Hi All

Dispite the careful and gentle way I drive my car I've got piston slap on 2 (yes 2) pistons.

On the block it says one is an A and the other is a B (whatever the hell that means).

Everyone I speak to tells me something different.

Some say the A and B are the size of the piston, others say that is the grade of piston and there are still over sized pistons available.

Some say I need a new block and others say I can have it bored and stick in some oversized jobbies.

Anyone have a definitive answer as to the Type R engine (which I think is blue printed (and of course I know exactly what that means!!)) and also whether it is a closed or open deck (again, fully clued up on that!!)

Thanks for any advice (sympathy would be nice too!)

All the best

Simon

 

Simon,

Sorry to hear of your problem. Hope you get it sorted without too much trouble. Wish I could be of help regarding the type R engine but unfortunatley I don't know much on the subject.

Most people usually have slap on one cylinder and Subaru just replace the one piston, without re boring and the cars seem to run fine, that is, without problems, from what I've read on here. I think they fit an oversize one.

Cheers,

Wrexy.

[Edited by WREXY - 4/4/2002 3:33:18 PM]

 

Simon,

A or B is a size range.

You probably just have an open deck block.

I will let others fulfill your need for sympathy on this one.

As you have openly accused me of dishonesty and missrepresentation you may wish to question the accuracy of the above information.

Moray
bbs.22b.com www.i-club.com

 

Simon :The pistons are graded by size & stamped accordingly. I think there are 4no size ranges A,B, C & D but I have only seen As & Bs. Each bore is machined to fit each piston with a predetermined clearance. eg.2thou upto 4thou depending on the type of engine, its application & the preferences of the engine builder.
I do not think piston slap is anything to worry about unless it is bad.
Some engines will have piston slap on start up that goes as the engine warms up.
Hope this helps.

 

Ring me if you want more info. 07860 302020.

 

Just dropped my 98 Sport off at local dealer for investigation into Piston Slap when cold. Its done 58k and the guy there said much the same about bores being machined to suit one off 5 piston variables. Apparently its a rare but known fault on 98 engines when Subaru redesigned the piston crown. Having said that i've only found info on cars where it occured earlier on in their life (ie up to 15K) so i'm pooping myself a bit about the outcome tomorrow but then again they have serviced it from new!!
We'll see!!!!!!!!

Nick

 

Hi Guys

Thanks for the replies. It *does* go when it's warmed up, but it sounds really bad when cold. What kind of damage could I be doing to the rest of the engine? Is it actually something you don't need to worry about, just drive extra careful until the cars fully warned up?

Cheers

Simon

 

sounds like sound advice to me Adam, thanks.

So.. is it definitely doable to rebore and fit oversized cossie pistons then? Is there anything I need to do to the top end to make it safe?

Is this a half measure which means the engine could last only a few miles after the work was done?

Thanks in advance

Simon

 

Simon,

The "UK" fix won't be much help to you, since UK's use cast pistons, and the STi's forged.

The block can easily be rebored, and new pistons fitted, but you're talking about a full rebuild, and it would be worth considering replacing the rods too.

Apart from using a "real" engine builder, there's not too much you can do, unless you want to get involved in head work, etc', with a view to increasing the power, but then you'd need a decent ecu to take advantage.

Mark.

 

Hi Mark

Thanks for that. What is the "uk" fix?

Sorry if I'm being dense, but my knowledge of engines is slightly inferior to that of a new born baby.

Are you saying I need to get it rebored and new pistons fitted and that will solve the problem? When you say complete rebuild, does that mean there is more work to do? or do you mean that it needs the entire engine stripping and rebuilding in order to do that work?

I know someone from prodrive who is willing to do the stripping / rebuilding, etc.. but would need someone else to do the rebore / supply the pistons, etc. Are cossie pistons of any use to me or do I need genuine STi ones?

Thanks again

Simon

 

Simon

If the engine is in pieces the put cossie pistons in. As for the price I believe there is not much in it and it gives you scope to do more mods if you want.

With regards to the rebore etc speak to Mark as he knows everything!

Sam

 

Simon,

The "UK fix" was to fit a slightly larger piston. Since we're only talking about a few thou', reboring wasn't required.

I don't believe there was ever an STi fix offered, certainly in the UK.

There will be oversize STi pistons available, but not as a straight drop in, and Cossie/JE pistons are cheaper, anyway.

Using these would require a rebore, and the engine would need a total strip, and rebuild. It would also be worth replacing all the barings.

Unfortunately, there are no quick fixs, that I'm aware of, and be wary if any are offered.

Alternatively, run it until it dies, and get a second hand STi engine.

