Having hung the engine block in place on the top mounting stainless steel stud fitted with dome nuts, I used the remaining pieces of threaded stud to support the back of the engine in the frame whilst I waited for the proper engine mounting bolts to come back from the chromers.
Rebuilding the engine could now commence and first was the renovated exchange crankshaft form Draganfly. This fits into the block in two pieces. However, before you can fit it, you first need to fit the central main bearing and the two "back to back" crankshaft oil seals. At first glance this looked easy. Simply knock them in! But I soon realised that I could not get a hammer deep inside the engine casing and so had to devise an alternative method.
The answer was that I had to turn a steel mandrel, just slightly smaller than the bearing with a central boss to pass through the centre hole of the bearing. I then made a long drift with a shoulder on the end to fit in the mandrel's hole that was long enough to stick out of the engine casing so that I could hit it with a hammer. This was time consuming but well worth it and the drift and mandrel worked perfectly for both the bearing and the two oil seals, which by the way, both fit on the right side of the engine.
Now the crankshaft could be offered in.
The left hand half goes in first and you need to extend the con rod out as far as it will go from the crankshaft and then hook it into the casing allowing the con rod to go up into the cylinder space, while easing the centre spindle into the main bearing.
Once in place, the right half of the crankshaft goes in from the other side, repeating the process. This is made slightly more difficult as there is a locating ridge on the right crank to make sure it locates in the right orientation with the left crank. The two halves then push together on a taper and a central bolt, down the middle of the crankshaft tightens to pull the two halves solidly together. This central bolt has an Allen key head and is deep inside the crankshaft.
You will recall from a previous blog that I had already bought a suitable Allen key for this job, to enable me to strip the crank, however it became obvious that I couldn't use a right-angle Allen key on my torque wrench to ensure that this essential bolt was the correct tightness. So I had to get another long Allen key and saw the bend off it. (Sawing an Allen key is not easy, it's very hard!). That done I could now fit a socket over the end of the straight Allen key and use my torque wrench on the socket. Done! It fits and rotates smoothly.
Now for the end caps. Fitted with new bearings and oil seals, I started with the left end cap. These end caps have to go in a particular way round, as they have a cutout on the back to clear the piston as it goes down into the crank case. A generous helping of blue sealant, on both sides of the gasket and the left end cap was gently knocked into place. It was whilst securing the end cap with it's six fixings that I discovered another problem. You will recall that in my earlier blog, I mentioned that the primary chain tensioner lug appeared to have been welded on. Well it was now obvious that I could not get a good fixing bolt into the hole adjacent to the lug as the welding was too large and offered no flat surface for the bolt head to seat on. When I stripped the engine it had a small Philips screw in the hole and I had thought that I would replace it with a proper bolt when I did the rebuild. Now I could see that this was not so straight forward. The answer came with my trusty Dremel. I carefully ground away excess weld with the Dremel until a good open and flat surface was clear enough for the bolt head, I then ran an 8mm tap through the hole to cut a new thread and finally fitted a new stainless Allen key button headed bolt and it tightened down perfectly.
Now for the right side. Same procedure, new bearing, oil seal and gasket. I don't really know what went wrong with this procedure, but as you can see from the picture, once the right end cap was tightened down, it was obvious that the gasket had split around one of the fixing bolts. There was nothing for it but to strip it again as I could not chance losing crankcase compression. Once the cap had been removed again I could see that the gasket was broken and, as I didn't have another one, I had to order it and wait. But eventually it came And the new gasket, fitted in exactly the same way, did not split.
The new pistons could now be fitted to the con rods and then it was time to fit the cast iron cylinders. I'd already had a similar problem when I rebuilt my BSA A10, so I was expecting that I would probably have to make a piston ring compressor in order to get the barrels to fit, and I was right. It's not too difficult, just a thin aluminium strip bent around the piston with a clamping bolt to tighten it just enough to compress the rings, without gripping the piston. That in place, the cylinders slipped over the pistons, with new gaskets underneath and the heads could now be fitted with new gaskets and torqued down with the newly chromed cylinder head bolts and washers. A quick turn of the crankshaft, to see that everything still moves smoothly and two old spark plugs screwed into the holes just to stop anything accidentally being dropped inside. Lovely!
