Repairing valve on modern car

[James k]

Hi,
I've got a 2002 Vauxhall Zafira that has lost compression on cylinder 2. The engine management system reported a misfire as I was driving back from Germany and this was first misdiagnosed as the coil pack. It turns out now that actually, there's no compression on cylinder 2 which I'm guessing is a burnt valve (or could be something else?) Now, the question is, is it possible to repair myself? I've fully rebuilt a minor engine and would have no reservations about doing it on a minor or other old car but I'm imagining that this is different. It's got the 1.8 dual overhead cam engine which already sounds daunting! Getting it fixed by a garage is too expensive and I'd really rather not have to scrap the car. What do you reckon?

James

[Trickydicky]

Googling it brings up quite a few results so it would appear to be a common problem, this thread suggests a sticking valve, http://www.rac.co.uk/forum/showthread.p ... -6-misfire
If you do need to remove the head does the Haynes workshop manual not show how to do it?

[James k]

The Haynes manual is rather vague so I'm not entirely sure of how complicated it is. What I'm wondering is how complicated it will be compared to a minor engine. Whether it's doable or far too complicated.

[firehor5e]

What have you got to loose James?..if you have a comprehensive tool kit etc,and the time/having the car off the road etc. The car is not any use or of any value as it stands now.So i would do some investigation as to what is involved and make sure any "special" tools are to hand and go for it! I have done loads of rover K series head jobs,not to difficult,just time consuming.easily doable over a weekend..Good luck..

[James k]

That's what I'm thinking, It could go three ways: 1. Scrap the car, 2. Successfully fix the car or 3. Try to fix it, fail and scrap it anyway. Obviously the ideal option would be 2! How would you compare the difficulty of doing a K-series to a minor engine? I managed to fully rebuild my engine, is it likely I can manage the Vauxhall? It's the overhead cam that's putting me off. I imagine that it's difficult to remove and refit the cambelt, time the engine etc (judging by the amount garages charge to do it!) Plus I would have thought that it's built to a much higher precision than the a-series. Would I be able to lap in the valves, decoke the head etc. without ruining it?

Thanks

[panky]

Underneath all the plastic bits and fuel injection gubbins the engine is essentially the same(except for overhead cam). Go on the Zafira forum and learn all you can, be meticulous with the strip down and photograph everything. But why not give the engine flush and oil change a try, it worked for others and that's probably what they will advise on the forum

[philthehill]

James
Sorry to hear of your predicament.
I had a similar problem when my twin cam variable inlet cam timing Suzuki dropped a plug tip.
Whilst I did not loose compression I had to remove the head and have it skimmed.
It was a nightmare as Suzuki do not seem to sell workshop manuals so I had to go back to first principles.
Brought No 1 piston to TDC on compression - marked everything and took lots of photos during the dismantling.
I kept a battery connected at all times so as not to loose the engine management settings.
In retrospect it would have possibly been cheaper to have got a good s/h engine as the genuine Suzuki parts were slightly more than the cost of a s/h engine.
With once only use cylinder head studs at £10 each and gaskets not cheap either it set me back about £300 in parts and not include my labour over the three days it took me to do the job. I virtually had to dismantle the front of the car to get the head off.
Looking on 'e' bay there do seem to be suitable engines for sale at around £250 - £300.
The option of a good s/h engine may be worth a consideration.
Modern twin cam engines are not like simple Minor engines - they are much more complicated - but I admire your pluck in thinking about having a go.
Phil

[James k]

From what I've seen, the parts for the Zafira seem to be cheaper but I haven't researched it properly yet. I've had a look at those second hand engines on eBay and there do seem to be some good deals. The trouble would be getting it fitted though. That could be very expensive and something I'm pretty sure I couldn't do myself. I'm still undecided about what to do. Part of me thinks that I should just go for it; I had zero experience with engines before and managed to rebuild a minor engine, maybe it'll work out the same. The other part though thinks it'll be way too complicated. But the prospect of having done such a repair on a modern 'unfixable' engine is rather alluring!

[firehor5e]

If you were close to Devon i would give you a hand....i can remember doing a 16v twin cam on a vaux vectra years ago. valve compressor needs to be able to go "deep" into the head if i remember? cam belt easy peasy,no special tools.. just time consuming job..

