• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.

Announcement

Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

opinions on what to do about scratches inside piston wall

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts


  • #16
    Re: opinions on what to do about scratches inside piston wall

    Originally posted by apollothesun View Post
    yes i do, noticed the one side on it. i believe it started to hit the exhaust hole when the rings gave way
    I was asking for a photo of the head if you have one.
    sigpicMarada 2100 Executive Series, 5 Litre V8 with Mercruiser Alpha 1 outdrive. 2007 K-Z Spree 260 RBH, all = a whole lot of family fun !!!!

    Comment



    • #17
      Re: opinions on what to do about scratches inside piston wall

      Have you ever used muriatic acid? The stuff will destroy a swab in seconds. A neighbor used it to remove stains from his concrete driveway ... the brush he was using to spread it lasted about two minutes. Nylon and similar materials are the only common materials which survive this stuff. Use long neoprene gloves and safety glasses as minimum protection.
      Jim

      ===============================
      I don't respond to Private Messages PM's that are motor questions.

      For basic information on a wide range of topics, see Top Secret File
      Link: http://forums.iboats.com/showthread.php?t=299680

      OEM shop manual: outboardbooks.com or Ebay

      Comment



      • #18
        Re: opinions on what to do about scratches inside piston wall

        I have done the Muriatic acid trick to remove melted aluminum from cylinders before. On Motorcycles as well as smaller outboards. First off, Make sure that the cylinder taper is well within specs, and is also within spec for the new piston. If all is good, then its possible to do this without going in to the machine shop. Secondly, you need a face shield or really good safety glasses, and a Vapor respirator. The fumes from That acid will literally knock you out or even burn your sinuses. To do this, realize that the acid does not care what aluminum it eats away. It will destroy good metal too. So, to do only one hole and not affect the other cylinder/s is very difficult. The reason is, you need to have a way to neutralize any acid that pools in the bottom of the cylinder, while you are swabbing the affected areas. Also, any grit and metal shavings CANNOT get into any of the other cylinders at all! To keep excess acid from eating good metal, I use a spray bottle with water, and a little baking soda mixed in. Make sure the engine is in a position that any fluid running out of the cylinder bottom, does not trickle into one of the good cylinders. I have used regular old Q-Tips dipped in Acid to swab the affected area. They dont last long, but you dont really need them too. You will know when you have all the aluminum off the wall when it doesn't foam up any more. Once all the built up aluminum is removed you will have a better Idea what the damage is. If the scratches are not deep enough to feel with a finger nail, you are probably good. Now hone the cylinder. When the proper hone is achieved, remember to chamfer the edges of ALL the ports. I use a dremel and a ball hone. If you don't do this the new rings could catch on the port, and cause the same damage again. As far as a chip or scratch in the port, try to blend it evenly accross. If the chip is real big, then you need a new liner. period. When finished, CLEAN, CLEAN AND CLEAN AGAIN! This is why tryin to be sneaky and only do one cylinder is tricky. I would completely disassamble the motor, Mic all the cylinders, Clean them all up, hone them, Without the fear of getting junk into the other cylinders. Also re-ringing those other pistons is a cheap way to improve performance and longevity. You have the engine apart now, Why not? You will be happy you did...

        Comment



        • #19
          Re: opinions on what to do about scratches inside piston wall

          Nice information Jayrock.
          sigpicMarada 2100 Executive Series, 5 Litre V8 with Mercruiser Alpha 1 outdrive. 2007 K-Z Spree 260 RBH, all = a whole lot of family fun !!!!

          Comment



          • #20
            Re: opinions on what to do about scratches inside piston wall

            hey Jayrock,
            after reading your post you enlightened me to break the powerhead down completely.
            im glad i did too, piston 1 and 2 rings were broken also, probably from debri from
            piston 4. upon looking and feeling around at the piston 4 wall, im gonna have to rebore to a bigger piston. the scratches on the wall can be felt with my finger nail. all the other piston walls are good just need some honing to do.
            alot of carbon gunk inside the exhaust housing that i proceeded to clean. theres a machine shop that works on marine motors closeby. i will bring the powerhead to them and have them examine the piston wall.
            one bummer is i cant find one of those small roller bearing. i searched everywhere for it. im hoping i can still buy those still.

            Comment



            • #21
              Re: opinions on what to do about scratches inside piston wall

              hey Jayrock,
              where did you buy the ball hone for the exhaust cylinders at?

              Comment



              • #22
                Re: opinions on what to do about scratches inside piston wall

                i need help in finding a piston that will work to replace piston 4. im probably gonna need to bring in the new piston to the machine shop so they can measure properly. which wiseco piston would work? or do i just say cut it to .040?

                Comment



                • #23
                  Re: opinions on what to do about scratches inside piston wall

                  Unless you have the tools and skills to properly measure the bores, let the machine shop tell you the OS to get. Just tell them you will use brand "x" pistons. Once they measure, they should recommend the smallest OS that will allow proper bore cleanup.

                  Bearings are readily available.

