Vauxhall Astra timing trouble

[Stephen]

Hello,

The other half's Astra broke down today. It is a 56 plate, 1.4 petrol.

She says she was driving along when it suddenly and without warning
lost power and made a rattling noise.

The RAC sent someone out to tow the car away. The garage has not had
time to look at it yet but think it is a timing problem. The chap who
came to recover the car said he thought they have a timing chain which
may have lost tension and suggested that they would have to take the
top off the engine to have a look.

I can't give much more detail, as I wasn't there when it happened, and
I know I am jumping the gun when he garage has not diagnosed the
problem yet but could it be a timing chain problem? If so what are the
consequences of this?

I thought when timing belts snap, the results are catastrophic, but I
don't know anything about timing chains and whether they are any
different in failure?

Thanks,
Stephen.

[Chris Whelan]

That engine does have a cam chain.

Regardless of the means of driving the cams, modern OHC engines have such
tight piston to valve clearances that if the drive is lost and the engine
is turned, significant damage is likely.

The amount of damage is down to luck; in theory, when a chain breaks
there is always the chance that more damage will be caused by the broken
chain.

Repair costs are usually higher than with a belt-drive engine due to the
need for more dismantling.

Fingers crossed is something more trivial...

Chris

--
Remove prejudice to reply.

[Dave Plowman (News)]

In article <nrank71965le7s9qm...@4ax.com>,

Stephen <inv...@invalid.org> wrote:
> I thought when timing belts snap, the results are catastrophic, but I
> don't know anything about timing chains and whether they are any
> different in failure?

Principles are just the same - but a chain should last longer than a belt
and give some warning of impending failure by rattling.

--
*It sounds like English, but I can't understand a word you're saying.

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Gordon H]

In message <52682c5...@davenoise.co.uk>, "Dave Plowman (News)"
<da...@davenoise.co.uk> writes

>In article <nrank71965le7s9qm...@4ax.com>,
> Stephen <inv...@invalid.org> wrote:
>> I thought when timing belts snap, the results are catastrophic, but I
>> don't know anything about timing chains and whether they are any
>> different in failure?
>
>Principles are just the same - but a chain should last longer than a belt
>and give some warning of impending failure by rattling.
>

Unfortunately car stereos are so outrageously LOUD that many drivers
wouldn't even hear the engine blowing up. ;-)
--
Gordon H
Remove "invalid" to reply

[reg]

"Stephen" <inv...@invalid.org> wrote in message
news:nrank71965le7s9qm...@4ax.com...

Done a few of these, the chain snaps, they have all bent the valves, so its
goiing to need new valves, timing chain kit, timing chain cover
gasket,headgasket set, headbolts, modified cam sprockets, these engines are
notorious for the timing chain breaking, I bet when they take the oil filter
out it has collapsed as well !! you also need the oil pick-up in the sump to
be cleaned. I cant remember off the top of my head how much it was, but it
wasnt cheap !

[Duncan Wood]

And that's assuming the cam bearings haven't come loose &/or snapped the
cam :-(

[Mrcheerful]

Dave Plowman (News) wrote:
> In article <nrank71965le7s9qm...@4ax.com>,
> Stephen <inv...@invalid.org> wrote:
>> I thought when timing belts snap, the results are catastrophic, but I
>> don't know anything about timing chains and whether they are any
>> different in failure?
>
> Principles are just the same - but a chain should last longer than a
> belt and give some warning of impending failure by rattling.

From the net:

"the 1.4 16valve is the chain driven twinport engine.
the problem twinports had was the camshaft bearing cap bolts were
incorrectly torqued when they were assembled and over time has been causing
camshafts to snap."

There was also a problem with chain tensioners gunging up due to lack of
proper servicing.

[reg]

"Duncan Wood" <nnt...@dmx512.co.uk> wrote in message
news:op.wacmw...@duncan-tosh.gateway.2wire.net...

never come across the cam bearings being loose or the cam's snapping, but
there is always a 1st. It does tend to be down to the lack of oil service.,
hence why the oil pick up should be cleaned out as it gunges up.

[Duncan Wood]

Every one I've seen with a snapped cam had badly scored cam bearings & had
obviously not had the oil changed as often as necessary.

[Stephen]

On Mon, 27 Feb 2012 16:40:12 GMT, Chris Whelan
<cawh...@prejudicentlworld.com> wrote:

>The amount of damage is down to luck; in theory, when a chain breaks
>there is always the chance that more damage will be caused by the broken
>chain.

