We had a friend at the local Porsche dealer come by and give us another opinion before we tore the engine down. It was a difficult noise to diagnose. He was not sure whether it was a bearing or a broken piston skirt. His best guess was the piston. He was wrong.

We pulled the head first, the cylinders looked great, not a scratch. There was no sign of any cylinder wear what so ever. You could even see some crosshatch remaining in the cylinder wall. With 50k on the clock, that was amazing. It really says a lot for Porsche’s choice of alloys in the cylinder. If the piston skirt was broken, there would be some evidence in the cylinder wall, so off came the exhaust (what a pain in the ass) and the oil pan. We found a lot of material in the oil pan, it didn’t look good. We took the #1 rod cap off, no problem. #2 was a different story though. We were very lucky to catch the bearing before it had done any more damage. Believe it or not, the crank was OK!!!! It had a slight scratch, but upon measuring the journal, it was not worn at all. The rod was a different story though. The rod end was slightly blue, and was worn on the sides, not the diameter. A phone call to Oklahoma Foreign took care of that problem. Owning a body shop and the paint mixing equipment that goes along with it, I used the digital scale and compared the weights of the rods. Porsche definitely does blueprint their engines at the factory. The rods were within .01 grams. Outstanding.

The pistons were in pretty good shape, we sent them to get the tops ceramic coated, and the skirts were Teflon coated as well. The more heat you can keep in the cylinder and out the exhaust to drive the turbo, the better. I was surprised to find the rings had a lot of wear to them. The end gap was twice the maximum factory wear limit. I located a set of them in California and had them red labeled to we could assemble the short block that weekend. We polished the crank and were ready to reassemble the bottom end.

We had sent the oil pan out to Powerhaus to have the baffle system installed that they claim helps to prevent the bearing failure. They also extended the oil pickup slightly too. They did a nice job, but once I realized what they did, if I had it to do all over again, I would definitely do it myself. Nothing fancy about it. The short block went back together very well.

Since we had to pull all the exhaust to get the oil pan off, now was the ideal time to upgrade the Turbocharger. I checked with Powerhaus and Windward. We opted to go with the exchange program that Windward offers. They will replace the compressor housing with a K-27 piece, but leave the exhaust side alone. . This was the less costly of the options we had presented to us. This gives one the flow of a K-27 and still spools up quickly. We even chose to stay with the #6 hot housing since most of the tracks in our area are relatively short (1.8 to 2.9 mile) and we were more concerned about quick boost our of the turns rather that a little more horsepower down the straightaway. Texas World Speedway has 18 turns and only 1 long straight. Topeka has 16 turns and again, 1 long straight. The math was easy.

We spent a little time on the cylinder head too. Powerhaus said they had motors making over 400 HP with the stock camshaft, so we left well enough alone. I heard that the valve springs were another weak area in the engines, so we replaced the set with a new factory set. We found two of the lifters were collapsed so we replaced them. Dave did a port match between the intake and Cylinder head. A local Porsche garage did the cleanup on the valve job and assembled the head for us. It was ready to go back on now.

We didn’t intend to exceed 1 bar boost, so we didn’t bother to change the head studs. Windward sold us the head gasket that was the hot number, it had a wider sealing ring around the cylinder.

One aspect of the engine buildup that got a lot of discussion was the necessity of the counterbalance shafts in the motor. I have seen cars at the track that had removed the belt and had no problems, but the factory trained mechanics at the dealer said it’s a no-no to run the engine without. They are supposed to counter act the weight of the piston as it moves up and down in the cylinder, the larger displacement 4-cylinder engines experience this vibration. The maximum vibration is supposed to be around 3500 rpm, we were told. We decided to go ahead and try running the engine for a while without the belt and see how much vibration was noticeable. There was virtually none.

One thing that most people that advised us not to remove the belt failed to take into account was that this engine is never sitting at a steady RPM, especially not 3500. We have run the engine this way for several events now and have noticed no problems. I would not recommend this for a streetcar, which does sit at a steady RPM while driving. I was told by one service advisor at the dealer that he had noticed more vibration on cars that the belt had been timed wrong then off alltogether.

Another major task we undertook was to remove the AC compressor. That sounds like it should not be that difficult, Wrong. The compressor is the tensioning device for the alternator belt too. We chose to remove the power steering as well, so now was the time to re-engineer both things at one time. We decided to fabricate our own bracket to replace the factory cast piece that held the compressor and alternator. With the power steering removed, there was a v-belt pulley on the front of the balancer that was no longer being used. Hmm. Another call to Oklahoma Foriegnlocated an early 924 alternator that used a v-belt. A little custom work on the aluminum mount and we had the alternator mounted and we used the tensioning rod that the AC compressor had used to tighten it up. Another thing that was beneficial was that the pulley diameters on the crank and the alternator were such that we ended up underdriving the alternator. Great!! Most people spend a lot of money buying special pulleys to underdrive the alternator, these did the job as they stood. There is no reason to take to horsepower that a 100 amp alternator draws when you have nothing left in the car electrical except the engine controls, cooling fans and brake lights. The 924 alternator was a 55 amp unit and so far has done the job as required.

The final addition to the engine to help prevent further bearing failure was a larger oil cooler. There were a couple of expensive aftermarket pieces available, but as you can imagine by now, that was not going to be the case here, again. A phone call to a friend at a Mercedes garage turned up a large diesel oil cooler from an early 80’s 116 body. This unit had almost three times the surface area of the stock cooler. Since we have the fiberglass bumper and space was not a concern, we fabricated the lines and mounted the cooler. We made sure that the cooler came off of a running car. The last thing we wanted to do was to end up with debris from a contaminated cooler causing damage to our engine. We had the cooler flushed out and we were ready to go.