: Sticking or Burnt out valves??


Snoopeeezy
13-02-2006, 19:49
Hi there ya'll. My 220 Coupe ( T16 Engine M reg) doesnt have compression in cylinder 4 ( When you remove the ht lead to that Cylinder while the car is running , there is no change in idling ). One person suggested that its a burnt out valve or could be sticking valves. At the moment, the car is misfiring but the idling is normal (1000rpm on idle). the engine sounds nice when idling and is as quite as it was before. I am not loosing any oil as well.

Does anyone out there know how to tell the difference between sticking valves or burnt out exhaust valves. I did some research here and found out that you can cheaply fix sticking valves using additives etc. I have the car booked in at my local garage and the mechanic said the job was going to cost me £400. If i can save any money i would really appreciate it. Thanks

aboard_epsilon
13-02-2006, 20:49
Well I've read up a bit on this trouble with the t16 valves ..
seams it caused by carbon deposits on the valve stem.
mainly occurs on vehicles driven to gently.
if your problem was intermittent .i would suggest a good high speed motorway run in fourth gear..

but seams your has gone beyond that..........
and not even firing on that cylinder any more.

because maybe the valve is stuck permanently open.

you don't want to spend £400 to put this right
you are asking a way round it .
if you are.......
are you willing to take risks...
the following is risky
if you like risks go ahead .........there is great danger of further damage,if you don't know what your doing.
usually only used on ohv strait acting valve engines

it's called the Indian rope trick

Involves putting coil of string down that cylinder bore.. thru spark plug hole,whilst it is moving up to the compression stroke.
you are turning the engine over by hand...coiling the string up on top of the piston,so that it pushes the valve back up..when the piston comes up to TDC...it should fully push the valve/valves back up.
you then remove the string when finished

it may work ..it may not.............once you have the valve actuating ........you can then do the high speed run.
if this does not fix...then it's a strip.
all the best.mark

Dr Dave
13-02-2006, 20:51
I'd say it was a burnt out exhaust valve.....

Snoopeeezy
13-02-2006, 22:04
I'd say it was a burnt out exhaust valve.....

so is stripping the only way to fix a burnt out valve? How much do the valves cost roughly

Cirian75
13-02-2006, 22:11
Valves, not much.

Head gasket and Cam belt job to get them though, its the Labour cost that'll hurt you.

doug
13-02-2006, 22:14
have you actually done a compression test just to confirm?

Dan Coupe
13-02-2006, 22:20
valves are cheap - about 20 quid (or less) each, but to fit involves removing the head, identifying the dodgy valve, emoven the camshaft and reffitting the whole lot with new head gasket, timing belt etc.

If in doubt, I'd try an engine oil flush followed by new engine oil and filter, followed by a high rev drive (once the engine is warm!!!)

Cheap, and got to be worth a shot :) If this doesn't sort it, you are looking at a broken valve...

Snoopeeezy
13-02-2006, 22:21
have you actually done a compression test just to confirm?
i havnt done the actual compression test. how do i do this. The car does not change its idling if you remove the spark plug lead on cylinder 4 when the car is running.

do you know where i can buy the valves cheaply. i already have a gasket set. If one cylinder is down, do i have to change all 16 valves?

aboard_epsilon
13-02-2006, 22:37
I SEE i was under the impression you had done a comp test.
now then ..it may not be a burnt or sticking valve at all .
firstly swap the plug lead and check or swap spark plug over ....
then come back ...if you have the same results,then we can move on to telling you how to do a comp test.
all the best.mark

Snoopeeezy
13-02-2006, 22:40
I SEE i was under the impression you had done a comp test.
now then ..it may not be a burnt or sticking valve at all .
firstly swap the plug lead and check or swap spark plug over ....
then come back ...if you have the same results,then we can move on to telling you how to do a comp test.
all the best.mark

I did try swapping the spak plugs and lead with a working one. but thi sdid not change anything.

doug
13-02-2006, 22:42
yep, simple/cheaper things FIRST, may or may not be burnt/sticking valve, but eliminate spark plug/lead on number 4 first! ignore this one then if you've replaced plug/lead on 4! may turn out to be burnt/sticking valve being "M reg" and possibly escaping the modified valve jobbie

Snoopeeezy
13-02-2006, 22:55
oOK. SOo how do i do the compression test. and what results should i expect after this. cheers

doug
13-02-2006, 23:00
you can buy "cheapo" comp tester from halfords/local m,factors, intructions supplied, easy job, or trusted local garage/dealer should do one for nominal £, doug.

