Another thing to check for is gudgeon pin wear. On an Essex, the pin is a press/interference fit in the conrod, so the wear is on the piston and pin, not the rod. This often gets overlooked when rebuilding after a cursory inspection.
As with all cast iron blocks, the main bearing housings were line-bored with the caps in place, but due to the poor quality of many block castings it was often necessary to bore the housings 0.015 inches oversize. Such blocks must be fitted with main bearing caps having a plus 0.015 inch outside diameter. Measure the block before ordering bearings.
It's also been known to find oversize pistons in a supposedly never-been-opened motor. You can see different graded pistons occasionally, because the blocks were sometimes poorly machined. Unless you're going for new caps and a line bore, the main bearing caps have to go back on in their original position, as they're machined on the engine.
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Tuning the Essex V6
Tuning the Essex V6
Crankshaft, Main Caps and Conecting Rods
The Essex, bless its big old crank, suffers from big end overheating and subsequent wear. So, to cut this down as much as possible, Martin recommends grinding the crankshaft to the bottom end of the tolerance, which allows more clearance for oil.The minimum and maximum tolerances are 2.3761 to 2.3769 inches, so grind to the former.Another trick with the crank is tear-dropping the oil drillings, this improves the lubrication flow on the crank.
Crankshaft Journal With Tear Dropping. The oil is scooped in on the main bearing journals and drawn out of the big end journals by the venturi effect.In Martin's experience, he's found the replacement billet crankshafts to be 6-7 lb heavier than standard, and no better.
If anything, It's less reliable because billet steel is less granular than cast iron, so it's far more susceptible to torsional oscillation. This means as the billet item is that much more springy, you can have different timing at either end of the engine.
Basically, stick with the standard crankshaft, and if you're going racing, get it tear-dropped and nitro-carburized. When it comes to billet conrods, these are heavier, as the machining doesn't give such an intricate shape as the original Ford forgings. Don't bother. For all 3-litre engines, Martin assures us the standard rod is more than adequate with new bolts. Just make sure they're not Cosworth big end bolts, as they don't exist for this engine - they're actually Lotus twin-cam bolts. To fit these you have to machine down the caps, so why not just use new originals?
For high performance use, Martin torques them to 40 Ibf.ft instead of 25-30 as standard.
Essex 3.4 Litre Crankshaft
Tuning the Essex V6
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