Author Topic: McDonald Imperial Super Diesel  (Read 11165 times)

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #120 on: 20 September, 2020, 04:23:52 pm »
And the winner is.....cobbadog! I got the bastard!
There was definitely 2 different issues, the bore for what ever reason was undersized at the bottom end and believe or not there was a bump on the piston skirt. So with a long time honing, washing it out and then checking it was time to go to the lathe.
As suggested I set it up using the dial indicator and this time with the piston top in the chuck and at that point it ran true. As I went down the skirt things were good but then I rotated the chuck and presto a lump on the skirt. So no amount of honing would fix this issue and would make the bore completely the wrong size if I didn't machine the piston. So yes something must have been dropped onto it and caused this problem. Now I have the same clearance top and bottom and that is 0.010".
In the pics you can see the hone in position ready to have the drill connected to it which is a socket on an extension with a slot to engage the small lugs to drive it around. Liberal amounts of kero was used and it certainly hooked into cleaning things up and it works far better than the spring loaded hones.
You can see the high spot on the skirt and as I took 0.01mm off at a time it slowly progressed towards the oil ring land then from there up all was good.
A picture of the Australian made Somers brand rigid hone.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #121 on: 21 September, 2020, 04:32:54 pm »
Got the rings onto the piston and gapped them using the cut off wheel of my grinder. (that will be a talking point).
Fitted the piston then the crank into place and connected the big end to the conrod and then to the crank. Made a new gasket out of 1.5mm paper for the side cover that houses the other crank main, fitted a new oil seal and then put the cover on and tightened it. The rings a have a good hold of the bore but once I have it moving I can move it with a struggle by turning the crank by hand. Once the flywheels are on it will be a lot easier.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #122 on: 01 October, 2020, 04:08:26 pm »
Well I now have the valves fitted and made the new colletts to hold the caps in place. You can see one of the original "C" clips that came with the engine, I much prefer mine. New valves worked out well and are a good fit into the new guides.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #123 on: 01 October, 2020, 04:21:38 pm »
Next I started to assemble the driven gears for behind the side cover. First the new speedi-sleeve had to come off using a chisel, BUGGER!
Then slid the crankshaft driven gear in place being carefull to fit it onto the correct key, there is 2 there and I have no idea why. Then fit the cam gear and bolt the shaft to the engine case which is an odd thing but it works. Then came time to fit the governor gear and could not find the woodruff key so I will pick one up in town tomorrow and then installed the cam follower. Now if I was thinking straight I would fit the cam follower first then the cam gear but not me, I have to make it bloody hard for myself. Finally a pic of the old and new speedi-sleeve which wont be fitted until later. I also made a flat sheet metal section to hold the governor gear from sliding off the shaft. I never saw a washer or a bolt here when I stripped it but there is one now. The head of the small 1/4" Whitworth bolt just sits inside the width of the cam gear.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #124 on: 03 October, 2020, 04:47:55 pm »
today was a day of just cruising through the little jobs that end up achieving a lot. I got the governor gear on and bolted in place with my new design flat washer and bog standard 1/4" Whitworth bolt and loctite. Next was the head gasket. I forgot I had some manifold gasket type paper given to me and it has the metal sandwiched between the paper top and bottom. I fitted the 5/8" ID "O" rings that were 1/8" thick and gave them a coating of STAG jointing paste to ensure a good seal. Sprayed the gasket with a copper head gasket spray top and bottom and fitted the head and that rocker assembly and pulled up the 4 head bolts.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #125 on: 03 October, 2020, 04:50:25 pm »
Next it was time fit the rocker gear and also put 1 flywheel on and use the old keyway to align the slot so when the new Gib key is ready I can throw it in place.
Cheers, John & Dee. Coopernook. NSW.

Grasshopper

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Re: McDonald Imperial Super Diesel
« Reply #126 on: 03 October, 2020, 09:44:00 pm »
Light at the end of the tunnel John,
A long tunnel nearing success with your McDonald.
Been a long journey.
Grasshopper Max

