Blue timing belt noise..

[CHANGES]

I recall reading somewhere about people experiencing  a whistle noise emulating from

the new blue timing belt, something to do with its construction and needing a different

tension..I  had a search but can not find the thread. Was it on the forum or did i read it 

somewhere else..?

 

[Bibs]

https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=esprit+blue+timing+belt+noise+whistle+site:www.thelotusforums.com

 

Anything there?

[CHANGES]

Found it, thanks...

It does seen that when the same tension as the std. is applied to these blue belts, after a short time

they generate a high pitched whistle.

At first it is very difficult to identify the origin, it sounds like it comes from the tension bearing. If you

study the whistle it does change pitch occasionally when the rev's are constant which would seem to

rule out the Brg.  Also it does not have that duff Brg, sound.. 

I would be interested in anyone else who has experienced this, with possible solutions.. 

 

Dave

[ragingfool35]

Dave

some new bearings supplied in the USA squealed after a very short time, someone opened one and found no lubricant.

I reduced the tension on my blue belt to rid the whine.  the two sounds are not the same however. the belt zings and whirs, the bearing has more of a squeal.  certainly easier to distinguish between the two when one has had the privilege that I had to hear them both

the common belief and mine too is that it does not stretch as much as stock belt, so if tension is set cold to stock spec, there is too much tension at engine operating temperature.  after a short use (4k miles),

I disassembled engine to find that the 1st main bearing had serious wear only in the direction of the head.

perhaps a more scientific method would be to measure the tension of the stock belt with engine hot, install and tension the blue belt to same measurement also with engine hot.  then measure blue belt tension with engine cold for future reference.

not a perfect method, but a rational start

[lotus4s]

Dave,

 

Have installed several blue belts and personally, I prefer the stock belts due to the tensioning issues and I'm going to change mine every couple of years anyway.

 

As Chris said, belt whine is common but I wouldn't describe it as a whistle at all so I'm thinking your noise is something else like the tensioner bearing. The blue ones I've done all sound like a typical timing belt that is too tight like the clip below. This one was actually set a little below the tension spec for the black belt.

 

Let us know what you find...

 

Jim

blue belt whine.wmv

[Vulcan Grey]

Dave,

 

I haven't used the blue belt, same reasons Jim mentioned, and I change mine often.

 

I had a weird noise after the head was machined, and it was the belt rubbing on the pulley, since it was running towards the front of the engine... Machinist had tapered the head.

 

Later I got a really strange noise after replacing a check valve between the intake manifold and the crank case breather!  It was the new check valve was trumpeting intake noise through the air filter box.

Sounded like this (cell phone format)

https://drive.google.com/file/d/0B2nifoCpaFSfMjY3MzZmNmEtNjVhMi00OTdmLWE4NTYtYjkzOTgzZDFmNWU3/view?usp=sharing

[Don.Hasi]

On 21/03/2015 at 03:20, ragingfool35 said:

the common belief and mine too is that it does not stretch as much as stock belt, so if tension is set cold to stock spec, there is too much tension at engine operating temperature.  after a short use (4k miles),

I would have thought, it is just the other way round: with hotter engine and hotter belt as well, the original belt stretches which the blue belt reduces. And after a time of use it stretches as well...? 

Are there more experiences by time? Or is it a matter of which exact engine and therefore which tensioner it is (semi automatic or fixed)?

[ragingfool35]

its been a long time since i've looked at a black belt.  I think the cross section of the blue belt is thicker and may be fiber reinforced, meaning all things being equal, the belt will undergo less deformation from the same tensile force.  A buddy of mine at work did some development on the blue belts;  i'll ask him the differences.  so the engine gets hot and the distance between the crank and cam sprocket increases slightly from thermal expansion, increasing the tension on the belt.  that's pretty straight forward.  what the belt undergoes is out of my education, but if the blue belt is indeed less elastic then for the same cold tension, the hot (engine) tension will be higher for the blue belt.  too bad the Esprit doesn't have a spring-loaded tensioner.  that would solve a couple of issues.  Tim Engel posted some comments on the blue belt cold tension.  do a search or PM him for a more detailed discussion