Timing Gear Set Selection

[George Woodford clc21025]

When selecting a timing gear set, what Center Distance should be selected: Standard, or 0.005 inch or 0.010 inch Reduced Center Distance?

[Bruce Reynolds # 18992]

Gday George,

The correct selection will depend on just what machining has been performed on either the crankshaft bearing locations and the camshaft tunnel.

If either of the areas have been reconditioned by Line Boring, then the measurements will have to be worked out to see how much closer together the machining has created.

If no machining has been performed, and normal over, or undersize bearings are used, then the standard set is the way to go.

Using a reduced set on a standard block will cause problems.

Bruce,
The Tassie Devil(le),
60 CDV

[George Woodford clc21025]

For an original, stock (unmodified), low mileage engine, the Standard Set should be used? Due to the age of my 1977 Eldorado it is my understanding to replace the timing gear set before the nylon gear(s) start to break apart.  Therefore, my plan is to use a Standard Center Distance roller-chain timing set.

[Bruce Reynolds # 18992]

George,

Whenever I install a new timing set, I use the best timing set that I can get my hands on for that motor.

Your use of a roller timing chain is commendable, but a double row timing set would be better.  That way, you get an extra linkset to resist stretching.

And to replace the nylon-toothed set before the self-destruction takes place is also commendable.   Once the nylon starts to break up, it doesnt take long for nylon chips to start clogging the oil pickup screen.

Bruce,
The Tassie Devil(le),
60 CDV

[George Woodford clc21025]

What do you think about the Cloyes brand?  Cloyes have a basic set that does not use the roller chain.  The other sets they offer use a roller chain in Standard Center Distance, and 0.005 and 0.010-inch Reduced Center Distance.  As you stated, the Standard Center Distance roller chain would be most appropriate for my application.  

[Bruce Reynolds # 18992]

George,

As far as I am aware, the Cloyes brand is very good, but, I try and stay clear of the Morse type Timing Sets.

The Morse type seem to cause damage to the gears after a long time of use.   One of the reasons why the nylon covering on the camshaft gear is that the multiple links that make up each link gradually groove the teeth and they ultimately split and disintegrate.   Look at the crankshaft gear and you will see the grooves that I mentioned.  

The beauty of the roller chain is that the rollers spread the load all over the teeth, and therefore there is less chance of the teeth being worn away.

My choice is the Roller type, but in some applications, one has to purchase the OEM sets as the aftermarket suppliers mightnt make parts for unusual engines.

Bruce,
The Tassie Devil(le),
60 CDV