Logic check required

Hi all,

Just want a quick check on my logic before proceeding any further...

I've recently embarked on a HG change, and got to the stage of timing the engine, cams are timed and locked but trying to undo the crankshaft bolt I felt it skip a couple of teeth... not overly concerned at this stage, but don't want to fall behind whilst waiting on a flywheel locking tool...

Would it make sense to cut the existing timing belt and remove it in order to get the HG changed then pick up where I left of with the timing belt (I have the new one already) as and when I can? As I said the timing may be out now by a couple of teeth so I personally don't see the harm in this as the overall intention is to replace the belt etc which will require the timing to be properly set

Thanks again

My logic is to think that as the cams and crank are out of phase due to the belt jumping, there is quite likely to be damage. I would cut the belt and remove the head before doing any more. Don't turn the crank again until everything is back in phase! Wile you have the head inverted, pour paraffin into the combustion chambers and hope it stays there. If it doesn't you have bent valves to show for your impatience (but you have reminded me to buy a tool before I embark on doing my own cam belts.)

If the cams are locked with their timing marks facing each other, and engine WAS on its timing mark, then in that position it is not possible for the pistons to hit the valves, so no damage should occure.

I am sure you can not easily remove the head with the belt covers still in place. The rear one is a right pain to get off normally!

Personally I would not remove the head untill the crank pulley is off, otherwise ther is a risk of turning crank when undoing, and potentially dislodging the liners.

Spend your time taking the starter motor off, and releasing the offside engine mount, and changing the water pump...and any other jobs you can think off..

Thanks for the replies peeps,

I can confirm that the cam timing marks were correctly facing each other, therefore I assume that the crank timing was 90 degrees BTDC (as the engine was running OK before I started...)

My assumption now is that I skipped two teeth on the belt, but turned back and hopefully (very confidently) skipped the same two in the opposite direction which should have returned it to the correct position...

My plan at present is to cut the belt for 2 reasons... If I skipped the teeth then the belt is goosed anyways, and I have a new one to fit.

I will remove the head and replace the gasket (at the same time I can visually verify that all pistons are half way down the bores), only once the head is refitted I will reset the timing of the crank to align the marks...

I do not understand your new logic! :omg:

You still need to get the crank pulley off.

You should get it off BEFORE you take the head off, to eliminate the risk of dislodging the liners. Especially as you do not have a crank locking tool!

Cutting the belt will not gain anything (except a small amount of time), as you still need to get a new belt on.
You still need to remove the engine mount (or at least undue one end), to get the new belt in

If you jumped teeth trying to undo the crank pulley (while locking the camshafts with the tool), then, unless you slackened the tensioner first, you have either a very worn belt (virtually no teeth), or a bigger problem. Correctly tensioned a belt in good condition will take an immense amount of force, and would likely snap before jumping, or stripping teeth.

The aluminium cam locking tool would have also have gotten chewed up before the belt slipped a tooth! (I know because I tried it that way before getting a crank locking tool).

You would replace the belt regardless of its condition anyway.

Why are you worried about the timing of the engine now when you are about to remove the timing belt? With the head locked in the correct position, the valves are in a "safe" position, and I believe impossible for pistons to hit them (though not tried!) You would at least need to turn the crank 90 deg. before they came anywhere close, so a few teeth will make no difference (with the locking tool in place!!!!)

Do not turn the crank with the head off!

Hi G0RSQ,

Thanks for taking the time to respond...

Judging by the maintenance history of the car that I have, its a 2003 with 51k on the clock and has never had the timing belt replaced, so I wouldn't even contemplate re-using the current belt and would tally with your suggestion that the belt is potentially very worn...

Thanks to the wisdom of this forum i'm consciously aware of the potential risks of dislodging liners by turning the crank with the head removed so that has never been an intention...

In my mind, I just want to be clear that so long as the cams are in the correct position, and the crank is in roughly the correct position, I could in theory remove the head, replace the gasket and refit the head... then once that is done i can set the correct timing of the crank before fitting the new belt?

flywheel locking tool should be arriving tomorrow, so it doesn't make a huge amount of difference if I have to wait another day, but being an engineer I have that nagging need to understand whats happening inside... :lol:

Thanks again!

Hi again everyone...

So I followed the advice and remained patient until my flywheel locking tool arrived.... needless to say the crank bolt was well behaved and came out without a struggle...

I'm guessing I was correct and the belt skipped a few teeth judging by the photo's attached (cam locked but crank marks not aligning with the datum)...

Knowing this now, am I correct in saying that once I remove the belt, I can turn the crank (before removing the head) to align the marks to the datum line and all pistons should be correctly set?

Also, the markings on the crank pulley are 2 dots, should this be positioned so that the dots are on either side of the datum line?

Thanks again

Hi, PLEASE DONT TURN THE ENGINE OVER WITH THE HEAD REMOVED, unless you clamp the liners down, if you do this you are likely to lift the liners and they will need resetting. which is a sump off job.!!!! Couple of further points, the cam locking tool dosent look right and the in the crank pulley photo the pulley dosent look as though its jumped two teeth as no damage to belt!!!! Just my thoughts

As I said in my last post, it is impossible to jump teeth while undoing crank bolt so long as belt tensioner has NOT been looseded, or there is serious damage to the belt or pulleys. Your belt looks old, but in good condition.

I enclose a page from the K-Seies engine manual, which shows all the timing marks for assembly position.



You can see your crank marks are miles off, if the cam position is right! Please double check the cam assembly position (document enclosed) and check the locking tool for damage, as this will break before the belt can jump teeth!
If the cam position is correct, then yes remove the belt and crank locking tool, reposition the crank, and lock again, with tool, to prevent ANY movement (You can twist the locking tool slightly to stop any movement before locking the bolts).

The procede with removing cam sprockets, rear belt cover and then remove the head.

Is your tensioner automatic, or manual? Are you replacing this also?

Also looks like you have an oil leak from front of engine! oil pump? Head gasket? Camshaft seals? Cam carrier gasket? Cam cover gasket? Or just sloppy oil changes :oops: