911 2.2S Engine Rebuild – Part 1: Taking The Plunge

Wed 3rd July 2013

Leaving the 911 at Jaz Porsche
Leaving the 911 at Jaz Porsche
It had an engine when I brought it in - honest!
It had an engine when I brought it in – honest!

 

 

 

 

 

 

 

Having had the bodywork and particularly the underside of the car sorted out by Bruce Cooper and his team at Sportwagen it was clear that the next and most expensive priority was the engine.

When purchased in 1997 as a restoration project – my Oct 1970 manufactured 2.2L 911E came with the wrong (and what turnbed out to be badly rebuilt) 2.2L T engine with Zenith carbs.

After much wrangling – the garage that had rebuilt the engine took it back to fix pulled head studs etc. but I decided in the meantime to sell the T engine (once returned) and replace it with a more original and appropriate 2nd hand MFI 2.2S engine that Peter Andrews from Transend found for me.

The logic behind this was that 911 owners often upgraded their cars from new or nearly new – especially their engines so a contemporary 2.2S engine in an 2.2E was still maintaining originality and this was important given the short 2 year life of the 2.2 model before Porsche brought out the long stroke 2.4 engined cars.

Steve Winter at Jaz fitted the 2nd hand engine which came with its Bosch mechanical fuel injection and got it running reasonably well but we never knew the true state of the engine or what mileage it had done.

Once up and running in my car – the 2.2S engine gave me 15 years worth of motoring albeit with a degree of smoke and with some issues along the way with warped magnesium cam covers, knackered throttle bodies etc. which were sorted along the way. At one point Steve also found a very helpful engineer in Belgium to rebuild the phenomenally expensive CD ignition unit that failed on a test drive after he’d carried out a service.

I’m digressing – Steve at Jaz finally gave me the nudge in 2012 to think about an engine rebuild. Having enquired about the likely price I thought about it some more as I had to save up some cash to fund it. Steve in the meantime was tasked with coming up with a plan for the rebuild to deliver a broadly original engine tweaked with period modifications (i.e. re-using as many parts as possible but with recognised factory modifications to improve power, torque and overall driveability).

Steve’s master plan involved the following:-

  1. Strip the engine right down to the bottom end and measure it all up.
  2. Assuming the crankshaft is all ok and doesn’t need a grind, re-assemble it with new upgraded (3.2 Carrera) oil pump + associated crank case modifications, new bearings & shells, new rod bolts and timing chains…
  3. Strip the heads and fit new valve guides, lap the valves, decoke etc. Set the valve spring heights, check cams for wear.
  4. Bore existing Biral (cast iron with aluminium fins) barrels out to 1mm bigger than standard (i.e. bore out from 84mm to 85mm) and fit Omega high compression pistons then set the compression ratio to suit.
  5. Powder coat all the tinware and detail the engine as a matter of course.

This sounded perfect as it effectively took the engine some way towards what the factory did in the early 70’s to build the short stroke 2.3 ST race engines.

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