Help with diagnosis of whine from front of engine

[Robho]

Having checked and adjusted my timing chain (thanks for the tips), after finding it was a little looser than the manual states, I was optimistic the whine would be solved. I should have known better!

As accurately as I can describe:

Immediately on restarting the whine as absent (which gave a moment of pleasure) but, after 5-10 seconds returned.

It is definitely from the front area of the engine. Difficult to describe the noise in words. Not loud but audible a part whine and part whoosh.

I was midway through jobs on another car so didn't get the time to remove the 'fan' belt to isolate that and, of course am anxious that it might be the water pump.

All diagnostic tips gratefully received

Thanks.

[gherlt]

A whine should be a bearing, maybe dynamo/alternator ?

[Robho]

Yes, that's what I'm hoping. I'll disconnect it (alternator) as soon as I get a chance. Thanks

[elans3]

+1 for the alternator or generator. When I bought my old Elan back last August, the dynamo had a goosed rear bearing. As the unit was very old (date coded 1973 on a '68 car), I elected to change the whole thing and fitted a new dynamo. Noise disappeared immediately.

[billwill]

Inside the timing case, the tiny hole that feeds oil to the timing chain might be blocked..

[Robho]

Unfortunately, not the alternator - drive belt disconnected and no change.

Thanks for the suggestion are the oil feed hole - how do I access / check it please?

[mark030358]

timing chain too tight..

[Robho]

I don't believe its too tight, checked and set to spec. (It was in fact a little loose)

[Craven]

You can gain some idea of the timing chain wear by the position of the inner part ( threaded ) to the lock nut, average length of protruding thread is 5/8”
The adjuster quadrant, gear and pin can wear quite badly on high mileage cars.

[Robho]

That's very helpful, thanks. My car's engine was rebuilt in the prior ownership so unfortunately I don't know every component used (I'll have a rummage through the receipts)...its done c 5k since rebuild.

[Robho]

Just checked the length of adjuster visible - a little over 5/8"

[billwill]

Unfortunately, not the alternator - drive belt disconnected and no change.

Thanks for the suggestion are the oil feed hole - how do I access / check it please?

It's a major job, because it involves taking off the front of the timing case and possibly the back of the timing case as well. For which it is easiest if you first remove the cylinder head. It can be done by lowering the sump cover, but that is also difficult and may lead to subsequent oil-leaks at the top edge of the timing case/head interface.

~~~~~

Your description above of adjusting the chain tension did sound as if you did it too tight. As mentioned by later comments. the whole chain needs to be able to move about a half inch, i.e say the top edge midway between the cam sprockets needs to be able to move up & down about a half inch, the thickness of the chain (vertically) is not a factor.

Also check that your cam sprocket teeth have not worn into a hooked-shape, if so you would need new sprockets.

To check if the chain is being oiled, take the cam cover off and see if the chain is oily. Try using an oil can to apply a liberal amount of oil on all reachable parts of the chain & put the top back on. See if the whine has gone. If the whine has gone you may need a major engine dismantle to clear the tiny oiling hole.

[Robho]

Hi Bill

Thanks for the further detail.

May I task a couple of questions for further clarity, and avoid any ambiguity, pls:

The timing chain adjustment I have is as I read the illustration in the workshop manual (just seeking to be sure I have it correct)... in that with finger pressure in each direction alternately: from the 'high' point the top of the chain reaches to the 'low' point the bottom of the edge reaches is 1/2". Correct?

and regards the oil on the chain, aside of it being dry (it wasn't) can you give me a guide as to how much oil should be present? (I will try the oil can idea too, thanks.) The sprockets looked fine, btw, though to be fair I didn't really examine them, I'll take a closer look when the cover's off next time.

Thanks again

[ericbushby]

Hi Robbo,
May I chip in here as I have just done this as instructed by the engine builder.
Give the chain a smack downwards with something like the back end of a hammer shaft to move all slack to that point and rotate the jackshaft a little if necessary. It needs something like a karati chop.
Now at the midpoint between the cam sprockets, measure the vertical distance from the chain to the cylinder head top surface.
The whole chain should move up and down by half an inch.
I hope this is clear
Best of luck
Eric in Burnley
1967 S3SE DHC

[pharriso]

The timing chain adjustment I have is as I read the illustration in the workshop manual (just seeking to be sure I have it correct)... in that with finger pressure in each direction alternately: from the 'high' point the top of the chain reaches to the 'low' point the bottom of the edge reaches is 1/2". Correct?

I think this is where you are going wrong.... you're going from "'high' point the top of the chain reaches to the 'low' point the bottom ", minus the thickness of the chain you actually have maybe 1/8" slack & thus are too tight.

You should be measuring the slack at the same point, the top of chain when it is pushed up, to pushed down.