Worrying noise

[NonMember]

It could be that it only does it when the oil's hot. Your initial 20 miles including some A1 would have got the oil warm, but not hot. The St Neots traffic followed by a bit of a blatt could get it proper hot.

[cliff.b]

24 minutes ago, Pete Lewis said:

its a classic   noyhing that happens can be explained  

they have amind of theyre own  you know 

heat soak may have some input but if pootling around for 2 hour all will be up to the the   thermostat temperature 

Pete

Yes, would think it was well warmed up but it was quite a slow "pootle" with the heater on and the temp gauge was well below halfway.

After the traffic and putting my foot down for a few miles it was just about in the middle of the gauge, where it normally is.

 

Think I need someone that knows about these things to hear it when it's making the noise, which was the idea today, but the car decided otherwise 😒

[cliff.b]

46 minutes ago, NonMember said:

It could be that it only does it when the oil's hot. Your initial 20 miles including some A1 would have got the oil warm, but not hot. The St Neots traffic followed by a bit of a blatt could get it proper hot.

That's what I was wondering, but unsure how that would explain the symptoms. 

Would a bearing be quiet when oil is cooler but noisy when it gets hotter & presumably thinner? 

Unfortunately, this is outside of my experience.

 

[NonMember]

23 minutes ago, cliff.b said:

Would a bearing be quiet when oil is cooler but noisy when it gets hotter & presumably thinner?

Yes, they can, if it's "on its way out" but not yet terminal.

[cliff.b]

2 minutes ago, NonMember said:

Yes, they can, if it's "on its way out" but not yet terminal.

Hmm. If that was the case, how would it likely develop?

 

[Mark B]

The origins of engine rattles and  knocks can be hard to pin down. I had a rattle from my Vitesse engine when I bliped the throttle. Rattle  sounded like it was coming from the n/s, of the block, and  started to think it was the ends rattling. Bought a mechanics stethoscope, cheap as chips off eBay. Very good at pin pointing the sorce of the noise. The cause? Front SU dashpot had no oil in it. Piston was hitting the inside of the dashpot. Noise was going down the inlet manifold, like a trumpet. Wearing the stethoscope blocks out most of the other engine noises, and makes it easy to track down metalic clatters.

https://youtu.be/fGnHc3cores

[cliff.b]

33 minutes ago, Mark B said:

The origins of engine rattles and  knocks can be hard to pin down. I had a rattle from my Vitesse engine when I bliped the throttle. Rattle  sounded like it was coming from the n/s, of the block, and  started to think it was the ends rattling. Bought a mechanics stethoscope, cheap as chips off eBay. Very good at pin pointing the sorce of the noise. The cause? Front SU dashpot had no oil in it. Piston was hitting the inside of the dashpot. Noise was going down the inlet manifold, like a trumpet. Wearing the stethoscope blocks out most of the other engine noises, and makes it easy to track down metalic clatters.

https://youtu.be/fGnHc3cores

That's a good idea. I will get one 👍

[mpbarrett]

there is a TSSC/CT meet at the Plough, Fen Ditton on Monday night if you wanted to bring it along. Should be a few people there who could lend a ear or two. Not too far from Huntingdon.

mike

[NonMember]

11 hours ago, cliff.b said:

Hmm. If that was the case, how would it likely develop?

 

A loose bearing can move about and make a "death rattle". It's the same as the well-known startup noise and is silenced by the film of protective oil between crank pin and bearing. As long as that film is good (which usually goes with having decent oil pressure) the metal surfaces don't actually make harsh contact and all is well (and quiet). If there is a rattle it means there's impact happening, and the soft metal bearing is gradually being hammered flat, increasing the gap and making the problem worse. This process will be slow if the noise is only there at hot idle, and as long as you blip the throttle before pulling away (so that there's a bit of oil pressure before any load is applied).

[johny]

9 minutes ago, NonMember said:

As long as that film is good (which usually goes with having decent oil pressure) the metal surfaces don't actually make harsh contact and all is well (and quiet). If there is a rattle it means there's impact happening, and the soft metal bearing is gradually being hammered flat, increasing the gap and making the problem worse. This process will be slow if the noise is only there at hot idle, and as long as you blip the throttle before pulling away (so that there's a bit of oil pressure before any load is applied).

The thing is the oil pressure is good even at tickover when hot and I wouldnt expect that if the bearings were worn...

[cliff.b]

20 minutes ago, johny said:

The thing is the oil pressure is good even at tickover when hot and I wouldnt expect that if the bearings were worn...

I don't know the history of this engine but before I heard this noise I felt it was in good condition.   Not aware of any smoke at all and very low oil usage. 

The oil pressure is good when cold but has always dropped when thoroughly hot. It is pretty much the same now as it has always been. Changing the oil last week raised it very slightly. 

So I'm wondering, if the main bearings were good but just one big end was on the way out, would that drop the oil pressure noticeably?

I have no experience of this stuff in practice but just trying to think it through.

[cliff.b]

1 hour ago, mpbarrett said:

there is a TSSC/CT meet at the Plough, Fen Ditton on Monday night if you wanted to bring it along. Should be a few people there who could lend a ear or two. Not too far from Huntingdon.

mike

Mike, I might see if I can make that. What time do people start getting there? A blast down the A14 getting there should warm it up nicely.

