Head off - WTF HAPPENED?! - May have spotted problem!

[Adammcf]

Ive got the head off and am horrified at whats inside. It wasnt a broken valve as I had first thought, the piston on number 5 looks like its been hitting the chamber on the head! Number 1 has a few marks as well.
As you can see in the pics piston no5 is now f***ed and the head is completely f***ed as well!!

All that time and money spent rebuilding the bastard is now wasted. Ive got a f***ed head and the bottom end now might as well be scrap as well as one of the pistons is screwed. Also number 4 looks rusty inside?

Can anyone shed any light into this? Did I f*** up when rebuilding it or is the head faulty/wrong for the car.

I dont know how much more of this I can take. I cant remember the last time Ive felt this s***.

[gareth]

looks like strray nut / bolt / stone / annoying lump of whatever has got into the inlet tract and hammered around in there a while... shame...

[Adammcf]

Can think how. Its been fine for over a month. Could the head have been skimmed too much and caused it? But then if this was the case why would it have been fine until now. Im completely confused.

[A1BMW325iSport]

sorry to hear thats happened mate.

yeah it seems like something has got in there to do that damage

[psychochild187]

was plug five ok.

[Emotechnik]

Can think how. Its been fine for over a month. Could the head have been skimmed too much and caused it? But then if this was the case why would it have been fine until now. Im completely confused.

Just been back through a few of your recent post (last 10 days) and I would say this failure could have been anticipated, sounds like it's been a ticking bomb for a while now.

Some of the answers in this thread may shed light on your problem and you have been having a 'ticking' noise from the top of the engine, just don't ignore anything out of the ordinary.

http://www.e30zone.co.uk/modules.php?na ... ht=#157890

What was the last sequence of work that you did on the engine.

Have you done the tappets recently, or had the rocker cover off?



This exhaust valve looks bent, or something is stuck under it, although it doesn't look like it's had a recent impact with anything, could be before you built it, also if you put longer bolts in the inlet manifold to rocker bracket (you know the ones that the thread strips on) you can break off the 'blind' end of the casting this then falls into the manifold and next the engine.

All that rust in the cylider, does it clean when you turn the engine?

[E30Adam]

Looks like the head may have been skimmed too much but that wouldn't explain why only 2 of the pistons have hit.

It certainly sounds like something's got in there.

[Martinaston]

Could be worn or bent gudgion pins, alowing the piston to rise higher than it should.
Rock the crank back and forth and see if there's any play in the movement on 5.

It's worth checking the cylinders to see if they are out of shape.
What milage had the engine done before the new head?
and are you sure you had the right gasket?

The valves look undamaged to me, Are they?

The rust will set in overnight on the cylinder so thats nothing to worry about (he says optomisticaly)

I think if something was bouncing around in the chamber the valve faces would show signs of dammage.

[boybimmerm3]

the exhaust valve no 5 cyl is a different colour to all the others, indicating a problem which has been developing. looks like something has entered or broke up, what condition is the spark plug electrode in too? could the plug have fallen apart?

[M5pilot]

Really sad to hear your having so much problems.

Get a good healthy engine in there or do an engine conversion if you have the funds.

I hope everything works out for you. Just sit down and work out your next step and dont wind yourself up. Whats done is done, no point losing hair over it.

[Adammcf]

The plug in 5 hasnt broken at all, the end is just slightly bent.
I adjusted the tappets about a week ago to let them out a little bit as I could hear a faint ticking noise some times. I thought one of them was a little too tight maybe. Now I know what was really happening!
Its just so strange how it came on suddenly when it was fine for the first month after the rebuild.
If the head was skimmed too much is there anything I could possibly do to get my money back?
Basically I forked out a fortune for it along with all the other bits and now my engine is scrap.

[calder]

possibly worn shell bearings could allow pistons to get loose. Only seen this on no. 6 piston on someone elses car though.

[Adammcf]

Right I was pissed off so went out and had another look at the head and Im pretty sure Ive spotted the problem.
Pic no1 below is one of the valves in a good cylinder.
Pic no2 is from the wrecked cylinder. If you compare them you can see that the entire valve seat on the second one is gone! You can also see a spot of weld on the port. The seat must have come off and got smashed up by the piston into the head!!!
If so then it looks like they sold me a dodgy head!

Normal valve


Wrecked valve

[Widge]

Yeah, there is deffo a load of metal missing there!
Who did you get the head from?

[Adammcf]

A place called Linwar motors. www.linwar.co.uk

I want to make sure it was the fault of the head though before I go calling them asking for a refund etc.

[Widge]

Well who cut the valve seats / ground the valves in?
And you need to make sure it's not a dodgy guide too, although they probably put them in.
Was it a recon one or new etc, and was there any guarentee?

