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Engine

Engine Work Part 4 – Repair

Putting the new bits on.

Having stripped the engine down, the problem parts removed, it was time for the fun part, putting the new bits on and getting the engine back together. With the top dead centre located and the flywheel lock in place I was able to get on and remove pretty much everything I wanted / needed.

Starting at the front of the engine, there were seals for the upper and lower balance shafts, and the crank an cam shafts. I also checked the rollers for the and tensioners for the belts, but they all appeared to be in good order.

Top left and top right of the photos are the upper and lower balance shafts, before I began the work – as you can see they are both looking a little worse for wear. These were a little difficult to remove, despite the poor condition there is a metal ring inside which make them difficult to lever out.

The second photo down, on the right, is the upper balance shaft seal, the new one. It looks very different with the plastic cover and other bits removed. I took advantage of the fact I had easy access and gave the engine a good clean up while I was in there. I used Jizer, an emulsified degreaser. I used a little grease around the new seals when I put them back, to help keep the oil in. The middle left photo shows the new seal on the cam shaft, attached to that is the housing, rotor and distributor cap. Middle middle is the crank shaft, as re-assembly begins.

The photo to the right of the middle are the old and new top hats, from the crank shaft, the old one (left of the two) has a small groove worn into it, this is most likely where the oil was getting out.

The photo at the bottom is the top balance shaft gear. The ‘O’  goes at the top and the mark in the lip should line up with the notch on the plastic cover. There is a similar setup on the lower balance shaft. If these aren’t aligned the balance shafts will be out of alignment and the engine will make a hell of a racket.

There is a slight problem tightening up the balance shaft bolts as they rotate while you’re trying to torque them up. Porsche make a special tool, but frankly it’s frickin’ expensive so I had to be a little inventive to get around the problem. In the gallery below, top left, is my solution – the red bar is from the engine hoist and a couple of long allen head keys to fit into the holes on the gear and hold it while I tighten the bolt.

On the right top and middle, are the balance shaft and seals, old and new. The balance shaft seal fits at the back of the balance shaft. Why it isn’t sealed with the rest of the cover I really can’t imagine. The balance shaft was cleaned up, as was the housing. This needed a Loctite sealant around the edge before being bolted back on. I only needed to reseal the cover on the exhaust side.

On the bottom row, left is the oil cooler having been removed from the engine. I put a bowl underneath to catch the excess oil – that had not already drained off. Naturally I managed to knock the oil cooler into the bowl at one point. The bottom middle photo shows the oil cooler separated, you can just about see on the top where the oil filter screws on. The oil cooler feeds the oil through one chamber and collant through another, to cool the oil! Problems arise when the gaskets give up, which they are inclined to do, this allows the oil and coolant to mix. Externally this shows all the symptoms of a head gasket failure, this is more common.

Putting the oil cooler back requires refitting of the oil pressure release valve, bottom right. The OPRV is the springy looking thing – there is a later version which is a sealed unit. The oil cooler and the head must line up perfectly or the valve can stick. To help line the two parts up Porsche has, yep, another special tool, it’s that sort of bolt looking thing. Simple? Yes. Cheap? No. I think it was about £40, but there isn’t really an alternative.

The oil filler, as it is often referred to, is the oil-air separator, top right photo. When I removed this from the engine I could see that there was a lot of gunk in the bottom, and looking where it connected to the engine, that was pretty well blocked too. The oil-air separator was taken inside to clean up. Every time I thought it was finished I gave it a final flush through and another bunch of gunk fell out. It took ages! As the engine hole was blocked too I thought I’d better remove the oil pan and clean that out too. Top left shows the bottom of the engine, with the sump off, and the oil pickup – someone wasn’t overly careful when removing the oil pan before and had broken the plastic insert, this was replaced and the residue (crap) removed from the inside the oil pan. Putting the oil pan back, I replaced the seal which had been squashed slightly in one corner.

The bottom photo shows the front top of the engine as things are going back on – note the shiny new timing belt! Also, the throttle body, this was spruced up using intake cleaner, I really don’t know what’s in that stuff, but it’ll remove anything. I also took some time to clean up the intake manifold, there’s little practical benefit, but it does look so much better.

The whole job took a lot longer than I expected, given the limited number of parts that I was replacing, I would say that most of the additional time was spent cleaning; there was a lot of oil and the engine wouldn’t fit in the dish washer. Added to this were the problems encountered, detailed in the previous post, and my checking and double checking everything before fitting.

The final point, the photo above shows a new coolant pipe.  The old one had corroded back quite badly, about two inches from the end, the metal from which would have been sloshing around in the coolant system somewhere.

This was a lot of hard work, as much in the prep as anything else, but I got it done. I took some confidence from the fact that I could replace the engine if I needed too, for not too much money, relative to 911 engines and, well, special Porsche tools! If you have an interest in mechanics I would recommend getting stuck in, assuming a replacement can be had for reasonable money.

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