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+--- Thread: A very minor thing... (/showthread.php?tid=4879)
A very minor thing... - Tony Griffiths - 29-08-2020
Just had a couple of cylinder head core plugs start to leak badly which, considering they looked to be original, is hardly surprising. Here's what one looked like - wafer-thin and almost rusted through - against a new example. Of course, the replacements I had were too large, but earlier I'd been looking at a cylinder head where somebody had made their own, as brass plugs, rather crudely bashed-in. So, nothing to lose, I fired up the lathe and made a couple myself. Quite tricky to get the diameter right, but with a bit of fiddling - by putting the discs in the freezer for a couple of hours and running the engine to heat the head - the Goldilocks moment was achieved and both were driven in good and tight.
RE: A very minor thing... - Bob Culver - 29-08-2020
The tricky part is turning thin discs in the lathe from sheet (other than parting off from solid). What was your technique? Can be dished by hammering into a hollow or hole in a block of wood .
RE: A very minor thing... - Tony Griffiths - 29-08-2020
(29-08-2020, 08:51 PM)Bob Culver Wrote: The tricky part is turning thin discs in the lathe from sheet (other than parting off from solid). What was your technique? Can be dished by hammering into a hollow or hole in a block of wood .I tried that some time ago, turning blanks from a steel bar, but it was very difficult to get them right - and dishing them into a turned hollow was not successful. The brass ones I made had vertical sides with flat tops and bottoms - but made to be a very tight fit, assembled with a smear of Araldite and driven into place with a hammer and punch. Having made one a firm sliding fit as a trial, the next was made 0.005" oversize, frozen for a couple of hours and fitted to a hot cylinder head. The brass core plugs in the spare head that I examined had material peened over the edge of the hole - and so appear to have been made with either a narrow top-hat section or just surplus material sticking up above the level of the head.
RE: A very minor thing... - bob46320 - 30-08-2020
Easier method - Cut off a square of flat metal, correct thickness. Trim off corners to 45degrees. Araldite onto end of a bar which has been faced off in the lathe and just smaller than required diameter. Turn to size plus a few thou" . Remove disc from bar - heat ?? Find/ make a washer 1/8" thick with a hole just a bit smaller than the disk. Open your vice jaws so you can get Washer, Disc,Ball pin hammer in-between the jaws and tighten to dome the disc. You should now have your Welch Plug.
RE: A very minor thing... - Steve Jones - 30-08-2020
Even easier method. Simply buy replacements from one of our suppliers.
Steve
RE: A very minor thing... - Austin Nippy - 30-08-2020
Even easier method. Simply buy replacements from one of our suppliers.
I couldn't agree more!
RE: A very minor thing... - Duncan Grimmond - 30-08-2020
Are you implying that Austin owners should put their hands into their pockets? Shame on you!
RE: A very minor thing... - Tony Griffiths - 30-08-2020
(30-08-2020, 09:12 AM)Steve Jones Wrote: Even easier method. Simply buy replacements from one of our suppliers.The obvious thing to do - and a wonderful solution - - if they were not too large for my cylinder head. That's why ones had to be made.....
Steve
(30-08-2020, 08:05 AM)bob46320 Wrote: Easier method - Cut off a square of flat metal, correct thickness. Trim off corners to 45degrees. Araldite onto end of a bar which has been faced off in the lathe and just smaller than required diameter. Turn to size plus a few thou" . Remove disc from bar - heat ?? Find/ make a washer 1/8" thick with a hole just a bit smaller than the disk. Open your vice jaws so you can get Washer, Disc,Ball pin hammer in-between the jaws and tighten to dome the disc. You should now have your Welch Plug.As ever, great ideas from the forum. Many thanks, Bob.
(30-08-2020, 10:55 AM)Duncan Grimmond Wrote: Are you implying that Austin owners should put their hands into their pockets? Shame on you!While not in the DW class of being able to forge a new con-rod from a 56lb weight scrounged from a coal merchant's lorry, it is rather fun - and satisfying if it works - to have a go oneself at these little tasks.
RE: A very minor thing... - john deacon - 30-08-2020
My special has an old sixpenny piece in one of the cylinder head core plugs, its been there since I bought the car 12 years ago, the machine shop who skimmed the head even took pictures for their rouges gallery.
RE: A very minor thing... - Tony Griffiths - 30-08-2020
(30-08-2020, 06:32 PM)john deacon Wrote: My special has an old sixpenny piece in one of the cylinder head core plugs, its been there since I bought the car 12 years ago, the machine shop who skimmed the head even took pictures for their rouges gallery.I knew that there was a coin that could be made to do the job - I just could not remember what it was.