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'Orrible rattle from/around front of engine


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As the title says, I have a nasty "bag of nuts and bolts" rattle at the front of the engine somewhere.

My car is a TR2, original engine. No mechanical fan as there is no room with R&P steering, so I have a puller electric fan on the inside of the radiator.

I've checked the rocker arm clearances, put four or five pumps of grease into the water pump, tensioned the fan belt a bit in case the cause was any of those.

My next thoughts were to take the fan belt off and run the engine for a short while to eliminate the dynamo and water pump as sources of the noise.

 

I have a feeling it may be the cam drive chain tensioner, but of course that is a bit of a bugger to get to.

 

Any one any thoughts, advice?

Edited by Rod1883
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Hi Rod,

it sounds like the tensioner or something attached to it as they do eventually wear.

 

When did the noise start

How did it start - suddenly or gradually getting worse.

 

Have you used the stethoscope screwdriver to localise the noise.

Tappets can make a racket even when adjusted correctly. TRy closing the tappet gaps (for diagnostic purposes) down to 0.005 or 0,006 to see if that helps.

 

Roger

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Thanks Roger.

It started a little while ago - probably difficult to be precise.

It comes and goes, but is getting rattlier and louder I think.

I've set the valve clearances at 10 thou - a couple were a bit tight when checked, and one slightly wide, but the adjustment made no difference to the ratlle.

 

I have tried the use of a couple of socket extensions as a stethoscope, but this doesn't seem to suggest it is from the rocker area, or the water pump, or the dynamo. It's a bit difficult to get a good contact onto the timing chain cover.

 

If it is the tensioner - what sort of risk am I exposing myself to if I continue to drive the car for a while? The reason I ask is that we are booked on the TRR stand at Carfest in 10 days time (a round trip of circa 100 miles)

Edited by Rod1883
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Hi Rod,

when the chain wears through the tensioner it cuts two slots in it.

As the tensioner is curved the slots start in the middle and work towards either end.

 

I don;t think the tensioner will part company completely with what it is attached to.

The chain will lose its tension and this is (I think) the noise you are hearing.

 

I would do the Carfest then consider a fix.

 

What could possibly go wrong

 

Roger

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Does the rattle get worse or better if you increase revs ? In my (limited) experience timing chains sound at their worst at tickover

 

Bob.

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Without hearing the sound, first guess would be the tensioner.

 

Bought My tr4 with a horrible sound just as you describe. Owner wanted to get rid of it because he didnt want to spend more time on the car. Took me a couple of hours to replace chain and tensioner.

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Hi Rod,

if you find that the tensioner is dead then be careful with replacements as they appear to not be as strong as the OEM ones.

If you have a replacement chain in there or need a new one get one of the German chains. They have n rough edges and will allow the new tensioner to last longer.

 

Roger

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Well - running with no fan belt - no noise!

As I was getting the belt off the dynamo, I found that the front pulley and bolt are loose!

Incredible how sound seems to come from somewhere other than its source - I was convinced it was lower on the front of the engine - transmitted through the belt perhaps?

 

So, thanks for everyone's thoughts. I now need to get the dynamo off completely and retighten the pulley. Any tips for ensuring it doesn't work loose again?

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I think so Bob.

No noise from the vicinity of the timing chain cover, and the water pump feels smooth turning by hand - so by elimination I think it must be the loose dynamo pulley causing the fan vanes to rattle as it spins I assume. It is a newly reconditioned dynamo, only fitted a couple of months or so ago. Obviously the pulley wasn't bolted up tightly enough by the refurbisher.

Edited by Rod1883
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Difficult to tighten a dynamo, or alaternator fan bolt - nothing to brace against.

Case for an impact driver/whizzy gun

 

Take dynamo, with the right socket (they may not have imperials!) to a friendly local garage, who WILL have a driver.

And of course, a drink for them!

John

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I know exactly the noise you heard, Rod. Had the same thing in my car with a loose dynamo pulley.

Tightened it using a large square-shanked screwdriver to wedge the pulley tight by bearing against the raised nubs on the pulley front face and a socket on the pulley nut. It's held for several years now.

Edited by Don H.
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Update - as Stan says good news it was "just" the dynamo.

The bad news is that the dynamo is a bit odd in that the pulley isn't a one piece item rather a two part assembly.

Whilst working loose - it has chewed up the woodruff key and some of the threads on the shaft, and the back of the outer part of the pulley.

 

Don - I went to follow your advice when it became clear that the pulley wasn't the correct type as it doesn't have the "raised nubs".

The nut was pretty loose and upon taking it off - it was clear the pulley was in two parts and had chewed itself etc.

 

Hopefully the pictures show the assembly and the problem.

 

post-4992-0-40766300-1502901993_thumb.png post-4992-0-12033300-1502902005_thumb.png post-4992-0-29653600-1502902014_thumb.png

 

The two part pulley has two extra holes in it which presumably should have had something in them to hold the two parts together (in addition to the main shaft nut and washer).

The Dynamo is a C39PV2 which I got from a well known refurbisher as I wanted to fit the correct one for the car. It's only been on the car since March, and done 400 miles.

 

I've sent a note and the picture to the supplier, we'll see what they say.

 

In the meantime I've fitted a secondhand C40 that I picked up at the IWE last year (before I decided to go the originality route) - flashed it to polarise it to positive earth, as per a Stuart instruction that I found here on the forum, and it appears to be working.

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Yes, that pulley is very different from the cast original, Rod. I'm travelling these last two weeks and not near an image of mine, but the original pulley has three raised wedges cast into the front face.

 

The Moss Europe shows what I have.

tr24_16_03_01.jpg

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Thanks Don - yes I looked at that diagram on the Moss site as part of my deliberations today.

I have told the supplier that the unit should have had a one piece pulley - unfortunately I didn't spot or realise the difference before I fitted it in March. I had been in dialogue with the supplier as the unit was being built and they knew the car it was for, and the fact it needed the wide belt pulley.

Hopefully they will be responsive.

 

The C40 I have now fitted has the correct "nubbed" pulley.

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