How is the lining added to the cam chain tensioner blade

redax5

redax5

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Staff member
I ask this question as it appears I need to start making my own heavy duty cam chain tensioner blades as we have broken another one, FFS
Reason the Mule lost 5th and then 4th gear on the weekend is because her cam chain tensioner blade is now in numerous pieces, not certain how many yet but is more then 4 that is for sure
And as we break them at very high rpm we now have swarf and shit all through that race engine, which means I have to totally strip her once again, including pressing the crank apart just to clean the fucker out

So over the last 5 years of racing we have gone from breaking gearboxes every meeting which we cured and now we break cam chain tensioner blades every fucking meeting which is pissing me off

Is the wear medium whatever it is just glued on to the spring steel backing with some NASA top secret glue or is it some form of heat specific vulcanizing process ?
Someone out there must have experience of this process, plenty of lurkers out there with unknown skills that could really help out on this subject

How does one go about making their own cam chain tensioner blades?

Looked at making a roller set up similar to the 750 set up but do not believe that will work as the whole point of the 280mm long tensioner blade in the triple engine is to try and dampen out the harmonics that would be in play with a singular spinning cam chain
So I just need to make a dozen heavy duty cam chain tensioner blades that will not break, 2 to be installed in the engines and 10 spare just in case they do break

Any help out there ?
 
Is it worth looking into how other engine manufacturers do it, Red? How do high end sportscar people do it?

Total bloody piss off having such a relatively insignificant engine part causing so much grief - I recall the blade at a previous meeting locking the Mule in 4th.
 
Is the wear strip flaking off the steel blade or the steel blade cracking and breaking up?
I wonder if an aluminium bronze strip silver soldered on to the steel replacing the fibre one would last the distance.
 
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This should be interesting, shattered into Multiple bits, how old is the plastic or whatever it is. Original stock from the 80s? Must be some impact to do that. Some of that car panel glue is insanely strong.
 
Hi Red

try looking at this material Nylon 46/ PA46 we use it a lot in the marine industry for bushings running high temp worm drives through it.
we try and mechanically attach it , but adhesives like Methylmethacrylate or Plexus would or should work

​

https://en.wikipedia.org/wiki/Nylon_46 your probably know about it

www.permabond.com

Methylmethacrylate Adhesives (MMAs), Acrylic Adhesives

Methylmethacrylate adhesives (MMAs) are reactive acrylic adhesives normally comprising resin and initiator (or a resin and hardener).
www.permabond.com www.permabond.com

itwperformancepolymers.com

Plexus Structural Adhesives | Industrial Metal & Methacrylate Adhesive

Plexus® is the leading adhesive distributor that offers industrial and structural bonding adhesives for long-lasting bonds for the toughest applications. Find advanced polymer panel adhesive, methacrylate adhesive (MMA), metal to metal, metal sign assembly adhesives, and more.
itwperformancepolymers.com itwperformancepolymers.com


It may pay to set up a jib and see how it works for you, thats the best ideas I have
 
Vince said:
This should be interesting, shattered into Multiple bits, how old is the plastic or whatever it is. Original stock from the 80s? Must be some impact to do that. Some of that car panel glue is insanely strong.
Click to expand...
FFS Vince, we use brand new tensioner blades, if you spend $30k on a race engine you do not use 40 year old cam chain blades
and it is the steel blade breaking, not the "plastic"
 
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Reunited Chris said:
Is the wear strip flaking off the steel blade or the steel blade cracking and breaking up?
I wonder if an aluminium bronze strip silver soldered on to the steel replacing the fibre one would last the distance.
Click to expand...
steel blade breaks in half
 
redax5 said:
steel blade breaks in half
Click to expand...
Ok so i guess those bonding agents would work on what ever nylon material you want to use to bond it to your upgraded steel part
stupid question , do you or anyone have any idea of the load on them? I can run FEA load testing on what ever design you come up with?
 
sideshow said:
Hi Red

try looking at this material Nylon 46/ PA46 we use it a lot in the marine industry for bushings running high temp worm drives through it.
we try and mechanically attach it , but adhesives like Methylmethacrylate or Plexus would or should work

​

https://en.wikipedia.org/wiki/Nylon_46 your probably know about it

www.permabond.com

Methylmethacrylate Adhesives (MMAs), Acrylic Adhesives

Methylmethacrylate adhesives (MMAs) are reactive acrylic adhesives normally comprising resin and initiator (or a resin and hardener).
www.permabond.com www.permabond.com

itwperformancepolymers.com

Plexus Structural Adhesives | Industrial Metal & Methacrylate Adhesive

Plexus® is the leading adhesive distributor that offers industrial and structural bonding adhesives for long-lasting bonds for the toughest applications. Find advanced polymer panel adhesive, methacrylate adhesive (MMA), metal to metal, metal sign assembly adhesives, and more.
itwperformancepolymers.com itwperformancepolymers.com


It may pay to set up a jib and see how it works for you, thats the best ideas I have
Click to expand...
Thanks Todd, some interesting leads there, I like the look of the MMA's if I make my own blades
Been sitting here at night on my computer sipping Bourbon and searching for different spring steel products trying to find a thicker section off of the shelf so to speak, current backing blade is 18.4mm x 1.5mm x 280mm long
Still searching
Thanks for the leads
 
Hi Red.

