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Discussion in 'A3/S3 Forum (8L Chassis)' started by Welly, Feb 7, 2010.
Oh no!!! Mmate i feel for you. Unlucky
OK, A definition....
This initially led me to think mone of the rods had come off the crank and fired up to the head. However, this was fairly swiftly capped when I realised that the piston couldn't possibly of hit the spark plug, due to the recess in the piston. Inspection of the spare head confirmed this. It would of hit the body of the head before going anywhere near the spark plug....
The damage to the plug is obviously impact damage of some type. If not the piston then WTF was it?
Looked down the bore.... Ooooooooh. What's that? It looks like a valve. That because it is.....
Here are some photos I tool from earlier last night of our 'success', prior to the breakage.... lol
Can't bloody believe we'll have to take the head back off. The valve looks to have put a few surfasce dents in the pis,ton. Hope fully there isn't any lasting bottom end damage. A few small dents in the piston I can cope with, sand them back with some fine wet and dry and they should be fine.
Still, only taking the head back off will tell.
If it proves to be A & M's fault, I shall be getting anew (and free) head gasket and bolts. I don't judge a company by the mistakes they make, since everyone makes them. I do however, define them by how they rectify those mistakes. I can't see it being anything lese but a collet not being done up properly....
Jeez mate... you ain't having a good time of it are you....
Another possible failure is that the valve has separated which can also happen... (they are 2 piece)
One thing I have noticed in the first pic after the plugs is the other head face down on the deck... At TDC there are valves proud of the heads surface... if you have done similar with the new head then its also possible you have bent a valve or two and this would have contributed to the failure... just s thought mate...
Hope its not too bad when you get the head off
gutted for you the whole job from fmic fitting has been a nightmare bet you just want to go drive it scince all the hard work put into it, im with you only logical reason would be the collet wasnt seating correctly then dropped the valve which in turn bent and caused damage to the plug id expect the people who done the head rebuild to pay for new valve gasket etc also you need to take head to them to check the guide hasnt cracked or for them to change it anyway..
also in your sig you say 3inch dwon pipe where is it?? std fitted to your car by looks of it
That's a sad tale.
I was all ready to hear how well it was running, after the clutch pedal bit.
You won't know what to do with yourself, once you get it finished. All the free time in the evenings.
Best of luck getting it sorted this week.
Yeah, it's cyl 2's exhaust valves which sit slightly proud (but they don't come from the head face much at TDC).
The head fitted had lived upside down with valves facing up since I picked it up for exactly that reason mate, that and I didn't want the nice shiny face on the floor! lol. So it's not that.
Like I said, I've always got the AGU head if needs be.
Yeah, I noticed that too once the head came off. Appears to have been a slight fib told by the dude selling the car. That combined with all the other ****** he said.... Most of which I could look at and see was ******, but DP I couldn't sadly.
I'll whip it down to Longlife and get one made for me when spare cash recuperates.
Thats the most annoying thing of all. It was running sweet as a nut! Then it just wasn't very happy......
I was looking forward to driving it tonight!
have fun with the spannering. youll get there soon enough
Awesome work on your behalf mate, very impressed! Although I feel for you with all the bad luck im loving the progress you post.
That reminds me actually, I wanted to share with you the cause of my lack of oil pressure.
Turns out that where the oil strainer bolts to the oil pump there are 2 very slightly different sized bolts. Both 10mm and both look like sump bolts. However, one is 2-3mm smaller than the other.
One of the threads winds into the actual oil pump's casing. If you use the long one in this hole....like I did, you WILL FUBAR your oil pump as the tip of the bolts will jam the gears.
Trap for new players - you wouldn't know without taking the pump apart - which we did.
Welly's helpful tip for the day....
Your having no luck are you welly. How did you time the engine when you put the head back on. You may have lost a collet which has dropped a valve or might not have timed the engine correctly and got piston to valve contact.
When you say the engine doesnt rotate by hand, does it go so far and wont rotate anymore. If so, I had this problem on a race engine we got and in uni and it was something really stupid, the cams were the wrong way around so the valve on a cylinder were fully open at TDC. Something to think about as its easily done but saying that the engine wouldnt idle up to temp.
Does the new head have the same valve lift as the one it replaced.
It's OK mate, not new to timing engines so made sure it turned through four full revolutions before firing it up. Besides, it has run for about half an hour on idle perfectly, so timing is unlikely.
Also, have just started taking the head off. Inlet mani is now off and I can see the 3 inlet valves in cylinder 1 are perfect.
It is 100% NOT timing.
not read your thread for a day or two and was expecting to read that you had fired it up, taken it for a blast and you were happy chappy again, so gutted to hear about the fresh problems, a buggered oil pump im sure you could of lived with but dropping a valve/marking a piston is just a fork in the eye!!
so another week of early starts and late finishes then
dont lose hope mate, you will get there soon and it will be totally worth it im sure!!
Have you checked the collets then as you may have dropped a valve. What are the rest of the valves like.
Only a true enthusiast would go to all this trouble and see them as hiccups !!
Dude i feel for ya, but she is so close now and mistakes happen, whom ever is at fault.
I went to fit a gearbox today, chanded the clutch etc got the box to find one of the output flanges missing from the rebuilders. AS its the inboard one i chose not to fit the box and hope for access late, its not worth it. So you are not alone!
