oil in the cylinders and pulled the prop through by hand to get a "bump" on the pressure gauge. When I didn't, I primed through the pressure relief hole and got pressure (don't know why, but we have some theories after the discussion here I will be testing). When my plane was parked with the fuselage level I never had a problem.
                      I WOULD NOT worry too much if I didn't get immediate pressure on starting. I also know I have NEVER waited my 10 second limit before I got pressure of panicked and shut her off.



                      Hank

                      Of course I would usually rather tinker with the plane than fly her. Got to change that.
                      My airplane sat for 3 years without running, started and had oil pressure within 5 seconds, so they do work when they are not worn even after sitting for years. Tim
                      N29787
                      '41 BC12-65

                      Comment


                      • #56
                        Re: Priming the oil pump through the relief valve?

                        I 'think" we started out with storage engines (over a week or so). The discussion evolved a lot over time. All of it is relevant. If an engine has been stored for MONTHS i don't expect it to have oil and try to pre-lube, even if it always did have good start up pressure.
                        If I had an engine that needed manual prime after only a few days I would be worried. Before I started redoing my plane it could go a couple weeks and still have immediate pressure, a month or more and have pressure in 10 seconds. That was with the fuselage level, but not because of oil problems, but floor flooding and my being sick of repacking the tail wheel bearing. When the water got deep enough to get my mains I started putting the mains on jack stands and the tail on a table.
                        I would bet your tractors have a pump that stays wet with oil. If we didn't have that long pipe from the kidney tank to the pump we wouldn't have these problems. It is NOT a very good design, even if it has worked well for almost a century.
                        Glad to be in REAL hangar at an airport that has drainage now.

                        Hnak

                        Originally posted by drude View Post
                        Hi Hank,

                        Are we discussing 1) persistent behavior of no oil pressure on start up unless some doctoring is done or 2)starting an engine that has been in long term storage?

                        I thought it was #1 please correct me if I am wrong about that.

                        BTW - I have tractors and planes that sit 4-6 months and then start with oil pressure right away.

                        Comment


                        • #57
                          Re: Priming the oil pump through the relief valve?

                          Yea, I saw the 30 second number, but I would be screaming in terror if I went that long. I set a personal limit at 15 seconds and have never been able to hold out that long. Ten seconds is an ETERNITY!

                          Hank

                          Originally posted by drude View Post
                          Just an FYI but my Continental A65 manual says give it 30 seconds.

                          I have had that manual for a long time so there is some chance that the number has been revised.

                          Perhaps the owner of a later manual could check.

                          Dave

                          Comment


                          • #58
                            Re: Priming the oil pump through the relief valve?

                            If you check your Your Tachometer drive oil seal can be bad. Check the oil seal on the tachometer drive. It can suck air and cause the pump not to prime. I have an AI friend with lots and lots of experience fixing this problem on not getting pressure. CHECK THE SEAL!!!. They get old and hard and will suck air. you can replace them easily and will help. Hope this helps. You can find oil seals that have a double lip that will really help cure the problem.

                            Comment


                            • #59
                              Re: Priming the oil pump through the relief valve?

                              There is a brand new -8 accessory case advertised on Barnstormers for 695. tim

                              ACCESSORY COVER CONTINENTAL • $695 • FOR SALE • New Continental Accessory Cover for the -8 motors, email for pics • Contact Richard P. Karpik, Owner - located Grand Rapids, MN USA • Telephone: 218-326-4928 • Posted August 17, 2014 • Show all Ads posted by this Advertiser • Recommend This Ad to a Friend • Email Advertiser • Save to Watchlist • Report This Ad
                              Last edited by astjp2; 08-21-2014, 00:39.
                              N29787
                              '41 BC12-65

                              Comment


                              • #60
                                Re: Priming the oil pump through the relief valve?

                                Divco quoted me $500 for one they had almost ready to go 3weeks ago
                                Robbie
                                TF#832
                                N44338
                                "46" BC12D
                                Fond du lac WI

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