turbo900

Its a long story but basically
Bought car from subaru dealer with 1 year warranty
Car has misbehaved since bought
Found piston ring failure
Dealer replaced with a 2.5 built locally by a proper engine builder with forged pistons etc
Car now runs ok once the ecu is reset but within 2-3 days especially when very cold outside the piston slap on start up is causing the car to detect knock and retards timing etc.
Car is totally standard bar a cat back and panel filter.
Dealer is not happy with the knock detection, SW, Andy F, posts on here and a few mechanic mates all say that the cold start up knock is expected on forged piston motors and can be mapped to suit to sort this issue.
Dealer not happy to do this as they think remap means 500000bhp and wont warranty work.
There is obviously behind the scenes reasons for this nonsense but i'm now getting a bit peeved as its been over a month and car is doing 16mpg due to fault codes.
Andy F reset codes for me and car ran great again for a day or so then performance tails off with low boost, max ignition retard and buckets of fuel

scooby1929

iTrader: (1)

What mileage was on your car when this happened? Any thoughts on why it happened?

turbo900

No idea mate, its got just over 60k on it with FSSH. Had cat back and apparently an Andy F remap only.

scooby1929

iTrader: (1)

You should ask apidavid for his advice. At least it was under warranty but am surprised the dealer let them fit forged internals and not just a direct replacement. If it was mine I would just pay andy f or jgm to tweak the map and have peace of mind. Hope you get sorted

turbo900

Like i say i think there is something behind it, like they had this motor available or something but who knows. I'd do this but i'd loose 10 months of warranty which is one reason why i bought from a dealer. I've no doubt it'll get fixed in the end as the dealer is a good one but its the hassle i'm getting to get there

rob84

iTrader: (5)

if it already had a remap on it, then how would they know if you'd had it tweeked to suit ??

scooby1929

iTrader: (1)

Good point plus a tweak might only be around £100

turbo900

There ecu reader or whatever they use cant read ecu's that have been done with ecutek. Thats why they removed ecu in the first place and put it back to standard thinking the map was causing a hesitation but turned out to be piston failure.
If anything fails, turbo, maf, engine and they cant read ecu they will know its been fiddled with and invalidate my warranty.
They offered me remapped ecu back for Andy F to sort but hinted i'd no have warranty

rob84

iTrader: (5)

The ssm3 can read a remapped car without issue, all it cant do is re-program the rom files. sounds like there not confident of the work they've done to me

scooby1929

iTrader: (1)

Something sounds a bit dodgy to me

Never heard of not being able to read ecutek software

jazzyjembreaze

iTrader: (11)

The warranty isn't worth ****e m8
You need to put the ecutek software back & go from there
Also forged pistons when cold (slap) not knock
Knocking would likely to be a Rid, Bearing , or loose fit Gudgeon Pin
The Forged piston slapping is common , but if the clearance is 2 large it's no good

turbo900

The dealer only fitted engine. I think your right though and they are not confident in the engine build. I thought this would be an easy fix with them paying £200 and get Andy F to remap the tuned ecu back to standard but adjusting the knock detection setting/sensitivity. I can then get it done again once my warranty is out lol
They have had a couple of remapped cars they couldnt read in the past i believe. They normally dont deal much with tuned cars other than prodrive stuff.

turbo900

Yes sorry i mean piston slap being detected as knock on cold start up. Its sweet as a nut once warm and Andy F has heard and ran it. Once it was reset she drove sweet as until cold again and then the performance tails off and she starts to run rough. Its been fine for last cople of days but its never been over 3k rpm, ambient has been 10deg+ and i have warmed her fully before driving off. This however cant always be done as i leave house at 5am and it sitting running til warm will only pee off neighbours.

rob84

iTrader: (5)

If the engine has been built to the correct clearances then on a new build the slap should be minimal to none in my opinion. certainly not enough to retard the timing that far back that it runs like a bag of S**T on cold start.

your gonna be pretty much F**ked this weekend then as the temps are gonna drop and it will be horrid again..

turbo900

Its kind of hard to tell what makes it worse. I have driven it for last 2-3 days since ecu reset and its okish. Its never really been on boost much though. If cold and i keep it off boost u dont see much issues as it idles fine and runs ok but over a few days of using it and a bit of boost (say 3500-3750 max) from cold (not straight away!) you can usually feel a hesitation start that gets worse and worse.

K3ogh_sti

engine ****! Im saving for this ! Not far from me either

honeybadger

is Mahle the strongest pistons you can get for this engine? Why don't more guys bore/stroke it out to a 2.7, I mean, while you're in there and rebuilding.... ???

