Noise from engine under labour.

[MorrisJohn]

I don't understand why the mechanic says it's the timing chain 'when under labour'.
Nor do I. I can't see why it would make any difference under labour or no as to rattling - was hoping someone with expert knowledge could clarify this, please.

Thanks for this. I’ve been a bit perplexed by it too. I was wondering why, if it is the timing chain, the noise was considerably reduced following timing adjustment and tuning. And why it doesn’t do it in the slightest when revving the engine at a stand, and why it doesn’t do it at all going downhill or on a perfectly flat road. It’s only really when there’s an uphill gradient.

[oliver90owner]

A long shot might be crank end-thrust if only when going up hill.

The only experience I have of this was with my ex BiL and his Triumph PI (which were apparently prone to this defect). He scrapped his nice (cheap) car because of it - it got so bad that engaging the clutch became an issue. That was about 40 years ago.

Are you finding any difference with clutch operation dependent on gradient? That might induce clatter from the timing chain if sprockets are out of alignment.

[Nickol]

As promised, I can report now that the crankshaft replacement has been completed and the engine is back inside the car.

Firstly the rumble I got for a few seconds after the cold start is gone. So too the knocking/rumble/clanging when accelerating at ca. 70km/h. Therefore it was the crankshaft at fault. The supplier said that the main bearings were not too bad, only the big end bearings were seriously worn.

Hopefully, I have not done anything stupid with the engine rebuid such that subsequent oil leeaks or worse , bits come loose in use.

[oliver90owner]

Thanks for the update. Boffer9 has not been active since late September and either didn’t like the diagnosis or has gone away to sulk (over the cost and dodgy diagnoses he has had to endure without sorting the problem, or the cost to get it fixed properly).

It is good to read the outcome - we can all learn from feed-back - whether the diagnosis was right or wrong.

I am guessing the crank was the problem all the way along. Even ‘shade tree’ mechanics benefit from decent measuring instruments.