TonyAus

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About TonyAus

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  • Birthday 12/04/1949

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  1. The original method of holding the impeller to the shaft is a number one taper pin (standard taper of 1/4" per foot). In theory you should be able to drive it out easily from the rear. However, the pin may be rusted in place. I managed to remove mine by tapping the pin at both ends after applying heat and WD40. You will note that the pin is slightly offset to the shaft. I suspect that originally the impellers were individually drilled and pinned. Therefore a replacement shaft should, in theory, be drilled to suit your impeller. Being a bit of a perfectionist I made up my own shaft and taper pin, reaming the impeller and shaft to suit. The pin was then driven in with a little Loctite for good measure. I'm not sure that using a roll pin in this location is a good idea given the alternate heating and cooling cycle which may degrade the spring in the pin. You might consider using a plain pin riveted over at both ends. In any event the tapered hole in the impeller would need to be drilled parallel to suit the pin.
  2. I can only quote from the Book of Information. "Since the primary current must be broken while at its maximum to give the hottest spark, the gears driving the distributor rotor must never be disturbed". Sound like your extra performance came from additional advance but a weaker spark. The rebuilder was only following sound practice. I understand that Cled Davies in Bendigo sells an adjustable magneto coupling to achieve additional advance without compromising the spark - could be your answer.
  3. Problem now solved. The drive gear keyway on the shaft I had made nearly forty years ago was cut approximately 15 degrees out. Not enough spark advance and therefore overheating. It should go like a bomb after I get a new shaft made!
  4. For all you hanging on this topic I've been able to determine from a local source that, viewed from the front, the drive gear keyways on original shafts were cut approximately 28 degrees behind the others - which were in line. This means that the use of a shaft as supplied by Myers would give me a retard position of 20 degrees before TDC and an advance position of 40 degrees before TDC. Probably not good given the correct figures of 8 degrees after TDC and 12 degrees before TDC respectively. Moving the drive gear from the timing marks would give a 16.36 degree correction per tooth. Two teeth would therefore give a 3.28 degree ATDC retard and 16.72 degree BTDC advance - possibly not ideal. Looks like I'll have to get a shaft made locally.
  5. The purpose of this hatch is to provide access to the trunk when the top is folded back. The folded top doesn't allow the trunk lid to fully open.
  6. Thanks again Mike This video was interesting but unfortunately it doesn't show the old shaft coming out (he lost charge on his phone) - bugger! The new shaft he used is from Myers and has the key slots in line - the arrangement I have questioned. Perhaps I worry too much. At least it confirms my conclusion to another problem that the impeller pins were drilled for individual fit. Regarding your photo , I think that the apparent offset may be an optical illusion caused by the camera angle. Has anyone else got an old shaft which might kill my doubts? Please! Tony
  7. Thanks for that Mike. Looks like it's time to come clean with the full story. Since getting the car back on the road I've been plagued with variable overheating - mainly associated with hot weather and higher speeds. Most of the usual suspects, blocked radiator, lean mixture, loose fan belt etc have been addressed. I've now turned to the possibility of not enough spark advance or that the water pump impeller has somehow come loose. Both these could be associated with the stainless steel water pump shaft I had made up nearly forty years ago. In any event I was not happy with the fit of the impeller on the shaft and raised the surface with a series of centre punch marks (a bodge dictated by not knowing better). Being slightly under size the new shaft also has a habit of chewing up and spitting out the packing - another source of annoyance. I also didn't check that the key slots were in the same places as the old shaft which had been cut in half to release the water pump (another bodge on my part). Before pulling the whole mess apart to check I decided to order a new shaft from Myers but noticed that theirs has all the key slots in line. The remains (front) of mine has the impeller key slot offset to the others which, of course, has no significance to the ignition timing. As the magneto end is missing I started to worry that the problem may be the relationship between the drive gear and magneto yoke slots - and without a way of checking. I also thought that having all the slots in line was an easier way to make the reproductions and may have relied on the use of a distributor, timed by the method dwollom suggests. Mike, I take it that the fan pulley end of the shaft is at the right side of your photo. If so, I can't see a key slot at the left hand end, which is the one in question. There should be four slots rather than three. Have my eyes failed? If the left hand end slot is further around the shaft than the drive gear one you may have answered my original question. I'd be grateful for clarification. Regards Tony
  8. Yes - but I have a magneto which doesn't have this luxury.
  9. The question is whether the slots are aligned or not. If not I can make suitable arrangements.
  10. For reasons too long to explain here I need to clarify one aspect of water pump shafts used on single electrical unit (starter/generator) DB engines. Does anyone have an old shaft that they can check for me? These shafts have (from the front) a woodruff key slot and cross drilled hole for the fan pulley, a key slot without drilling for the drive gear, a key slot and hole for the water pump impeller and a key slot and hole for the distributor/magneto drive yoke. Clearly the positions of the drive gear and yoke are critical to ignition timing. What I need to know is are the key slots for the drive gear and yoke in line along the shaft or are they offset from each other? Thanks in anticipation Tony
  11. The short answer is no. But you might like to consider painting the joint faces with cavity wax (non hardening) before assembly to avoid squeaks and rust. See your automotive paint dealer for the wax.
  12. Yes, that's the bolt (a particularly daggy example). The head is 9/16" AF and the thread is 5/16" UNC. The bolt fits into a cup washer which is 1" in diameter, 1/4" thick and has rounded edges. The original nut is 3/4" square but can be made larger to engage flush with the inside of the dumb irons where it is inaccessible after the front valance is put in place (held down by the front guards). See attached photo.
  13. To answer your specific questions: 1. and 2. The correct material to use between the chassis and the body is uncured rubber. This material , prescribed for such usage, is available from Spectrum Rubber in Sydney or from Peter Jackson (Old Era Services). The rubber goes on top of the chassis as far as the front of the scuttle - not under the front guards. 3. The valances (side skirts) sit on top of the rubber and should have clearance notches for the body bolts and chassis rivets. They do not have bolt holes as such but are secured by a combination of the body being bolted on from the top and the running boards holding down their lower edge. 4. The bolts holding the lower parts of the front guards at the clash strip and dumb iron ends are of a special type - 9/16" thick head with a taper under which fits into a countersunk washer. The nut is an oversize square which bears against the side of the chassis for tightening purposes. I had to make these as the old ones tend to rust and break. Send me a PM if you can't find any and I can turn some up for you. 5. I'm not sure about that hole. The later guards are different to mine in that they appear to have integral clash strips. Tony