McDonald Imperial Super Diesel Crude Oil Engine

[cobbadog]

I am about halfway into the rebuild of this McDonald 2.5HP crude oil / diesel engine. It left the factory in Victoria on 18th May 1945 so it is coming up for its 75 birthday soon. It was donated to me, well a pair of them were, in the hope that one day I would bite the bullet and get one running, that time has come. It uses a Hyvid / Brons fuel injection system which is a tricky bugger on a good day and of which I know next to nothing about as yet. It took close to 4 days of hard yakka to get the flywheels off as the Gib key heads broke off easily and then it was a case of welding a bolt to it and a slide hammer and the other had to be drilled out and then collapsed. So far I have been at this for around a month and a half found the reason for it being pushed into a corner as the roller for the cam seized up and then wore that cam down and that stopped opening the valves enough to make power. I have had the engine for a minimum of 5 -6 years looking for the damaged or missing parts and the biggest issue was the broken injector which I managed to find one.
Other missing parts but promising just recently are an oil primer for pushing oil down through the water hopper to the piston, rings and gudgeon pin. A cap for the crank case lid which I think I can make and a fuel tank again will make. I've ordered a new set of rings, 6 in total for this engine and have been making new gaskets including the head gasket as well.
I will post a couple of pics of this monster, small in size but bloody heavy when assembles as the 2 engines in the box trailer rated at 750kg flattened the springs.
These pics show both engines waiting to be looked at,drilling the Gib key and finally getting one out and the absolute mess inside the gears.

[cobbadog]

Finally today is the unique piston, conrod and big end bearing set up. As you can see you can adjust the compression ration by adding or subtracting the shims. Then a pic of the worn cam gear.

[AdeV]

If it really will run on crude oil, I believe the big oil co's can't give it away at the moment!

[dax021]

Well done Cobba, thanks for starting this thread.  I shall be following with interest.

[cobbadog]

Thanks for the feed back guys. Everything on this engine is heavy and when you go to pick something up you have to be certain that you have a good hold of it. Even the side cover over the gears is solid cast steel and not cast iron so it is that but extra in weight. So far the only light parts are the ones I don't have. All the oil pressure lines were brass tubing as well as the oil primer line but that and one of the high pressure oil lines (all of 7 psi) are now 5/16" copper tube.
Made the ehad gasket today as well. The gasket is a simple ring shaped gasket 1mm thick and fits into a recess in the head and then the top of the bore fits into the recess to seal it off along with 5 "O" rings around the new cooling tubes I fitted into place at the top of the bore. When I can I will put up random pics of the nightmare I started with but we are now slowly getting an understanding that I don't like coming second and this engine will run once again.
My absolute biggest test is yet to come, all of the linkages for the head and injector.

[cobbadog]

Back at the beginning of doing this job I first had to get the engine of choice around to where I was going to work on it. So I winched it onto the carry all of the David Brown 30C Cropmaster, in the background is Lorry our main transport when going to Rallies with our caravan towed behind it. Then there is the good injector that will need stripping and cleaning. The flat belt pulley came off like a dream even though the 3 bolts were badly rusted away and each a different size socket was required to undo them.

[cobbadog]

This is the oil pick up from the bottom of the sump. The original screen was almost non existent so I found some stainless steel 'termi-mesh' used for pest control on houses and soldered it in place. It looks rough but it wont let go.

[cobbadog]

Thanks Glort, I put around a total of 2 years into the D.B and last run was about 6 months of being in a rush. Even this engine when loaded is a counterweight for the steering. When we go to a Rally I usually put the carry all onto which ever tractor is going and an engine on that and a couple of mowers around the truck tray.
I had no choice but to finally replace all the timber on the deck of the carry all as the original had rotted completely. It is 25mm thick hardwood. If I build another one I would use the usual T piece set up for the 3pl pins and use channel iron and some checker plate.
I have done a trial on the engine oil I use in Lorry which is what I will run in this and the oil runs straight through as fast as I can pour it and ambient temps so I dont expect any issues there. Engine also runs at a huge 7psi oil pressure as it only pumps oil to both crank shaft babbit bushes. All other parts are splash fed like the big end and the bottom of the bore and gudgeon pin once running. The gears that drive the oil pump, cam and governor are fed oil by picking it up using the gears and it winds its way up to the top then drips over the roller that follows the cam and operates the push rod to the valve.

[cobbadog]

This is one of the offending gibb keys. Welded a bolt to the gibb key with the head cut off so to use the thread with a nut, then tried using the slide hammer with little result so next was a piece of pipe and try to tighten the nut up. All the time using this oversized "C" burner for the LPG. After the key was out the 3 leg puller was loaded up to pull the flywheel off.
The second pic is of the gibb key that broke off flush with the flywheel and then required many holes to be drilled  through the key to remove as much metal as possible. I actually got a 3/16" hole down the centre and almost full depth when it snapped off. Next was to circle that using 1/8" bit and got four holes and again one snapped off. I kept stepping the small holes up in size until it was either touch the flywheel or the crank shaft then used a home made slotting chisel to dig out the key.

[dax021]

Good one for your perseverence in getting that wheel off.  I would have lost my patience after it broke off like that and taken an 8 lb hammer to the thing

[cobbadog]

lol, that was just one side, the other one was just as bad but with it's own unique problems. I was about to give up on the first one as my back was hurting after being bent over the mongrel for about an hour straight pulling back on the big new slide hammer I bought especially for this job. I thought one more pull and I felt something let go and it did, The gibb key started to come out.

[cobbadog]

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.
The pic at the bottom is the tool I made up to grab hold of the needle that is stuck inside the body. I have been soaking it for a few days in thinners to try to soften the crap up inside but so far no joy.
This injector has a second stage to it that is off at the moment to give me access to this section. The cap is hel on with a screw that is rock solid and the impact driver is not looking at it so far, just twisting the slot only.

[cobbadog]

This is the tool, not me for posting the wrong pic.

[mikenash]

I wonder - since the wheels are cast & the crank is heavy - what would happen if you tried to gas-out a snapped-off gib key?  Apart from it shooting molten crap out at you every time you gave it a puff of oxygen?

[cobbadog]

G'Day Mike, thanks for your interest and question but I have long passed that point and becasue I have been so slack in posting here the story is a light year behind. I have the engine totally stripped down with only the injector to sort out and spare parts to arrive.
In answer to your question I am not sure as I never did buy my plasma cutter and have no oxy set up either. Best guess is that this being cast steel it would blow part of the crankshaft away and possibly part of the flywheel.
The removal of the flywheels took around a total of days worth of hard slog but I won. You can see the sludge that was inside the engine by looking in the side cover and this was nothing compared to what was in the sump.
Rings are being made in N.Z. and will be made and sent as soon as they go back to work. Oil primer pump has been found and will be sent by the end of this month.  Cam gear will be ready to pick up very soon as you will see the wear on the lobe in the pic below.