Thanks for the replies.

I hadn't thought to of that before but yes, I can see that a chain
would have more momentum than a belt, so could damage something if it
flew off. What is in the way for it to hit?

>Repair costs are usually higher than with a belt-drive engine due to the
>need for more dismantling.

Really? Why is that? I would have thought the chain would be connected
to the same things that a belt would be?

[Stephen]

On Mon, 27 Feb 2012 16:55:39 +0000 (GMT), "Dave Plowman (News)"
<da...@davenoise.co.uk> wrote:

>a chain should last longer than a belt
>and give some warning of impending failure by rattling.

Thanks. I had heard that chains were supposed to be longer lasting.
What causes the rattling before failure? Is it that it is getting
loose?

[Stephen]

On Mon, 27 Feb 2012 17:58:52 -0000, "Duncan Wood"
<nnt...@dmx512.co.uk> wrote:

>And that's assuming the cam bearings haven't come loose &/or snapped the
>cam

The recovery man removed the oil cap and looked into the engine and
said it looked ok. I'm not quite sure what that means but at least
something isn't broken!

[Stephen]

On Mon, 27 Feb 2012 18:09:53 -0000, "reg" <r...@nospam.com> wrote:

>never come across the cam bearings being loose or the cam's snapping, but
>there is always a 1st. It does tend to be down to the lack of oil service.

The car doesn't/didn't cover many miles a year. I think I changed the
oil last summer, so hopefully oil changes are not an issue.

[Stephen]

On Mon, 27 Feb 2012 16:40:12 GMT, Chris Whelan
<cawh...@prejudicentlworld.com> wrote:

>Regardless of the means of driving the cams, modern OHC engines have such
>tight piston to valve clearances that if the drive is lost and the engine
>is turned, significant damage is likely.

This is what I thought would happen but if the pistons destroyed the
valves, wouldn't the engine stop turning when everything was mangled?

From what I can tell, the engine idled ok but misfired under revs. I
would have thought if there was permanent damage it would not idle at
all?

[Chris Whelan]

On Tue, 28 Feb 2012 10:11:22 +0000, Stephen wrote:

> On Mon, 27 Feb 2012 16:40:12 GMT, Chris Whelan
> <cawh...@prejudicentlworld.com> wrote:
>
>>The amount of damage is down to luck; in theory, when a chain breaks
>>there is always the chance that more damage will be caused by the broken
>>chain.
>
> Thanks for the replies.
>
> I hadn't thought to of that before but yes, I can see that a chain would
> have more momentum than a belt, so could damage something if it flew
> off. What is in the way for it to hit?

Its surroundings; belts are pretty much in fresh air. with a few cheap
bits of plastic or a sensor to destroy if you are really unlucky.

Chains are internal, and the broken chain may penetrate its housing. It
can also tangle with the sprocket(s), and break them, especially if they
are plastic ones. There are often chain guides that can also be destroyed.

>>Repair costs are usually higher than with a belt-drive engine due to the
>>need for more dismantling.
>
> Really? Why is that? I would have thought the chain would be connected
> to the same things that a belt would be?

It's not connected to anything once it's broken!

It depends on each individual design how much dismantling is needed, but
it's always more than a belt-drive. If you really want to see a worst-
case design (for cam chain replacement), Google VR6.

Retrieving the broken chain might also be an issue.

[Chris Whelan]

If it ran in any way at all, the cam chain isn't broken.

I'm not entirely familiar with that engine, but perhaps a tensioner has
failed, allowing the chain to be slack enough to put the timing out
enough to just bend a valve or two?

[Rob]

On 28/02/2012 9:11 PM, Stephen wrote:
> On Mon, 27 Feb 2012 16:40:12 GMT, Chris Whelan
> <cawh...@prejudicentlworld.com> wrote:
>
>> The amount of damage is down to luck; in theory, when a chain breaks
>> there is always the chance that more damage will be caused by the broken
>> chain.
>
> Thanks for the replies.
>
> I hadn't thought to of that before but yes, I can see that a chain
> would have more momentum than a belt, so could damage something if it
> flew off. What is in the way for it to hit?
>

Internally when the cam stops the valves stop and the pistons hit and
they bend. Nothing to do with either belt or chain.

>> Repair costs are usually higher than with a belt-drive engine due to the
>> need for more dismantling.
>
> Really? Why is that? I would have thought the chain would be connected
> to the same things that a belt would be?

Chains are internal and run in oil. Hence the engine needs more pulling
apart.


