Got my head off, take a look.. now the rebuild. crikey.

[pictonroad]

Well, after some overheating, the garage tested my coolant and diagnosed head gasket.

After getting my head (round one with eyes) in the right place, I've taken the head off (m30 3.5)

Can, I say, this was the single hardest thing I've ever done literally no bolts were easy to get at, an absolute PIG of a job, no wonder the garage quoted £800.

Anyway, the head bolts were covered in a foul black goop, really thick but not mayonaissey. When I took the head off it was still full of coolant, how do you drain the head and blockof these damn things.

Gasket looked like this:







Head like this:







I've cleaned up the head and block:









A quick go round the head with my square tells me it's pretty damn straight:



but I'll take it to be checked and pressure tested in the week.

According to the pictures in my Haynes it's running too rich:



what could be causing this?

Many thanks people.

James

[Gunni]

it´s not been serviced correctly probably for a LONG time,
that black goop is old oil,

probably also it´s been burning oil for a good while and that´s what on your plugs.
And that square you have is no where near correct to assume if the head is straight or not.

You need to look for burn marks on the fire rings to try and determine if gases where escaping into the coolant system.
It´s hard to see from those pictures.

[Jon_Bmw]

On the second picture down between the middle two cylinders I would have said that was a burn mark. But being an M30, i am not sure whether that is a water channel or not? As gunni says, pictures are a pain in the arse to work out what is crud and oil and what is a burn mark.

Whilst you have the head off, pop a bit of oil in all of the cylinders to check the rings.

[pictonroad]

Old oil? hmm

The oil that came out of the sump was very clean. I thought the head bolt channels would be isolated from the oil channels, they were covered in thick black filth.

How do I check the rings. oh no, not more work...

[pictonroad]

anyone?

ta.

James

[jamie325isport]

I thought the head bolt channels would be isolated from the oil channels, they were covered in thick black filth.

All the heads Ive ever taken off none of the head bolts have been isolated from oil, i assume thats normal. As has already been said the square you used is not a accurate way of checking if the head is still straight. Your square wouldnt show up microns (1000 microns = 1mm) which is all it would take. As a precaution I would have the head skimmed and pressure tested before refitting.

Why its gone? Well nothing is jumping out at me from the pictures you have shown. Maybe the head wasnt torqued down correctly some time ago? Did you put the engine in the car or did you buy it like that? Its been running rich, have you noticed much black or blue smoke out the rear end before the gasket went? When was the last time you serviced it? I wouldnt think that the lack of service is anything to do with the head gasket going, but I could be wrong. How much coolant was it going through, how often were you topping it up? You in Worthing West Sussex?

[pictonroad]

I thought the head bolt channels would be isolated from the oil channels, they were covered in thick black filth.

All the heads Ive ever taken off none of the head bolts have been isolated from oil, i assume thats normal. As has already been said the square you used is not a accurate way of checking if the head is still straight. Your square wouldnt show up microns (1000 microns = 1mm) which is all it would take. As a precaution I would have the head skimmed and pressure tested before refitting.

Why its gone? Well nothing is jumping out at me from the pictures you have shown. Maybe the head wasnt torqued down correctly some time ago? Did you put the engine in the car or did you buy it like that? Its been running rich, have you noticed much black or blue smoke out the rear end before the gasket went? When was the last time you serviced it? I wouldnt think that the lack of service is anything to do with the head gasket going, but I could be wrong. How much coolant was it going through, how often were you topping it up? You in Worthing West Sussex?

lol at my square, I will get it pressure tested as soon as I find out where will do it.

Zoner built and run car, believe the head gasket is original, never noticed any smoke in the last 600 miles which is all it lasted after i bought it, I think the last service was about 5k miles ago.

Didn't use any coolant, it happened like this:

http://www.e30zone.net/modules.php?name ... highlight=

Yes I am in Worthing, you local mate?

[Gunni]

The black oil is from old lack of servicing not recent oil change.
that stuff will not go off unless you clean it real good.

pic from inside the head , rockers and valves. should be full of oil burned oil.

[jamie325isport]

Didn't use any coolant, it happened like this:

http://www.e30zone.net/modules.php?name ... highlight=

Yes I am in Worthing, you local mate?

I see. Well from reading your other thread its possible its cracked, repairable? Have you got someone to check the head for you? I was recommended this company from a guy at work http://www.cbpowell.co.uk/ Im yet to use them myself. My dad used a firm in Crawley to repair his Merc cylinder head (porous water ways), they were reasonable and did a good job I can get there details if you need them. Oh yeah I am local! Also In Worthing. I may also know a guy who maybe willing to tackle this for you if you decide you dont fancy doing it all.

[kimbo]

If you're stuck, try QEP in Burgess Hill. Haven't got their number to hand, but just Google them.
Theyve got all the facilities there to test and repair your head if necessary.
Our 325 head is going down there in the next couple of days.

Kim.

[Andy335Touring]

Manky oil down the head bolts is normal for a head thats been on for ages, don't knock the plastic chain guard with the head when you put it back on as they go brittle with age and snap off.