Mark.

 

Thanks again Mark

Any idea how much I'm likely to pay for a second hand STi engine? And if there are better places to go to be more reassured that it won't blow up quicker than my own!!

Cheers

Simon

 

Simon, what oil are you running ? and has this been changed recently.

 

Steve, I think I know where you are going with that! It happened to my friends sti not to long ago.

 

Hi Chaps

Not sure on the oil, aparently the stuff they use in the group a cars though. Also changed regularly.

cheers

Simon

 

simon,

gradeA tend to be fairly good for this kind of thing.

I hate to say it, but in your position, any company that sells you a duffer is unlike;y to let that situation remain, even if you dont abuse your postion, I cant imagine they will let you remian unsatisfied with a situation, so you need not worry too much about that.

You need only make sure it is an sti 3 or four engine.

You could even buy simply a short block. ChristianR recently sold off a completely sti4 engine for a fantastic price.

Check the for sale pages regularly you would be surprised what comes up.

If the worst comes to the worse then consider rebuilding yours with a rebore, uprated rods and uprated pistons. I know you arent one for tuning, but even i standard guise the engine will be able to handle a lot more in the way of stress.

It will be cheaper to just bolt in another engine no question, and if you do, I think I know someone who will take your sti 4 heads from you in order for you to regain some of the outlay for a new engine .

You should be looking at around the 2k mark for your requirements.

 

Thanks adam

I'll give them a call and keep an eye open.

All the best

Simon

 

Thought i'd let you know, left the car with garage over weekend and monday confirmed PISTON SLAP in number four pot!! Am now awaiting Subaru's decision as to whether they'll cough up. Fingers and toes crossed!!

 

good luck ****

All the best

Simon

 

This is far too common a problem on 98 Impreza's. Guess what I've got - a 98 WRX with piston slap... I've seen many people with the same problem on this board and nearly all are 98's like your STI Type R v4 Simon - Subaru really f****d up that year. Anyway rant over. Does anyone know if my WRX (non STI) can be helped by the UK fix? Afaik the engine in mine is basically the same as the UK car except for the turbo, ECU and injectors along with some other minor stuff. Are the pistons and block the same then, or am I talking rubbish?

 

I think the pistons are the same.

Not much harm in replacing all four pistons with forged lightweight ones as it puts less strain on the rods. The labour costs wont be much more as they have to take the engine out and heads off anyway!

 

But doesn't the UK fix with a single new slightly oversized piston use some sort of easy access point on the engine which makes it a much smaller and cheaper job than replacing all 4?

 

Im back!!
Well after alot of conversations with Dealerships and Subaru UK so-called Customer Services, no bugger wants to know about my Piston Slap. Subaru UK are absolutely non helpful and just keep saying that its out of manufactures warranty therefore, 'nothing to do with us' Even though its a 98 Sport Full service history 58K miles!!
They wont even admit to the supposedly known piston slap/piston design problem.
The warranty company dont want to know because the car is still running!! Probably will until no.4 wears right through the lining and i'm doing a very good impression of a London Cab!!

So as far as i can understand the situation at the moment;-
Subaru are quite happy with the fact that my 1998 Sport 58K miles, fully dealer serviced from new until i bought it 6000 miles ago will probably only last until, say 80K max unless I fork out 1500 squid cause the engine wont last that long on its own!!!

Who said Subaru engines go on forever??
Wouldn't maybe mind so much if it had double the brake of its older brother, the TURBO

Puzzled first time Subaru owner

****

PS can anyone give me any ideas to the problems i would encounter trying to change the 2=4 piston myself. Obviously realise its an engine out job but have built enough Mini and Nova engines in the past as to be curious

Cheers

 

**** - In the same boat mate. Late 97 Sport, 72k, slapper, extended warranty, but nobody wants to know

 

DJ Dunk

Did it come on slowly (so to speak)
How long have u been running with it? How long before you goin to do something??

****

 

simon, I would have thought you risk having the wrong tolerance for a long time.

When the pistons are slapping, they are moving laterally in the cyclinder bore, I would have thought that if this is worsened by not being fixed. Eventually the clearance will be beyond tolerance, and the pistons may pick up, that could lead to a seized engine, and the engine momentum could destroy a big end or main bearing.

I could be wrong, (it happens often) but I would not want to risk it.

Forged after market pistons can sound very slappy when first started up before they expand, but since yours never did that before, who's to say it isnt going to get worse?

[Edited by Adam M - 4/8/2002 11:38:54 AM]

 

Ouch!



[Edited by 6 Speed Subaru Killer - 4/8/2002 1:19:43 PM]