Snoopeeezy
13-02-2006, 23:23
you can buy "cheapo" comp tester from halfords/local m,factors, intructions supplied, easy job, or trusted local garage/dealer should do one for nominal £, doug.

thanks doug. so what results should i expect to get for normal compression levels.

aboard_epsilon
13-02-2006, 23:33



from haynes manual

Compression test -description and interpretation.

1 When engine performance is down, or if
misfiring occurs which cannot be attributed to
the ignition or fuel systems, a compression
test can provide diagnostic clues as to the
engine’s condition. If the test is performed
regularly, it can give warning of trouble before
any other symptoms become apparent.
2 The engine must be fully warmed-up to
normal operating temperature, the oil level
must be correct, the battery must be fully
charged, and the spark plugs must be
removed. The aid of an assistant will also be
required.
3 Disable the ignition system by
disconnecting the LT wiring connectors from
the ignition coil.
4 Fit a compression tester to the No 1
cylinder spark plug hole - the type of tester
which screws into the plug thread is to be
preferred.
5 Arrange for an assistant to hold the
accelerator pedal fully depressed to the floor
while at the same time cranking the engine
over several times on the starter motor.
Observe the compression gauge reading. The
compression will build up fairly quickly in a
healthy engine. Low compression on the first
stroke, followed by gradually increasing
pressure on successive strokes indicates
worn piston rings. A low compression on the
first stroke which does not rise on successive
strokes, indicates leaking valves or a blown
head gasket (a cracked cylinder head could
also be the cause). Deposits on the underside
of the valve heads can also cause low
compression. Record the highest gauge
reading obtained, then repeat the procedure
for the remaining cylinders.
6 Due to the variety of testers available, and
the fluctuation in starter motor speed when
cranking the engine, different readings are
often obtained when carrying out the
compression test. However, the most
important factor is that the compression
pressures are uniform in all cylinders, and that
is what this test is mainly concerned with.
7 Add some engine oil (about three squirts
from a plunger type oil can) to each cylinder
through the spark plug holes and repeat the
test.
8 If the compression increases after the oil is
added it is indicative that the piston rings are
definitely worn. If the compression does not
increase significantly, the leakage is occurring
at the valves or the head gasket. Leakage
past the valves may be caused by burned
valve seats and/or faces or warped, cracked
or bent valves.
9 If two adjacent cylinders have equally low
compressions, it is most likely that the head
gasket has blown between them. The
appearance of coolant in the combustion
chambers or crankcase would verify this
condition.
10 If one cylinder is about 20 percent lower
than the other, and the engine has a rough
idle, a worn lobe on the camshaft could be the
cause.
11 On completion of the checks, refit the
spark plugs and reconnect the LT wiring at
the ignition coil.

Snoopeeezy
13-02-2006, 23:40
thanks very much. will try this tommorow and come back with the results

aboard_epsilon
14-02-2006, 00:10
Then if you are still not happy ..you can do a leakdown test if you have a compressor.

I made the leak down test adaptor by smashing the ceramic bit out of an old sparkplug...must be one that will fit the rover ..one of your old ones.
Then you just weld onto it a male air hose coupling.
Jam your engine with a spanner on the crank bolt .because the air will try to move the piston down.

Put the cylinder you're testing on its compression stroke about half the way up
Connect your air hose to the now screwed in adaptor and set it so that it puts say 45 psi into it.
Watch the gauge on your filter regulator unit .
turn off the air on the inlet side of the filter regulator unit......perhaps at the compressor because some filter regulators dump the air out of the line when you shut them off.
Then just watch the gauge.......with all four valves closed on the cylinder your testing ( on its way up to tdc).

