Friday, 12 August 2011

End of the strip down - its all build up from here.

Having managed to arrive at a bare engine block, I finished the strip down by removing the gudgeon (wrist) pins from the original pistons in order to recover the original connecting rods. The pins are a press fit, but fortunately I have access to a 50 tonne press at work which made light work of the job requiring a measly 5 tonne to push them out. The next job was to get the parts over to the machinist, so with a borrowed van, I hauled the block, crank shaft and con rods from the original engine along with new pistons, piston rings, bearings (main and connecting rod), flywheel, clutch, damper and timing set to Rob Walker Engineering near Oxford. This company comes highly recommended from a few guys in the office, so I knew it would be worth the effort. The machining list was quite comprehensive:
  • Deck the block to zero clearance (increases the compression ratio to improve power output)
  • Bore out and hone the cylinders to the new (oversize) pistons
  • Grind the crank journals to the next under size diameter
  • Weight match the pistons
  • Weight match the connecting rods
  • Dynamically balance the rotating assembly
  • Install the con-rods onto the new pistons
Two weeks later I was on my way back to collect everything and the quality of the machining work was excellent - the recommendations were well placed. Since it was a bare (and now substantially oil-free) iron block, I proceeded to de-grease the outer raw surfaces then treat them with ‘Metal Ready’ as used on the suspension parts. This serves to both neutralise any remaining rust and provide a Zinc Phosphate coat to which the top coat can adhere well. The last stage was to apply the Ford Blue engine enamel - this is not an original colour for this engine nor the installation in the Cobra, but I liked it!

From here, I need to continue to collect together the parts to rebuild the engine. Matching the camshaft, rocker ratio and cylinder heads will be key to get the most out of the package and I believe I am homing in on a combination that should work well together. Only time (and the dyno) will tell!

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