Belts are external, have a dust cover over them, which is a 2-3hr job to
replace.

[Chris Whelan]

On Tue, 28 Feb 2012 10:12:21 +0000, Stephen wrote:

> On Mon, 27 Feb 2012 16:55:39 +0000 (GMT), "Dave Plowman (News)"
> <da...@davenoise.co.uk> wrote:
>
>>a chain should last longer than a belt and give some warning of
>>impending failure by rattling.
>
> Thanks. I had heard that chains were supposed to be longer lasting.

Not necessarily. Many belts have intervals of 10 years/100K miles; some
are 120K miles now.

It's not unknown for cam chains to fail before that mileage. Also, some
engines use plastic chain sprockets, and it's not unknown for these to
break up.

> What causes the rattling before failure? Is it that it is getting loose?

Well yes. The reasons for it getting loose can include chain wear, but
often there are chain guides that also act as tensioners, and wear or
failure of those is more usually the cause.

[Rob]

On 28/02/2012 9:14 PM, Stephen wrote:
> On Mon, 27 Feb 2012 17:58:52 -0000, "Duncan Wood"
> <nnt...@dmx512.co.uk> wrote:
>

>> And that's assuming the cam bearings haven't come loose&/or snapped the

>> cam
>
> The recovery man removed the oil cap and looked into the engine and
> said it looked ok. I'm not quite sure what that means but at least
> something isn't broken!

He would have checked if the cam was rotating.

[Rob]

On 28/02/2012 9:20 PM, Stephen wrote:
> On Mon, 27 Feb 2012 16:40:12 GMT, Chris Whelan
> <cawh...@prejudicentlworld.com> wrote:
>
>> Regardless of the means of driving the cams, modern OHC engines have such
>> tight piston to valve clearances that if the drive is lost and the engine
>> is turned, significant damage is likely.
>
> This is what I thought would happen but if the pistons destroyed the
> valves, wouldn't the engine stop turning when everything was mangled?
>

The pistons clip the valves and only bend them slightly. Buggers up the
compression tho.

> From what I can tell, the engine idled ok but misfired under revs. I
> would have thought if there was permanent damage it would not idle at
> all?

Start with having a look at the plugs and down the holes, pull the
rocker cover off and see if every thing is working.

[Rob]

Usually bigger tolerance than that.

[Dave Plowman (News)]

In article <r2apk7ps6tpd1u1o9...@4ax.com>,

Stephen <inv...@invalid.org> wrote:
> >a chain should last longer than a belt
> >and give some warning of impending failure by rattling.

> Thanks. I had heard that chains were supposed to be longer lasting.
> What causes the rattling before failure? Is it that it is getting
> loose?

Chains stretch so have some form of tensioner. They also wear in other
ways. So with luck they get slightly noisy before breaking. But not always.

--
*Why are they called apartments, when they're all stuck together? *

[Duncan Wood]

Yup, if it's running like a bag of nails then it's normally just the
timing that's at fault.

[Rob]

With regards to the chain its usual to have a direct pull from the cam
to the crank pulleys, the slack is taken up, with tensioners on the
return side.

Lots of things can happen in there.

[Stephen]

Hello,

We have collected the car from the garage. I don't know whether we
have been very lucky or very unlucky. The good news is that the timing
chain was ok and the engine was not damaged. The bad news is that the
garage were convinced it was the timing chain and wasted a lot of time
(which we have been charged for) removing half the engine to look at
the chain before doing anything else.

When they found the chain to be ok, as Rob said in his post (quoted
above), they did a compression test. When they got to the fourth plug
they found the plug was broken and this was the cause of the noise:
the car was firing on only three cylinders.

It's very interesting that Rob's post says to remove the plugs and
look down the holes. Wouldn't it make sense for the garage to have
done this before looking at the chain? I'm puzzled why they didn't
start with the quick and easy checks before starting the biggest and
most expensive one? As usual, I didn't think of this until I got home,
so I didn't ask them!

As I drove home, it also occurred to me that the engine management
light was on when the car broke down and I am wondering what the code
would have been? Shouldn't the garage have read any codes before
starting anything? Would the code have been specific enough to tell
them it was a spark plug rather than the timing chain? Since the
garage has cleared the light, I presume any error codes are lost
forever now?

I guess we just had a faulty plug. The garage said the plugs were due
for replacing but I find that hard to believe. The Haynes manual says
the plugs should be changed at 4 years or 32000 miles (IIRC, I don't
have the book in front of me). The plugs were changed a year or two
ago when the car was about 4 years old and had covered 30 something
thousand miles, so either way they were due to be done then. I can't
believe that they have worn out since then; the car has not been
driven long or hard since.

