My Porsche 911 | The Engine Build

This is the story of the engine build programme. Having spec'd what I wanted from my engine I set about a ground up rebuild. I have used mainly POrsche OEM components. The photo's below show the major engine build stages.

The Engine Case Work started by preparing the engine case halves. The engine case mating surfaces were shuffle pinned with ten stainless steel pins to prevent twisting from the expected increased bhp. The barrel bores were machined out to accomodate the larger diameter Porsche 3.5l Mahle barrels. To keep everything aligned and balanced the the case halves were surface ground and then the main bearing housings bore aligned. Finally the crank case was gas flowed to allow gases on the down stroke to more more easily and help squeaze every little extra hp from the engine.

The Crankshaft The Crankshaft received a complete overhaul too. The crankshaft was checked for straightness, then balanced and polished. Each of the conrods were capped and honed, balanced end over end, fitted with phospherous bronze bushes and reunited with the crankshaft with new bearings and titanium ARP bolts.

Crank and Case Reunited The crank is reunited with the case together with a the oil pump, secondary shaft, new tensioner chains, main bearings and case bolds ready for the closing ceremoney.

Bottom End Complete After countless hours, the bottom end is completed as the case halves are closed. You can see here more clearly that the bores for the barrels have been machined to receive the larger diameter 3.5l barrels and also the chamfered ribs to help with gas flow.

The Heads All the heads received a complete rebuild. All were ultrasonically cleaned, then new valve phosphor bronze guides fitted, new inlet valves, tripple valve seats were re-seated and a second spark plug was drilled and tapped into place. This last part was key as the tandem firing sequence would ignite both plugs at the same time and both balance the pist face load and reduce the advance ignition timing requirement. The surface was also re-ground to ensure a tight gasketless seal with the barrels (They were also hand lapped and matched to each barrel just to make sure the seal was perfect). The valves are held in place with titaniun springs and retainers to cope with the expected higher rev range.

Heads Almost Complete Thead shown here are have been reunited with the cam carriers. The cam carriers were also ultrasonically cleaned and here they have had the Porsche GTII camshafts fitted. The camshaft rockers were also refaced and blanced.

Barrels Heads Here you can see that the barrels and pistons have been assembled onto the engine case and the heads secure to the barrels. The oil return tubes are fitted and thge air cooling baffles which were powder coated have also been fitted.

Onwards and Upwards Now she's really starting to take shape. Here you can see the cam covers have been re-fitted, along with the engine sheet metalwork and the engine mounting brace bar. All these components were powder coated. Also the fan housing strap has been fitted after being newly zinc plated. The cam carrier hopusings are also in place along with new tensioners and chains.

Looking Cool. Here the cooling fan, alternator and cooling shroud are in place. The Shroud has been repainted and the cooling fan has been powdercoated. The alternator fan belt assembly has also been zincplated. The other big addition is the exhaust system. This is a custom made, stainless steel equal length system with twin 4 inch outlets.