Don Palmer

Make sure they do at least six months warranty on the engine work.

millband

Now it's been suggested, I think I'll push for at least 12 months extension on the engine if they'll go for that.

Cheers,

Stephen

PS That's one-all now in the battle of the boards! (yes, I know it's not a battle really since most of us live in both places!)

millband

With only 6 weeks of warranty left, my car (UK 97MY, 42000 miles, no mods) has been diagnosed as suffering from the dreaded piston slap.

I was expecting that, and the dealer (K T Green) has been very helpful and is now in touch with IM. I was expecting a new engine, but I've been told there is now a piston kit for the turbo. I know they do that for Sports, but has anyone heard of this for Turbos? Any experiences?

With the talk going round of big-end failure in some Turbo cars I'd prefer a whole new engine while the warranty still holds, but I guess if a piston replacement fixes the existing problem I can't really argue.

What do you think?

Cheers,

Steve

PS This is also on the "technical" 22b.com - now where will all the replies land?

millband

Looks like a result - a short engine is on order, and if I time this right the dealer will be looking after my car while I'm on holiday, so I don't have to worry about it being in an airport carpark

I've got to say I'm well pleased with the service from the dealer (K T Green nr. Leeds), but I hope the new engine lasts longer than the original did...

Steve

munna

had the engine changed on mine....it was making a clicking sound upon start up from cold......number four cylinder had gone!!....new engine placed in.....Brilliant is all that I can say....It picks up faster and pulls very cleaner and quicker that before....some thing to do with 99spec short based engine I think??has any one else had the same effect?

letdown

Excuse my stupidity, but I also have MY97 with 3 weeks of warranty left!!Arrhh!! How do I know if I am getting piston slap?? I kinda hope it would be obvious!! I did ask on the main board but got flamed!!! ho hum!

millband

Flamed? Don't see why. Do a search though, there are quite a few threads on this subject.

Piston slap as I understand it is bascially the pistons knocking side to side due to too much clearence in the cylinder. In my car, the engine sounds like a diesel when first started and put under load (ie pulling away). The knocking is "heavier" than valve gear rattle.

On mine it goes away once the engine is warmed up, but it will get worse and worse if not sorted now.

Steve

Matt Porritt

Piston Slap is usaully an ovaling of the bore, in relation to the rotation of the crank.
There has ot be a serious manufaucturing problem to get slap on an engine thats done bugger all work.
I recently assisted in rebuilding an engine that had been used on the road for at least 120,00km and then done about season of rally work and daily driving.
The bores were only about 1/2 way through the ovalility spec and it had been thrashed!
We also get about 35,000 hrs from liners on the ship.. and they're poking about 5500hp with about 80 tons of force on each cylinder each time they fire.

That rattling noise like a diesel is probably more octane related (pinking), timing or possibly just lean.

Blackscooby

I'm not sure of the size of the Cosworth pistons to know whether they are oversided, or what.

Its loudest when cold, but is still evident when hot.

They do give a HUGE increase in power thou'. Its about as quick now running 17PSI as it was when I blew it up on 23+ PSI.

:-)

My Harewood Hillclimb times are 2 tenths slower running a lower (safer) boost.

Blackscooby

My UK MY94 damaged a piston due to too much boost (23+ PSI) which resulted in a rebuild with Cosworth pistons. Since then it had piston slap at 1200 RPM. The engine builder said this was acceptable with this type of piston.

Now I'm worried though.

firefox

Hi there,

Find out what version of Cossie piston they were, what bore size/clearance they used.

Does it just happen at cold or warm ?

You will get more noise with "aftermarket" pistons, the bore clearances are larger.. sometimes twice or three times...

J.

Gary Foster

I've just got a phone call from my dealer (Sparshatts) and I will be having a new short block fitted in a couple of weeks (to fix a piston slap problem) !

I was initially worried as I thought I may be fobbed off. It seems however Subaru are quite committed to keeping us happy ! and a good job too !

I'm quite impressed, a new engine must be costing a pretty penny for them, yet they really didn't argue at all, dealer simply put in a warranty claim, and now a week later I've got the answer

Have to say, I'm pretty impressed so far with the level of service - they could have made this very difficult for me.

Gary

WAL

Gary
Our Scoob is in at Sparshatts at the moment having a new short engine for same reasons, should get it back on friday.
I think we should consider ourselves fortunate as I spoke to a guy (hello Steve)with a ,IMO, worse sounding car that they refused to do. I really cannot say a bad word about them from my personal experience though.
Just the pain of running it in again, although the last 2 weeks of "enthusiastic driving " in France will tide me over!

Warren

millband

The whole piston-slap issue must have been a major problem for Subaru. Anyone got access to any stats?

Given the large number of reported engine-swaps on this board, and given that only a tiny proportion of scooby owners use the BBS, it must have been a biggy. Why has it never been reported in any of the motoring press?

