Checking cambelt timing alignment marks

Firstly, if you've not removed the belt, make your own marks with paint/tippex...it's far easier.

Secondly, stick the car in a high gear and chock the wheels.

Yes you have to take off the bottom pulley, the pas pump can be put to one side without disconnecting hoses.

To undo the bolt with home tools it may be easiest to expose the ring gear and jam it with a large screwdriver while undoing in the normal direction.

mrcheerful

Good idea, will do. Cheers.

I can see the toothed crankshaft sensor ring which I might be able to jam. Alternatively, following on from Conor's suggestion of putting it in gear and chock the wheels. At the moment the one side is on axle stand with the wheel removed for easier access. Would it still work by putting it in gear and having someone press the footbrake? And just to make sure, is it still anti-clockwise to undo the pulley bolt if the normal rotation of the pulley is clockwise?

How much does a toothed ring ring cost when you break a tooth off? How much does a ring gear cost when it spins on the flywheel or snaps in half? Most FWD cars you have to take the wheel off to get to the bolt and then that axle just turns unless you have someone to stand on the brake. Take the plugs out, set timing so valves are closed on number 1, turn motor about 1/2 turn in direction to do up bolt, stuff cylinder with rope and undo the bolt. The rope locks the piston.

The sensor ring may not be substantial enough, I would use the starter ring teeth (well actually I would use an air wrench) In gear with a foot on the brake is ok, anticlockwise is the way to turn. Marking the pulleys is only useful if correct at present, you said you wanted to check for correctness. I have been caught out by inaccurate home made marks before, so only use the real ones and double check them.

mrcheerful

Jobs done and the marks line up perfect (although not sure whether to be happy or not about that!) Didn't need to remove the pas pump or bottom cam cover as cog & alignment marks were clearly visible once the pulley was removed.

why did you suspect that the cam timing might be wrong?

mrcheerful

It was suffering from lack of power, especially on steep roads I had to use plenty of throttle to maintain speed. I think I've finally found the problem to be a faulty O2 Lambda.

After a couple of hours googling O2 Lambda sensors, I followed the suggestions and unplugged the thing and it's made a big difference in performance. I can now take corners in 3rd gear and still have plenty of pull whereas before I had to knock it down to 2nd and use plenty of throttle to pull away. It looks like the 02 sensor was not responding fast enough with the correct voltage, so when I needed more power the engine was running too lean and not enriching the fuel to compensate. I can kick myself for not doing this simple test first instead of arsing about under the car disconnecting pulleys and cables - But hey, we live and learn!

While I price up a new O2, does anyone know if it can do harm by running with it disconnected? Although if it's running much better with it disconnected I would think it was doing more harm leaving it connected!

If there's room, whack the spanner with a large hammer. The engine has a fair old mass to start turning, so a sharp enough impact will usually loosen it. Or an impact driver, if you have one and it'll fit.