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Old 4th May 2018, 08:07   #71
SD1too
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Apologies for any thread hijacking ...
That's very considerate of you Mike but honestly there's no need for any apologies. You didn't hijack the thread, nobody did, it just evolved. At least it explored a technically related issue in a mature fashion which is more than can be said for some of the malicious remarks made elsewhere.


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Old 19th May 2018, 17:19   #72
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And so we all get older!
Have we learned something along the way?

Inquiring minds would like to know.
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Old 21st May 2018, 11:46   #73
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What Simon has done, is that in order to fit the special locking tools, he has rotated the sprocket(s) and in the process ditched the timing the car was issued with, to fit the tools. The belt will obviously get taut again when tensioned, but in doing that, the relative positions of the front sprockets will have to move, after the timing tools are removed! That should be clear to almost all.
Now he has a different timing to what it came out with from the factory.
The interesting question then becomes who do you trust?

1. The assembly line at Rover, the lines clearly marked on the engine, and the designer of the engine?
2. The manufacturer of the special tools?.

Absent any official notices from Rover, I will go with the clearly marked timing marks made by the factory. Not that it will make much difference. But it should be clear to all but the most diehard, that the timing tools are a waste of time, and a normal belt change would keep the timing spot on, even on this engine.
This comment now raises a fundamental point - can we trust the timing tools to be correct? I, along with most others here, have always assumed that the better quality tools ARE correct, and can therefore be relied on to reset the camshafts in the correct original position for fitting new belts.

Now IF it is known that the wheels on the front of the inlet cams have never been disturbed since the engine was built, and that's a big if, then, in theory, just replacing the belts without slackening the wheels will maintain the setting when the engine was built.

Personally, I'll continue o use the tools.
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Old 21st May 2018, 14:30   #74
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This comment now raises a fundamental point - can we trust the timing tools to be correct? I, along with most others here, have always assumed that the better quality tools ARE correct, and can therefore be relied on to reset the camshafts in the correct original position for fitting new belts.

Now IF it is known that the wheels on the front of the inlet cams have never been disturbed since the engine was built, and that's a big if, then, in theory, just replacing the belts without slackening the wheels will maintain the setting when the engine was built.

Personally, I'll continue o use the tools.
It's not a fundamental point ; it's just more confusion
Of course we can trust the tools ; they set a logical "infallible" method for doing the job , with the only variable being the quality of the person using them . Please refer to my post #67 here
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Old 21st May 2018, 15:05   #75
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If the marks align in safe mode, the engine is timed. To deny this will be to say the engine constructor placed the timing marks wrongly. I think there will be too much checking before the casting is given the go ahead for this to have happened. Further, the timing on this particular engine was exactly there, the marks in the official instructions are also exactly there.
This then is, without any question, where you should end up when the job is done right.
Leaving the sprockets on a factory engine will give you exactly that.

The easiest way to achieve this, is to leave the sprocket well alone on a factory engine. Or, to make sure the marks align, on an engine that has been disturbed. That does not require any timing tools, just good eyesight.

There can be very little confusion about that, I would have thought.

But let's see where this ends.
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Old 21st May 2018, 15:45   #76
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If the marks align in safe mode, the engine is timed. To deny this will be to say the engine constructor placed the timing marks wrongly. I think there will be too much checking before the casting is given the go ahead for this to have happened. Further, the timing on this particular engine was exactly there, the marks in the official instructions are also exactly there.
This then is, without any question, where you should end up when the job is done right.
Leaving the sprockets on a factory engine will give you exactly that.
I'm inclined to agree with both points of view. If the engine is untouched from the factory, or if you don't have the tools, then just change the belts.
However, with an engine of unknown history, and if you have the tools, then I feel it is certainly worth checking the camshaft setting and correcting it if significantly out (mine was by over a tooth).
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Old 23rd May 2018, 09:08   #77
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I haven`t visited this forum for many months. Glad to see that the debate is still going on
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Old 23rd May 2018, 15:08   #78
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I haven`t visited this forum for many months. Glad to see that the debate is still going on
Slow learners?
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Old 24th May 2018, 09:20   #79
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Originally Posted by Mike Noc View Post
Again the real question is, if they didn't go for the floating cam arrangement for timing accuracy when replacing the belts, why did they?
I have been directed to a thread on mgrover.org which includes a post from member 1955diesel (who I understand is believed to be an ex-MGR employee involved in engine design):

“Unfortunately we were not able to hold the required cam timing tolerance without them [the ‘floating’ cam sprockets]. In fact the engine originally had them on the rear belts too, but we were just about able to get away with fixing their positions. However, this did push the timing tolerance to the limit which is why it is always a good idea to reset the timing using the setting tools if any of the components in the system are replaced. The Japanese were always better than us at controlling production tolerances!”


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Old 24th May 2018, 10:51   #80
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I have been directed to a thread on mgrover.org which includes a post from member 1955diesel (who I understand is believed to be an ex-MGR employee involved in engine design):

“Unfortunately we were not able to hold the required cam timing tolerance without them [the ‘floating’ cam sprockets]. In fact the engine originally had them on the rear belts too, but we were just about able to get away with fixing their positions. However, this did push the timing tolerance to the limit which is why it is always a good idea to reset the timing using the setting tools if any of the components in the system are replaced. The Japanese were always better than us at controlling production tolerances!”


Simon
Simon, please show me which and what tolerances might affect the cam timing, and then give me an estimate of the influence it would have.
The worst offender would be the cam belt, and I have already shown you the expected maximum deviation of the belt and its effect, which is insignificant!
Note the text from Diesel: only words and no calculations, no value at all plus an opt out, when pressed for specifics. Not convincing at all.
But why don't you complete your job, and show us where you end?
Then at least you can comment on an equal footing with people who have done the job.
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