McDonald Imperial Super-Diesel

I think I need 'injectoring' PDU

To try to remove the bottom needle from the body I made this tool up. It is a piece of 3/8" rod drilled to being undersize to the top of the needle and a slot cut in it. In theory I should be able to lightly tap the tool onto the needle and twist and lift out the stuck needle, hasn't happened yet and the next post will show why.

Started today with the big bunsen burner and got some entertainment out of it as well as this lump of grease like stuff when hot but sets firm when cool. This is part of the problem holding the needle in place.
I did like the flame that came out the bottom but when I turned it arse up and really got into it with the heat it went off like a flame thrower. By the time I got the camera out it had backed off to being this sedate little display. Once it had burnt out I continued to get serious with the heat and then I found the lump of crap that fell out. Once cooled I sat it on top to take the pic.

Did some work on some of the brackets and linkages and mixed and matched the best pieces and used the return spring that was on one of the set of brackets.

Next it was time to experiment. Still having no joy with getting the needle out of the bottom of the good injector I went investigating with the broken one. The bottom part of the injector housing was snapped off and stuck firmly in the cap. I lost many hours and brain cells trying to get inside. Tried many different ways of achieving what it almost too all day to get to.
In the end I knew it was to be the death of a cap but I had to learn something today. So eventually into the drill vice and away I went with the 1/4" drill bit, down deeper and deeper until I felt it go through but it was not the cap. So had a look with the good led light and nothing so I kept going and eventually the bloody housing finally let go and collapsed in and it was out.
It was then I found that I had drilled past the bottom of the housing and into a cavity in the cap. So that was the death of that cap but the good one is still intact as this is all about 'learning' I hope. So with the broken bits out of the way a copper washer gasket also fell out confirming I went way too deep and now left with a cap and a far better idea and a new plan to get this bloody needle out.
I forget what letter of the alphabet I'm up with all the plans I have gone through but lets says I might be learning the Greek Alphabet soon. New plan is to drill a nice neat smallish hole dead centre in the cap and push the needle out from that end then weld the small hole up. Any comments on this would be gratefully appreciated before I jump into the fire.
Pictures below are the old cap and is the sacrificial lamb as an aid to the education of a nutter.

To day I decided while waiting for the electrolysis to hopefully work on the injectors bottom needle I started to make a new pin for the rocker arm to pivot on and add a better oil hole for lube by cutting a groove in the shaft and boring an oil hole halfway down the pin and then cross drilling it. I also reground the end of the rocker arm where it meets the valve stem. Next is the pivoting ball, this will explain itself in the future pics but I may need to make another push rod from the cam follower through the pivot ball to the rocker arm. You will notice the old brazing repair from long ago but this one is better than the other one I have to choose from so this is it.

I'd be tempted to make a new rocker arm from some steel bar: it looks to be within the range of your talents, and straightforward enough. It would while away a few days for you . . . :whistle:

If I thought that it would really need to be replaced I would have a go at it as it is a simple straight forward lump of steel. Problem is there are other parts on this engine with similar "war wounds" and I have become attached to them, so much so that I even had a go at re-surfacing the rocker face where it rubs the valve stem. The old repairs are just that, old, and they have stood some time in operation so will see how it goes. At the end of the day this is going to be a rally engine, come out to play a few times then go back under cover until the next one comes along. Sometimes for me inperfect is perfect :woohoo:

hi,
"Sometimes for me inperfect is perfect"

'zackly, 100% agree, war wounds, genuine, "patina", can't be duplicated, tells its own story.

Well done keep it up, following with interest (is there gonna be a Hot Rod angle?

Ha ha

cya
-b

For today's entertainment I played about and completed, I think, all the linkages, cleaning up the parts and making a special collar to hold the fork from another linkage that operates the injector. I think it is all ready to go together when more parts arrive and try to work out how to adjust it all.