Timing chain

[rgh0]

I think "Always" is a very loose term and reflects the short memory of the current QED organisation which has lost most of its knowledge and is now a retailer rather than the Twincam experts they used to be

[nmauduit]

mmm. Maybe we should be careful here.

My screenshot above was from IWIS France who answered my question that the chains they supply here are seamless. I do not think he was referring to all IWIS chains world wide. In fact, he cannot, or should not refer to all IWIS chains - see another screenshot from the IWIS 'Elite' top of the range chain (recommended yesterday as the 'only' chain to use by an ex Cosworth technician near to me here...) Here, one can specify seamless or split bushes.

Screenshot 2023-11-10 at 09.15.49.png

this thread is catching my interest so I looked up the site to glance at the options, e.g.

https://www.iwis.com/en-en/products-ser ... lite~p3214

which shows solid rollers and split bushings (also they sell by 5m length) applications listed being more industrial than automotive on this one...

any suggestion for a supplier of say an assembled loop of 120 links solid roller solid bushing ready to fit in as LTC chain ?

[Europa88]

As I said the 122 link was purchased some time ago. However it was in a sealed bag that I only opened a couple of days ago! I believe Regina are an Italian company and their product is manufactured in Taiwan. I probably won’t use it now.

[alanr]

My take and thoughts based on what we know so far is that IWIS manufacture two grades of timing chain?
i think that they manufacture a basic type chain which is split roller chain and also manufacture a higher quality chain, maybe this is what is branded 'Elite' which is a solid roller type chain?
Who supplies which or what and to whom in the UK though still remains a bit of a mystery!

I don't know if the above is true or not but is just my thoughts based on what we know at the moment.

Personally though I would still prefer for my own use a solid roller chain be that an IWIS chain or perhaps some other brand.

Alan.

[HCA]

any suggestion for a supplier of say an assembled loop of 120 links solid roller solid bushing ready to fit in a LTC chain ?[/quote]

Try your local Rubix, Dexis, Mabeo or Sefi distribution outlets. I am going in to see Rubix in Toulouse as they are able to rivet up a chain while you wait! Ask for a chain to ISO 606, ⅜” pitch with solid bush/rollers. They will offer you a Euro chain or Elite - both IWIS, but not sure which is which, but I am waiting for an answer from an ex Cosworth technician….

[HCA]

My take and thoughts based on what we know so far is that IWIS manufacture two grades of timing chain?
i think that they manufacture a basic type chain which is split roller chain and also manufacture a higher quality chain, maybe this is what is branded 'Elite' which is a solid roller type chain?
Who supplies which or what and to whom in the UK though still remains a bit of a mystery!

I don't know if the above is true or not but is just my thoughts based on what we know at the moment.

Personally though I would still prefer for my own use a solid roller chain be that an IWIS chain or perhaps some other brand.

Alan.

I think in truth Alan, they make more than two grades, but yes at least two by their own admission.

Technically you should be able to get whatever grade they make from their distributer, Dennis Welch Racing. I just hope you get a better reception from them than I did…

[alanr]

Hal,
I definitely won't be contacting Denis Welsh Motorsport for an IWIS chain after your experience with them.
I am all for a peaceful life and don't wish to deal with anyone with that sort of attitude or behaviour!

It also seems that QED from whom I have bought quite a lot of parts in the past will not be able to supply a solid roller chain timing chain.
I don't know from quite where at the moment but I am sure though I can source a reputable brand solid roller chain from somewhere in the world.

Alan.

[2cams70]

On page 1 of that product data sheet for the "elite" 06B-1 IWIS chain you can clearly see in the side profile line drawing that the bush underneath the roller clearly has a split in it. It's the pin and the side links that take the tensile load. Not the bush or the roller.

[rgh0]

But..... these tensile loads get transmitted to the pin and links but the roller and bush from the teeth. The split in these in some chains means uneven distortion under load, higher stresses and greater wear.

[h20hamelan]

If this is any help, I have a boxed 122 link chain from QED bought about 15 years ago for a project which hasn't materialised yet

The maker is Regina and manufactured in Taiwan

yes It is a split roller

Are they still making those?
I cant seem to find them.

[2cams70]

But..... these tensile loads get transmitted to the pin and links but the roller and bush from the teeth. The split in these in some chains means uneven distortion under load, higher stresses and greater wear.

Yeah right Rohan. There’s no evidence of that just like there’s no evidence of chain failure caused by a split in the roller or bush. It’s the materials used that are more important. I’m sure if QED or IWIS were selling chains that failed it would be known about and acted on quickly given the reputations involved. It seems QED and IWIS have been selling chains like this for quite a while and given that timing chains are replaced during virtually every rebuild they would have sold quite a lot of them. There’s no engineering or practical evidence to support that there is a problem and I’m surprised that anyone claiming to be an engineer can’t see this.