Steve

nickt

I had my STI4 rebuilt with cosworth pistons and also had a piston slap problem.....
The rebuilders then swapped the pistons - it was OK for a month or so (not many miles!) before making loud slap noise again at cold.
Now sounds crap for first couple of miles, but great when hot.....

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Blackscooby:
<B>I'm not sure of the size of the Cosworth pistons to know whether they are oversided, or what.

Its loudest when cold, but is still evident when hot.

They do give a HUGE increase in power thou'. Its about as quick now running 17PSI as it was when I blew it up on 23+ PSI.

:-)

My Harewood Hillclimb times are 2 tenths slower running a lower (safer) boost.[/quote]

firefox

Again...

What bore clearance ?

What "issue" of pistons ?

J.

johnfelstead

piston slap on the standard engine is not bore wear related.

It is down to the piston running too hot and distorting.

It usually shows on no3 cylinder as that runs aprox 100 degrees C hotter than the other 3 on the impreza engine.

Once its distorted its fubard, needs a replacement.

The piston slap you may be seeing on the engines with cossie pistons may be down to the type of pistons you are using. If you are using forged pistons then they run larger clearances cold as they expand more with heat. It is completely normal for forged pistons to slap when cold, you must however make sure you wait till the engine is fully up to temperature before you allow it to see any boost, otherwise you will knacker the liners.

As Jay says, if you have had aftermarket pistons you should know the clearances, the piston manufacturer will tell you what is required.

johnfelstead

dont fancy living in your neck of the woods Jay. ROFLMAO

Blackscooby

Mine certainly doesn't get any hard throttle when its cold. I quite like my engine as it is...

Only problem is I don't have an oil temp gauge..so how do I know its warm enough...apart from the water temp gauge ?

I've been told by a number of people now not to worry about the clatter from the Cossie pistons...."they all do that Sir !".

Mark.

johnfelstead

fit an oil temp gauge

Blackscooby

What else should I expect from asking such a question ??

Thanks

PeteC

I had my car fitted with a set of three gauges (boost, oil pressure and temp). It's surprised me just how long it takes for the oil to get up to working temperature - very, very much longer than it takes for the water temp to get to normal, and certainly much longer than I would have expected.

Definitely worth getting an oil temp gauge fitted in my opinion.

Pete

Blackscooby

ooooh sod, cos I normally start to open it up once the water temp has reached its normal operating temp...

I'll look into the extra gauges in that case.

ta

Marcus.

millband

An update on my engine swap - all done, new engine has 12 months warranty, it's loads quieter, AND I got a new clutch fitted for less than £100 as they did it while the engine was off!

Excellent stuff, and good judgement from the dealer as I was not available to ask if they should fit the clutch or not. They did it anyway, solved my judder problems and I'm well happy (no, I don't think the clutch was a warranty issue as it was pretty much worn out - the biting point was almost at the top of the pedal travel).

They had to order 2 engines in the end though, as the first one they fitted suffered from overheating.

Sorted!

Now I just have to run it in...

Steve

JF: I'll take a couple of weeks over running it in, and THEN go to Scotland. Much more fun in my opinon! And I don't want to find out the new engine leaks oil or worse in the middle of nowhere...

Sith

Steve,

Good to see you have it sorted.

Pete C,

Oh T1Ts, Ive been waiting for the water temp gauge on average before mashing the load peddle. And I mean mashing it!

Will I have done anything to the engine in my soon to be 5 months of ownership? It is a MY96. Having said this, it is normally only used at weekends.

Last thing I want is Piston Slap. I'm paranoid as it is.

P. (aka Mr Paranoid) - who is now going to get an Oil temp gauge.

PS. Is a pressure gauge necessary?

[This message has been edited by Sith (edited 04 October 2000).]

millband

UPDATE:

Right, I've nearly run my new engine in now - 1000 mile service on Tuesday. It's been nearly 6 weeks since I've felt the turbo kick in and I'm getting really impatient!

So far:
Good: Much quieter engine, less clutch judder
Bad: Whining noise from power steering (it seems like) when car is warmed up - been getting worse, brake disk covers catching on corners, headlamp alignment all over the place (why? do the lights come off when you swap an engine?)

Hopefully my dealer will sort all this on Tuesday, and I can go back to being a happy camper again.

Fingers crossed,

S

firefox

Glad to hear you are nearly there

Power steering could be:

Low on fluid
Belt tension

Cover catching ? you mean the stone guards ? wierd.... slightly flex them back

J.

millband

Cheers Firefox - I've checked the power steering fluid, seems OK. Belt tension seems OK too, but I'm no expert. Maybe it's too tight?

The disk stone guards prob. just need bending back, like you say, but I'll let the dealer get his hands dirty instead of doing it myself.

Cheers,

Steve