Put oil in the cylinder to do a valve test.........if it will not keep its pressure.
You know then that the cylinder will keep its seal with oil.......and you have valve problems if the pressure continues to drop...
With manifolds removed sometimes you can tell which valve is leaking by listening.
With all sparkplugs removed you can tell if it's leaking between two adjacent cylinders..........you will be able to feel the air coming out of the next cylinders sparkplug hole.
If all cylinders hold 45 psi for a few Min's then you have a good engine.
all the best..mark

Corrida36
14-02-2006, 02:26
Sorry, came into the discussion a bit late. IMHO, if the valve was sticking your engine would probably be clattering (excessive valve clearance). Also unless you have had a catastrophic failure (cambelt or similar) the only other thing that is likely to cause a valve to stick is a build-up of carbon on the top of the valve head but this would require years of trundling (I have seen it on hearses and similar).
If the compression is that low that the cylinder is not even firing, the symptoms will be reasonably obvious. Wait until the engine is cold, remove the spark plug and put your thumb in the hole, that'll give you some idea at least.

Hope this helps.

Snoopeeezy
14-02-2006, 23:11
Hi there people. i had a mechanic do a compression test on the car today. he said he can fix da valve problem for 250 qid. with a service included. i thought this was a bargain and left the car with him. will be collecting it on thursday. hopefully my baby will be up and running again. cant wwait. thanks for all your help ere as well..

aboard_epsilon
15-02-2006, 00:17
Good I'm happy for you :)
but would have been even more happy if you tackled the repair yourself.
having said that .its not a beginners job, and you would have frown in at the deep end.
but i enjoy a challenge like that..I do nothing but learn .and sometimes from my mistakes.
but as you get more competent .you make less mistakes.
it's then that you can savour the thought of not spending or paying someone to do your work.

THOUGHT OF THE DAY
You know sometimes i believe that the British made cars are full of faults for a reason.
Maybe someone wants to keep us all busy ..so we don't end up all dummed down and unskilled..like the rest of the world. :)
i often wondered why the Germans bought British cars.
maybe the Germans on this forum enjoy the challenge because their stuff never goes wrong....well not in a spectacular interesting style like a Brit car.


All the best.mark

MGJohn
15-02-2006, 11:17
Good I'm happy for you :)
but would have been even more happy if you tackled the repair yourself.
having said that .its not a beginners job, and you would have frown in at the deep end.
but i enjoy a challenge like that..I do nothing but learn .and sometimes from my mistakes.
but as you get more competent .you make less mistakes.
it's then that you can savour the thought of not spending or paying someone to do your work.

THOUGHT OF THE DAY
You know sometimes i believe that the British made cars are full of faults for a reason.
Maybe someone wants to keep us all busy ..so we don't end up all dummed down and unskilled..like the rest of the world. :)
i often wondered why the Germans bought British cars.
maybe the Germans on this forum enjoy the challenge because their stuff never goes wrong....well not in a spectacular interesting style like a Brit car.


All the best.mark

Agree about tackling the job yourself. T16 Rover engines are one of the easiest 16 valve engines to work on.

That 250 quid quote sounds exceptional value. So exceptional that it's far from unknown for someone to spot that something minor is actually wrong and quote for a larger job which the owner is convinced is necessary, but, in actual fact maybe not. Why do I say this? On several occasions over the past few years I've bought used cars where their owners have been wrongly advised that expensive work is necessary so decided to get rid for rather less than their cars are actually worth. Sure, I took a chance in so doing, but, so far my judgement has been spot on. Maybe I've just been lucky... there's always a first time.

Like your style aboard_epsilon and yes indeed that is a fine way to learn with the additional bonus of knowing that the job has been done well and saving a few quid in the process is an even better bonus too.

Finally, so Gerry built stuff never goes wrong eh!.... Learn something new every day....:)

.

Cirian75
15-02-2006, 11:32
Too true, mate mine had a 220 turbo coupe, it suddenly lost power one day, he spent a small fortune getting fixed at the garage, headgasket, new piston rings etc, it turned out to be................................................ .................................................. .................................................. ........................................a collapsed cat, £40 to de-cat

Snoopeeezy
15-02-2006, 12:19
Haha. thanks lot. well i still have another 220 coupe lying in my garage after it started leaking oil a couple of months ago. maybe i can experiment with this one dont you think.

Snoopeeezy
15-02-2006, 12:22
Oh yer does anyone also know where i can buy i de-dat pipe for my 220 coupe . cheers