A Bit Deflating.

Even my latest loaf of bread couldn’t muster any enthusiasm for the day – a portent if ever there was one.

Flat loaf

It seemed that all the problems had been waiting to show themselves in the closing stages of the build. For instance, the new core plugs are too small – not cheap but definitely under size by about 1/2mm and a genuine 42mm plug is still too sloppy a fit. I’ll have to get some bigger ones and somehow make up a mandrel so I can turn them down to the exact size.


Also, I discovered, when I came to put the dynamo bracket on, the early blocks don’t have the same mounting procedure (the later blocks are drilled and tapped for the mounting bolts) so I’ve got to source an early dynamo mounting and hope the diameter of the new alternator is the same as the old dynamo – it should be.


Blocks 2And the brake return springs have been made 12mm too long so it’s a long trip back to the spring-maker to have them altered (it was probably my fault for chatting too much while chap was making them but he was very happy to pass the time of day as well). And that’s just today’s snags.

Drilling and tapping block

In the end, as cast iron is so easy to deal with (except when you want to weld it), I opted to drill and tap the block so that it would accept the later dynamo bracket. A drill block is essential when doing this, especially for starting off the tap in a straight line. No lubrication, nice and slow with a good sharp drill and you can’t go wrong.

Drilling guide

Instead of trying to measure things, I went for the safer option of taking a pattern with a bit of paper and an oily finger from the old block. When that was done, I put the head gasket on and couldn’t help noticing how times have changed…


You can multiply that by about 20 for a head set nowadays – if you can find one. So the next job is to slip the head back in place, torque it all up, wrestle with the camshaft balance weight for half an hour and then whizz the whole palaver back in the chassis. It shouldn’t take more than a couple of hours to put everything back together again and the elusive start-up will be a bit closer.

I went back to the spring-maker and he very obligingly corrected the over-size on the spot. They’re the very devil to put on now which is as they should be. With the old ones you could pull the shoes off their mountings with almost no effort at all. When the new master cylinder arrives, I’ll be able to set the brakes up again and a chum has very kindly offered to lend me his Fantastic Vacuum Brake Bleeder (FVBB).


So here we are again; I’m hoping for some encouraging signs from the engine and, having spoken to Blue Swallow Aircraft about the wings, things are looking a bit more buoyant.


8 comments on “A Bit Deflating.

  1. Doug Gordon says:

    You can turn core plugs to size by contouring a solid round piece of whatever is lying around in a lathe chuck to closely match the concave radius and diameter of the plug. Then you can duplicate the exercise to match the convex side and deeply centre-drill the back of it to locate on a live centre. Place some thickish pieces of rubber (3-5mm cut to size) either side of the plug and wedge it between the two dollies you have made using the tailstock hand wheel. This will be adequate to take a few fine cuts to carefully get down to a precise fit.

    • Thanks Doug, The carpenter a couple of doors along from me threw out some very nice off-cuts of a beech kitchen work surface the other day. I knew they’d come in handy – perfect for the dollies. I was thinking of drilling a hole for a mandrel and brazing it up afterwards but obviously that would affect the plugs ability to flatten out in the block. Thanks again.

      • Doug Gordon says:

        Yes, best not to mess about with your core plugs by drilling through to use a more “traditional” mandrel – it will upset the whole dynamic of them. It’s only compression forces that hold them in position. Brazing afterwards will just anneal the work-hardening needed to hold them in!!….and they risk falling out. I used some VERY slightly under-size ones on a racing MGTC and they popped out at 6000rpm on the back straight. Within about 50 metres I burnt a valve and melted the top off one of the pistons. Serious things – core plugs – VERY expensive if they fall out!!!
        Make sure they FIT AND SEAT PERFECTLY!!!…then knock them in. I even seal them, now, with Devcon high-temp metal-filled epoxy.
        You need to look after those new pistons!

  2. I’ve done exactly that for turning up flat discs before. I just used a flat head blot with some rubber on it on the chuck end and a fat circular rubber grommet on a live centre in the tail stock.The grommet is fat enough that the point sits into it but the rubber face fits hard up against whatever I was turning. Then very, very fine cuts.

    I also had issues with my original Austin brake springs. They were so saggy they wouldn’t pull the brakes off. I fitted new later ones. Luckily the Austin springs have loops on them so I popped down to the $2 shop, got the cheapest, large screwdriver I could find and with a cutting disc made a handy brake spring pulling tool: http://www.asciimation.co.nz/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=6038&g2_serialNumber=1&g2_GALLERYSID=2d07d6c9952a53e8a307578d12833a3e

    I have to drill my cast iron block once it’s back to add an extra stud to hold it to the crankcase.


  3. bsaa7500 says:

    Have you seen this website they can supply imperial sized core plugs…..

    • Thanks for that – the core plugs are actually metric rather than imperial. Why? I haven’t a clue.

      • Doug Gordon says:

        I guess it’s because it’s an early MORRIS engine. Like MGs – mostly metric threads with a few BSF mixed in. Lord Nuffield bought the French Hotchkiss company along with all their tooling. Therein lies your answer, methinks. He got everything CHEAP and stuck metric threads in a lot of Morris and Wolseley engines. Probably had a lot of other metric tooling as well.

  4. bsaa7500 says:

    That company also does metric I think. I need some for the Stude lump and it beats having to order from the USA

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