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Talk about engine building here. New products, tricky questions or showcase your work - If it's engine building related it's welcome here.
Hello, I took your engine building course and am building a new motor for my 2013 Ford Focus ST. The last task I had to do before final cleaning and assembly was to check the main bearing clearance and of course they turned out to be too big. The workshop manual says .0009"-.0018", the rule of thumb says up to .0025", I measured .0030"- .0034". My question is , is there a solution to this or am I getting a new block? My machinist decked, bored and align honed the block, so I'm not sure how it went wrong. My build is a reasonably high hp daily driver, forged internals, keyed crank, built Focus RS head with turbo upgrade, maybe 500hp. If you could let me know what you think that would be great. Thanx.
Have you mic'ed the journals to check if they're the issue, being polished/worn/ground slightly undersize?
While you're at it, might be worth checking the mains' bores in the block, it's possible the machinist took them out slightly to far and the loss of crush is part of the reason.
If that checks out OK, some bearing manufacturers can supply 0.001" undersizes for common engines, or make some specially for you - no recommendations, sorry, but a potential avenue for you to investigate.
Hey, thanx for the reply. Yeah, I checked the crank, several times actually, it's brand new oem and it's right in the sweet spot. My worry is my machinist took too much when he honed it. I think I need oversized bearings for less clearance and those I can't find for my car. I hadn't thought of custom made bearings though. I'll look into that.
Better check the main bores, first, so you know what to ask for. The bores may even be correct and you just have a set of bearing shells that are out of tolerance - they don't have a +0.001, or + 0.025 on them, just in case there was a mis-packing?
I know King make special O/S bearing shells for Subarus, for align boring without removing the flange face material, and they make custom shells, but can't comment on price, etc. There are also other companies that should be able to do something, but $$$.