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2007 Focus ST3
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Discussion Starter · #1 ·
After an over heating issue and need to replace head gasket I've managed to remove the head.
Gasket blew between cyl 3&4 allowing coolant into the cylinders which is turning rusty.
Is the block scrap or would a rebore and oversized pistons fix it?

Also, when I loosened the head bolts, some were tight, but some just gave way without much effort. Could this be from the bolts not being tightened properly a year ago when the gasket was replaced or could the overheating cause bolts to relax? Neil
 

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Discussion Starter · #4 ·
I thought it might be scrap due to rust, but yes, like you say it's just surface rust.
Thanks for reminding me about the thin liners, forgot all about them, so that rules out a rebore.
I'm now hoping a hone and new piston rings should be enough.
If the bores have worn to much I'll see if I can get them relined.
 

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Discussion Starter · #7 ·
Thanks for responses. I'm not sure if the bolts were reused but if so it might explain why some were loose if they were further stretched.
Researching loose head bolts, it could also be from the gasket being crushed/breaking up because of the exhaust heat which kind of makes sense.
Yes, definitely a pressure test on the head and strip down to check the valves.
Thanks for your advice :)
 

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Discussion Starter · #9 ·
I rubbed the rust spots down with some emery paper but they''ve left very faint pits that can just be felt with a finger.
I really can't be ***** be ***** removing the block to rework or replace it, so what do you guys think? Salvageable or scrap?
 

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Discussion Starter · #15 ·
I would have given the cylinders a good coating of oil and turned the engine over by hand a few times to sweep the bores with the pistons, then ensure a thin film of oil was left to stop them rusting up again anytime soon.
I bought the car spares or repair for a grand and by the time it was collected, trailered to the Midlands, diagnosed and head off, a month went by so the lubing piston boat has sailed.
At the end of the day, I am were I am and i need advice on what to do now, not what I should've done with insight a month back.
Imo the block needs relining, but would be nice to know if it can be honed?
 

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Discussion Starter · #18 · (Edited)
I've rebuilt a few engines so aware of the cost which is why relining is preferred route as a I can keep pistons and just fit new rings.
Apologies Teflon if I sound frustrated, I'm not, I just don't understand how barring the engine over will get rid of those rust pits. If a gentle rub with some emery paper exposed them, then IMO scraping them with piston ring would also do the same.
Either way it would leave pits and comprise new rings.
I've now removed everything from the block and will try lowering it and sliding it under the wheel arch the next week. There's a machine shop nearby in Daventry that might be able to re-line. If worse comes to worse, there's a good used block on eBay for £230
 

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Discussion Starter · #20 ·
Iirc if you get another block you have to get another part with it as they are machined to only work with that engine, sump 🤔head🤔 someone will tell you correctly though bud @Alb is the man to ask 👍
I know blocks are usually matched with the crank shaft ladder, or in this engine it's part of the lower housing as it's all bored as an assembly. If that's the case, it's fine as eBay block comes with it. But if it needs matching head or something else, then that's not good at all and will seriously screw things up.
 

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Discussion Starter · #26 ·
BTW, I lubed up the cylinders and barred it over a few times. There's still a very faint pit where the rust bubbles were but maybe I could get away with it?
Attached is latest pic 🤔
Automotive lighting Automotive tire Gas Circle Auto part
 

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Discussion Starter · #29 ·
It looks bad but does it feel as bad or feel smooth? Turn it more and see if its getting better.
I feel a strong urge to fill that engine with CocaCola :ROFLMAO:
Nah, the pits feel a little rough. I'm wishing myself into believing otherwise but it doesn't feel right.
I'm gonna remove the block anyway and take it to a machine shop to see what they think but my gut feeling is it needs relined or replaced.
 

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Discussion Starter · #30 ·
Bit of a lucky escape with the crankshaft and piston rods. They too are turning rusty but luckily, where it matters (bearing seats), the air's been kept out and they're nice and clean.
 

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Discussion Starter · #34 ·
Just took the head to a machinist and it had warped an eye watering 0.5mm, so the chances are the block will be just as bad so they're both scrap :-(
Anyway, looking at a used head and block from ebay tomorrow which looks tidy enough :)
 
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