Timing question

[GeoffB]

Hello to you all.

New to the forum and hoping to get a bit of help with a friends mgf.
Basically, the engine is running really rough on tickover and has a lack of power. We’ve been over the various sensors and they seem to test fine.
We then looked at the cam timing which appears to be quite a bit out. With the timing mark on the crank pulley at the uppermost timing mark, the cam timing marks do not line up by approximately 60-80 degrees.
Would the engine even run in this condition or are we looking at this completely wrong?
He’s only just bought the car and the guy he got it from, said it was working fine before he had the head gasket done. Could the mechanic have got the timing that wrong? Or could it have slipped if the tensioner was not set correctly.
Anyway, hopefully someone can offer a bit of advice as we’re really scratching our heads now.

Cheers
Geoff.

A

[Reckless Rat]

You need to make sure that you're using the correct timing marks as there aren't any "official" ones on the crank pulley - they are behind it and the only way you can see them is to remove the pulley - you'll need a windy gun to get it off. There are two marks on the cam belt lower pulley which should align either side of a casting mark on the crankcase - see photo. That places the crankshaft midway between TDC and BDC, at which point the camshaft pulley parks should align. Here are the crankshaft marks:



Assuming that the two dots are either side of the moulding as in the pic, the camshaft marks should be aligned and you can then insert the cam locking tool:



That should enable you to check whether the cam belt is properly fitted. It might just be a tooth out - any more and I doubt if the engine would run.

[RobboMC]

Sorry Reckless Rat but I beg to differ;

the pulley should have a mark that's about 90 degrees from the top dead centre marking
that allows setting of the crank to the 'service position' without removing the pulley first.

I agree the mark is not 'official' and once the pulley is off ( and belt removed if that's where the job is going )
then the correct assembly procedure is to use the mark on the drive pulley as Reckless recommends.

But to set aside your concerns, if the cam timing was 80 degrees out than the engine would not even turn over, and definitely not run.

This doesn't mean the cams are not 1 tooth out as this is quite easy to do ( yes I've done it but knew not to fire the engine )

If you are unsure about the timing belt and/or tensioner then REPLACE them. Discretion here is needed, failure of the belt will kill the engine.

When you find the correct service position mark on the pulley put some white paint on it for next time,
and for checking between belt changes.

PS you don't NEED a windy gun to get the crank bolt out, but as an alternative you do need the correct locking tool and
a very decent 1/2" drive set of sockets of 3/4" drive socket.

[Deepfat]

Just to add if you do a complete revolution of the crank the cam marks may line up (better) as the cams rotate at 1/2 engine speed

[GeoffB]

Hello all.

Sorry for the late reply, I’ve been working away.
So, we took the bottom pulley off to reveal the timing marks on the crank timing pulley. All the timing marks lined up perfectly.

Looks like we’re back to square one. Short of replacing every sensor, What would you suggest. The tickover is very lumpy and the exhaust smells of un burnt peteol. When the engine has warmed up, it seems to be worse and stalls when dropping back to tickover. The power seems very low too.

Cheers for all the advice so far.

[RobboMC]

What model is the engine? Plug Top coil or distributor ??

Unburnt petrol could be caused by poor or lack of spark.

If it's got a distributor check the rotor button and dissie cap, these are cheap enough to replace,
could even be the coil perhaps??

Or the plug leads?


Similar for the plug top coil engine, the leads or of the coils.

Pull out the spark plugs and look for signs of unburn fuel.

In previous cars I have had spark plugs fail, are they the correct plugs for that model engine??
The correct plugs are not cheap, has someone skimped on the plugs?

[GeoffB]

Morning.

Thanks for your reply. It’s plug top coil engine.

The last owner had changed the coils with what looks like non-genuine units. I don’t know if this is an issue, however, they do look quite new. We tried putting the old coils back on but it made no difference.

We’ll have a look at the leads and plugs later and get back to you.

I did notice that the leads don’t push down with a satisfying electrical connection kind of feel (if that makes sense haha).

Cheers
Geoff.