LATEST UPDATE

[Blackie_No1]

Im not sure if this is the correct place to post this but what the hay!!! Have eventually started to remove the head of my little sick baby, the reason it has taken me so long is due to lack of knowledge on BMW's, gimme a ford anyday and i can strip and rebuild them blindfolded, also, lack of tools, i.e: star head sockets, for head bolt removal and a puller, to remove pulley's!! Anyway here are the latest pics of the work:

[Jos]

What happened to it? gasket go or something more fatal?








500 posts at last Need more spam production

[Blackie_No1]

Have just got the head off, at first i thought that she slipped a tooth on the timing chain, but when i checked out the alignement all seemed normal, then i pulled the pulgs out and found the number two plug was fouled up by the oil water gunk mixture, so i suspected the head gasket, then i was told by an 'expert' that the head was most probably cracked!!

But this is what i found when i removed the head:




What im now thinkin is, the head gasket was on its way out, then somehow, she must have slipped a tooth on the chain.
When i think about it, from i bought the car 5days before she stopped, there was a rattle from the engine. On the day of death(so to speak) there was a hell of a rattle(im assuming that was the 8 inlet valves rattling of the piston crowns and or the chain slipping!) and that was when she lost compression!!

[tomstickland]

A friend of mine who worked for BMW said that the headgaskets always go near the 100K mark...

How does a chain slip by a tooth though? <I'm not being pointlessly argumentative, I just don't see how a chain can slip a tooth, or why it would do it>

[Dan318-is]

im fookin useless with shit so advise is pointless

but mate, i feel sorry for you!

if my IS did that id be screwed

theres on for sale on ere fella

[Blackie_No1]

A friend of mine who worked for BMW said that the headgaskets always go near the 100K mark...

How does a chain slip by a tooth though? <I'm not being pointlessly argumentative, I just don't see how a chain can slip a tooth, or why it would do it>

My car has 192000 miles on it so that wud bak up the theory of the 100k thing, assuming she had already been changed.

As far as the chain slipping a tooth, if the tensioner is faulty or worn then the chain could slip as the chain wud not be at the correct tension.

Thing is though , the guy i bought the car off said he 'thought' the tensioner was changed prior to his purchase of the vehicle, but im now thinkin that was bullsh1t!!

Thanx 318-is, im shit apon like but the car is worthless not running, and i cant afford to loose that sorta cash on her so i gotta try and fix her!!

[Dan318-is]

np mate, keep us all updated, a dead m42 is such a horrendous site!

[Jos]

U on the hunt for another M42 then? If you need the car back on the road I do have a complete 1.8 M10 with box and everything sitting in the garage, no idea how easy the change would be though, probably more hassle than its worth.

That is one knackered looking engine you have there though.. fu*king harsh too if u had on just bought it...feel for ya m8

[Dan318-is]

i would buy the IS engine for sale if u can mate

then sort that out while its out it looks fooked mate

[Fushion_Julz]

Blackie:

You are certainly going to need at least one new piston as No2 is screwed...

Check the seals on the others by having the piston half way up the bore and filling the remainder with petrol or diesel and seeing if it seeps into the sump past the rings ...The seal should hold it for several hours...

Do the same on the valves by removing the cams (so the valves are all closed) and filling the combustion chamber with petrol/diesel...should hold the liquid almost indefinitely...Any that seep indicate either worn/bent valves or damaged valve seats.

My advice would be check if the pistons and valves are OK apart from the obvious one...Then have the head crack-tested ultasonically and checked for starightness. If there are no further problems, replace the damaged piston, decoke the head and reassemble.

If there are other issues, then it is worth considering buying a working s/h engine to rebuild...

Whatever you do, replace the big-end shells and main shells since you have to remove the sump (at least) to get the damaged piston out...

If it were me, I'd remove the block and do the work on the bench as it is much simpler and you will be much more likely to get a top quality (clean) finished product...

Having built many (racing) engines, the best advice is: "cleanliness is nest to godliness" and "measure 20 times, assemble once and force nothing"

[Blackie_No1]

@ Jos, yea man only had her 5 days when she died!! How much are looking for that engine and box?? Have u the loom and brain? Is it injection??

