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Harmonic Crankshaft Balancer.


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2 hours ago, john.r.davies said:

Clearly I have to repeat, 'balancing' while an essential part of an engine build, does not test the function of the pulley damper against Torsion vibration in a running engine!

John

Thanks John...can you recommend a supplier.

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Yes. Me.

AFAIK I have the only damper test set up in the UK.    

"Give me your tired, your poor, scrambled dampers yearning to spin free,
Send these, the hopeless, engine-tossed to me,
I lift my lamp beside the golden door!"

Contact me by PM with your postal address and I'll send you mine.

After testing I'll return it with a readout of it's performance, like this:

image.png.22f942264b73ea3b2a701910466f47a8.png

John

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8 hours ago, john.r.davies said:

Yes. Me.

AFAIK I have the only damper test set up in the UK.    

"Give me your tired, your poor, scrambled dampers yearning to spin free,
Send these, the hopeless, engine-tossed to me,
I lift my lamp beside the golden door!"

Contact me by PM with your postal address and I'll send you mine.

After testing I'll return it with a readout of it's performance, like this:

image.png.22f942264b73ea3b2a701910466f47a8.png

John

Hi John so does the graph represent a good damper performance?

If so what does a bad one look like?

Andy  

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John,

It has been said that on the 4 cylinder engine the rubber mounted 4 blade engine fan attached to the cast iron crank extension provides some harmonic balancing.   Is this possible or folk lore?

Peter W

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Andy, Much more vibration at various frequencies, esp. at high rev rates:

image.png.03a7cba0df40c203917ddc3821d7163b.png

 

Peter said "It has been said that on the 4 cylinder engine the rubber mounted 4 blade engine fan attached to the cast iron crank extension provides some harmonic balancing.   Is this possible or folk lore?"    Triumph didn't consider that torsion vibration was a problem, before the longer six cylinder engine.    This was accepted theory and practice at the time and other manufacturers did the same.     I can't say if the fan on earlier 4s had any effect, as I don't own one, but I have developed 'bolt-on' brackets to allow me to attach the sensors to such an engine, temporarily, and have been seeking a willing volunteer!   But no takers!    

I can assure anyone interested that anything I fitted to your TR3/4 would be reversible.   A car that retained the mechanical fan would be best, so that tests could  be done with and without it.     I would hope that a single day would be enough, most of the time being consumed by fitting the sensors and testing them.    The actual measurements take a few minutes.

You are quite right, Peter, this controversy has thrived on complete lack of information, and I would hope that my technique could show definitely if the fan was a damper or not!

John

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Thank you for the reply John.

My own car has no mechanical fan fitted and there is no way to refit one as I have machine the fan mounting flange off the extension to allow the electric fan to be fitted.

Yes I agree it would be nice to discover if the metal fan had any damping effect.  That simple test could reinforce or scotch any of the fables we have told each other for so many years.  All we need to find is a standard 4 cyl TR (easiest to do would be TR4/4A because of access)  with a mechanical fan fitted that is near you.

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Hi John,

I also asked for volunteers for some technical issues and never got an offer.

Very likely no finding is better than a negative one….?

I would be very pleased to give you my TR4A, and I would also fit back the old cast iron extension and metal fan!

Also to test my lightweight extension and BMW fan would be very interesting for me.

P1150856-b.thumb.JPG.76faa0eee61ab612bd0daccebce15c37.JPG


P1150858-b.thumb.JPG.42a33f4010f011fc5e552df9d8f6ca2d.JPG

But hundreds of miles are between us!

Ciao, Marco 

Edited by Z320
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Any assembly like the original fan will have damping effects (anti-resonances) at some frequencies but resonances at others, as all mechanical structures do. The important thing is whether the vibration 'modes' occur at the same frequencies as the crankshaft torsional resonances in which case they might damp (good) or amplify (bad) the effect.  Just testing the damper in isolation only tells you how it performs in comparison against a known 'good one' but since no such animal exists for the four-pot engine there is nothing to benchmark against. 

To understand what is really going on, requires a 'modal survey'  of the complete crank and damper assembly when in the engine. This is a complicated and expensive process requiring very specialised test equipment (which was was not available when the TR engine was designed.) 

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RobH,

Completely agree with you!   That is why I developed my torsion vibration test kit on a six cylinder engine rig, so that dampers could be tested against one another in a real world situation.

The testing system can be transferred, temporarily, to a TR3/4 engine by attaching suitable bracketry.  Then, I expect to be able to measure the vibration present with and without the fan extension.  So, no need for a mythical 'four cylinder damper' but a direct measurement of the effect of the mechanical fan.

This is neither expensive nor complicated, but indeed was impossible when those engines were designed.

John

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On 7/5/2023 at 5:14 PM, RobH said:

Under the sale of goods legislation a customer can return faulty goods up to 6 years after purchase.   If you can prove it was faulty when sold, The seller must repair, replace  it. 

Quote:

"You must repair or replace an item if a customer returns it within 6 months - unless you can prove it was not faulty when they bought it.

You can ask a customer to prove an item was faulty when they bought it if they ask for a repair or replacement after 6 months.

Customers have up to 6 years to make a claim for an item they’ve bought from you (5 years in Scotland)."

https://www.gov.uk/accepting-returns-and-giving-refunds

 

On 7/5/2023 at 5:14 PM, RobH said:

I am not getting anywhere with Rimmers, even after the above suggestion regarding "returns/refunds".

Does anyone have an email address for the manager of Rimmers?

 

 

 

 

 

 

Edited by Malbaby
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A possible solution for this. Have a browse on eBay.com (U.S.) and find yourself a used crankshaft damper for a TR5/6, there's usually a few available at any given time. Purchase the one that may take your fancy for £20-30, have the seller ship it to Damper Dudes in California for a rebuild, once complete after only a couple of days they'll ship it to your home address. Total cost around £170. (what does the Rimmers offering cost?).

I've done this twice, John R. Davies tested one of these rebuilt dampers on his test rig and it passed with flying colours.

Usual disclaimers.

Richard.

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8 hours ago, Richard71 said:

A possible solution for this. Have a browse on eBay.com (U.S.) and find yourself a used crankshaft damper for a TR5/6, there's usually a few available at any given time. Purchase the one that may take your fancy for £20-30, have the seller ship it to Damper Dudes in California for a rebuild, once complete after only a couple of days they'll ship it to your home address. Total cost around £170. (what does the Rimmers offering cost?).

I've done this twice, John R. Davies tested one of these rebuilt dampers on his test rig and it passed with flying colours.

Usual disclaimers.

Richard.

Good link thank you.

https://www.damperdudes.net/harmonic-balancers/triumph/

 

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  • 2 months later...

My thanks to those who have faith in me!

I have a kind volunteer, but they are 200+ miles from me, and I'm sure that there are TR4s that live closer, the North.   I've been encouraged to do the testing at Malvern, where any volunteer and I might rendezvous.   That might be an alternative venue!

John

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