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Pistons - Is this to be expected??

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Old 17 May 2012 | 09:58 PM
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Default Pistons - Is this to be expected??

Evening,

Been lurking in the background for a while now, mainly post on two other forums hence the lack of posting on here!

I own a 2002 Uk Bug Sti which until recently had a (brand new when put in the car) 2009 EJ25 short block with standard internals and the car's original heads , was also running simtek, fmic, TD05-20G, ported headers and up pipe etc etc

I've just purchased an EJ22 block so the EJ25 is surplus to requirements, I've pulled the engine with the intention of selling it and am wondering if this is to be expected??

Cylinder 2


Cylinder 4


Cylinder 1


Cylinder 3 - I'd wiped this with a cloth to see what came off


The car didn't burn excessive amounts of oil but I topped it up a bit more than I thought was normal.

I'm just wondering if this is normal so I can decide whether to a) sell the block as it is with just under 15k miles on it or B) strip it down and sell the crank, rods and block halves seperately? Ideally I don't want to spend much if any money on it if needed!

I've stripped the heads and think a couple of the valve guides or stem seals are worn which may be the reason for the extra oil burning??

The two valves in question....



One of the valves compared to what the rest of the valves looked like....



Apologies for the long post!
Old 18 May 2012 | 09:56 PM
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For whatever reason you are running way too rich. This is not necessarily a mapping issue but who mapped your ECU, have you shown them these photographs and what injectors are you running?
Do you have the bad habit of starting the engine from cold and letting it tick over while it warms up or are most of your journeys two miles or less to work and back home in the evening?
Old 19 May 2012 | 09:52 AM
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I haven't shown them these photo's the last time the car was mapped was just before I brought it, it hasn't had any modifications since the map either, the car was running 650cc injectors with a Simtek ecu.

The car was never driven for short journeys, my daily commute is a 70 mile round trip that I have done a couple of times in the impreza but I have a daily driver so it was nearly always driven at weekends and days off. As for letting it tick over before I drove it 50% of the time I was guilty of that mainly because when the engine was cold it would stall/ conk out when I came to junctions or traffic lights for the first 5 minutes of driving.... the other 50% of the time I drove it straight away as it was early in the morning and didn't want to wake the neighbours!

Are these pistons in need of a change now do you think? I won't be using this short block again I just don't want to sell it to someone whole if they want to put it in their car if its not going to do its job

Last edited by Tomma4836; 19 May 2012 at 10:43 AM. Reason: typo
Old 19 May 2012 | 10:34 AM
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sorry to jump on the thread but i do very short journeys to work all week ( less than two miles as well) and occasionally let the car warm up on tickover in the mornings! is this a bad thing harvey and are the short journeys bad for the engine? glad to hear your on the mend by the way bud.
Old 19 May 2012 | 11:25 AM
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Originally Posted by yabbadoo4
sorry to jump on the thread but i do very short journeys to work all week ( less than two miles as well) and occasionally let the car warm up on tickover in the mornings! is this a bad thing harvey and are the short journeys bad for the engine? glad to hear your on the mend by the way bud.
+1 i always let my car tick over for a minute in the morning before i drive it is this bad for the engine then??
Old 19 May 2012 | 11:28 AM
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i do short journeys a lot lately and since fitting catch canthe amount of gunk that builds up is unreal and to think was going straight into engine again.short journeys mean car builds up condensation inside and that gets blown through the breathers into the inlet.lovely mayo colour.
Old 19 May 2012 | 12:17 PM
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letting a car warm up on the drive is a bad thing imo. its means the engine takes longer to get out of the cold phase. a lot of wear occurs in the cold phase. you want the engine to get up to temp as quickly as possible (without stressing/trashing it of course). drive of staright away and just stay off boost.
the longer its in the cold phase the more wear.
Old 19 May 2012 | 12:21 PM
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On modern engines there is absolutely no need for engines to be prewarmed. Start the engine and drive off without letting the engine strain ie. too high a gear and not enough revs and so not rev it hard. Subject to the driving conditions the water temperature will probably read normal by two miles but it will take a further 6-10 miles for the oil temperature to come up to around 80 C.
Keep the revs down while the engine is warming up. I always aim for 2000-2500 rpm max for the first couple of miles and not more than 3000 rpm until I think the oil is warming satisfactorily and say 3500 for a bit after that.
Something else I do on particular cold days is crank the engine for a period of around 10 seconds until I see the oil pressure guage starting to rise. At that point I deactivate the kill switch and allow the engine to fire. This means the oil system is fully primed and immediately has oil pressure. A bit **** perhaps but when I recently stripped one of my engines which had been run pretty hard there was no visible wear on crank, bearings, bore or pistons. .

Last edited by harvey; 24 May 2012 at 01:31 PM.
Old 23 May 2012 | 05:52 PM
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I'll get the block checked over and decide what to do with it from there then!
Old 23 May 2012 | 07:19 PM
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I reckon you might have a few broken ring lands. the standard pistons I took from my EJ257 looked like yours






Old 23 May 2012 | 08:13 PM
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Originally Posted by Baz82
I reckon you might have a few broken ring lands. the standard pistons I took from my EJ257 looked like yours

Thanks for the reply I now have some idea of what I could be looking at, looks like the pistons will be coming out then!
Old 23 May 2012 | 10:08 PM
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Originally Posted by Tomma4836
Thanks for the reply I now have some idea of what I could be looking at, looks like the pistons will be coming out then!

While you have it apart I would put a set of decent forged pistons in
Old 23 May 2012 | 10:33 PM
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really easy to take pistons out. no special tools needed.
Old 23 May 2012 | 11:37 PM
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Picture #2 ans 3 show a lovely crack on the piston crown As others have said fit a nice set of forged pistons and then sell the short motor. Most seem to break the ring lands but i have seen another ej257 with a crack like yours.
Old 24 May 2012 | 06:03 PM
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I didn't really want to spend any money on this block as I intend to sell it, I was also considering keeping the crank from it to use in the EJ22 I've got and sell the scdb halves?
Old 24 May 2012 | 07:14 PM
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Turns out you were right Baz, just taken the Pistons out and piston from Cylinder 2 looked like this..........



Old 25 May 2012 | 02:16 AM
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Thought so the standard pistons are useless.At least you know now. That engine was detonating at some point
Old 25 May 2012 | 10:22 AM
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Originally Posted by Baz82
Thought so the standard pistons are useless.At least you know now. That engine was detonating at some point
Yeah det can cause this but just boost pressure is enough to cause it on the std 2.5 pistons.
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