[gareth]

2.5 M20 heads are prone to cracking but 3.5 M30 ones are generally ok aren't they? last time i checked, pressure testing a head properly was very expensive...

if it was me, i'd get a new gasket (good quality), reface the head (£20 at a local engineering company is the usual rate) and lob it back together. if it's been burning oil, the exhaust valves will be crudded up. in this case, you may as well strip and rebuild the head with new stems seals etc (full head gasket set needed for this). oh, chuck a new spraybar on while you're there as if it's been lacking oil changes, the spraybar could be partially blocked which will nobble your cam / followers next.

i hope i never have to pull the head off mine, it looks like a pig of a job!

[jamie325isport]

2.5 M20 heads are prone to cracking but 3.5 M30 ones are generally ok aren't they? last time i checked, pressure testing a head properly was very expensive...

Dont know a massive amount about these engines, but because most of them dont doesnt mean the odd one will? Theres always the possibility.

i hope i never have to pull the head off mine, it looks like a pig of a job!

If your head gasket did go, with no obvious signs of why and with it being a pig of a job would you risk putting it all together again without being 100% sure you have checked everything? Im fairly sure I wouldnt and if it does come back all clear at least you have peace of mind?

It could be just warped but it appears from the photos that most of the contamination is on the right side (bottom in pics) of the block, if it was going to warp would it not be over the length of the head rather than the width?

What about the blocks cracking? Could it be possible the bottom end has failed rather than the top end? Or porousity on both head and block?

Pictonroad did it have anti freeze in it? It just we had that snow not that long ago could something have cracked then? Would that have even been cold enough?

[gareth]

if there's no obvious sign of where the gasket's blown then fair enough. i was getting prices into three figures for just pressure testing so i'd take the gamble myself. i've not heard of a cracked M30 head so far.

on a M20, a failed head gasket is very often actually a cracked head. i'm not aware of a similar problem on M30's but i could be wrong

it's hard to see from a pic if/where it's blown but may be more obvious in the flesh. i'd guess the corrosion on the head can't be helping things.

iirc, Andy335Touring had a cracked M30 block once...?

[Andy335Touring]

Yeah, the crack went from the head bolt hole to the coolant, i got oil in my water but not loads.

It's not a comon fault.

[Jhonno]

Pressure testing isnt expensive..

I got a 24v head skimmed, pressure tested, valves recut and seated and new oil seals for just over £300..

[nickso]

The black oil is from old lack of servicing not recent oil change.

actually it has. i owned it until a year ago. it had an oil change when i bought it and another about two months before i sold it. i was thrashing the pants off it daily so i serviced it very well. it also had antifreeze in it when i sold it.

the only thing i couldnt sort was it running very rich, it even failed its mot for it once.

ive no idea how old the engine is or what the service history is like from the 535 it came out of but i doubt its spectacular. i bought it as a cheap thrasharound and spent a fair bit of money tidying it up. i was genuinely sorry to see this go as it gave me no trouble apart from the battery, the gearbox mount jumping out of its rail and running rich. if i had kept it, and i wish i did, it was always going to get a rebuild at some point. just sorry that its pictonroad who has to deal with it.

derek who built it might remember the donor car details or type in the chassis number of the 535 it came off into realoem, the number is on the booklet that was in the glovebox, may still be there.

[pictonroad]

well, the head is being pressure tested over the next few days, interesting how they do it actually, pretty old school.

IF (big IF) it passes that, then it's going on the 'straightness tester', if it passes that, then a 0.3mm skim and a vacuam test on the valves. (can't rebuild the head, just too much money and time.. )

If it passes all these then it's getting a decoke, new consumables and going back together exactly as before.

If it fails, it's going to be made into bean tins in China and I'm getting a Fiesta diesel lease car.

The Wait begins. Beemer or Fiesta.

[gareth]

chucking new stem seals on and giving it a clean up really isn't that hard. an afternoons work if the head is already off.

you can give the valves a re-lap while you're there too for peace of mind

what's the testing costing you?

[SPADGE]

Pic 1 bottom left looks a bit suspect to me on cylinder 6.
Make sure you clean that block up so its spotless should everything go ok with the head and you re-assemble it!
Good luck.
Spadge...

[murran]

it just looks to me like the engine hasnt been apart for a long long time. head gaskets will fail over time, quite often for no actual reason other than deterioration of the gasket. the waterways look dirty/rusty so probably running without anti freeze for a while at some time in the past wont have helped.
m30 casting are tough as old boots. not like m20s. be very surprised if its cracked anywhere!

do strip the head fit new stem seals (will be part of the oil burning black plugs thing), and re lap in the valves. the valve seats will be scruffy as fook and loosing you compression! when its back together sort out the running rich thing.

oh and punch yourself in the mouth for even thinking about leaving bmw ownership!!!

[pictonroad]

chucking new stem seals on and giving it a clean up really isn't that hard. an afternoons work if the head is already off.

you can give the valves a re-lap while you're there too for peace of mind

what's the testing costing you?

Doing this then....

Guide please

I've got this far with the zone, don't leave me now... I was so worried taking parts of the engine apart I was shaking..

