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Head skimming tips & tricks?

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    Head skimming tips & tricks?

    I'll be taking my heads to the skimmers this week. They have done Stag heads before but is there anything I should particularly ask them to beware of, or anything that is good to mention before they wind the cut on? A brief measurement suggests that the heads will only need a light cut, I'm hoping that is all.
    Mabel is a white 1972 Mk1, TV8, ZF 4HP-22 auto,
    2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

    #2
    If there is anything you think you need to tell them they can't be much cop at what they do.
    Your wife is right, size matters. 3.9RV8

    Comment


      #3
      For what it's worth, I think you can't take anything for granted whoever is doing the work and you should be cautious, I would certainly mention the heads are close to the limit and to take off the least amount they can get away with.

      Cheers
      Steve
      sigpic

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        #4
        Did you have the heads skimmed on the last rebuild ?

        Dave
        73 mk 1/2 now gone to the dark side BLUE

        Comment


          #5
          Not the last time Dave, they measured flat on a faceplate. This time I'm being ultra-cautious and making sure the heads are flat by skimming as well as measuring the block faces for flatness. This time I had to encourage the heads to come off which might have left a little distortion to contend with.
          Something encouraged a gasket to let go after only 25,000 miles and I would like to be sure I found out what it is. The BGA gaskets seem to be in good condition except where there is evidence of leakage.

          As they say where I'm from - belt, braces and a piece of baler twine will stop your trousers falling down!
          Last edited by mole42; 8th July 2019, 20:56.
          Mabel is a white 1972 Mk1, TV8, ZF 4HP-22 auto,
          2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

          Comment


            #6
            Where were the gaskets showing signs of leakage?

            This is obviously the bit that needs closest examination.

            I am surprised your heads needed encouraging to come off as all the previous examples I have come across, the heads just fall off. Unless of course the BGA gaskets have some sort of sticky surface which I have never come across before on Stag head gaskets.

            Neil
            Neil
            TV8, efi, fast road cams and home built manifolds. 246bhp 220lbft torque

            Comment


              #7
              There's a consensus on here that, if an engine has a history of short head gasket life, check the block face for flatness. No amount of head skimming will make it better.

              Dave

              Comment


                #8
                Originally posted by flying farmer View Post
                Where were the gaskets showing signs of leakage?

                This is obviously the bit that needs closest examination.
                No8 here looks a tad leaky....

                Stag LH head.JPG

                Originally posted by flying farmer View Post
                I am surprised your heads needed encouraging to come off as all the previous examples I have come across, the heads just fall off. Unless of course the BGA gaskets have some sort of sticky surface which I have never come across before on Stag head gaskets.

                Neil
                The heads were loose on the block, but both had a single stud that siezed in the head, I had to saw them off after using the rope trick to get anough room for the blade. Last time both heads came off without any trouble at all.

                Desperate measures.jpg

                I will be in the garage again this afternoon with my straight-edge and the feeler guages to check the block, especially around No8.

                Richard
                Mabel is a white 1972 Mk1, TV8, ZF 4HP-22 auto,
                2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

                Comment


                  #9
                  the only clusterf*** that my machine shop fell into was trying to skim back local corrosion on the head face which blank against the dead end coolant holes on the block.

                  Took a pair of heads with shed loads of life in them down to their last skim.

                  Unhappy was I
                  Stags and Range Rover Classics - I must be a loony

                  Comment


                    #10
                    Ouch!
                    Mabel is a white 1972 Mk1, TV8, ZF 4HP-22 auto,
                    2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

                    Comment


                      #11
                      I'm fairly sure that I've found the source of the head gasket leakage:

                      Corrosion.jpg

                      Does anyone know a good TIG welder? The other head is nowhere near as bad as this.

                      I tried a quick check with a straightedge and a 2 thou feeler guage, I couldn't find anywhere near the rear of the block where I could get slide it under, I'll check further next time.

                      Richard
                      Last edited by mole42; 9th July 2019, 17:59.
                      Mabel is a white 1972 Mk1, TV8, ZF 4HP-22 auto,
                      2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

                      Comment


                        #12
                        That does look a bit close to the fire ring, definitely worth welding up.
                        Header tanks - you can't beat a bit of bling.

                        Comment


                          #13
                          One of my spare heads looked a lot like that before I welded it up, but I haven't had it skimmed yet after I welded it.

                          Richardthestags experience with head skimming has always been my greatest fear, fortunately it has never happened to me!

                          I am surprised you had two head studs seize that hard after such a short period of time. Did you forget to use some sort of anti seize compound? I recently had to remove a head on my Estate as I couldn't remove the water transfer housing and that came off easily after nearly 10 years.

                          Neil
                          Neil
                          TV8, efi, fast road cams and home built manifolds. 246bhp 220lbft torque

                          Comment


                            #14
                            Originally posted by flying farmer View Post
                            I am surprised you had two head studs seize that hard after such a short period of time. Did you forget to use some sort of anti seize compound? I recently had to remove a head on my Estate as I couldn't remove the water transfer housing and that came off easily after nearly 10 years.

                            Neil
                            I don't remember what anti-sieze treatment I used last time but it obviously wasn't good enough. What do you use Neil?

                            Richard
                            Mabel is a white 1972 Mk1, TV8, ZF 4HP-22 auto,
                            2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

                            Comment


                              #15
                              On the ones I have dismantled I used some of the copper grease stuff, but it does get rather stiff after 10 years.

                              For the last few years I have been using the ceramic grease used on diesel glow plugs but I haven't had the heads off any of these engines so I can't comment on its efficiency yet!

                              Neil
                              Neil
                              TV8, efi, fast road cams and home built manifolds. 246bhp 220lbft torque

                              Comment

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