@ Fushion_Julz, wat makes u say that the No2 piston is shagged??

[Fushion_Julz]

Well, perhaps it is just your photo (on closer inspection)...but it looks/looked like you had a small chunk missing AND it is the only one full of liquid (and I assume you drained all fluids from the block (water and oil) before taking the head off)

If not (any chip in/on the piston) then check and clean as necessary....along with the others....

If they are all good, then is the head-gasket OK?

[Blackie_No1]

Yea all the fluids where drained from the engine before the first bolt was even takin off!! The picture is from a mobile phone camera so isnt the best of quality tho i dont belive the piston is chipped.

As for the head gasket, it appeared to be ok, with no tears orperforations visable. If you look at the picture with the close up of the head face u can see a strange little mark near the lower rite exhaust valve which may be a small fracture line though it appeared to get less noticable when i rubbed it with a little bit of emery cloth. Can u have a head pressure tested without valves??

[E30Mark]

All of the pistons look like they have impact damage to them from the valves....

The valves all appear to have a 'witness' around the edge where they have been on a collision course with the pistons

As Fushion_Julz says try a drain down test on the head / pistons and see what happens.

Did you try a compression test before you took the head off?

best of luck

[Fushion_Julz]

You can have the head ultasonically tested for cracks...Dunno where you reside, but Oselli in Oxford or Clifford Cox in Reading both do the job...

I believe it needs all ancilleries removed, but ask the engineering shop before dismantling everything....

Test the valves/seats before taking anything apart....You might have got away with no damage...

[Blackie_No1]

Im from northern ireland mate. What kind of pressure test are u referring to mate??

If you mean a cooolant system pressure test, well it couldnt be accurate as the head gasket may have been burst so therefore giving incorrect readings, if you mean a cylinder pressure test, then again, no point as none of the inlet valves are closing correctly.

How can i test the valve/seats before taking them apart if they aint closing correctly mate??

Not meaning to sound cheeky here, just trying to get a different perspective than my own.

[Fushion_Julz]

I'm sure there is an engineering shop in NI, given the number of rally teams in the province, that can crack-test your head...

The test is and ultrasonic one...basically works by listening for changes in pitch when putting various frequencies of (ultra) sonic tones through it...
Shows up all cracks, seen or not; hairline or major!

To test your valves for seal:

Remove the cams (since you will need to do this anyway, start here) so all the valves are closed....

Now support the head horizontally and valve side up. Get a small bottle or can of diesel...Fill each combustion chamber and wait to see if the fluid leaks onto the table/floor on which the head sits...If it does, the cylinder it leaks from has one or more bent valves...By examining the valve seats for bubbles you will see which one(s) are leaking....

The valve to seat seal should be almost perfect and ideally should hold the liquid some while if not permenantly...
Obviously, if the valve doesn't close, then the valve needs replacing....With the valve out, you can see if the seat has any sort of damage...Small scratches can be ground out when you seat the new valve but big gashes mean the seats need to be replaced...

[Blackie_No1]

aye rite enuff havent checked the valve seats as u say!! Are they replaceable then?? They wud obviously require and engineering shop to do that tho??

She is going to Smiths Engineering in Ballymena on monday to get pressure tested(the head) from there i will see the next course of action

Cheers for your help mate!! Here, have you heard of this special tool to compress the valves so as not to damage the valve caps??

[Fushion_Julz]

Here, have you heard of this special tool to compress the valves so as not to damage the valve caps??

Valve spring compressor, perhaps?

Only I seem to recall that the valves in the iS are hydraulically operated....

That might require a special tool...
IME, it is often cheaper to fabricate the tool you need than to buy a factory supplied one...especially for a one-off job.

Over on the BMWCC forum someone has proposed a tool hire club for special tools...http://www.bmwcarclubforum.co.uk/forum_ ... 21518&PN=1

[Blackie_No1]

They are hydraulic, thats why i am confused about this so called tool, and it couldnt be the convential valves spring compressor tool as you would need to have the head of to use it. What is the RTAB tool he is talking about??

[tomstickland]

It's a special tool that's shown in the Haynes manual. It compresses all 8 valves so you can then remove the cam with no load on it.