markwild

Anyone ever known an STi to split a cam follower bucket ?

Had my 02 UK STi engine stripped to investigate a clackety tappet and its turned out to be a bucket that has split ....

Car has done 54000 miles, but I've only owned it for 15 of them.

All work is being done under warranty, but curious to know if anyone has had a similar failure and whether its likely to be cause or effect.

Ta,

Mark

p1mark

Never seen it on a scoob, but have see it on various other engines.

causes include worn bucket bores allowing excessive rock of the bucket, wild cam profiles that are a bit too much for the standard valve train, and have also seen the last few mm's of a valve spring end break off and get caught between the outside of the spring and the inside of the bucket.

this last one maybe a possibility in your case so check this. also get them to check/measure the bucket bore as it may well be damaged beyond repair. obviously this requires a new cyl head.

markwild

Cheers -

Car appears to be unmodified (except a strut brace, that has been fitted the wrong way around - so the previous owner has cut the I/C scoop skirt to fit !) so suspect that its standard internals.

The garage are replacing the buckets and currently have the engine out - I was/am just concerned incase the root cause may not have been found.

Had an oil-way block on a previous (non-scoob) car, that clattered for a couple of hundred miles, then the camshaft siezed at one end, snapping it in two !

Guess I'll make sure I get some miles on it as soon as I get it back, to try and make sure its OK now, but wanted to see if I could get a list of causes to keep an eye on/test on its return...

The spring end breaking sounds like it could be caused by faulting parts ? - Could a faulty part last 50K ?

p1mark

If you are concerned about root cause get them to check:

Bucket bores are still within manufacturers tolerance (they will need a bore mic or a comparitor though)

Oil feed to heads is 100%

spring seats and springs themselves are all ok.

Could be a friday afternoon job at the bucket manufacturers, could be over revving etc....etc.....who knows!

markwild

Thanks mate

As its covered by subaru warranty (rather than the dealer), and they've deliberately taken the time over it (removing the cams and checking them, removing the engine to fully examine, for instance), I'm re-assured that they'll be checking it - just wanted a 'second opinion', in case it was a common occurrence due to a particular item -

Cheers,

Mark

p1mark

I have never heard or seen of it on a subaru BUT i have limited experience of scoob engines so dont take my word as gospel. If API david or someone of his ilk sees this hopefully they will reply. The things i noted above i have seen on high reving NA race bike engines - but all engineering principles apply across the board

APIDavid

iTrader: (4)

Sometimes they split when we have to use our two pound lump hammer to get the late ones in the early heads

But when we fit the correct ones in the correct heads there is never a problem that we have seen. We've also seen some pretty horrible repairs over the years both ' professional ' and amateur and not seen it there either.

Can only really be explained as a faulty casting.

David APi
www.apiengines.com

markwild

Thanks David - In a funny kind of way that's actually very reasurring - It sounds like the part was always faulty and is really the cause, not just an effect.

The dealer is replacing all the buckets on that side, and rebuilding/fitting today (or early next week), so hopefully I'll get the car mid-next week at the latest.

Cheers for all input,

Mark