[bmcecosse]

The biggest problem will be correctly fitting/re-timing the cam belt. This is not straightforward at all - usually involves some pre-tensoning and then re -setting. And they always suggest a new water pump at the same time. There's also not much room to work. If the valve is just 'sticking' then I think I would be trying to unstick it without removing the head. Take the cover off and have a look as you turn the engine over by hand Could be camshaft problem. Some 'diagnosis' that thinks it's a dodgy coil when there is no compression..... Great system there..... I think I would be taking my own compression readings...

[James k]

I'll have a look at the valve when turning the engine over but it seems unlikely to me that it's just sticking. It's not intermittently misfiring, it's missing every time on cylinder 2 The cam belt was replaced recently so I'll have to check if the water pump was done at the same time. Space could certainly be an issue so I'll have a good look at what's involved and how much can be removed to get getter access to the engine. As I said before though, the car isn't worth the price the garage would charge to fix it. As far as I see it, the worst case scenario is that I dismantle the engine, can't get it back together and have to scrap the car. Not much to lose if I would be scrapping the car anyway.

[morris van]

My neighbour had the same sort of thing happen to his 11 reg VW Polo at Christmas and it went into a garage and fixed the problem and cost a few hundred pounds. The cam belt snapped on the way home from the garage and bent all the valves. He has since scrapped it as it needed a new engine and the engine was going to cost more than the car was worth.

[Longdog]

If you obtain a gates cam belt kit the timing belt is childs play to tension as there are detent marks on the follower which show correct position/tension. More problematic is removal of the water pump as they always corrode to the block but flush is worth a try first as the cam followers are very prone to sticking.

[bmcecosse]

I read a tech bulletin on this subject - and there was much locking of the cams with special pins - then fitting the belt and tensioning it to 'pre-tension' marks. Then running the engine (pins removed of course!) and then retensioning to other marks. I had been thinking of keeping a car with this engine - but the miles were up for a new belt. I decided to trade the car. Problem is - if it's not right and the belt snaps - then big bang and engine ruined. My SAABs with chains (and my TR7) were much easier to work on and understand - even when one of the SAABs dropped it's chain when starting one morning - it didn't do any damage. the engine of course is back to front in these cars - so it was 'fun ' fishing the chain back up and on the cam pulley - and then timing and tensioning it while working down a 2" gap.......

[James k]

Okay, time for an update. After a few days of working on and off on it, the head is off. It is indeed a burnt valve!! There's a chunk missing out of one of the exhausts on one cylinder. The bores look great, no scoring and not even a ridge. The engine is coked up a bit but nothing like what I was expecting. Most of the valves are not sealing properly (tested with white spirit down the ports) so I'm thinking that this could have caused the burn. I'm going to test and clean all the injectors too to see if one was causing it to run lean.

It was certainly more challenging than the Morris engine but everything has pretty much gone smoothly, except for needing a rattle gun for the crank bolt! I've carefully documented and stored everything too. I'm now planning on replacing the burnt valve, lapping in all of the valves, replacing all the oil seals, gaskets etc and giving everything a good clean. I'm considering new rings too.

Even if it goes wrong at some point, this has been a great learning experiences and has really demystified the modern 'unfixable' engine! I will keep you posted on the progress but so far, all is good!

[panky]

Bit the bullet big time, much admiration going your way

[stag36587]

Big respect - well done on progress so far

[philthehill]

Well done James

[James k]

Right... After countless hours of work, parts sourcing, struggling and neurotically checking every last bolt, IT LIVES! I dismantled the whole head, thoroughly cleaned and decoked everything, had the head skimmed, lapped in the valves and reassembled it with new oil seals. I replaced the timing belt and head gasket and all other relevant gaskets and cleaned out the fuel injectors (using a modified tyre stem valve, a can of carb cleaner and a 9 volt battery!). I made sure to check everything a million times as I assembled it for torque, alignment etc. and it just fired up first turn! After a couple of minutes of noisy tappets and smoke from spilled oil it was running like a sewing machine. I've just driven it and it's going better than ever It's almost running too well, it makes me nervous!

Of course there's still time for it to all go horribly wrong but, fingers crossed, it's fixed. At least it's running great at the moment. I'm going to drive it as much as possible these next few days as I've got to drive it over to Germany on Friday I'll do an oil change before then too.

Thank you to everyone for giving me the confidence to take on the job!! It was very challenging and although it could still go wrong, I've learnt an enormous amount about engines!!

[philthehill]

A round of applause for James.
Well done.
Phil