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #127 on: 04 October, 2020, 04:43:31 pm »
Probably a bloody train coming and not the light.
Today I went and tried out a milling machine for the first time ever. Well it is a drilling / milling machine. Didn't take long to work out left, right and down. How to zero it all without the Digital Read Out connected and away I went. So the end result was these are now very close to the final size required and will be finished off using 'blue'  and draw filling and a lot of trial fits.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #128 on: 14 October, 2020, 03:49:05 pm »
I think that train I mentioned is on its way.
Today I went back and visited the injector, took it apart again and double checked the injector needle and made sure it seats and seals off properly. Then I took the plunger out of the top section, cleaned it up, put new gland packing in and put what looks like a nut back on the end along with the heavy spring using a new roll pin.
Then when I assembled the injector I tried to push down on the round piece on the top of the plunger needle and it wont move down or up. As I screw the top section into place initially there is movement and I can feel the small spring under the needle move up and down but as I screw the top section in more then there is no more movement.
OR am I doing this back to front and I should be lifting that round section to open the needle?
Cheers, John & Dee. Coopernook. NSW.

asw120

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Re: McDonald Imperial Super Diesel
« Reply #129 on: 14 October, 2020, 04:47:23 pm »
Yes, the needle is lifted up to admit fuel.
The spring is quite strong, as it has to resist combustion pressure.

Jarrod.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #130 on: 15 October, 2020, 04:13:54 pm »
Cheers Jarrod, I tested that today and it works in that direction so I haven't stuffed that up.

They only need repacking if they leak. When I looked inside mine there was 3/5th of F.A. left of what looked like string made from leather and crumbled in my hands. The hand book states to use the graphite string packing and I could not find any that I thought I had left so I bought the teflon one and will use it. If it leaks I will source the graphite one and it is not hard to get to and fix.
I stuck the injector in place and connected the governor linkage which is a trick to do with the other lever that goes across to the push rod and I have tightened the injector in place.
In the hand book it mentions to have 1/32" clearance between the linkage and the injector.
Is this done by loosening the little arm from the governor rod that runs through the hopper?
If so at what position should the (speed control) hand wheel be? With the tension all the way off the flywheel governor inside the crankcase?
Sorry for all the questions but the hand book is not clear on that part.
Cheers, John & Dee. Coopernook. NSW.

asw120

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Re: McDonald Imperial Super Diesel
« Reply #131 on: 15 October, 2020, 11:03:43 pm »
The only adjustment I'm aware of is to move the double offset lever adjusting bolt. From memory, the pushrod comes out a bit for a while. I think this is where I adjusted it, I'll have to check. This is before the pushrod opens the exhaust valve.
If that didn't make sense, let me have a look tomorrow. I can ring you then.

Jarrod.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #132 on: 16 October, 2020, 04:16:30 pm »
CONFUSED here mate.
Will wait until further notice. At the moment between Lorry and this I am chasing my tail to get things done. But today I drilled the hole in my bullet proof fuel tank and fitted the fuel tap and then bolted the belt pulley on and that completes that side.

I am still looking at my valve timing and need confirmation if I have my gears in the correct alignment. I think they are right but not certain. With the marks on both gears in alignment and the piston is at TDC the highest lobe on the cam gear is pointing to 12 o'clock. Now the marks on the cam gear are ones I put there before taking it apart as there are no other marks on the gear.

I noticed the second keyway on the crankshaft gear but that has been explained and there is no timing mark for that position anyway.

Do you remember or have any pics of yours if you were this far inside your engine?
Cheers, John & Dee. Coopernook. NSW.

asw120

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Re: McDonald Imperial Super Diesel
« Reply #133 on: 16 October, 2020, 07:13:24 pm »
I've never been in there, so couldn't say.
The spring on the pushrod should hold it against the cam. Fully depressed is injection time. Wherever the pushrod is on the compression stroke, you can measure clearance between the injector knob and the lifting lever. If you have a dial and mag base, you could measure the full lift, which occurs throughout the intake stroke.
I sit here now, watching it cover everything in the McDonald measles. After re-ringing it, it's no better. Having said that, I haven't put proper oil in it yet, just multigrade that was at hand.

Jarrod.

cobbadog

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Re: McDonald Imperial Super Diesel
« Reply #134 on: 16 October, 2020, 09:15:13 pm »
Cheers Jarrod,
Yes I do have a mag base dial indicator so will drag it out and see if I can work it out.
I sort of get the idea but not fully as yet. I will connect the arm that goes from the injector body to the main push rod which hasn't been done as yet and then with that connected and a few rotations of the flywheel watching things the penny may drop.
I laughed when I read you have McDonald Measles as I knew exactly what you meant. At least I have some diesel oil here for Lorry so I will use it if it is suitable.
Cheers, John & Dee. Coopernook. NSW.