Copyright K. Hopcroft 21.02.15 All rights reserved
You can contact me on: hopcroftscoot@gmail.com
My Other Blogs:
My Other Blogs:
1961 BSA A10 Super Rocket Motorcycle:
https://60sclassicmotorbikes.blogspot.co.uk/2012/07/before.html
Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html
1971 VW Karmann Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html
Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html
Rebuilding the engine could now commence and first was the renovated exchange crankshaft form Draganfly. This fits into the block in two pieces. However, before you can fit it, you first need to fit the central main bearing and the two "back to back" crankshaft oil seals. At first glance this looked easy. Simply knock them in! But I soon realised that I could not get a hammer deep inside the engine casing and so had to devise an alternative method.
The answer was that I had to turn a steel mandrel, just slightly smaller than the bearing with a central boss to pass through the centre hole of the bearing. I then made a long drift with a shoulder on the end to fit in the mandrel's hole that was long enough to stick out of the engine casing so that I could hit it with a hammer. This was time consuming but well worth it and the drift and mandrel worked perfectly for both the bearing and the two oil seals, which by the way, both fit on the right side of the engine.
Now the crankshaft could be offered in. The left hand half goes in first and you need to extend the con rod out as far as it will go from the crankshaft and then hook it into the casing allowing the con rod to go up into the cylinder space, while easing the centre spindle into the main bearing.
Once in place, the right half of the crankshaft goes in from the other side, repeating the process. This is made slightly more difficult as there is a locating ridge on the right crank to make sure it locates in the right orientation with the left crank. The two halves then push together on a taper and a central bolt, down the middle of the crankshaft tightens to pull the two halves solidly together. This central bolt has an Allen key head and is deep inside the crankshaft.
You will recall from a previous blog that I had already bought a suitable Allen key for this job, to enable me to strip the crank, however it became obvious that I couldn't use a right-angle Allen key on my torque wrench to ensure that this essential bolt was the correct tightness. So I had to get another long Allen key and saw the bend off it. (Sawing an Allen key is not easy, it's very hard!). That done I could now fit a socket over the end of the straight Allen key and use my torque wrench on the socket. Done! It fits and rotates smoothly.
Now for the end caps. Fitted with new bearings and oil seals, I started with the left end cap. These end caps have to go in a particular way round, as they have a cutout on the back to clear the piston as it goes down into the crank case. A generous helping of blue sealant, on both sides of the gasket and the left end cap was gently knocked into place. It was whilst securing the end cap with it's six fixings that I discovered another problem. You will recall that in my earlier blog, I mentioned that the primary chain tensioner lug appeared to have been welded on. Well it was now obvious that I could not get a good fixing bolt into the hole adjacent to the lug as the welding was too large and offered no flat surface for the bolt head to seat on. When I stripped the engine it had a small Philips screw in the hole and I had thought that I would replace it with a proper bolt when I did the rebuild. Now I could see that this was not so straight forward. The answer came with my trusty Dremel. I carefully ground away excess weld with the Dremel until a good open and flat surface was clear enough for the bolt head, I then ran an 8mm tap through the hole to cut a new thread and finally fitted a new stainless Allen key button headed bolt and it tightened down perfectly.
Now for the right side. Same procedure, new bearing, oil seal and gasket. I don't really know what went wrong with this procedure, but as you can see from the picture, once the right end cap was tightened down, it was obvious that the gasket had split around one of the fixing bolts. There was nothing for it but to strip it again as I could not chance losing crankcase compression. Once the cap had been removed again I could see that the gasket was broken and, as I didn't have another one, I had to order it and wait. But eventually it came And the new gasket, fitted in exactly the same way, did not split.
The new pistons could now be fitted to the con rods and then it was time to fit the cast iron cylinders. I'd already had a similar problem when I rebuilt my BSA A10, so I was expecting that I would probably have to make a piston ring compressor in order to get the barrels to fit, and I was right. It's not too difficult, just a thin aluminium strip bent around the piston with a clamping bolt to tighten it just enough to compress the rings, without gripping the piston. That in place, the cylinders slipped over the pistons, with new gaskets underneath and the heads could now be fitted with new gaskets and torqued down with the newly chromed cylinder head bolts and washers. A quick turn of the crankshaft, to see that everything still moves smoothly and two old spark plugs screwed into the holes just to stop anything accidentally being dropped inside. Lovely! Copyright K. Hopcroft 21.02.15 All rights reserved
You can contact me on: hopcroftscoot@gmail.com
My Other Blogs:
My Other Blogs:
1961 BSA A10 Super Rocket Motorcycle:
https://60sclassicmotorbikes.blogspot.co.uk/2012/07/before.html
Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html
1971 VW Karmann Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html
Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html
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