[E327UKL]

i had this before but i caught it a bit earlier. didnt you notice the knocking for a few days prior?

it could be from over revving?

or

due to unclean oil such as dust or swarf getting in the engine possibly from machining? it eats the shells and dosent lasts a bit b4 the sheel is to big for the rod and due to small tolerences the piston hits the head (only noticable at high revs at first) extreme examples like yours it cracks and breaks away little bits of metal that run up the bore and float about doing damage in you bores.


drop the sump and take the cap off and take a peek of you shell.

post a pic of mine in a sec

[Adammcf]

Well who cut the valve seats / ground the valves in?
And you need to make sure it's not a dodgy guide too, although they probably put them in.
Was it a recon one or new etc, and was there any guarentee?

The head came fully re-conditioned with newly machined valve seats and guides. I ground the valves in but it only took an hour or two to get a good seal on all the valves.
There is a guarantee with the head of 6 months and it comes with a temp sensor on it which renders the guarantee void if it heats up beyond a certain amount. Thankfully the car has run sweet until now and never heated up.

I did notice an ocasional ping noise in the last couple of days but it only happened every so often and thought it was one of the valves sticking.

[Widge]

They should accept responsiblity for it then, especially if the temp sensor hasn't gone over the limit. It looks like some sort of material failure, just a pity it has wrecked the bottom end. Were there any bits of metal in the cylinder when you took it to pieces.

[Sjoerd320i]

well lets hope that they will at least give you a "new" head and maybe pay for the rest of the damage

[Adammcf]

Yeah there were quite a few little bits still loose on top of the piston. The engine only ran for about 3 seconds after it happened.
Im going to give them a call maybe tomorrow and see what they say.

[Widge]

I hope you put the bit's an a bag as evidence!
And I hope there were no loose nuts etc in there which may have caused this monumental damage. Personally I think the loose piston theory isn't right to do this damage unless there was somthing else in there for it to push in to the head. I would be interested to know why that bore is rusty though. Good luck

[Martinaston]

If they had a warped head to start with and then skimmed it to level it off the mating surface will be flat but the combustion cambers will vary in size slightly.
So if number five is/was sitting to close to the piston it could have struck the valve when closed and shatterd the valve seat

I'm thinking this because i was looking at the second picture and the variation in colour of the gasket between cylinder 4 and 5 compared to the others. And in the third pic that dark strip across the back of the head.

If you have a steel rule with a straight edge you should check the top of the head where the rocker cover sits and it may show a bow along the lenght of the head.

There is a measurement for the minimum height of the whole head that makes it un-servicable once its been machined to that limit (but i don't know it) so you may want to check it's height all the way along.

[Jos]

the head should be 125.0mm, the machining limit according to the TIS is 124.7mm

[Adammcf]

I'll try and get a decent ruler today and measure it tonight. There was a noticeable difference between this head and the old one along the bottom. The number in the bottom face of the this head had some of its surface taken off whereas on the old head it wasnt touched.

[pacerpete]

Looks to me like a poorly fitted valve seat has come loose and bits of it have become embedded in the combustion chamber and adjoining ones. Unfortunately this is not an uncommon occurrence on heads that have had lots of welding/machine work carried out. There is no way through incorrect fitting or 'misuse' a valve seat can fall out. Un fortunately your warranty is probably parts only as in the cylinder head casting so valves etc will be down to you. Best of luck.

[Adammcf]

I got a new metal ruler today and Im just back from measuring everything up. The head is 125mm all along each side give or take 0.1mm or so. Its reading almost exactly 125mm on the ruler so it looks like they havent over skimmed it.
A dodgy valve seat must have caused all this. On close inspection of the head it has been welded inside that exhaust port so maybe part of the weld came off in the heat and caused the valve seat to loosen and break away?

[Martinaston]

How comes cylinder 1 is affected as well ?

[Adammcf]

The other cylinders had a couple of tiny bits of metal in them but no real damage. My only guess is that some of the debris from no5 worked its way back up the inlet when it was smashed by the piston and came down into the others.

[tourer-dan]

I'd say it's pretty conclusive mechanical failure due to dodgy parts. I'd definately be laying claim on the suppliers of the head. they need to supply you with another good head and help rectify the damage caused by their faulty component.

I'm really interested in the outcome of this, so keep us posted!

It's a real bummer though mate, I feel really sorry for you.

[Martinaston]

Did you stand the ruler on edge on the top of the head and try to fit the smallest feeler guage you have between the ruler and head all the way along the head to see if it's warped ? Do this on the top of the head as the face will not show as it's been skimmed

(2B.10 in the old haynes book)

[Adammcf]

I never tried that but I'll give it a go when Im stripping the cam and valves etc from it.