Thats what I thought mate, either a collet or possibly a mis-seated valve spring I have been advised is a likely cause. Haven't got head off yet, but will be done tonight. Just got to remove cam belt and unbolt.
Will photo findings as usual!!
Fairplay Welly youre not having much luck recently il drop that yellow into manny this week sometime least you can bang that in
Evening all. Again.
Well, head is off.
I will start with a few photos.
I didn't caption the images as they speak for themselves. Obviously the base of the valve has snapped clean off. The damage to the piston is severe, where the stem has hit the piston repeatedly is pretty obvious. It has gone deep enough to have formed a crack on the underside of the piston itself....
Anyway. Tonight we've had the head off, the sump off (again) and the damaged piston out. Cleaned up a spare piston ready to install to the rod and refit.
Obviously the APY head won't be being reused as the damage is pretty bad to it. Not unsalvageable, but more hassle than is necessary when I have a spare head. So the big port head is going to be a feature of my S3, all be it unwillingly.
I have a question with regard to the AGU's pistons. Standard bore size on the 1.8T is 81mm. However all 4 of the AGU's pistons have been stamped with 80.95 -. This obviously meaning that they are undersized by 0.05mm. My question to you who know much more about these things than me is why? Is it to do with the big port head? I would guess that it is to drop the compression ratio, but I can't figure why. They also appear to have extremely recently replaced rings - much newer than the APY's....
Anyway, I have the evidence to take the head back to the guys who did it tomorrow, a shafted head, a cream crackered spark plug, and a valve in 3 bits.... Let us see what they say....
Anyone shed some light on this for me?
hope the guys who done your head are the decent kind and dont **** you around
to be fair they will probably see the rage on your face and bend over backwards for ya lol
If they don't bend over backwards pal, then they will be bending over forwards.....
I'm sure it will be fine, I can't see it being a problem. If it is I shall take them to trading standards! I hope it doesn't come to that because they're a good pair of blokes.... Only time will tell.
Its a dame shame that
If all the timing was right as you said then a valve wouldn't snap off like that? unless it was sticking in the guide thus keeping the valve open when the piston came up?
Hard to say mate really. The timing is spot on, that is confirmed by the fact there is absolutely no damage to the other exhaust valve. If caused by piston collision due to timing, then both would be damaged. The other is perfect.
I suspect it was what Bill said to me about the valve spring being incorrectly seated.
Has the head be rebuilt?
Have a look and see if the washer that sit under the springs are still there?
The head was fully rebuilt last week mate, all the valves came out and were re-lapped. It was done by a local company, where it will be going back to tomorrow....
(Mentioned at length earlier in the thread....)
If you had jamemd the oil pump gears with that wrong bolt, but the engine turned, how did it manage this?
something else snapped? chain driven off crank. If motor turned over but oil pump was jammed, something must have sheared off
People fitting 20v valves need to take heed of this:
odd the head has gone off the valve, was expecting to see the stem sat down with it, and the collets still secured but snapped off at the lowest collect groove..
hydraulic followers not pumped up too much jacking open the valve?
struggling to think of cause if the valve did'nt snap at the collet groove..
heads fallign off these is not unheard of.. they are not strong valves
Well, would you believe I had a bit of luck with that....? The sprocket bolt wasn't even remotely tight, and the sprocket came off the pump and was spinning round on the bolt itself.... Fortunately. There was a bit of internal damage to the pump, the metal was pretty badly dented inside, and yes, a bit had sheared off which was in the pump on removal.
Is an odd one I grant you, thats not what I was expecting to see either. The piston is smashed to absolute death from the remains of the stem hitting it repeatedly.
Just taken it back to them now, they are going to swap the timing chain tensioner over to the AGU head and skim it for me. I asked them not to touch the valves! lol. And provide me with a new head gasket and bolts. On the whole, I'd rate their customer service very highly indeed. Couldn't of been more apologetic if they had tried. :icon_thumright:
unexplained failure tho..
I've got a set of std pistons if you need any (all have been hit by valves but have been inspected and are fine) £50 delivered
Agreed, but I can't see any other cause for it to be honest. If it was a hydraulic issue I would of thought it would of affected more than just that one valve. It's deffo not timing. It must just of been a weak valve, what other explanation is there?
I've got spares mate, but thanks anyway
Welly, what induction kit you useing, some sort of HKS filter, looks mint lol.
'Twas an ebay special dude - works really really well actually, flows beautifully. Saw one on there and bought it for £30, and haven't seen any since!!
from what i can tell they really dont filter that well tho!
Very nice, so it is HKS then mate?
I tested a spare cone filter whihc is the same as those 2, using small particles of dirt and a dyson, seemed to do pretty well! I grant you foarm filters aren't the best for smaller particles, but they flow very well. Swings and rounabouts. Been using it on my A3 for ages, and the S3 up untill now with no issues.
No - some Ali Benn Singh make mate. No idea who actually makes it
well when i went down the "performance filter" route on my golf i got a pipercross, reason being that its job primarily is to filter. i know a few motorcross types and the only use foam filters because they keep the crud out the best.
ive seen the sort you have (HKS-alike) and its a single thin layer of foam thats not particualy dense so lets all sorts through.