I offered to help a guy on the S2k forum when he needed a new engine for his car, apparently his was making some disturbing noises and despite his efforts to rectify them by fitting an aftermarket 'uprated' chain tensioner it still wasn't fixed. It baffles me the number of people out there that think a new oil pressure light switch will cure their oil surge issues or a new tensioner will fix their knackered chains....but anyway.
I paid 250 quid for this engine, which was an absolute bargain when you see 120 thousand mile runners going for £3000 and lower mileage engines fetching £5000. Its been sat in the workshop for a few months but i've been itching to strip it and see what was left inside, so the other day I did.
Turns out it had suffered from the fairly common issue of a piston picking up in the bore and dragging itself up and down the side in an attempt to weld itself to the block. They do this when they get old and when they get hot. The bores are fibre reinforced metal (FRM) and have no steel liner like a conventional engine would, so because the bores are alloy and the pistons are forged alloy they run extremely tight piston to bore clearance, less than a thou from new (whereas a conventional iron bore would be 3 to 5 thou). The only thing stopping the pistons from sticking to the bores is the coating on the sides, basically a form of hard anodising that is microns thick.
So the block is shagged, but thankfully we have the technology here to bore and hone FRM so it could be recovered and a set of oversize oem honda pistons installed, only the pistons cost the best part of two grand. Alternatively I could fit liners to the block and then run conventional forged pistons in it, which in turn gives you the option of going for a much bigger bore. The pistons are much cheaper but the liners cost about a grand.
The good news is the rest of the engine is absolutely mint. The previous owner claimed to have put most of the miles on this engine by motorway commuting and had barely ever had it in vtec. The wear on the valvetrain absolutely backs this up, i've never seen an engine like it. The crank is also absolutely mint and the oil pump looks better than a lot of new ones i've seen. I was about to throw it in the scrap bin when I decided to open it up and have a look, there's not a single mark on it anywhere.
Now I just have to decide what to do with it.
