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engine wear

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boosted
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engine wear

Post by boosted »

Hey guys,

my cherry turbo is blowing smoke so i went to check my spare engine for wear out:
Image

The pistons all measure 75.97mm, so apart from conicity and out of round, the maximum piston to wall clearance is also reached. :-(

Can anyone tell from experience if such engine will already blow out noticeable amounts of smoke?
I'm thinking of throwing in the spare engine, as i have to go to MOT.
In the meantime i could rebuild the engine that is currently in use....

cheers
martin
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tassuperkart
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Post by tassuperkart »

There is no guarantee that the motor will smoke or not.
High piston to bore clearance is not usually a problem oil wise and mostly results in excessive noise when cold.

Smoking, if you can definitely rule out leaking valve guides is usually a result of worn oil control rings.

Im guessing you have it apart already so id hone the bore as lightly as possible to remove any glazing, throw a set of rings at it and get it out that work it hard right away.

Oracle
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.
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boosted
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Post by boosted »

Thanks E, thats interesting.
Yes, the spare engine is still apart and i will take a closer look at the oil rings when i'm in the garage again.

It seems a set of rings would set me back nearly the amount i would have to pay for boring and honing the block.
As i have a set of oversize pistons lying around, i think i would rather go this way.

In the actual engine i replaced the valve guide seals about 2 weeks ago, but unforunately i was still blowing the same amount of smoke, although the old ones were really brittle...

I'm sorry, i didn't get the meaning of that part of your last sentence:
and get it out that work it hard right away.
cheers
martin
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tassuperkart
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Post by tassuperkart »

Even if you fit OS pistons, your still going to have to fit new rings so...yer.

Re-ringing a used engine and pussy-footing around "running it in" can result in glazed bores very quickly and incessant crankcase blowby. So just fire it up and go play hard!

Rings cant be that expensive if you buy online and have them posted to you. They are very light and a relatively small package.

Oracle
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Post by boosted »

tassuperkart wrote:Even if you fit OS pistons, your still going to have to fit new rings so...yer.
I have the full 0,5mm oversize-set lying here, i.e. pistons and rings :-)
Re-ringing a used engine and pussy-footing around "running it in" can result in glazed bores very quickly and incessant crankcase blowby. So just fire it up and go play hard!
Now i get it! Thanks for the info.

Rings cant be that expensive if you buy online and have them posted to you. They are very light and a relatively small package.
Oracle
A quick internet search didn't bring any useable results, do you happen to know a good source on the internet?
I also have a set of std e15s piston rings lying around also, but they are not the same (another thread covered this topic before, but i cant find it anymore).
I already thought of simply throwing them in and give them a try :-D

cheers
martin
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Post by tassuperkart »

I use Precision International in Australia.

if you have stock bores, stock pistons and stock (new) rings then just go ahead, give it the lightest hone you can do and away you go.

Oracle
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.
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