It's not a technical question so I've posted it here...
By piston replacement, I mean parts and labour to fit the oversized piston to cure piston slap on a MY98 WRX.
Can anyone help?

 

I suppose quite a bit, since they have to remove the engine and split the block. If you are going to pay the labour, you might as well get uprated rods and pistons. Call graham goode for an estimate on parts and labour as they offer uprated internals.

edited due to crup spullling

[This message has been edited by Adam M (edited 13 September 2001).]

 

Hi,

Actually, if the fix is as per the UK cars I believe that they simply take the heads off, drive the gudgeon pin out of the rod, and extract/refit the piston through the top of the block..

GGR's prices for a Piston ring kit is around £45+vat and the piston should be around £75+vat. A rebore and re-honing would cost £150-£300, but would require the engine to be removed and stripped before sending it out to an engineering shop, which will bump up the labour.

Assuming there is no damage to the bore, labour costs should be manageable.. talk to Steve Lawson (all-round mechanical good guy) to get an idea of labour costs..

He knows his Subarus, and is meticulous and methodical in his approach.

Cheers,

Alex

 

Done a few of these now. The block does not have to be split, but the engine does have to come out. Just under £600 inc vat, piston, rings, all gaskets, labour.

Fitting uprated rods and pistons will add about £3000.

If the bore is badly ovalled, its a different story.

 

mine (MY99 uk)is in for a rebuild under warranty to replace a holed piston but to be honest i would rather it was done at some where like scoobysport as i am not exactly happy with my dealers attitude (trying to wriggle out of the repair).....will give him the benefit of the doubt for now.

manny (ready to name and shame)

 

Manny
My MY99 is in for the same at the moment
What causes a hole in a piston?
Have they told you anything?
My dealer said he'd never heard of it before!
Has anyone elses Scoob suffered the same fate?
Doug

 

Peter,

Is it likely that on a typical 'MY98 piston slapper' (55k miles) the bore will be badly ovalled? Also, if the slap goes away when warm is it serious enough to be worth paying for this job done and how long does it take? Is early engine failure the inevitable conclusion to this situation? Maybe I should call Scoobysport for some advice...

 

pete is it really that bad?

I thought that most of the work was engine out. I know that without replacing rods there is no need to split the block, I didn't know it changed the cost that much.

I take it back. Only split the block if you want stronger internals.

Bloody eck.

 

Doogsy,

The dealer ain't saying much at all at the mo' i've actually had more help and advice from an independent specialist who prepares rally cars which really shouldn't be the case, subaru have so far been crap. As far as i'm concerned it's not my fault, the car wasn't being over revved, and i look after it like a right saddo, cleaned and serviced regularly. It just gave up the ghost...interesting that your MY99 has similar trouble, what happened?

 

There is NO WAY I would just replace a piston, after it had been holed. It's highly likely that the bore has been damaged from the piston debris, let alone what's circulating around the rest of the system.

Take some advise from an "engine builder".

As for "piston slap", it seems that a pretty high percentage of "Subaru repaired" engines end up with the problem reoccurring.

I very much doubt that any of the Subaru dealers are measuring the bores, just whacking in another piston. It's very unlikely that anyone other than a "specialist engine rebuilder" would have the right tools to do the job.

Mark.

 

Is piston slap as serious as some poeple think? I've never seen any stories about engines blowing etc because of it. If it goes away when the engine is warmed up is it worth the cost of fixing? I've heard some engines with forged Cosworth pistons for example also have it when cold and this is considered normal so why's it so bad when in standard Scoobs? I've never had a definitive answer to this question so maybe someone here can help.

 

Manny
You have been a good boy
I was driving fairly enthusiastically at the time
Hard acceleration close to redline,low speed to high and hard braking
No warning of probs in fact the car was pulling better than normal
Floored it coming out of slow corner and there was nothing there
Limped to nearest town v slowly, idling v lumpy
Called breakdown guy big puddle of oil by the time he arrived
Would there be a major oil leak after a hole in a piston?
Think from what garage said they were going to replace piston and hope it would do
Have to wait and see exactly what they do though so do hold me to that
Still can't believe he'd never seen this happen before!
Doug

 

Scoobysnacks - I'm earwigging as I too have a 98 slapper - listened to and confirmed by Subaru "engineer" but no replacement teflon piston "due to extra stress on engine which may have caused the slap down to my mods" - rising rate fuel reg, backbox and DP replacement. So my £588 extended warranty is down the drain as they will blame anything that happens on all that extra power (!) causing the problem. I've been told (by Subaru !!) that slap is not terminal or engine threatening - so thats alright then.
Stan

 

Are Subaru telling the truth when they say slap is not terminal or engine threatening?

 

My car ,'98, has now been done twice for piston slap. First time was early in the cars life when the previous owner received a short engine under warranty and the second time was at 51k done under my warranty when it received a piston only. Dealer had the car for 7 days as a head bolt snapped off and had to be spark eroded and re-tapped. Hate to think what this would have cost me if I had no warranty ( 2 weeks left!!! ) If you have holed a piston , it is not likely to be piston slap. Did it drop a valve and hit the piston? A pool of oil would maybe suggest a holed block or sump ?

 

I've never heard of an engine failure caused by piston slap, although it would be possible in a very extreme state. Your ears would tell you that something was very very wrong if this was the case.

If it goes away when the engine is warm, then running clearences are sufficiently tight for you not to be suffering piston slap any more, hence it isn't an issue.

Cheers,

A.