                  If you don't have one, now would be a good time to get an OEM shop manual.
                  Jim

                  ===============================
                  I don't respond to Private Messages PM's that are motor questions.

                  For basic information on a wide range of topics, see Top Secret File
                  Link: http://forums.iboats.com/showthread.php?t=299680

                  OEM shop manual: outboardbooks.com or Ebay

                  Comment



                  • #24
                    Re: opinions on what to do about scratches inside piston wall

                    Originally posted by apollothesun View Post
                    hey Jayrock,
                    where did you buy the ball hone for the exhaust cylinders at?
                    I used to use a Carbide Ball shaped deburring bit, Carbide cone deburring bits work good too, but they are spendy. So, Its not exactly a Ball hone that I use now. I use a cone shaped sanding bit that Dremel Makes. I paid less that 10 bux for the one I have now, and I have used it several times.

                    Comment



                    • #25
                      Re: opinions on what to do about scratches inside piston wall

                      Originally posted by apollothesun View Post
                      hey Jayrock,
                      after reading your post you enlightened me to break the powerhead down completely.
                      im glad i did too, piston 1 and 2 rings were broken also, probably from debri from
                      piston 4. upon looking and feeling around at the piston 4 wall, im gonna have to rebore to a bigger piston. the scratches on the wall can be felt with my finger nail. all the other piston walls are good just need some honing to do.
                      alot of carbon gunk inside the exhaust housing that i proceeded to clean. theres a machine shop that works on marine motors closeby. i will bring the powerhead to them and have them examine the piston wall.
                      one bummer is i cant find one of those small roller bearing. i searched everywhere for it. im hoping i can still buy those still.
                      Once you have an idea what everything will cost, STOP before proceeding. Now, look into what a used crankcase costs, that has never been bored, or has all the machine work already done. Might be less expensive to just replace the crankcase... Food for thought.

                      Comment



                      • #26
                        Re: opinions on what to do about scratches inside piston wall

                        Originally posted by wilde1j View Post
                        Unless you have the tools and skills to properly measure the bores, let the machine shop tell you the OS to get. Just tell them you will use brand "x" pistons. Once they measure, they should recommend the smallest OS that will allow proper bore cleanup.

                        Bearings are readily available.

                        If you don't have one, now would be a good time to get an OEM shop manual.
                        thanks jim for the valuable information about piston sizing, i would of never of thought that.
                        i hear ya jim, if i didnt have the oem manual, i would be stripping bolts off the motor and would be still on the lower unit.

                        Comment



                        • #27
                          Re: opinions on what to do about scratches inside piston wall

                          Originally posted by Jayrock View Post
                          I used to use a Carbide Ball shaped deburring bit, Carbide cone deburring bits work good too, but they are spendy. So, Its not exactly a Ball hone that I use now. I use a cone shaped sanding bit that Dremel Makes. I paid less that 10 bux for the one I have now, and I have used it several times.
                          fantastic idea, now i have a reason to use that sanding bit!

                          Comment



                          • #28
                            Re: opinions on what to do about scratches inside piston wall

                            Jayrock, i like how you think. toast to you bro. if i was close down to diego i would definately buy you a drink. i will try the local craigslist, no sense in spending more cash than i have too and i can spend more time with the family.
                            i went by to that local machine shop and they only do cars.
                            anybody tried sending their powerheads out to get them rebored and pistoned up? any good shops out there that do this?

                            Comment



                            • #29
                              Re: opinions on what to do about scratches inside piston wall

                              I stripped my block which only had one out of round piston. but the bore was right at max spec, and you always need to hone to get the rings to seat...so I went .020 over size on all cylinders...because for all the work I am doing , I dont want it to bite me in the behind, because i tried to save $200 someplace..

                              I sent my block to Lashelle Engine Restorations( freeport lll). I actually got the number from a palce that didnt really want to do my block, and mention that he sends all his blocks out...so i asked who.. this was the guy.. It came back really nice( i have the measuring equipment and tools to know!!) I am thinking that a bore and hone was about $40 per hole...

                              but you can ask him... he had already done hundreds of 60 degree blocks like mine...which are a little tricky with that flat bottom bore!! need special hones to do blocks like these.


                              good luck

                              bob

                              Comment



                              • #30
                                Sign up today
                                Re: opinions on what to do about scratches inside piston wall

                                I rebuilt my own 60hp this last summer. The only tool I don't have is the mill for boring so I had a local machine shop do that work. Once I got it back I brought the cylinders up to size with the hones. Then debured all the ports, debured the pistons, cleaned everything up and assembled. I have ran 3 tanks of gas threw the motor already and everything is working great! The pistons are .020 over. We got the motor in to be a parts motor for our 70hp on the work boat but the only parts we ever needed off this motor was the trim relays. lol

                                We got this 60 without a head and all 3 pistons and cylinders were scored from heat. It was a very fun build and I think I have $300 total in the motor with new pistons, head, and complete gasket set.

                                I just posted a couple pics here: http://forums.iboats.com/showthread.php?t=97206

                                Comment


                                Working...
                                X