Rebuilding the Engine

I decided to rebuild the engine so I would not have any worries about its reliability. I brought it home in the back of a small hatchback so that I could work on it in more comfort. However, progress was slow and an opportunity arose to buy a newly rebuilt engine at a very reasonable price, so I collected this in June 2012. Here it is sitting on the garage floor before I collected it. It is now safely in my garage at home and awaits installation in the back of the Variant.

The story of the original engine rebuild continues below.


This is the car I was using as a run-about at the time, it was a bit low at the back with the 412 lump and some spares.
The Type 4’s 1800 engine completely fills the hatchback! It’s well packed with cardboard to ensure the boot carpeting isn’t damaged.
Anyone who has a Type 4 will know that the original Haynes Manual for the car only covered the 1700 (1679 cc) models, it didn’t cover the 1800 engine, so anyone with a 412LS will be out of luck. However, the 4-cylinder version of the VW-Porsche 914 produced from 1969 to 1976 used the same engines as the VW412 and then had a 2 litre engine after the 412 ceased production. Haynes also produced a manual for this car, the 914-4, that covered all the engines fitted including the 1800 (1795 cc) twin carburettor engine used in my 412LS. I expect they also produced a manual for the 6-cylinder 914-6 but I never bothered looking for it and both will be long out of print by now. However, in March 2008 I managed to obtain a later reprint of the Haynes Manual that included a five-page supplement with details of the 1800 engine. The detail is pretty sparse and there are no photographs but, nonetheless, worth getting.
The engine and spares on the bench in my garage, there are more on the floor out of sight. The lifting slings are still draped around the engine.
I spent a whole day sorting out the garage and managed to more than double my bench space. The worktops now extend down the whole side of the garage and everything is now off the floor. I also installed an extra couple of strip lights so that I can see what I’m up to.
The engine stripped down as far as I could get without splitting the crankcase – which was firmly stuck after 30 years. I couldn’t split the crankcase without the special tool I bought from VW Heritge.
This shows the tool installed in the aperture for the oil pump. It’s very simple but very effective. Now all I have to do is to tighten up the silver coloured nut in the middle.
When the case didn’t split easily, I realised that there had to be some more studs still not undone. After looking again, I found three more tucked away on the left hand side. After undoing those, the case opened up nicely like this. But I have to remove the pistons before I can go any further, they won’t go through the openings in the crankcase.
Here are the two halves opened up with the crankshaft and camshaft still in place in the left-hand half.
I had decided to replace all the bearings “just in case” to give me peace of mind about the engine’s reliability. Here I have drawn off the two gear wheels for the camshaft and the distributor from the back end of the crankshaft so that I can replace the end bearing. The connecting rods are still in place.

My next job was to clean the outside of the crankcase thoroughly, it was well coated with a hard-baked layer of oil and dust which took some shifting. My initial attack with a proprietary cleaner followed by a pressure washer didn’t shift it all so I needed something stronger to shift the rest. I tried brushing on some petrol which seemed to do the trick. It managed to penetrate the baked gunge but needed several applications and a stiff brush to shift it.

I also needed to clean my bench before I started reassembling things to avoid contamination.

Replacing the big-end bearings was straight forward but getting the camshaft gear drive wheel back on proved tricky. The book says, quite glibly, to heat the gear up to 85°C and then press it back onto the shaft. So I placed the gear into a saucepan of water which I brought to the boil for a couple of minutes and tried placing it over the shaft. It was clearly not going to work and I didn’t want it to get stuck half-way on. My eventual solution was to find a short off-cut of scaffold tube and very carefully dress the end square, to act as a drift. I then put the gear back on at a fast boil for half an hour to ensure it was thoroughly heated through. After liberally coating the shaft in engine oil and carefully lining everything up again, the gear slipped on beautifully. I then applied more engine oil to the gear itself and was confident that the residual heat would ensure that any remaining moisture would be driven out without leaving any corrosion.

I then replaced the remaining bearings, placed the crankshaft and camshaft in correct mesh, and reassembled the two halves. Following the book’s advice, I checked for free rotation before fully tightening up and was most dischuffed to find that it was binding. It’s a good job that I did check as I found that the centre shell bearings weren’t seated properly. After a couple of attempts, all was well and I torqued up the crankcase progressivly, checking the crankshaft’s rotation as I went.

I was left wondering how VW managed to assemble everything in the factory, I found it quite a juggling act to stop things falling out when lining up the crankcase halves on the long studs!

 To be continued . . .