[rgh0]

"There’s no engineering or practical evidence to support that there is a problem and I’m surprised that anyone claiming to be an engineer can’t see this."

I dont "claim" to be an engineer... I am an engineer !

So lets do some engineering analysis of a couple of IWIS chains shall we and see what we can see

I have dismantled and measured up an IWIS (branded JWIS) split roller, split bush chain and and IWIS (branded JWIS) solid roller chain which you discover has split bushes when you dismantle it.

IWIS split roller and bush

Pins - 3.31 mm dia a little pitting wear
Split bushes - out of round 4.61 to 4.63 mm dia a little pitting wear
Split roller - out of round 6.35 to 6.38 mm dia a little pitting more signficant wear damage at edges of split. (Spec diameter is 6.35mm)
Side links Inner 1.25 mm tk, outer 1.27mm thick hardness 42 Rc
Side links are light in colour and dont appear to have been heat treated and oil quenched
Riveted by centre punch on the pins
120 link chain weight 482.6 g


IWIS solid roller and split bush

Pins - 3.31 mm dia a little pitting wear
Split bushes - round 4.60 mm dia a little pitting wear
Solid roller - round 6.35 mm dia a little pitting wear
Side links Inner 1.24 mm tk, outer 1.22mm thick hardness 48 Rc
Side links are dark in colour and appear to have been heat treated and oil quenched
Riveted by shoulder punches on the pins
Weight of 120 link chain 474.0 g




Both chains examined were used and had less than 0.5 % stretch wear and were well within the 1.5% allowable stretch wear but the split roller chain has 60% more sideways flexibility than the solid roller chain due to looser tolerances on components



Conclusions

The chains are made on different production lines or factories
Both the chains comply dimensionally with the ISO standard 606 -B1 standard except for the split rollers
The split rollers have signficant out of round distortion and wear at the splits, this will lead to shorter life, increased sprocket wear and increased chain noise.
The links on the split roller chain are softer and thus lower tensile strength
I tried to measure the roller hardness but they are too small for my tester. i also dont have access to a tensile tester to determine chain strength versus the specification

Is there are problem with the split roller chain in terms of servicability and life ? I dont know and and no reliable data has been published either way specifically for the IWIS chains but general data indicates longer life for solid roller / solid bush chains. It also depends on your definition of servicability and life when it becomes a problem. In a Lotus Twincam almost no one is looking for 100,000 km life these days. The IWIS split roller chains are clearly servicable when new, but they are clearly inferior in terms of tolerances, wear life and strength so i would not put them in any engine I build these days. I would now look for a maker that uses both solid bushes and solid rollers such as Reynold or some of the Japanese makers as even IWIS solid roller chains do not have solid bushes. All this is just my opinion and others are free to do otherwise based on their opinion.


cheers
Rohan

[2cams70]

Thanks Rohan. I'd be interested if you could post some pictures. By the way one thing I disagree with that seems to be commonly spouted as a determination of a good versus a not so good new chain on those ever reliable internet you tube clips is sideways slack in the chain. The timing chain when in use does not have a side loading on it so the fact that it may have a little sideways slack is of no consequence. It's probably even desirable that the chain has some sideways clearance to allow for the timing gears being slightly out of alignment with each other.

[h20hamelan]

When a pedal bike chain, or motorbike chain breaks. I can only ever assume it was from the weak-link.

I have been through 3 or 4 different tools to break, and a bunch of different chain-pin install tools.
Is it guess work? Or that of precision. Maybe the tools, maybe the craftsperson. Either way, it seems difficult and for the value in an engine, or a snowbike 50km from a road, or cycling across _____________

Thank you for the great content here.

[rgh0]

Unfortunately I dont have access to the digital microscope i used at work for machine component failure analysis now that i have retired.

I have just ordered a cheap amazon USB microscope which should be good enough to see the details on the chain components and be here in a couple of days. I will post some photos then.

The side deflection tells you a lot about the clearance between the pins, bushes and rollers, its not important in terms of deflection during operation. A new quality twin cam chain with unworn components has about 5 mm deflection over 30 cm. The used solid roller IWIS chain I measured had about 10mm and the used split roller chain had about 15mm deflection. I would prefer a chain with minimal deflection showing consistent tight clearances on the components. What is ideal I dont know but clearly it increases with wear even when stretch length increase is not signficantly measurable.

cheers
Rohan