So I set about renovating each piston in turn being careful to keep the same piston with the same barrel. With the old piston rings removed, I could clean and polish the pistons and clean out any carbon from the piston ring grooves and then fit the new rings and clean and paint the barrels with "cylinder black".
As you can see from the picture this process produced quite an improvement. What was unusual for me was the bottom piston ring. As I mentioned, I haven't built a VW engine since the 1960's and was expecting a normal "oil scraper" type bottom ring. This one was different. It has a thin bottom ring, about 1mm thick, then a concertina type metal spring and then another thin top ring, all fitting in the same bottom ring groove in the piston. These were not easy to assemble but with a little perseverance I succeeded.
Next was to fit the four renovated pistons onto the conrods on the engine. Just a simple matter of tapping the Gudeon pin through the little end bearing and fitting the two circlips. Then the hard bit, fitting the barrels. Now I have got a set of motorcycle piston ring clamps, so I thought that I would try one of those. Well that wasn't too successful, as the largest clamp was still a bit too small. So I now had the choice of either making a ring clamp or trying to do it the hard way. Don't ask me why, but I decided on the second option and slid the barrel over the top of the piston and then squeezed the rings together, one at a time with a screwdriver levered against the studs.
Well that worked OK until I got to the new oil ring. This ring, being in three parts would not squeeze together. So, and I don't recommend this, I decided to take advantage of the taper on the inside bottom of the barrel and try gently knocking the barrel over the bottom ring with a rubber hammer. To my total surprise it worked perfectly with no damage on all four pistons.
Now it's time to look at the cylinder heads. These have also been aqua-blasted and are beautifully clean. So it was just a case of cleaning up the old valves, which again show no sign of wear, and then the slow and laborious job of grinding them into the valve seats. I cleaned the carbon off the valves with a rotary wire brush and the ground each one into its seat carefully and with the exception of one valve, that took much longer than the others, they all seated beautifully. So then it was just a case of cleaning up the valve springs and rockers and the fitting the springs, caps and collets to the valve stems.
So with the heads assembled I could now fit them. I looked in my box of new gaskets for the copper rings that I used to fit between the heads and the barrels and found none!. So I rang VW Heritage and was informed that later models have no cylinder head gaskets. Again my knowledge from the sixties was not up to date enough. So with that knowledge, I now carefully inspected the mating surfaces to ensure that they were clean and flat before offering the heads onto the barrels. Just before starting to fit the heads I remembered to fit the two heat deflector plates under the cylinder barrels. These just clip in, but must be fitted before the pushrod tubes.
Fitting the heads is not quite as strait forward as it may seem, because at the same time you have to trap 4 pushrod tubes between the head and the crankcase. The way to achieve this is to slide the head onto the studs and then take 4 new pushrod tubes, fitted with new seals at both ends and trap them between the head and the crankcase by passing a push rod through the head and tube and into the cam follower in the crank case, so that the tube cannot drop out. I should mention that when I was building engines in the 1960's, it was always good practise to stretch the ends of the tubes a little before fitting them. This allowed the head to squash them up again as you tighten then head down, giving a better seal.
Now the heads could be tightened down, in a "criss-cross" pattern to the correct torque and they are on. Although I still must admit that I am uncomfortable with the knowledge that there are no cylinder head gaskets. Finally the rockers could be located onto the pushrods and the then, after fitting the new bottom pulley and the first bit of tinware behind it, I could rotate the engine with a socket on the pulley nut and see that all of the valves opened and closed correctly.
You will notice that the first bit of tin-ware is chromed. I was originally going to renovate the old tin-ware and paint it. But it was in such a badly corroded condition and the cost cost of new chrome tin ware was so cheap, that I decided to replace it. I should say at this point, that if you are contemplating doing the same, then the new tin-ware needs considerable modification and it is not for the faint-hearted. As you will discover later in the blog.
The next two things to look at were the fuel pump and distributor. The original fuel pump worked fine but looked terrible and needed renovation. So I set about stripping it and cleaning each part separately and the polishing each part. The difference was amazing. I then set about the distributor and cleaned and polished that too.
With both of them now fit for the engine I could attempt the fitting of them. The distributor first. This involves fitting the distributor drive gear shaft first. This is a "worm-gear" and fits down the hole that the distributor fits in, and mates with the brass gear on the crankshaft. First it is necessary to feed two steel thrust washers down the hole for the drive gear to sit on. If you don't do this then the gear will wear into the aluminium casing. So I opened my "bit draw" and took out the distributor drive and then looked for the two thrust washers. There was only one! Despite very lengthy searching, a second thrust washer was nowhere to be found. So I checked on the Internet to see if later engines only had one. But the answer came back every time "there must be two". So I got onto VW Heritage and they sold them in pairs (No surprise there) so I ordered two and now have a spare one.
The trick now is to insert the two thrust washers without dropping them into the engine. This is achieved by putting a little grease on them and then sliding them down a long screwdriver into position. Once they were sitting safely on the shelf deep inside the engine, I could slide in the distributor drive shaft. This has a small "D" and a large "D" on the top and the small "D" must go towards the crankshaft pulley. So standing in front of the pulley, You offer the shaft slightly turned to the left so that as it engages with the gear on the crankshaft, the inter meshing gears turn the shaft until the small "D" is in the right position. A small spring then goes into a hole on the top of the distributor shaft and the newly polished distributor, with new points, rotor arm and cap pushes in on top of the spring.