The blade and it's concept is a pretty bad design. The slipper material is on the outside of an arc and is therefore placed in tension when in use. Add to that the shape of the arc is constantly changing (around the push-on wheel) as the chain fmoves against it and you have a recipe for tension cracks in the slipper material. If the slipper material is to hard it cracks, if too soft then the glue will be stressed and that will fail. At high rpm I suspect the bottom and of the slipper is being given a hard time my the spinning chain and is being bent more that it would be under normal use. I think you will have to invent a redesign, rather than just find the right glue.

Edit, ah ha the steel is breaking, then a bit thicker, say 1,8mm of a 'spring' grade steel would be the go (not sure what grade off the top of my head)
 
redax5 said:
Thanks Todd, some interesting leads there, I like the look of the MMA's if I make my own blades
Been sitting here at night on my computer sipping Bourbon and searching for different spring steel products trying to find a thicker section off of the shelf so to speak, current backing blade is 18.4mm x 1.5mm x 280mm long
Still searching
Thanks for the leads
Click to expand...
if you have trouble finding metal, let me know, i can get most things pretty quickly from Italy
 
piranha-bro2 said:
Is it worth looking into how other engine manufacturers do it, Red? How do high end sportscar people do it?

Total bloody piss off having such a relatively insignificant engine part causing so much grief - I recall the blade at a previous meeting locking the Mule in 4th.
Click to expand...
wrong bike, Veloce broke her tensioner blade at Broadford and got stuck in 4th
This time it was the Mule's turn
 
Hi Red - I wonder if a roller wheel (same idea as the 750's) could be viable. I had an SF here that had a bronze roller wheel that showed no signs of wear after two seasons or more of racing. Perhaps even the Acetal Delrin roller would be OK? - haven't got a triple motor here to investigate myself. - Regards - Phil
 
I'd suggest dropping Julian a message he may have a contact.
The only thought, thinking aloud which is dangerous, is a partial redesign with a fixed small wheel at the top of the cam chain tensioner that sits say a few mm away from the chain at rest, and only comes into play when the chain starts 'whipping' and thus reduce/steady that effect.
Or how about a nylon 'damping ' block between the back of the tensioner and the inner wall of the barrels thus limiting the movement of the tensioner.
Brain storming over the internet!
OK you can stop laughing now.
Andy
 
If you are going to make heavy duty tensioners to combat breakage and are just worried about how to adhere the rubber lining to the blade , would it be possible to forget the lining and have the blades PTFE Teflon coated instead (or something similar) ?
With a race engine a top end inspection at regular intervals would keep an eye on how things are getting on.
I take it that it`s the tensioned blade at the rear that is breaking up , not the static one at the front. ( Yes I see it is).
Makes me wonder if it would be possible to junk the tensioner blade altogether . Whenever I fitted a new (Regina) camchain , play between the sprockets was always on the tight side if anything , so the tensioner never came into play , the adjuster bolt just tightened enough so the roller just made contact with the blade and no more.
I know the blade acts as a guide as well as a tensioner , and the distance between cam and crank sprockets would produce more chain free play than between the two cam sprockets at the top and cause fluctuation with no blade to dampen it down , but wonder if a new camchain fitted each time the engine is used in anger would keep this to a minimum , providing there is enough clearance within the camchain tunnel to accommodate this extra movement .
Actually thinking about it again , with a final drive chain under load , the top run between gearbox and rear wheel sprockets is kept in tension , whilst the lower run is going to fluctuate , so with the camchain run at the front between the crank sprocket and cam sprocket being the one under load , then the run at the rear is most likely to suffer near terminal fluctuation with no blade fitted , so maybe not such a good idea after all .
 
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Red,

If it is the steel blade breaking, I'd look into supporting it at the lower end, something along the line of the 500/zane engines. These have a bar between the inner crank mains behind which the tensioner rests, the tensioner screw bends the blade in the middle with the bottom end firmly pressed against the bar. This also keeps the un-coated end away from the chain. The stock design allows the bottom of the blade to flop around too much, added to the hammering it gets from the flailing chain. Bloody things weren't designed to cope with 13000 rpm.

The rubber is vulcanised onto the blade, guess not a job for the hobbyist.

Just saw Paul beat me to it...

piet
 
It sounds like it's time to replace the chain with gears!

What RPM are you running the motor when the tensioner fails?

You may want to ask Wolfgang as he can possibly talk to whoever is making the new ones now and see how they do it.
 
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Hi Red. Thinking aloud...
52019392079_9e8af7c94f.jpg
 
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