MOTORS S GT

iTrader: (2)

Sounds to me like they have fitted 2618 material pistons where 4032 for a road car would of been the right choice, this forged piston noise issue is something that need not be an issue with correct choice of component & its correct clearence for the job its put too.

Alan Jeffery

Mahle are top quality and very consistent. The material we use reflects the use we're putting them to. You could spend more and use Cosworth but I doubt you'd notice the difference.
Considering the relative weakness of the blocks, certainly compared to the closed deck types, we're happy leaving the bore as it is.

APIDavid

iTrader: (4)

I have done so before, but looking at how long this thread is it is probably a few aeons back.
At current prices, a permanent fix [ subject to the nut behind the wheel behaving ]

Drive in - drive out £2300.00 + VAT

Forged pistons + new rings bores honed, new STi late spec head gaskets, new 11mm studs. new tri metal big end shells. We automatically upgrade oil pumps in any rebuild we do whether budget or full spec.
Optional extras are a sump baffle, and a cam belt - some have just been done -

Forma queue guys, no barging.......

David APi 01926 614333

APIDavid

iTrader: (4)

Just seen the other bit about pistons and slap and so on. We use Supertech from California as our 'in house ' pistons and they never give us a moments trouble all the way up to 600 + horsepower.

When we do the job noted above we have just fitted the Supertech pistons with the lightest of honing to give the rings something to settle into. BUT the 'drop in ' piston thing has limitations as you get more miles [ and bore wear ] on an engine. We have done exactly that up to a 62,000 mile car and apart from a bit of inevitable cold start piston slap it runs fine and no excess oil consumption.

Not ideal doing drop in pistons unless you are certain of the quality of the product. We wouldn't dream of doing this job with anything other than Supertech or Mahle pistons, as they are consistently good. Nothing wrong with Cosworth or Omega, it is just that I personally don't like to use a race derived slipper skirt pistons in a high mileage road car. I prefer full skirted pistons.

If you put the Supertechs in a fresh bore [ NEVER rebore a 2.5 they won't take it ] they make no noise hot or cold - really impressed with that.

David

turbo900

David,
My car has had Mahle ones fitted. If you were to fit these to a standard engine and running gear would you expect this issue I have with ignition retarding and a kind of limp home mode after a couple of days light use but with a few starts each day? if so how would you resolve it? The engine is only a little noisey on start up then seems silent.

Martyn

APIDavid

iTrader: (4)

Tricky one that, it depends entirely upon bore clearance. We aim for a tad under 3 thou as a start point. If the bore won't take that and is larger, we have a conversation with the customer about the consequences. If it matters, we recommend a new pair of crankcases, if not and the customer will tolerate a bit of slap when cold and I mean a bit. We let it go.

But we have done some work for a specialist, who was having engines built elsewhere [ I'll never tell you who in both cases that is unprofessional ] that had clearances up to 5.5 and 6 thou FROM NEW. They clattered like you would not believe and did exactly what yours is doing - yank all the timing out. They were unmappable they were so bad.

We sorted them out and all parties are now happy.

David

turbo900

Thanks for reply David. Yes I wont mention either about parties involved as its not good practise. I suppose i'll need to listen to what they have to say on sat and what their solution is. I'm just stuck in the middle with a bad running car that no one is in a hurry to sort! Wonder if they have tested that knock sensor is ok??? LOL

urban

iTrader: (1)

Out of curiosity, how long does such a process actually require David?

APIDavid

iTrader: (4)

If I recall Bob Rawle has a trick he plays on sensitive knock sensors. He puts a damper [ piece of plastic or cardboard ] between the knock sensor and the block which calms it down a bit. He may even tighten them up normally instead of the correct torque setting which also helps.

Just purely to overcome a problem similar to yours.

I Think !

Ask him. He may say l am crackers, which is probably true. He's at Autosport today so, probably no answer until tonight.

David

APIDavid

iTrader: (4)

We ask for 3 weeks to get it in and through the system without giving unrealistic delivery dates.

D

Alan Jeffery

We're quite happy going to .25mm on a 2.5 block, and in any event, we prefer to hone to fit rather than just "drop in".

turbo900

Yes others mentioned fitting a fibre washer to sensor or moving it entirely. The dealer is not happy hiding issue this way probably as i want the engine warrantied.

APIDavid

iTrader: (4)

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KABOOM



Seriously though, If you are happy at that, then fine. We all have our ways.

David