Are my Valves Bent?

[Twisty]

How does one work out if a valve is bent? Can it be determined without pulling the head? If I pull the head is it visually obvious from looking at how they sit in the valve seats?

My timing belt snapped when I was stop-start traffic, so low revs/speed, however I have cranked over the engine quite a bit working out what was wrong with the car (my final diagnosis was looking through the oil filler hole and noticing that the cams are not turning when the engine is cranked.) The car just crept over 72,000 miles and I was about to put it through a full service

Hopefully there is no valve damage and I can just replace the belt. If I have bent valves then I need to work out if its cheaper/better to rebuild the head or find a new lump, there does not appear to be many 1.6 16V out there.

 

[Paddy_g46]

182 conversion

 

[tidyclio]

You could get a compression test done first if it's badly bent this will show something but better just taking the head off it will be noticable.
If your right though and the camshaft isn't turning you have to work out is the engine locking or is the camshaft snapped?Assuming theirs a new timing belt on it?

 

[dangerous dave]

compression test.. no compression = fecked head/valves

 

[lemonnobby]

yep bent valves every time mate.

 

[Twisty]

I am assuming that the camshaft is not turning becasue the belt is snapped and I have not replaced it yet. I dont think the engine is locking as this would stop the starter motor from turning.

I have a compression testing gauge. However to test compression I would need to install a new belt, and it would be annoying to go through the whole process of installing the belt only to find that the valves are bent.

Before I got this Clio I owned a few Suzuki Swifts, with these there are examples where people have got good compression with bent valves as the valve stems are narrow and springy enough to be push to make a seal by the springs, however the valve seats then proceed to wear rapidly until the engine is wrecked. From what you guys have said am I right to assume that this will not happen with a Clio?

Yes I have thought of the possibility of putting in 172/182 lump. However it looks like a lot of work (engine,gearbox,loom,ecu,brakes,struts,dash,exhaust,more?) and would also open up a whole bunch of insurance problems.

 

[tidyclio]

If you havn't changed the belt then yes that's why the cams arn't turning.
It's worth trying it with a new belt as you never no it might run. If not your only options really are to spend fortuner on getting someone with a camera down the spark plug hole or take the head off.
A belt is nothing compared to a new engine so your aswell trying this first

 

[RSTuning]

They'll be bent. If not they should be!

Paul

 

[Laura]

dont be a pussy that the head off and have a good old gander

 

[donsrno1]

afaik there isn't any way other than a compression test or taking the head off, but as you say to do a compression test you need to fit a new belt. I don't know much about the 1.6 engines but I would be very doubtfull that you won't have bent some valves as unless I'm wrong none of the clio engines are non-interferance so if you have been cranking over they will almost certainly be bent.

 

[Twisty]

Well I started to take the head off but was stopped stopped by lack of light.

The belt isnt snapped but it has lost a bunch of teeth so the crank sprocket is just spinning without turning the cams. It looks like a piece of gravel may have found its way inside the cam cover and caused the problem.

I am struggling to remove the 16mm nut in the middle of the upper cam belt cover. The threaded stud in the centre is too tall to allow me to fit a standard length 3/8" socket onto it, even if I had one there is not enough room to fit a deep socket; I'll have to buy some swivel end socket wrenches or something!

 

[lemonnobby]

is it a nut in a hole, if so take the o/s/f wheel arch liner out there might be a hole cut in the chassis so you can undo it better.

 

[BenR]

why not take off the inlet manifold and just have a look at the valves?

 

[BenR]

why not take off the inlet manifold and just have a look at the valves?

 

[benji&eka]

time it up, put a belt on it and see if it starts, if not its fuked

 

[Twisty]

I took the inlet manifold off yesterday and none of the exhaust valves were obviously bent. Maybe I have got away with it!

 

[BenR]

took the inlet off and looked at the exhaust valves?

It doesnt take a lot to bend a valve, they can be bent by a couple thou and you wouldnt notice it by eye, but they wont seal.

Get a leakdown test done and it will reveal all.

 

[stan*]

lol Ben, you never looked at exhst valves through the inlet ports?!

 

[BenR]

only when i've got 4mm overlap.