Notices
ScoobyNet General General Subaru Discussion

Slappers (piston!) - Need advice!!!

Thread Tools
 
Search this Thread
 
Old Feb 4, 2008 | 09:53 AM
  #1  
simog's Avatar
simog
Thread Starter
Scooby Regular
iTrader: (1)
 
Joined: May 2007
Posts: 542
Likes: 0
From: Milton Keynes
Default Slappers (piston!) - Need advice!!!

Hi all,

My 98 UK turbo has the slaps and the trouble is I can hear it (not loud) when warm. It's bothering me now!!

What is the cheapest way to sort this out? Replace the engine by buying a replacement from a breaker or replace the piston ala the way they fixed it under warrenty?

How many of you still have this problem out there?!

Car isn't consuming oil, level stays constant but the knocking is getting me down especially given that I came from a 95 wrx which was totally sound!

Don't suppose there is any outside chance that Subaru would still replace the piston under some sort of agreement given that it hasn't been done?

Reply
Old Feb 4, 2008 | 10:02 AM
  #2  
Gear Head's Avatar
Gear Head
Scooby Regular
iTrader: (2)
 
Joined: Apr 2004
Posts: 15,029
Likes: 0
From: Somewhere in Kent, sniffing some V-Power
Default

no chance mate.
If it is still there when warm, you may have spun a bearing, which means a new engine anyways.

what oil are you using?
Reply
Old Feb 4, 2008 | 10:04 AM
  #3  
Shark Man's Avatar
Shark Man
Scooby Regular
 
Joined: May 2004
Posts: 7,498
Likes: 0
From: Ascended to the next level
Default

Rebuild. You could replace the piston, but whilst the engine is out and half, disassembled, one may as well go whole hog and inspect all the other prone problem areas (big-ends etc).

But I'd say its best to get that noise checked and get a seond opinion to make sure its not bigs ends your hearing.

I wouldn't touch an engine from a breakers....

How do you know its any good without stripping it down? It may last 100 miles, 1000 miles, 10,000miles...who knows... It's a lottery.


Every engine I've bought second hand, upon stripping down has been found to be worn out and past its prime, probably good for a gentle 10,000miles (if that, probably 100 miles if it was took round a track ) - thus needed a rebuild anyway. Therefore its a false economy.
Reply
Old Feb 4, 2008 | 10:12 AM
  #4  
simog's Avatar
simog
Thread Starter
Scooby Regular
iTrader: (1)
 
Joined: May 2007
Posts: 542
Likes: 0
From: Milton Keynes
Default

Thanks for the replies...sounds grim doesn't it.

In answer to your question : 10w 40 Mobil oil is what is in there at the mo.

Ok, fair comment on the engine purchase, without knowing a history then its a bit of a gamble, but what I was thinking more of was a more trusted person from this forum maybe?

Definatly piston slap as I was provided a sound file from someones forrester which was suffering quite badly and it is exactly the same.

Should the noise be completely gone when warm then? No hint of it at all?
Reply
Old Feb 4, 2008 | 10:13 AM
  #5  
andy97's Avatar
andy97
Scooby Regular
iTrader: (1)
 
Joined: Aug 2004
Posts: 6,296
Likes: 118
From: Api 500+bhp MD321T @91dB Probably SN's longest owner of an Impreza Turbo
Default

Api all the way. David will give you no bull **** advice. Very nice man!

Andy

Hi David, if you read this how's my car coming along?
Reply
Old Feb 4, 2008 | 10:42 AM
  #6  
Gear Head's Avatar
Gear Head
Scooby Regular
iTrader: (2)
 
Joined: Apr 2004
Posts: 15,029
Likes: 0
From: Somewhere in Kent, sniffing some V-Power
Default

Originally Posted by simog
Thanks for the replies...sounds grim doesn't it.

In answer to your question : 10w 40 Mobil oil is what is in there at the mo.

