[Dragncar]

Originally Posted by mgarblik

Once again, I come back to the good, better, best scenario. There are roller timing sets I wouldn't put on a bicycle because I wouldn't want to injure my ankle when the chain snapped. On the other end of the spectrum we ran a STOCK out of the box Cloyes billet timing chain set with the "Z" chain, in the nitro funny car Boss Bird. No tricks, no extra oiling, no torrington bearing. No crank support, no harmonic balancer. 450 lbs. closed spring pressure, 1050 lbs. open pressure, 35 lbs. of boost through an ancient 1980's vintage roots SSI blower. 8000 RPM's typical, but reached 10,700 RPM's when transmission failed to shift once. All valvetrain components stayed where they belonged. We had a blower explosion once that stopped the engine and sheared off the camshaft key. I re-used the timing set on the next build. I would put Rollmaster timing sets in the slightly better category among the roller sets. Cloyes sets are so easily available, and reasonably priced, I don't know why people are always looking for something better. Cloyes even has a flat link set for Cliff! American company and they make the sprockets in USA. Full disclosure, (Chains are sourced from numerous world suppliers but made to Cloyes specs.) JWIS are the best chains along with Renold of France. Some other brands are using more and more Rolon branded chains. Made in India. Quality is marginal. I will not put a Chinese chain in anything I care about. FWIW

Slightly confusing item: The "Best" Rollmaster IWIS chian they offer is the same as the standard Cloyes IWIS roller chain. The "Z" series IWIS chain is proprietary to Cloyes. Essentially, additional heat treat and micro polishing. Cloyes has 100% verification of each timing set on their race stuff. Every set goes on a fixture and sprockets and chains are select fit for center to center distance and deflection.

The Cloyes .005 short chain I have does say JWIS on it. The Rollermaster .005 Red Series I bought from Butler you can not see any markings on the chain.
What would be nice is if Cloyes offered their best Z chain in ,005 short. And I have one of those too but for the life of me I can not find it but I remember it did not fit too bad even though it was std.
I have one of those Cloyes 3/4" wide link types sets. 30$ so I thought I would take a look at one. Its way looser than my Elgin/Morse chain set.

[mgarblik]

Originally Posted by Dragncar

The Cloyes .005 short chain I have does say JWIS on it. The Rollermaster .005 Red Series I bought from Butler you can not see any markings on the chain.
What would be nice is if Cloyes offered their best Z chain in ,005 short. And I have one of those too but for the life of me I can not find it but I remember it did not fit too bad even though it was std.
I have one of those Cloyes 3/4" wide link types sets. 30$ so I thought I would take a look at one. Its way looser than my Elgin/Morse chain set.

This is what I was told by the design engineer at Cloyes. The Z chain was designed for the LS1 engine when they were having issues with them failing the other chains in that engine. The Pontiac chain is the same part number. The Pontiac has a different tooth count and a different center to center distance, but uses the same chain. They only needed a STD chain for the LS1 because so few of them are line honed in the field. When the mains get torn out of an LS1, I guess they just scrap most of them. They would certainly never make a special super high strength chain just for a Pontiac. It is just a happy coincidence that it fits. FWIW, we ran the regular IWIS Cloyes chain in the Grocery Getter for 17 years and in the funny car for 3-4 years before the "Z" chain became available. Never had a timing chain failure or excessive slack develop. But I admit drag racing is not the same as 10's of thousands of street miles. We had so many other things to worry about on those engines with the power we were making and the other parts we were failing, if a part was simple, reasonably priced and worked, it stayed on the engine unless there was a reason to change it. We put incredible stress on that chain drive in the funny car. In addition to my previous post, we drove a 44 AMP MSD magneto directly off the cam sprocket, also an Enderle dual drive off of the cam. That in turn drove a 43 GPM oil pump
@ 200 + PSI and the fuel pump for the nitro. All that stuff off that double roller timing chain. Zero failures in 11 years.