Pressure testing is £50 + VAT
Skim is £45 + VAT
Vacuam Test is £10 + VAT

Sussex Engine Supplies in Bognor Regis, (01243 866 621) the guy even took me into the workshop and showed me the machines they use to test the heads.

Spadge, how should I clean the block up, how can I decoke the top of the pistons?, I can still see the hone marks in the block so I really don't want to be messing about down there with files and the like.

Engine was about 145k miles when it was put in apparently, no idea what it's on now.....

kinda regret getting this car now.

[nickso]

Engine was about 145k miles when it was put in apparently, no idea what it's on now.....

kinda regret getting this car now.

then based on the mileage i did in it and an estimate of what the guy i sold it to did i would guess its 160k-ish

its a high mile/high abuse car, when you get it fixed it will be fine for a good while after that, its a good conversion. if you get it fixed and still want shot of it, pm me, i might have it back

[SPADGE]

Spadge, how should I clean the block up, how can I decoke the top of the pistons?, I can still see the hone marks in the block so I really don't want to be messing about down there with files and the like.

Just turn the engine and clean the top of the pistons at tdc with a wire brush attachment on a drill mate.
Smear a little grease around the sides to stop any shit getting down to the rings.

[pictonroad]

Spadge, how should I clean the block up, how can I decoke the top of the pistons?, I can still see the hone marks in the block so I really don't want to be messing about down there with files and the like.

Just turn the engine and clean the top of the pistons at tdc with a wire brush attachment on a drill mate.
Smear a little grease around the sides to stop any shit getting down to the rings.

I knew you were going to day that... lol..

I marked the chain and cam timing cog together..

be prepared for the... how do I time an M30 post


cars eh..


OK Nick, it's a deal, I'd planned to stick a decent sound system in it, some BBS splits, replace the tailgate and cruise around until next May, you can buy it back then.

[nickso]

OK Nick, it's a deal, I'd planned to stick a decent sound system in it, some BBS splits, replace the tailgate and cruise around until next May, you can buy it back then.

sounds ok, pm me when you're selling it then and ill have a look

[gareth]

chucking new stem seals on and giving it a clean up really isn't that hard. an afternoons work if the head is already off.

you can give the valves a re-lap while you're there too for peace of mind

what's the testing costing you?

Doing this then....

Guide please

I've got this far with the zone, don't leave me now... I was so worried taking parts of the engine apart I was shaking..

Pressure testing is £50 + VAT
Skim is £45 + VAT
Vacuam Test is £10 + VAT

that testing price doesn't seem that bad actually. a lot less than i was quoted anyway. the skim seems overpriced but as it's at a proper engine machining place, i guess you get what you pay for and it's not a "lunchtime job" like most machining places are! plus you'll be getting the whole service done at one place which is handy

afaik, the head is very similar internally to a M20. there's a M20 guide here:
http://www.e30zone.net/modules.php?name ... lhead1.htm
it's also covered in the haynes jokebook

[pictonroad]

Right.

Head is now done.

Pressure tested ok to 70psi, took a skim ok, new valve stem seals and valves ground in giving zero loss of vacuum pressure.

Now to put it back together and hope it wasn't a cracked block all along...

I take it the bores, block surface and head have to be cleaner than an operating theatre when it goes together?

[Andy335Touring]

I take it the bores, block surface and head have to be cleaner than an operating theatre when it goes together?

Head block face should be oil free and no lumps of old gasket/etc. Apply a little instant gasket either side of the H/G where the upper and lower timing chain covers meet the block.

VERY LIGHTLY oil the cylinder head bolt threads/heads/washers and the threads in the block after you have thoroughly cleaned them out.

Don't knock the plastic chain guard with the head.

Replace both head to block dowels if they are missing from the skim.

Don't use any instant gasket on the plate on the back of the head.

[Andyboy]

DO NOT clean the carbon off the edge of the pistons. It acts as a remarkably good oil seal and many M30's have smoked like a bastard after having the pistons cleaned. The carbon will be back in next to no time anyway and it's easily removed by a good caning. The block face is cleaned up with a rubbing down block and some coarse emery soaked in WD40. Clean out the head bolt holes with aerosol carb cleaner. Stick a bit of thin pipe (like screen washer pipe) down each hole and blow all the shyte out. The holes need to be very clean as the threads are under a great deal of stress.

Finally - set the cam to the correct position like this:



There are no timing marks, but note how the threaded hole at the top of the cam pulley boss aligns with a raised lug on the front of the head. No.1 and 6 pistons must be at TDC, both valves on No.1 closed.

[gareth]

if you're replacing the head bolts, you can make a quick and easy thread cleaner by grinding the side of an old head bolt to form a 'D' shape. it'll rake any hardened crud out before a blast with some form of cleaner.

[Theo]

Good quality cotton buds are ideal for getting every last bit of crud out of the headbolt holes.

[pictonroad]

I'm getting the vibe that the head bolt threads need to be clean

[GDBN]

I went to a computer shop and bought a can of "air" - Has a long plastic nozzle - the type used for cleaning out keyboards etc.
Used this after cleaning out with cotton buds.

G