Ok, fair comment on the engine purchase, without knowing a history then its a bit of a gamble, but what I was thinking more of was a more trusted person from this forum maybe?

Definatly piston slap as I was provided a sound file from someones forrester which was suffering quite badly and it is exactly the same.

Should the noise be completely gone when warm then? No hint of it at all?
Should be, but don't confuse the noise with the injectors.
Reply
Old Feb 4, 2008 | 10:57 AM
  #7  
simog's Avatar
simog
Thread Starter
Scooby Regular
iTrader: (1)
 
Joined: May 2007
Posts: 542
Likes: 0
From: Milton Keynes
Default

All this is so confusing!! Wish I was a mechanic and then I would just do it myself!!!!

The sound does seem to be exactly the same as it is when cold but just far more quiet when warm. Some times it is inaudible when warm but during these colder days it has been noticable.

Does anyone have the instructions to test for this? I think it was a case of unplugging an injector but I am not sure.
Reply
Old Feb 4, 2008 | 11:06 AM
  #8  
Shark Man's Avatar
Shark Man
Scooby Regular
 
Joined: May 2004
Posts: 7,498
Likes: 0
From: Ascended to the next level
Default

Originally Posted by simog
Ok, fair comment on the engine purchase, without knowing a history then its a bit of a gamble, but what I was thinking more of was a more trusted person from this forum maybe?
If its a private sale: No! Two reasons; there are plenty of people who sign up this board and are happy to spout caveat empire.

Secondly, dispite service history; there is no way that even the current owner of the car will know how worn out it is (especially if they aren't the orginal owner), unless they rebuilt it recently (and that opens up another can of worms in the case of a bad rebuild done on the cheap, or they just lied about the rebuild, and it never had one). It's well documented that some engines last barley 40,000miles, whilst other soldier on past 100,000miles. So the element of risk remains.

All my second hand engines were sourced like the above (one was allegedly rebuilt, and th rest were calimed to be "mint", "good runners" etc.). Thankfully, they were purchased as doner engines to rebuild (due to the orginal engines having a rod go through the block, or to build a spare engine on a track/strip car). So were stripped anyway, and found past their prime.

If its a trader; Then as long as they give full guarantee, that's fine. But still beware; the get-out clauses (especially if they don't install the new engine). For example, they can claim you used it with a modifed ECU map, or with a failed MAF sensor etc.


Should the noise be completely gone when warm then? No hint of it at all?
Nope, should make zero slap when warm. The only thing you should hear are the injectors and tappets...both of which can normally be a bit noisy (MY98 had shims instead of hydraulic tappets)
Reply
Old Feb 4, 2008 | 11:22 AM
  #9  
Eprom's Avatar
Eprom
Scooby Regular
20 Year Member
 
Joined: May 2003
Posts: 502
Likes: 1
Default

To be honest I would not worry about it, Subaru’s fix was to replace the piston that was making the noise.
If you car is quietens down when warm it will be O.K.
The problem is down to slightly out of specification piston to bore clearance; this gets taken up when the engine warms up due to thermal expansion of the piston.
Cars can run with piston slap for many miles and if it’s not burning oil, it’s not a problem.
Reply
Old Feb 4, 2008 | 11:36 AM
  #10  
chocolate_o_brian's Avatar
chocolate_o_brian
Scooby Regular
iTrader: (22)
 
Joined: May 2006
Posts: 21,415
Likes: 0
From: Doncaster, S. Yorks.
Default

Originally Posted by Eprom
To be honest I would not worry about it, Subaru’s fix was to replace the piston that was making the noise.
If you car is quietens down when warm it will be O.K.
The problem is down to slightly out of specification piston to bore clearance; this gets taken up when the engine warms up due to thermal expansion of the piston.
Cars can run with piston slap for many miles and if it’s not burning oil, it’s not a problem.

read the first post. he says its still there when warm

to the o.p. have you ruled out noisy tappets and/or injectors?

ive got noisy tappets on my my99, had it for months, car tuns fine, just taps to itself
Reply
Old Feb 4, 2008 | 11:45 AM
  #11  
simog's Avatar
simog
Thread Starter
Scooby Regular
iTrader: (1)
 
Joined: May 2007
Posts: 542
Likes: 0
From: Milton Keynes
Default

Pretty sure it is not tappets, have a wrx also which has a tapety noise so I have compared the two.

