1500 duplex timing chain

[storeyn]

Hi All

Has anyone had any experience of these?

https://www.ebay.co.uk/itm/Triumph-dolo ... 890.l49292

And is there any benefit over the standard set up...

I am doing an engine refurb so wondered if it was worth considering

[tinweevil]

My opinion is thus:

First:

• There's no significant history of 1500 simplex chains breaking that I'm aware of.
• A duplex chain will create more noise, it cannot be otherwise.
• A stock six pot runs a simplex chain, again with no notable history of failure.

Second:

• I know how long it takes me to pop the cover1 off and check or change a chain & tensioner that costs peanuts.

Third:

• My engines get driven on the torque not on the revs/power.

• If I were building a screamer I would not hesitate to try the best quality duplex kit I could find.

Finally:

• duplex kits with known history and vendors interested in 'tomorrow' are available for very similar money from Canley or Rimmers.

Regards
Tinweevil

1 I mention this because, if I recall correctly (and I often don't), the 1500 crank pulley bolt is the highest torque fixing on the entire range. I have the tools that make it a non issue. I do have a clear mental picture of a 3/4 drive breaker bar a meter or more long and a correctly sized socket that was an absolute bugger to find short enough to fit in the gap. Total cost of those two items was roughly (2xduplex kit) - (2xsimplex kit). I.e. change a simplex kit twice with the right tools and you are quids in. I have absolutely no recollection at all what I used to use to lock the flywheel. It wasn't the starter. That works on a sprint a dream but not on a 1500.

[Carledo]

My opinion is thus:

First:

• There's no significant history of 1500 simplex chains breaking that I'm aware of.
• A duplex chain will create more noise, it cannot be otherwise.
• A stock six pot runs a simplex chain, again with no notable history of failure.

Second:

• I know how long it takes me to pop the cover1 off and check or change a chain & tensioner that costs peanuts.

Third:

• My engines get driven on the torque not on the revs/power.

• If I were building a screamer I would not hesitate to try the best quality duplex kit I could find.

Finally:

• duplex kits with known history and vendors interested in 'tomorrow' are available for very similar money from Canley or Rimmers.

Regards
Tinweevil

1 I mention this because, if I recall correctly (and I often don't), the 1500 crank pulley bolt is the highest torque fixing on the entire range. I have the tools that make it a non issue. I do have a clear mental picture of a 3/4 drive breaker bar a meter or more long and a correctly sized socket that was an absolute bugger to find short enough to fit in the gap. Total cost of those two items was roughly (2xduplex kit) - (2-simplex kit). I.e. change a simplex kit twice with the right tools and you are quids in. I have absolutely no recollection at all what I used to use to lock the flywheel. It wasn't the starter. That works on a sprint a dream but not on a 1500.

Just a quick add on to this, the 2.5PI 6 cylinder engine came as standard with a duplex chain. It's this fitment that the accessory duplex kits are based on. Whether or not any of the OHV engines, including the PI actually NEED a duplex chain is not for me to say, but even if the simplex chains don't break often in service, fitting a duplex will more than double the effective lifespan of the chain, so it saves some time and money and gives a bit of extra futureproofing. It's also slightly less likely to break when badly worn. If that's enough to justify it is your decision, being a subjective one.

Steve

PS, i've looked at the kit advertised and the seller is Mark Field late proprietor of Jigsaw Racing before ill health caused to him to close the business. He's obviously feeling better and doing a bit from home. I've known him for years, one of the good guys!

[tinweevil]

The pi metering unit is teed off the distributor drive so there is a higher load on the chain in those engines. Agreed about the duplex lifespan, if you'd be paying someone else to change it in future that's a strong argument in favour.

[storeyn]

Thanks for the feedback

I think there are still some benefits for the reasons you guys described...and the kit I saw comes from a good guy.

I think I will go for it...

On another point is there an adapter plate fir a 1500 to fit it too an engine stand?...

[Jod Clark]

My 'fastest ever...' 1500 engine had such a kit installed, from Moss. That was a nice kit, dead easy to install and silent in use. If you're into peace-of-mind upgrades I'd say it was worth it, especially if you're going to put a livelier camshaft in there.

[SprintV8]

This is a bit like converting the original Minis from single to a duplex chain.
There wasn’t that many failures on the single chain.
But it’s literally a fit and forget scenario.

Wonder if any one does a belt drive for a Triumph 1500.