Lebro Posted July 4, 2017 Report Share Posted July 4, 2017 I would not be afraid of unscrewing the block drain tap, that way you can dig out a lot of the cr*p which builds up behind it, & it will give you a chance to free up the tap while not on the car. Bob. Quote Link to post Share on other sites
Fireman049 Posted July 4, 2017 Report Share Posted July 4, 2017 This is what my 3A block was like when I rebuilt my engine. I had the block chemically cleaned to get rid of all the crud. Puzzle find the drain hole?? Tom. Quote Link to post Share on other sites
Charlie D Posted July 5, 2017 Report Share Posted July 5, 2017 Hello All, The part number for the engine tap, as mentioned by Don, is 61478. ANG has it on eBay for about £18.00 and claims the thread is 0.5 x 20NTP (National Pipe Thread.) As far as I know “NTP” is an American thread… (WHY do some advertisers put totally the wrong information in their descriptions!!!) Leacy (and others) have the same part number on sale for half the price and claim the thread is ½” UNF. Having just fitted mine 10 mins ago I can confirm it is ½” UNF. And as such is a parallel thread, not taper. Something I discovered when refitting the tap was that is seemed to get tighter the more I screwed it in, making me think that it WAS a taper thread. But UNF does not come in taper flavour… However…. As mentioned by Tom and Bob, just behind the tap is one of the worst places for rust/scale/crud. I removed all this with a hammer and chisel and thought I’d made a good job. I forget about inside the thread where the tap screwed in and there was obviously a build up of crud in there as well. (I’d poked a drill through but no where near the full diameter of the hole.) When I screws the tap back in it must have come into contact with “crud dust” that had fallen the wrong side of the threaded hole, and the further I screwed the tap in, the more compressed it became. After about an hour of head scratching I ran a ½” UNF tap (Threading tap, not water tap) through the hole and was amazed at the amount of black dust (Mixed with the lubricating oil I was using) to appear. After that the tap (Water tap) went in fully without a problem. I can not say for certain what thread the radiator tap uses, but I would “Guess” it is BSP, but taper or parallel I don’t know. Maybe of use to someone. Charlie D. Quote Link to post Share on other sites
alexander Posted July 7, 2017 Report Share Posted July 7, 2017 Dave Gleed had taps on his stall, he's at Malvern this weekend. Quote Link to post Share on other sites
niklas Posted July 7, 2017 Report Share Posted July 7, 2017 Available on eBay: http://www.ebay.co.uk/itm/Triumph-TR2-TR3-TR4-Morris-Minor-MGB-Radiator-Block-Brass-Drain-Tap-061864-/222464136701?hash=item33cbe555fd:g:F0wAAOSwo4pYhi8M Quote Link to post Share on other sites
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