McDonald Imperial Super-Diesel

cobbadog wrote: Hi John,
If I did this I may have to remove those 4 head studs and that would be another bloody challenge.

Come on Cobba,

If you didn't like a challenge, you wouldn't be doing this.

Too bloody right Zuffen, I do enjoy it plus I really want this to run again and show oliver1950 that it runs again. I dont have a rigid hone so it looks like when we come back from a short break away with our newer caravan I will be sitting back with a battery drill and a heap of spare batteries and give it what for.

I now have in my pocession and on loan a rigid hone to attack this mongrel. Going away for a few days so when we get back it will be play time again.

The Viets next to my yard at Willawong honed the bores of a Volvo F10 motor with a fencepost wrapped in cheap flea market sandpaper......funny thing was ,there was not much wrong with the motor ,trouble was a rubber mounted fan hub that was chopped out ,and the fan was spinning .

F10's had a thermo fan and while they do expire lots of people wrongly assume they have failed because they can turn the fan and then lock them up, wasting up to 5hp.

Still enjoying some 'away time' in our latest aquisition a Jayco Freedom pop top. After all the work I did to it prior to this trip I find that the town mains tap at the sink was tuffed. Typical of spare parts places. no tap washer available or an "O" ring but bought a new tap assembly with a ceramic washer in it for $30.00, I can only assume it is a genuine Chinese model but what the heck it works and I will buy an "O" ring when I get home and will turn down a 1/2" tap washer to being 1/4" and throw it in the boot of the van.
Back to the fun times at home soon.

We were away last weekend in our van after having a new fridge element fitted. The fridge worked brilliantly but we had an unidentified problem with the lights!? Nothing like reading a book by the light of torch/phone/tablet!! Stupid part was the fridge, toaster, microwave were fine.

When we packed up the last thing I did was take the power cord out and when I tried the lights they were working perfectly. Very strange.

Following day, after coming home, I took it back to caravan centre to check - and absolutely nothing wrong that could be found other than battery charger not plugged in fully (not enough to effect it though) and everything working 100% . . . maybe dirty contacts with power cord into van?

You see, I don't just have problems with B for :oops:

We had a great few days away, found a couple of minor issues, the mains pressure tap at the sink was stuffed and repalced for $33.00 with a 1/4 turn ceramic washer tap. For some reason and more investigation will happen our van bettery does not charge from the transformer when running on mains power.

Back to the Mac.
Today I started using the rigid hone and this is a better tool for the job than the spring loaded ones along with nice brand new stones and using kero when in use.
Gave it a short work out and then wiped excess out and still the piston sticks at a certain point, near the bottom of the skirt of the piston. So I went back to thinking if the skirt is out of round. It appears to have high spots on the top and bottom of the skirt as the piston is fitted with oil hole facing up. Measurements from the high to low spots are 3.995" - 3.990" 0.009" out of round. You can see in the pics where the blue has been rubbed and where I have just wiped it on and is not rubbed.
So I put some 'blue on the skirt and placed it inside and it is transferred at the same place top and bottom of the bore.
Also a couple of pics of the bore.
IS that 0.009" enough to give me this clearance problem and how much clearance should there be between piston and bore?

The piston needs to be out of round when cold ....when it heats up ,it will be round (hopefully)...anyway 010 larger at 90deg to the pin is good......Work the hone in the tight spots ,crosshatch all the time ,until the piston has clearance (was .004 right?).Eventually ,the hone should have equal drag when stroked the full length of the bore ,the the bore will be correct......Never rotate the hone without stroking ,you will groove the bore........Whenever the hone is loose ,adjust back to tight ,it should always have a fair bit of drag to turn....Test the clearance with a feeler ,003 would be good for 004 clearance.