23 replies to this topic

[KernowCooper]

 @Tiger The tensioner DOES NOT run correctly against the duplex chain, and so is NOT used.

 

Ask AC Dodd both he and I beg to differ.

[sledgehammer]

I have seen wide tensioners made for the duplex chains - & also seen std tensioners run on duplex - which I suspect wear quickly - 

 

because the outer links on the chains miss the nylon totally

 

can't see why the wider ones wouldn't work - esp now nylon is much better than the 60 / 70's

 

we use nylon chain tensioners at work (asa 60) - with hundreds of kilo's force on them - they last well

Edited by sledgehammer, 26 April 2014 - 08:19 PM.

[Gremlin]

I was talking to ACDodd today and he said that he never builds an engine without a tensioner - simplex or duplex, and always strongly advises people to put tensioners on their engines

[KernowCooper]

When chains stretch the obvious is a bit of noise but perfrmance is seriously efffected on cam and ignition timing.

[ACDodd]

Tensioner all the way.

 

AC

[Captain Mainwaring]

When chains stretch the obvious is a bit of noise but perfrmance is seriously efffected on cam and ignition timing.

 

Sorry to differ a bit, but chains don't stretch, they wear, together with the sprockets.

[KernowCooper]

 

When chains stretch the obvious is a bit of noise but perfrmance is seriously efffected on cam and ignition timing.

 

Sorry to differ a bit, but chains don't stretch, they wear, together with the sprockets.

 

So they wear and therefore there overhaul length goes beyond specifacation, chicken and the egg ! lol

 

But side plates do in fact stretch I have a chain here off a superbike which the sideplates stretched before they broke

[sledgehammer]

Chains definitely stretch - but most are now pre-stretched

 

the machinery I produce for a living , is calibrated to accommodate stretch 

 

even with pre stretched chain , its asa-60 etc - and still stretches when under load

 

timing chain is short on a series, so stretch will be minimal , but still a factor esp with sprocket bedding in added on

 

longer timing chain stretch on some engines will be a problem later on

[Captain Mainwaring]

 

 

When chains stretch the obvious is a bit of noise but perfrmance is seriously efffected on cam and ignition timing.

 

Sorry to differ a bit, but chains don't stretch, they wear, together with the sprockets.

 

So they wear and therefore there overhaul length goes beyond specifacation, chicken and the egg ! lol

 

But side plates do in fact stretch I have a chain here off a superbike which the sideplates stretched before they broke

 

 

It's an interesting topic amongst bikers And with bikes producing huge outputs there is the possibility of mechanical damage but it's unlikely - I can't even get 130 HP on the ground in 3rd gear, on a dry road a 500Kg bike (600 + Kg with me on it) will spin it's back tyre., just guessing but perhaps your chain was off a bike engined conversion?

 

Anyhow, back to the plot, a chain in normal usage will not stretch, it will wear it's rollers, pins and bushes and appear to get longer, but won't stretch

And more pertinent to this discussion, the usage of a tensioner ensures that correct chain to sprocket geometry is maintained, reducing sprocket tooth and flank wear on chain pickup.

A mini cam chain is very lightly loaded, particularly a duplex - take a look at a british bike primary chain - they are tiny in comparison and transmit 50 horsepower with very high shock loadings and reversals.