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Old 20th April 2018, 16:02   #21
chris75
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Originally Posted by SD1too View Post
But really, it shouldn’t make any difference which is inserted first should it? The tool either fits or it doesn’t.
Simon
It does make a difference as with the belt off the inlet cam moves a bit under valve spring forces . It is necessary to move it back to a) restore the timing and b) allow the tool to fit . See 4.1.10 on the Sealey notes , including the warning note about lack of fit ! .


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Step 4.1.19 - -- Replace the engine oil. -- ??

TC
See 4.1.2 on the Sealey notes . When the dipstick tube is removed oil spillage can occur so draining is recommended From memory , it's not just on automatics either
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Old 20th April 2018, 16:45   #22
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... with the belt off the inlet cam moves a bit under valve spring forces ...
Quite a lot actually Chris, 20° in fact!
But I see your point now about inserting the claw end into the inlet cam first, thanks! I had been doing a dry run before removing the old belt which is now off.
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When the dipstick tube is removed oil spillage can occur ...
Indeed it can. The dipstick is contained wholly within the tube. It doesn't enter the sump at all, so the oil must rise up the dipstick tube in order to give a reading.

Oh, welcome along T-Cut, nice to hear from you.

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Old 20th April 2018, 20:50   #23
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Indeed you cant seem to have both.

With the front tools fitted and the lockng pin in the rears will of course nearly be meeting however not exactly or not enough for the rear tool to slot in whilst in the safe position. I have found this on 4 of my own KV6 engined cars some un touched from the factory some with previous rover dealer changes (all varients i.e 2.0 litre, 177, 190). You will see there are plenty of forum discussions on the matter if you do a quick search.
When fitting the new belts, it is possible to have the locking pin engaged, the front tools engaged and to fit the rear tool at the same time, but only j-u-s-t.... I had to turn the nut on the bit of the front tool that engages the exhaust cam.

I didn't like the tension that doing this put onto my new belt, but I proved that it was possible! RAVE says with the pin fitted the front tools fit, and with the pin fitted the rear tool fits, therefore both front and rear should fit at the same time, and it is possible.

I did try to fit my rear belts with the front tools engaged but it was bleedin' difficult - I had to turn the nut on the front tool whilst trying to maneuver the rear belt and pullies assembly into place. Very very difficult. After a ridiculous amount of failures, I think I did achieve it this way - but I might have given up, removed the front tools and pin and moved the crankshaft a tad. Cannot quite remember for sure, but I think I did succeed in what I was trying. But I am not sure it is worth bothering with, it seems to be fine to remove the pin and move the crank a tiny bit to fit the rears as the timing is set by the front tools

Either way, the engine sounded beautiful afterwards

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Even now the tool is touching the a.c. hose which is not very satisfactory. Nobody else has mentioned this!
I'm sure I had the same issue, not a problem really, I might have put a rag between them to protect the hose/pipe ferrule.

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Then I discovered that with the holding tool engaged in the end of the exhaust camshaft, the holes on the inlet sprocket were not quite aligned with the pins so the tool wouldn't fit that! The engine needed to be turned clockwise by a miniscule amount. To do this the locking pin had to be removed. Looking at the alignment of the notches on the rear sprockets they must have moved closer by a small amount.
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I had been doing a dry run before removing the old belt which is now off.
I am pretty sure that the front tools did not fit before removing the old belt, on both occasions that I have been in there (first time I didn't even change the belt being 8,500 miles/2yrs, just replaced the hydraulic tensioner and tensioner pulley, I probably didn't even need to do that, problem was that Andy Willi hadn't adjusted and tightened the tensioner pulley).

Now the first time I think they were a bit out (probably due to movement of the tensioner pulley which resulted in a horrible noise and tiny blisters on the belt), but the second time (after I had done the procedure correctly 4 years earlier) I think the LH front tool was not too far off from fitting, but still wouldn't. I don't think the RH tool fitted either, can't remember how far out it was. So it showed that after ~12,500 miles over 4 years the timing position had moved (any thoughts on this Kaiser?), presumably due to belt/component wear (according to that Gates document cambelts don't stretch, yet it is known that some secondary KV6 belts have been able to flap against the belt covers, so surely that is stretch?).

Simon, I am certain that your engine would have had the belts fitted with the locking pin in and front tools engaged at the factory - so I think that as you now find that the front tools don't fit with the pin, that the timing position has moved from the original setting. Your thoughts?

But the key to everything I am sure is the locking pin. With that in and the front tools in, the timing will be perfect.
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Last edited by Bolin; 20th April 2018 at 20:57..
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Old 20th April 2018, 21:10   #24
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One further thought - before I removed the old cambelt, I tried to insert the pin into the hydraulic tensioner plunger (~12,500 miles/4 years after I had set it up).

The pin went in the outermost side of the tensioner body, through the plunger, but wouldn't go through the innermost side of the tensioner body - showing that the plunger was now sticking out by a fraction more than when I had set it up. Surely this must have been due to belt stretch? Or wear on the plastic idler or metal tensioner pulley perhaps? (much less likely I think).