[johny]

In my experience its the bearings not combustion chambers that are usually the first thing to show signs of wear in our Triumph engines and I read a recommendation once that on the sixes if the big ends and mains are changed at 40k and 70k miles respectively the crank will last almost indefinitely.

Its true the mains dont wear evenly and one or two will be worse than the others but the bigends tend to be more equal so as I say I would expect to see a drop in oil pressure if they are the problem.

I know youve recently changed the oil but how about doing it again but with a 20w-60 grade (about the thickest you can get once hot) to see if that makes a difference.... 

[Pete Lewis]

as for bearings   there is no noises under load   its only at idle  thats not exactly  pointing to bearings 

and stethoscope   use an decent (wooden handle is best )  screwdriver   position on the block and put ear to the handle  amazing what that will detect 

move around the block to determine just where   ( if any )

dont get near the fan or its up A &E to get it removed   !!!

Pete

 

[cliff.b]

7 minutes ago, johny said:

In my experience its the bearings not combustion chambers that are usually the first thing to show signs of wear in our Triumph engines and I read a recommendation once that on the sixes if the big ends and mains are changed at 40k and 70k miles respectively the crank will last almost indefinitely.

Its true the mains dont wear evenly and one or two will be worse than the others but the bigends tend to be more equal so as I say I would expect to see a drop in oil pressure if they are the problem.

I know youve recently changed the oil but how about doing it again but with a 20w-60 grade (about the thickest you can get once hot) to see if that makes a difference.... 

Yes, that's a good idea.

But first I think I should try and get some opinion from people who know more about this sort of thing than I do as it might just hide an issue that should be dealt with.

 

[cliff.b]

2 minutes ago, Pete Lewis said:

as for bearings   there is no noises under load   its only at idle  thats not exactly  pointing to bearings 

and stethoscope   use an decent (wooden handle is best )  screwdriver   position on the block and put ear to the handle  amazing what that will detect 

move around the block to determine just where   ( if any )

dont get near the fan or its up A &E to get it removed   !!!

Pete

 

That's what is confusing me Pete and why the flywheel bolt thing sounded plausible. But why would that only be noticeable when hot?

 

Whatever it is, I think I need to get more knowledgeable people to listen to it when it is making the noise. 

 

[Pete Lewis]

there is probably some relation of heat expansion on crank/bolt /flywheel  all are heat affected 

if an big end was playing a part i would expect some clatter when under load  and then its more a cannon ball in a drum not a clatter 

the idea its only at idle is when the crank unsympathetic vibtaions are possible more evident 

you now have 4 pages of ideas  with no firm conclusion  get some more views is good plan  but i still reckon as she is running fine  the clatter is going to be external 

not bottom end     always open to be wrong  but i dont feel  the clues  point to shell problems  

Pete

dig out the old screwdriver and get listening  !!!!

[johny]

48 minutes ago, cliff.b said:

But first I think I should try and get some opinion from people who know more about this sort of thing than I do as it might just hide an issue that should be dealt with.

Yes I didnt mean put in thicker oil and forget it but if it does reduce the noise youd definitely know its time to plan a bottom end overhaul. Its a much cheaper and simpler job to replace the bearings than wait until the crank is damaged☹️

 

[cliff.b]

41 minutes ago, johny said:

Yes I didnt mean put in thicker oil and forget it but if it does reduce the noise youd definitely know its time to plan a bottom end overhaul. Its a much cheaper and simpler job to replace the bearings than wait until the crank is damaged☹️

 

Ok, yes I agree that could well be a reasonably simple way of proving what sort of issue I am dealing with.

Good idea 👍

 

[cliff.b]

3 hours ago, Pete Lewis said:

there is probably some relation of heat expansion on crank/bolt /flywheel  all are heat affected 

if an big end was playing a part i would expect some clatter when under load  and then its more a cannon ball in a drum not a clatter 

the idea its only at idle is when the crank unsympathetic vibtaions are possible more evident 

you now have 4 pages of ideas  with no firm conclusion  get some more views is good plan  but i still reckon as she is running fine  the clatter is going to be external 

not bottom end     always open to be wrong  but i dont feel  the clues  point to shell problems  

Pete

dig out the old screwdriver and get listening  !!!!

As you say, many ideas and I appreciate all of them 👍

I will work through it all, easiest things first.

[mpbarrett]

4 hours ago, cliff.b said:

Mike, I might see if I can make that. What time do people start getting there? A blast down the A14 getting there should warm it up nicely.

usually 8 ~ 8:30pm
The Plough, Green End, Cambridge, Cambridgeshire, CB5 8SX

If you havent been there before worth a look at Google maps as you have to drive thru the village past the church right to the end of the road to get to the pub.

You should find one or two Triumphs in the Car park.

cheers

Mike

[cliff.b]

1 hour ago, mpbarrett said:

usually 8 ~ 8:30pm
The Plough, Green End, Cambridge, Cambridgeshire, CB5 8SX

If you havent been there before worth a look at Google maps as you have to drive thru the village past the church right to the end of the road to get to the pub.

You should find one or two Triumphs in the Car park.

cheers

Mike

Many thanks. 

[johny]

keep us informed of the findings as it all adds to the hive knowledge🙂

[cliff.b]

45 minutes ago, johny said:

keep us informed of the findings as it all adds to the hive knowledge🙂

Will do 👍

[NonMember]

8 hours ago, johny said:

the bigends tend to be more equal

You'd certainly expect that but in my experience it has always been number 3 that fails (on the four cylinder). I've no idea why.