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I think a lot of chains are made you-know-where now. In a few applications they have added an oil hole in the rollers to aid lubrication, not that it has made much difference. In many cases, manufacturers have wanted as light a chain as possible, requiring less of a bhp loss to fling it around. A really high quality single row simplex chain is better than a Duplex. In the case of Mercedes V8's from the 70's and 80's, the Duplex chain was so heavy that it was often worn out by 70,000 miles.

Hipwell wrote: ↑Sun Feb 21, 2021 10:08 pmThe box in Iain’s photo is one supplied by The Chain Man who finished the chains himself

Ah, that makes sense. Keith does mention on the website that he sources them at low volume from an intermediary.

Zooming in on the above CalverST photo, it shows both an un-stamped chain draped over the box, and a JWIS stamped chain alongside the box. So I suspect it’s “random” whether you get a JWIS stamped chain or an un-stamped one.

I don’t remember whether it had split rollers or not, but anyway the valve spring pressure from an A-series isn’t exactly pushing things to the limit compared to, say, the big springs on an American muscle car V8.

Like I said, this chain has been fine for general road use in my S for the last few years. I did re-check the cam timing after 6 months so when I changed head gasket for an unrelated failure, and it was still bang-on where I set it to originally, still with very little lash.

4XMOKE wrote: ↑Sun Feb 21, 2021 10:23 pm Costafortune,
interesting info that they've changed spec.
I'm inclined to agree that they've penny pinched and cut corners, I just can't see split rollers being as strong as seamless and endless chains ought to be better than those with a split link. Maybe Iwis have fallen from top spot now..... ?

Roger G

Again I have it on good authority the split roller is by design and on two occasions I have pulled parts of one piece rollers out of race engines on magnetic sump plugs where the rollers have failed. It’s not changed in a couple of years, been using IwIS chains for maybe ten years and remember been told upfront some race engine builders swerve IWIS chains because of the split roller. Yet to see a problem.

I'd rather use a good original chain from a 1978 Marina than a lot of this modern stuff. The A Series chain isn't under a lot of stress: it's short, stoutly made and only has one small cam to spin around. Modern chain designs are long, very skinny for light weight and have two cams to operate - plus stupidly long oil change intervals.

A Jwis Mini chain should be OK but for serious stuff I'd want a BL original.

So did some digging, every chain I have in the workshop is marked JWIS and from different suppliers.

Alfa Romeo race chains from Alfaholics in IWIS factory boxes.
Chains from Timing chain solutions(Dennis Welch) for Aston Martins, Lotus TC etc
Mini simplex chain from Minispares

I also today stripped a 1986 Porsche 911 engine, never been apart and one owner car, it has JWIS marked chains with split rollers which are apparently good for 200k miles according to my Porsche engine buddy.

The two chains side by side are the different singleplex chain for the mini, g68 roller chain which has two copper coloured plates for some reason and the G67 Pin/bush chain that Calver and Swiftune sell.