It is the same noise only much quieter and only when pulling away at around 2 - 2.5K revs.
Engine is definatly warm at this point as it has already covered the journey from MK to Oxford.
Don't get me wrong, the noise is not overpowering, but I know what I am listening for now and can pick it out from all the other little noises that are the norm for the engine!!

Very bad when cold though!! Sounds like an old land rover!!
Reply
Old Feb 4, 2008 | 12:32 PM
  #12  
markietay's Avatar
markietay
Scooby Regular
 
Joined: Dec 2007
Posts: 137
Likes: 0
From: southampton
Default

Originally Posted by Eprom
To be honest I would not worry about it, Subaru’s fix was to replace the piston that was making the noise.
If you car is quietens down when warm it will be O.K.
The problem is down to slightly out of specification piston to bore clearance; this gets taken up when the engine warms up due to thermal expansion of the piston.
Cars can run with piston slap for many miles and if it’s not burning oil, it’s not a problem.
My 135k 97 uk turbo has piston slap when cold but seems to be ok when warm.It seems ok otherwise so i am just gonna leave it be for now.
Reply
Old Feb 5, 2008 | 09:28 AM
  #13  
Shark Man's Avatar
Shark Man
Scooby Regular
 
Joined: May 2004
Posts: 7,498
Likes: 0
From: Ascended to the next level
Default

Originally Posted by simog
Pretty sure it is not tappets, have a wrx also which has a tapety noise so I have compared the two.
If it s a pre-97 wrx, it will have hydraulic tappets as opposed to shims....so they will sound different.
Reply
Old Feb 5, 2008 | 11:28 AM
  #14  
scoobysnacks's Avatar
scoobysnacks
Scooby Regular
 
Joined: Jul 2000
Posts: 644
Likes: 0
Post

I agree with Eprom.
I had a MY98 WRX with piston slap and it had been slapping for a couple of years when I eventually sold it.
It was very audible when cold but did quieten down when warmed up (but was still audible).
I read a lot about the problem and came to the conclusion it would be a waste of money (and it was expensive!) to get it fixed as the engine was running fine and wasn't burning any oil.
I think it's something that 'could' shorten the life of the engine slightly but you may well not own the car by the time that day comes...
I haven't been on here much recently but a few years ago I hadn't read any storeis of engine failure specifically due to piston slap.
Reply
Old Feb 5, 2008 | 02:42 PM
  #15  
simog's Avatar
simog
Thread Starter
Scooby Regular
iTrader: (1)
 
Joined: May 2007
Posts: 542
Likes: 0
From: Milton Keynes
Default

Thanks guys for all your comments. I am going to sell it on I think, as I would prefer an STI and tbh wish I had just gone the whole hog and bought one in the first place!!!

I guess I was lured in by the prodrive malarky and the fact that it is a blue impreza (my fave colour!!).

Don't get me wrong, it's not a bad car...far from it, and very good looking, I just have a hankering for the STI variant!!
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
just me
Non Scooby Related
26
Jan 3, 2020 11:12 AM
Sam Witwicky
Engine Management and ECU Remapping
17
Nov 13, 2015 10:49 AM
scoobhunter722
ScoobyNet General
52
Oct 20, 2015 04:32 PM
bluebullet29
General Technical
9
Oct 5, 2015 02:17 PM
Ganz1983
Subaru
5
Oct 2, 2015 09:22 AM




All times are GMT +1. The time now is 08:04 PM.