Worth fixing?
05 January 2014, 04:16 PM
#1
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Worth fixing?
Is it worth putting new rings and forged pistons into an engine that has some scoring on one of the cylinders? Will the compression losses and oil into chamber/fuel into oil be minimal?
05 January 2014, 04:34 PM
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Its hard to say, a old engine I had in my mr2 had minimal scoring on the bores when I disassembled it. Which then explained why it used to pass some smoke through the exhaust.
There was never any compression loss though, nor was there compression loss after it was re assembled after its head gasket change.
No noticeable fuel into oil either.
This was very very faith scoring though.
There was never any compression loss though, nor was there compression loss after it was re assembled after its head gasket change.
No noticeable fuel into oil either.
This was very very faith scoring though.
05 January 2014, 05:21 PM
#4
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I'd like to know, the tuner who discovered it on Billy said my best option would be to get a used bottom end but then I'd have the worry that other parts of it might be on borrowed time.
My cylinder one has ring failure and has had half of a spark plug tip bouncing around in the chamber.
My cylinder one has ring failure and has had half of a spark plug tip bouncing around in the chamber.
05 January 2014, 05:48 PM
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Depends how deep.but I melted a piston in mine and the rings scored the cylinder,so I used a honing tool on a drill till it was smooth,worked fine for me! But ideally you should go have them bored the same I would think
05 January 2014, 06:02 PM
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I think the tuner said it couldn't be re-bored 
TBH it was hard to get an answer out of him at times. To be frank he works for another company now and he recently quoted me £500 for an up-pipe fitting. Hence why I'm asking if my scored engine is worth putting new rings in, sometimes perfectionists aren't the best people to work with when you are willing to work with a little bit of tolerance.
The car runs fine as it stands, most tuners tell me there isn't anything wrong with it but it was compression tested (circa 40% loss) and viewed with a bore-scope. I'd be happy with 10% losses and forged pistons so I could bring on the big boost.
TBH it was hard to get an answer out of him at times. To be frank he works for another company now and he recently quoted me £500 for an up-pipe fitting. Hence why I'm asking if my scored engine is worth putting new rings in, sometimes perfectionists aren't the best people to work with when you are willing to work with a little bit of tolerance.
The car runs fine as it stands, most tuners tell me there isn't anything wrong with it but it was compression tested (circa 40% loss) and viewed with a bore-scope. I'd be happy with 10% losses and forged pistons so I could bring on the big boost.
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05 January 2014, 06:19 PM
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I think the tuner said it couldn't be re-bored
TBH it was hard to get an answer out of him at times. To be frank he works for another company now and he recently quoted me £500 for an up-pipe fitting. Hence why I'm asking if my scored engine is worth putting new rings in, sometimes perfectionists aren't the best people to work with when you are willing to work with a little bit of tolerance.
The car runs fine as it stands, most tuners tell me there isn't anything wrong with it but it was compression tested (circa 40% loss) and viewed with a bore-scope. I'd be happy with 10% losses and forged pistons so I could bring on the big boost.
TBH it was hard to get an answer out of him at times. To be frank he works for another company now and he recently quoted me £500 for an up-pipe fitting. Hence why I'm asking if my scored engine is worth putting new rings in, sometimes perfectionists aren't the best people to work with when you are willing to work with a little bit of tolerance.
The car runs fine as it stands, most tuners tell me there isn't anything wrong with it but it was compression tested (circa 40% loss) and viewed with a bore-scope. I'd be happy with 10% losses and forged pistons so I could bring on the big boost.
05 January 2014, 07:01 PM
#9
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Thanks, I'll let you know as soon as my car can't pass emissions or starts smoking badly.
Tuner told me that the engine would last a year. 4 years ago.
Tuner told me that the engine would last a year. 4 years ago.
05 January 2014, 08:09 PM
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It's that VTA chav trumpet you have fitted's fault. 
Better off with a recirc. 
Hope you get it sorted Matt, as above, a rebore to the next size up piston should suffice.
Although, it may not, since you mention ring damage and a broken plug.
Better off with a recirc. Hope you get it sorted Matt, as above, a rebore to the next size up piston should suffice.
Although, it may not, since you mention ring damage and a broken plug.
05 January 2014, 08:15 PM
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Although, it may not, since you mention ring damage and a broken plug.
05 January 2014, 08:24 PM
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No worries,good luck with it mate. If the score is at top end of cylinder then oil wont pass the oil piston ring anyway (this is the bottom one of the 3 rings) so won't burn oil and will be fine
05 January 2014, 08:31 PM
#17
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The car pulls great at the moment, passes emmisions and sees well over 30mpg so I can live with just a small loss.
05 January 2014, 08:33 PM
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05 January 2014, 10:32 PM
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If your going for new pistons then go for +0.5 and give the pistons and rings to the machine shop and they will bore to the piston.
So you will end up with bore matched pistons, and if you give hem the crank they will polish and supply heavy duty bearings to suit gor less than £100.
So you will end up with bore matched pistons, and if you give hem the crank they will polish and supply heavy duty bearings to suit gor less than £100.
05 January 2014, 10:37 PM
#23
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I can get a WRX block fitted for 1,000, would it be worth it? I have the feeling the scoring was too deep to bore out on an open deck block that will see 400bhp in the future.
05 January 2014, 10:39 PM
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05 January 2014, 10:41 PM
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If only lol. Most people don't have the expendable cash in one hit to upgrade from wrx to sti
So to repair is cheaper short fix.
Imo i would source another engine and replace the whole lot. Then strip what i had, find out whats wrong and ebay the rest...
So to repair is cheaper short fix.
Imo i would source another engine and replace the whole lot. Then strip what i had, find out whats wrong and ebay the rest...
05 January 2014, 10:41 PM
#28
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I don't want to rebore, my cheap *** self just wanted to know if I could get away with dropping in new pistons and rings and go.
05 January 2014, 10:45 PM
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IF its just a hone and new rings, that should cost around £200.
If its a bore and new pistons then i personally would source another engine