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Triumph Crank Damper Pulley Survey

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tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
I retired a while ago, and since then I've gone back to college, where I'm now studying for a degree in Motorsport Engineering. I need a research project and chose to investigate the crank damper pulleys that Triumph fitted to all the six-cylinder engines it made. The crank damper was needed to suppress 'torsional', twisting vibration in the long crankshafts, and has a rubber layer between the inner hub and outer ring. They were suspect even in the day, when they were new. Kas Kastner described in his Handbooks his technique to ensure that the outer hadn't shifted, which would make the timing marks on them completely false. Worse, a faulty damper could lead to crankshaft failure!

Today, none of those dampers are less than forty years old, and many show the rubber to have deteriorated. How many still work as timing indicators, let alone to suppress crank vibration?

My study has two parts: In the workshop, I'm building an engine rig with sensors on the pulley and flywheel to detect vibration, and I'm asking Triumpheroes about their experiences with the dampers. Please help me by completeing the short survey questionanire I've put up on Survey Monkey?

Go to https://www.surveymonkey.co.uk/r/GPTCDSG There are only five questions and it will take you less than two minutes!

Thank you!

John

PS I'm posting this on several websites, to catch as many people as I can but no need to complete it more than once!

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tomshobby Avatar
tomshobby Tom Smith
Windsor, WI, USA   USA
I have done some work on this subject when designing a serpentine belt system for my TR6.



Tom Smith
1976 TR6
1974 Midget


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new_damper_2b.JPG

new_damper_1b.JPG    16.4 KB
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sys.JPG    42 KB
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ed.h Ed Hollingsworth
Omaha, NE, USA   USA
Real science! Bravo! I hope you can share your results with us. It's a mysterious topic to most.

Ed

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shynsy Avatar
shynsy tim dafforn
Kenilworth UK, Warwickshire, UK   GBR
The supercharger setup uses a serpentine belt setup with a solid crank pulley. Seems to work quite well, although not done many miles as yet..
Cheers
Tim

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Thank you all! Please contribute to the survey, if you have had a TR6/250, even if the damper gave no problems - that's as imporatnt as knowing those that failed.

Tom,
Is your drawing of a replacement outer ring, to be installed on an OE hub to the pulley, with a new rubber insert? Please PM me; we can exchange email addresses if you're willing to share. I'd love to know more on your work!

John

tomshobby Avatar
tomshobby Tom Smith
Windsor, WI, USA   USA
John, check your pm"s
Tom



Tom Smith
1976 TR6
1974 Midget

ng19delta Avatar
ng19delta Scott Roberts
Merchantville, NJ, USA   USA
1974 Triumph TR6 "Gypsy Rose T..."
I contributed, but NOT re Triumph: My TR6 pulley seems ok (knock wood) but the one in my F-150 died at 25 years and 196k miles... It actually shifted, came loose, and tilted, and I heard it striking the oil pan as it went! Of course, I was off to the parts store and had it swapped in no time.

Also, question 5 needs a "not applicable" choice...

Scott

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poolboy Avatar
poolboy Ken D
Sandy Hook, MS, USA   USA
John, anybody over in your part of the UK recondition dampers ?
We have several. I posted a link on your survey to the one I've used and would use again if need be.....Dale Manufacturing

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Scott,
Thank you, but no thanks! This survey is about TRIUMPH dampers, and I may not be able to weed out any that aren't relevant, unless you have told me in your comments.

Poolboy, no I don't think there are! But that's only peripheral to my survey. I'm most grateful to all of you who have contributed about Triumphs, if they give good service or have failed. BOTH are as important to the survey!

John

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ng19delta Avatar
ng19delta Scott Roberts
Merchantville, NJ, USA   USA
1974 Triumph TR6 "Gypsy Rose T..."
In reply to # 1509720 by tapkaJohnD Scott,
Thank you, but no thanks! This survey is about TRIUMPH dampers, and I may not be able to weed out any that aren't relevant, unless you have told me in your comments.

Poolboy, no I don't think there are! But that's only peripheral to my survey. I'm most grateful to all of you who have contributed about Triumphs, if they give good service or have failed. BOTH are as important to the survey!

John

Hi John- I didn't realize it was for ONLY Triumph dampers... I did mention that my entry was for a Ford in my comments...Sorry about that. I do imagine the same problems affect both marques, however, when it comes to the blasted things.

Scott

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
The survey is about Triumph dampers, but I will be grateful for anything people have to say about the subject!

Viscous rubber dampers were a cheap way of ding the job - look how expensive the modern viscous fluid ones are! They di the job well, amazing well as they are still on the nose of thousands on T6 engines, and I can say already that the reports of problems are few.

If you can tell me about other marque's dmapers, please do. I can't use them in the survey, but I can for my research!

John

dsixnero Avatar
dsixnero Dan Colanero
Westville, NJ, USA   USA
John, I feel I must mention that Scott's engine idles well at 24 btdc which is 10 or 12 too many. I've seen this on some other tr6's and can only blame the pulley. I will also add that mine was rebuilt when my engine had a balanced rebuild 10 years ago. A short nose piece and electric fan with an alum.flywheel and I don't think the pulley is doing it's job of balancing at high rpm's. I think I need one of those racing dampers, very costly, where does it end? keep them stock. Dan

dicta dick Taylor
Downey, Callifornia, USA   USA
Easy enough to check as to whether the timing marks have 'moved' due to a separation of the rubber and hub. With the head off, bring #1(or #6) piston to TDC and see if the pointer is still at "0" this can also be checked with a tool* down thru #1 spark plug hole. Move engine in a forward direction till the piston contact stops the rotation. By adjusting the tool to where you can see a BTDC numbered timing mark, then reversing the engine rotation to pick up this same mark on the ATDC side. Mine was within one degree. Close enough... Original pulley,now with 350,000+ on the odo.

Dick

* Home made, but it works!



Edited 1 time(s). Last edit at 2018-02-03 04:50 PM by dicta.


Attachments:
Tool to find TDC.JPG    28.2 KB
Tool to find TDC.JPG

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
And once you have confirmed that, use Kas kastner's idea?

Drill a hole in the Vee of the pulley, right through into the hub, to a depth greater than a split pin's length
Later, probe it with the pin - if it won't go right in, the outer has moved!

Damned clever , these Americans!
John

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