Now for the fuel pump. Firstly I cleaned up and fitted the Bakelite pump flange with new gaskets, top and bottom. Then the pump push rod can be dropped in the centre hole (point first). This engages onto a cam that is part of the distributor drive shaft. Then finally the nice clean fuel pump.
The next two bits were easy. I popped on the new Oil Filler and breather pipe and pushed in the new Dip Stick. But I should have read the manual on the next bit.
I decided it would be a good idea to fit the Oil Cooler Support casting. Not knowing that, if you do, you can't fit the oil cooler later. So, not knowing any better, I found the two rubber seals that fit under it and fastened the Oil Cooler support casting down with the three fixing nuts and washers.
Once fitted, I turned my attention to the new tin-ware and decided to fit the two new cylinder top covers. These simply drop on and are fixed in place by two screws on each side that fix the cover to the cylinder head either side of the inlet ports.
It was now time to discover the first of many problems with the new tin-ware. I took a look at the new "Fan Housing" and compared it with the old one. The old one had thermostatically controlled flaps inside that control the flow of air over the cylinders. The new fan housing had nothing. Furthermore it had no provision for these flaps. I read on the Internet that these flaps are essential and so decided that I would have to fit the old ones into the new housing. This meant measuring exactly where they fit and then cutting slots in the new fan housing to accommodate the linkage that works the flaps.
So first I had to find a way of positioning them in the new fan housing. This is difficult because they have an actuating lever that runs between the two sets, so they have to be exactly the correct distance apart and they also have to be positioned so that the rod that drops through the 1&2 cylinder head lines up so that it can connect to the thermostat and with no straight edges to measure from, this required the making of cardboard templates so that I could drill the fixing holes in exactly the correct position.
Once the I had managed to mount the two sets of flaps and checked that the external actuating rod still reached between them, I then had to renovate the flaps and all their working parts. This picture shows the 3&4 cylinder flaps done and the 1&2 cylinder flaps awaiting attention. You can also spot the actuating rod on the 1&2 flaps that drops through the fins of the cylinder head and connects to the thermostat.
So now I could look at the generator and fan and like almost everything on this engine, they were in good working order but filthy. So I stripped off the old tin-ware and renovated everything except the outer fan plate, which I replaced with a new chrome one.
The fan was particularly difficult to clean and I worked my way thought about 10 small rotary wire brushes for my Dremel before I was happy with it.
So now with the fan and generator reassembled I could fit them in the fan housing and try them in place.
Two more problems soon became apparent. Firstly, the cylinder covers seemed to stand away from the fan housing by about 5mm on each side. Secondly, I happened to be looking at the old cylinder covers and noticed some air deflector vanes inside the old covers just between the spark plug holes. A quick search on the Internet revealed that these were additions added to later engines to stop overheating in this area. I didn't remember seeing them on the new covers. There was only one thing to do, strip it again. Sure enough there were no such vanes in the new tin-ware. Obviously, I couldn't just buy the vanes as they are a welded on part of the cylinder covers. So there was only one thing I could do, I used a small cutting disc on the Dremel and slowly ground away the spot welds on the old covers and then drilled and pop-riveted them back onto the new covers. Then, of course I had to rebuild it again.
Just before rebuilding it I decided to fit the oil cooler, except it will not go on as there is insufficient space between the back of the crankcase and the mounting studs to get it in. I should have fitted it to the oil cooler mount casting before fitting the casting to the crankcase. I didn't want to remove the casting again because I didn't want to disturb the rubber seals so I removed the studs instead, passed them through the oil cooler and then put them back in and it worked a treat. So here you can see the back of the fan housing showing the connecting linkage on the thermostat flaps in place and the fan housing now covering the oil cooler.
I was reading about the oil cooler on the Internet and discovered that there was a small metal plate that fits around the base of the oil cooler to stop air escaping before it passes through it. I'd missed that and had to find the offending plate in a draw, strip it down again, fit the plate and then put it all back together again.
Finally the old heat exchange boxes were inspected and found to be unserviceable. So I ordered new ones and a new sports exhaust. So I decided to do a "dry build" and slip them in place to see how they fit. No surprise, they didn't! Once again the new tin-ware stopped them fitting and I had to remove everything again and cut 4mm off the cylinder covers where they touch the crankcase, to enable them to slide on further and allow the exhaust flanges to line up. One final adjustment. As I was, by now, very nervous or anything that touches the new tin-ware, I decided to try the two inlet manifolds, for my new twin carburettors, in place. As expected they didn't fit and I had to linish the sides of the manifolds to get them to fit through the hole provided in the tin-ware.
But there it is. Much more to do yet but it is beginning to look like an engine.
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Copyright 05.11.17 all rights reserved.
My Other Blogs:
BSA A10 Super Rocket
Ariel Arrow Restoration: http://60sclassicmotorbikes.blogspot.co.uk/2014/01/1961-aerial-golden-arrow-restoration.html
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