Whatever was the cause for the tensioner plunger to be sticking out a fraction more is probably also the cause for the front tools not to fit and the timed position to have moved.
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Old 20th April 2018, 21:59   #25
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Timing does not "move", unless jumping teeth.
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Old 20th April 2018, 22:29   #26
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- - - So it showed that after ~12,500 miles over 4 years the timing position had moved, - - - presumably due to belt/component wear. According to that Gates document cam belts don't stretch, yet it is known that some secondary KV6 belts have been able to flap against the belt covers, so surely that is stretch?
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Surely this must have been due to belt stretch? Or wear on the plastic idler or metal tensioner pulley perhaps?
If we accept that Gates know what they're talking about and that wear on the tensioner/jockey/pump wheels must be infinitesimal so nowhere near enough to 'slacken' the belt, then all I can propose is that the belt thickness decreases. This might happen due to the compressive forces of the sprockets and pulleys on the rubber compound from which it's made. Decreasing belt thickness will slacken it even though it hasn't stretched.

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Old 20th April 2018, 22:57   #27
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If we accept that Gates know what they're talking about and that wear on the tensioner/jockey/pump wheels must be infinitesimal so nowhere near enough to 'slacken' the belt, then all I can propose is that the belt thickness decreases. This might happen due to the compressive forces of the sprockets and pulleys on the rubber compound from which it's made. Decreasing belt thickness will slacken it even though it hasn't stretched.

TC
I have been following these belt posts recently with interest and curiosity.

Looking at the first image in this thread, you can see the belt 'rippled' as it sits on a sprocket.




Then looking at the image Brian posts of a newly fitted belt, it doesnt have these depressions.



I can kind of understand and accept how the belts cannot stretch as they have cord as reinforcement, which does not stretch. Well that is how I imagine it not able to stretch. Then as you say T-Cut, I can see how compression could make the belt 'shrink' (and become slack at the same time!)

As a question, could this compression, if allowed to continue, compress the belt so much, that it eventually becomes brittle or at least loose its flexibility?

(this is not a question to enflame or resume the 'discussion' in the closed thread, rather a thought that popped into my mind with T-Cut's suggestion of the compression)
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Old 20th April 2018, 23:19   #28
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Originally Posted by T-Cut View Post
If we accept that Gates know what they're talking about and that wear on the tensioner/jockey/pump wheels must be infinitesimal so nowhere near enough to 'slacken' the belt, then all I can propose is that the belt thickness decreases. This might happen due to the compressive forces of the sprockets and pulleys on the rubber compound from which it's made. Decreasing belt thickness will slacken it even though it hasn't stretched.

TC
Absolutely correct, as the teeth wear, then there is an increase in backlash between the belt and pulleys, which is overcome to an extent by the hydraulic tensioner.

When the belt is at end of life, the lower lands of the belt wear as well as appearing to give a fuller engagement in the pulley, however when compared to a new belt, and this is why I always use Gates HTD Powergrip over Dayco, the teeth of the Gates Powergrip being a circular round profile, rather than the Dayco reinforced parabolic tooth profile.

The Dayco tooth profile is supposed to disperse wear dust more efficiently, however I have found when removing Dayco belts from various cars fitted with them, there is evidence of more backlash compared to Gates given similar mileage covered.

This tooth wear also can crate the anomaly of the timing marks "not quite lining up" as the amount of backlash can be multiplied by the number of teeth fully engaged in each pulley, in the case of the front belt of the KV6 sixty fully engaged teeth in contact with the three pulleys.

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Old 20th April 2018, 23:41   #29
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Interesting stuff, so it is thickness wear not stretch.

But it does affect the timing!

And if you were to fit a new belt using marks from where the timing had moved to with a worn belt, and then do the same every 6 years, the timing will surely get more and more away from where it should be?

Question is, how significant would this be? There was a service procedure for replacing KV6 belts without tools for diplomatic cars, by making new marks on the secondary pullies, but I think that related to the earlier KV6 in the 800 (apparently the engine would run OK but the timing wouldn't be spot on due to the belt manufacturing tolerances).

I guess that the belt manufacturing tolerance would be more significant, based on the above, but it's a guess

P.S. Simon, did you check how much the plunger protruded before removing the tensioner bolt? Would be interesting to compare.
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Old 20th April 2018, 23:59   #30
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Originally Posted by Bolin View Post
Interesting stuff, so it is thickness wear not stretch.

But it does affect the timing!

And if you were to fit a new belt using marks from where the timing had moved to with a worn belt, and then do the same every 6 years, the timing will surely get more and more away from where it should be?

Question is, how significant would this be? There was a service procedure for replacing KV6 belts without tools for diplomatic cars, by making new marks on the secondary pullies, but I think that related to the earlier KV6 in the 800 (apparently the engine would run OK but the timing wouldn't be spot on due to the belt manufacturing tolerances).

I guess that the belt manufacturing tolerance would be more significant, based on the above, but it's a guess

P.S. Simon, did you check how much the plunger protruded before removing the tensioner bolt? Would be interesting to compare.
You also don't understand. And any "thinning" of the belt?
Absolute nonsense in terms of any measurable effect.
Fitting a new belt, and all is back to where you were!. ExactlY.
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