There used to be a colour photo showing plugs in the back of Haynes
books but it seems they now use that space to advertise other books,
which is a shame. The "old" plugs did not look worn to me. I realise
it makes sense to replace the plugs as a set, I'm not arguing about
that, but the excuse that they were ready to be changed is what I
think is wrong.

Thanks,
Stephen.

[Rob]

If they had pulled the plugs would have found three clean and one black
and isolated it to that cylinder.

They could have checked the timing statically spun the engine with the
plugs out to see if the rockers were working.

In other words they do not understand the basics to diagnose a problem.


Plugs wear off the back edge of the electrode. when new are square. If

Colours are not as pronounced as they were before injection and lean
mixtures.

Depending on plug type (tip) we change them at 20k, after that they will
go off.

[Mrcheerful]

"Stephen" <ste...@nowhere.com.invalid> wrote in message
news:968al75gf2nn15nsh...@4ax.com...

sorry to hear that, I am surprised that the recovery firm did not diagnose
it, they usually hook up a diagnostic first!
I have found that the three cylinder ecotec is very hard on plugs and they
can actually fail at about 20,000. so it may well be that yours were just
knackered, but it is very rare (I can't remember the last one) to see a
broken (internally) plug. Plug colour charts are pretty irrelevant these
days.

[Stephen]

On Tue, 06 Mar 2012 13:59:29 +1100, Rob <mesa...@gmail.com> wrote:

>If they had pulled the plugs would have found three clean and one black
>and isolated it to that cylinder.
>
>They could have checked the timing statically spun the engine with the
>plugs out to see if the rockers were working.
>
>In other words they do not understand the basics to diagnose a problem.

Sadly, that is the conclusion I came to but I didn't think about all
this until after I had paid them and driven home. They were so sure it
was the chain that they didn't check the plugs first and foolishly I
have paid the for the time they spent stripping and looking at the
chain. I think they labour ill could have been halved if they had
checked the plugs first. Oh well, that's the way the cookie crumbles.
The problem is when you break down, it's a bit of a lottery where you
are and what garages are near and whether they are any good and
whether you know if they are any good!

>Plugs wear off the back edge of the electrode. when new are square. If
>
>Colours are not as pronounced as they were before injection and lean
>mixtures.

Is that why they have stopped printing the back page?

>Depending on plug type (tip) we change them at 20k, after that they will
>go off.

I know they were Bosch that were in but I don't remember what the
electrode was made of and I have no idea what make they have put in
now.

I read on the internet that you can get P0301 to P0304 error codes,
where the last digit tells you which cylinder is misfiring. I wonder
whether that code was present or if they even read it? I have an ELM
interface I bought off ebay and I have used the freeware scantool.net
but it says there are on errors, so I guess whatever was there has
been cleared for good, or would an expensive scanner be able to read
old codes? I'm not planning on buying one to find out, just curious
for next time ;)

Thanks,
Stephen.

[Chris Whelan]

On Tue, 06 Mar 2012 08:58:30 +0000, Stephen wrote:

[...]

> I read on the internet that you can get P0301 to P0304 error codes,
> where the last digit tells you which cylinder is misfiring. I wonder
> whether that code was present or if they even read it? I have an ELM
> interface I bought off ebay and I have used the freeware scantool.net
> but it says there are on errors, so I guess whatever was there has been
> cleared for good, or would an expensive scanner be able to read old
> codes? I'm not planning on buying one to find out, just curious for next
> time ;)

Once they're gone, they're gone, I'm afraid.

[Stephen]

On Tue, 6 Mar 2012 08:35:58 -0000, "Mrcheerful"
<g.odon...@yahoo.co.uk> wrote:

>sorry to hear that, I am surprised that the recovery firm did not diagnose
>it, they usually hook up a diagnostic first!

Me too!

I see some sellers on ebay are selling "vauxhall op com" diagnostic
tools. Would these show me anything that a generic obd scanner would
not?

>I have found that the three cylinder ecotec is very hard on plugs and they
>can actually fail at about 20,000.

Do three cylinder engines demand more of their plugs than four
cylinder engines, or would you expect them to be the same? The car had
done 30-something thousand miles when the plugs were changed and it
has done 39k now, so less than 10k miles have passed, so I don't think
the plugs were worn out, I think we were just unlucky and had a bad
one.