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Engine block preparation
Take one Block, preferably A+ but an A series will do, albeit with a little more preparation, but make sure it's the right type, for your intended application.
Watch out for those AUTO blocks!(Unless you want an automatic!)
Check EVERY SINGLE THREAD in the block.
The most common ones to be damaged or re-threaded with some obscure size and pitch are the two that take the top engine steady.
Check for damage to the face.
The engine number being present is the obvious one to
look for. The same applies to the gearbox/flywheel housing/timing backplate
faces too. Large 'nicks' may not be sealed by the gaskets causing oil leaks.
Check that no damage has been done to the outer edges of the block. The 'lug' at the rear where the flywheel housing bolts up(behind the oil pump) can be broken off if the block has been chucked around.
Check for location where the caps meet the block. Are the caps the correct ones for the block?
Has someone ran the block with worn out bearings or thrust, leading to damage to the bearing housings, caps and thrust face. If its been run with thrust washers fitted the wrong way, this can wipe out the thrust face completely making the block scrap.
Is the block linered? If so, forget a +.060" rebore. Its +.040" max or all the way out to 73.5/74mm. Make sure it isn't bored to 74mm already!
Another tip here, get your pistons BEFORE machining to be sure they're available in the size you need. The manufacturers are cutting back on production numbers these days all the time and it might be weeks before pistons in your size are available.
Cam bearings! Are they badly scored and need replacing? If you're replacing them (after the prep work) make sure the oil feeds line up!
If its an A series:
How can you tell? The steel caps are stamped with an ID
number(4 or 5 figures). This number will be stamped on all three caps AND on the
side of the block. This will tie up the correct caps to the block.
Once you are satisfied that the block is the one for you, then prepare it for machining by removing all the oil gallery plugs and core plugs. Remove the oil pressure relief valve.
Don't bother cleaning it yourself, let the machine shop clean it for you. It might cost #4-#5 but it is definintely worth it, as it will be done with hot chemicals at high pressure, so it will be clean... but not clean enough because machine shops typically clean it BEFORE machining so all your oilways and waterways and threads will be full of swarf.
You will have to give it a final clean before assembly. Countersink your threads in the block face then blow out all the galleries, threads etc with compressed air. Don't forget to remove the main caps and clean under them. Take the main bolts out completely and clean them too.
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