The timing chain on my 1968 225 Slant 6 snapped. When I opened up the engine I discovered that it was a single roller set. I would like to upgrade to the heavy duty double roller set, but there is one issue I have identified:

The crankshaft only has a single key. The Rollmaster has a multi-keyway. I am wondering if I need a multi-keyway crankshaft in order to run it.

Here is what the original style looks like:



And the new one I want to use:



Are there any issues I need to be aware of?

Thanks for any help! - JRH

The multi-key is so you can vary the cam timing.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

THIS /\

Be very careful installing that set to make sure you have the right marks lined up or bad things will happen and you will get to do it all over again.

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Official Cookie and Mater Tormentor.

Thanks for your response. My concern is for the strength of the multi-key gear. Since all the torque is borne on a single keyway do I have to be concerned about key breakage due to the lack of material? Wil the torque of the engine make the teeth break off since it's only contacting on one tooth?

Do any industrial shops sell these double-row chain sets or are they only available through performance outlets?

Are there any other manufacturers of these sets you would recommend?

Thanks for any additional information you can provide. I really appreciate it!

the crank gear is an interference fit onto the crankshaft.

The key is for timing the radial location of the crank gear to the crankshaft. The key does not prevent the gear from turning on the crankshaft, the interference fit does that.

Even though the Rollmaster crank gear has multiple keyways machined into it, only one keyway is in use at any time. The multiple keyways allow the crank gear to be assembled in eight ( or whatever the number of keyways is) different settings
Cloyes is a respectable timing set manufacturer

I went with a Cloyes Double Row Timing Chain I got from a group buy on this board and it has been Perfect! Easy to install, just like stock single. Quiet, and no problems within the last 25,000 miles since rebuild!

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1964 Dart GT

I have had mine on a 10:1 hi-po slant, and repurposed it to a 12:1 race only build....that set has probably 50K of highway miles and has outlasted 3 clutches at the drag strip... I have yet to break it even at 6000 rpm launches and sustained high rpm driving....This unit would be overkill on a stock daily driver though.

The crank gear is a very tight fit on the crank. I worked the ID of the crank gear with some fine emory cloth so it pressed on a little easier.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

In my opinion Rollmaster is the best on the market ...guys run these things huge HP solid roller cam small blocks and never have an issue. There's very little load on the key way,you will have no problem,except the can be a tight fit,I've never had a problem,debur the snout and the sprocket,take the chill off the gear and put some lube on it during installation so it doesn't pick up...job done.

Thanks for all the great feedback everyone! It is much appreciated.