325 cam belt failure Update: rebuild in progress :)

[spiny]

I was just wondering in case I try and grab the head then drop it and crack something, that'd make me swear a bit, even if it has 12 bent valves already

[Morat]

If you've still got the manifolds on, take care putting it back on....

[johnl320]

Take 2 of your old head bolts and cut the heads off, screw them in hand tight a few threads in opposite corners before you fit the new gasket and replace the head, they stop everything shifting about as you lower it onto place, remove when you have got a couple of bolts in. Thats what I do anyway.

[spiny]

Take 2 of your old head bolts and cut the heads off, screw them in hand tight a few threads in opposite corners before you fit the new gasket and replace the head, they stop everything shifting about as you lower it onto place, remove when you have got a couple of bolts in. Thats what I do anyway.

it's also useful to cut a slot in them so you can undo them with a flat screwdriver works on exhast manifolds as well.

[spiny]

ok, the torx socket turned up and I now have the head off (after using the Haynes removal order instructions to remove the bolts)

none of the pistons are holed, and none of the valves have snapped off, but all the exhaust valves appear to be bent, none are seated, and if i rotate the ones that stick ouit a bit, it's obvious they are not centered :/

soooo, can people who know stuff have a look at the pics and advise on the next course of action ? cheers

head bolts removed:


my method of getting the head out, carefully levered some long planks under it, made it easier to lift to 'wing' level, then when it was neaer the side of the car, easy to lift out and onto a bench:


valves (cambelt end to windscreen end)

(others here: http://www.spiny.org/e30/head/ )

pistons:



the pistons are marked where the exhaust valves have hit, but the inlet side -seems- ok.

thanks !

[Grrrmachine]

Considering all your exhaust valves have been bent, it would seem that the belt jumped a tooth or two; enough to get the exhaust valves out of sync with the pistons (impact) without doing too much damage.

You're going to have to replace all the exhaust valves (plus the head gasket and bolts) but you may have been very very lucky here.

[spiny]

any tips on the best place to buy a set of valves ? the usual GSF / eurocarparts suppliers ok for this ?

[maggspower]

Hi there spiny, I have sent you a PM to consider, alternativly I could cut you some good used valves to as new spec or better if you want.

I'm sorry to say it but looking at the carbon removed from the inlet valve pockets and on the inlet valve you have pictured, I would say they have hit as well The only way to check for sure which ones are shot is to vac test them in the head as is or get them out and check.

HTH

[Grrrmachine]

No idea what UK prices are like, but over here a set of 12 valves will cost about 35 quid.

[spiny]

GSF want £7 each, I'll keep looking

maggs: cheers for the offer, I enjoy doing this sort of stuff (when it goes smoothly) but if it all goes tits up then I'll be in contact I expect

[Grrrmachine]

If GSF want that much, then I'll order them here and post them to you! Even with postage it'll be half price.

[spiny]

slight update for an old thread

been lapping in the valves very kindly supplied by Grrrmachine, and i'm a bit concerned by the condition of some parts of the head.

first off, the pump housing - can I just buy a new one of these, the hose connectors are very corroded.



and secondly, there is this worrying corrosion on the water jacket, the headgasket seems to cover the 'gap' and it hasn't broken completely though, but it there anything I should be aware of ? I'm trying to fix this on a budget (as much as possible) so having the head ali welded and skimmed is probably too expensive.



one final question, as i've been busy with other stuff, the bores on the bottom end of the engine have quite a bit of surface rust now, would it be best to just rub it gently off with some pine grit fabric backed sandpaper ?

thanks, Phil

[maggspower]

The top picture is of the thermostat housing, get a wire brush on it, if it is really bad and you are on a budget get some chemical metal on it, if it won't seal, but try it first. A good second hand one is about £25. They seem to always be made of a really poor grade of alumnium, and corrode when in contact with the head, like a sacrificial anode.

The corrosion in the water jacket really needs to have something done about it, there looks to be about 1mm left for the fire ring to clamp on to, if you put it back together, it may last a year, six months, a month who knows. But once a head has started to corrode it is as though the corrosion consentrates all its effort to one area but exhaust side of the water jacket is favorite. The correct coolant and ratio is all important here.

Have you checked the inlets? As they have defintely hit the pistons

The best thing to do with the bores would have been put some oil on them when the head came off!! Get some WD40 on a rag and wipe as much of the rust off as possible, then wipe some engine oil on it you will probably get away with it but it is far from ideal.

I was always taught that the cheapest way to do something is the right way, as then you dont end up doing it twice

[spiny]

yes, the old 'buy the best and cry once' approach

I have six inlets to go on too, I was hoping to find a valve spring remover that works from the top only, so I could leave the inlet on, but they seem to be thin on the ground, so I'll be adding a manifold gasket to the list

I don't know if it's just me, but the longer this takes, the less daunting it becomes - everything seemed bewildering when I first took the head off, but with a few weeks of pondering everything I pop in the garage, it's looking clearer

When it's all back together, and hopefully running I'll drain and flush the coolant, what came out was pretty clear, it didn't seem to have much anti freeze in it, perhaps it's been topped up continuously but never changed ? who knows ...

expect more questions ...

thanks again, Phil.

[spiny]

ok, another quick one, took the thermostat housing and the inlet off earlier and i've just realised that what I thought were blanking bolts are actually some kind of bodge on the thermostat housing, one random screw and what looks like a wheel bolt all with a generous helping of PTFE, soooo, what -should- be in these ? or should they have a neater OEM blank there ?

[Speedtouch]

Blue and Brown temperature senders, I'd have thought:



Blue lets the ECU know the engine water temperature to adjust it for cold or hot running, brown sender for the temp gauge.

[Cloggy Saint]

Blue temp'sender goes where the wheel bolt is

[spiny]

ok, just been out to the garage to take a few pics as i'm confused

I took two wires off when i removed the housing, should there be four ?

the two connectors in the photo are orange-ish and blue (the flash has washed out the colours a bit)

[Speedtouch]

Those are indeed the blue/brown temp senders.

The diagram on RealOEM shows a blanking plug (2):

http://www.realoem.com/bmw/showparts.do ... g=11&fg=35

[spiny]

so some previous owner has been fiddling then ? I wonder what they were trying to do ?

[maxfield]

Maybe trying to bleed it and lost the original bolt

[Demlotcrew]

Are those not pipes that go to the throttle body heater plate? They normally rot away and leak, maybe someone has tapped them and plugged with an M12 bolt?

Andrew