Timing Chain Loads

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Jan 6, 2008 | 05:43 PM

vettenuts

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From: Little Rhody

Timing Chain Loads

Does anyone have any information on how much loading is transmitted by the timing chain? I am curious about some of the aftermarket timing sets that have separated the lower crankshaft sprocket into two pieces, one being the chain sprocket and the other being the oil drive. The chain sprocket typically has more than one key machined for timing purposes. Cloyes, Comp and Rollmaster single chain timing sets all have this type of design.

What I am wondering is "has the load limit now been shifted from the timing chain being the weak link in the system to the crankshaft key", which now has minimal engagement as compared to the stock crankshaft sprocket design.

Any technical information out there on this one?

Jan 6, 2008 | 06:21 PM

2002_Z28_Six_Speed

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No.

Easier/cheaper for manufacturing.

Keyway is an index not load bearing or not supposed to be. Balancers must have frictional contact to work although yea an index could keep from spinning on modified motors.

Jan 6, 2008 | 06:50 PM

vettenuts

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From: Little Rhody

Not the balancer, this is the sprocket driving the timing chain and it will transmit loads through the key in the crankshaft.

Jan 6, 2008 | 07:51 PM

2002_Z28_Six_Speed

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Quote:

Originally Posted by vettenuts

Not the balancer, this is the sprocket driving the timing chain and it will transmit loads through the key in the crankshaft.

In reference to our types of motors, the balancer IS part of the story. The keyway isn't a driving/driven member. Given the balancer bolt is properly torqued.... The ASM is supposed to be sandwitched and that is how it works and why some people have problems with supercharging and such.

http://www.gmhightechperformance.com.../photo_09.html

Last edited by 2002_Z28_Six_Speed; Jan 6, 2008 at 10:09 PM.

Jan 7, 2008 | 05:08 AM

vettenuts

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From: Little Rhody

How is the balancer driving the timing chain and the camshaft? There is some friction there, but isn't the majority of the load is through the key.

Last edited by vettenuts; Jan 7, 2008 at 11:05 AM.

Jan 7, 2008 | 11:06 AM

vettenuts

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From: Little Rhody

Yes, you are correct. I just spoke with someone at Cloyes and they told me (which I didn't know) there is a taper on the crank and the press fit through the balancer and the geroter provides enough frictional load to drive the crank sprocket and valve train without the key in place.

Learn something every day

Jan 7, 2008 | 01:43 PM

2002_Z28_Six_Speed

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Quote:

Originally Posted by vettenuts

Yea! That is what I was trying to explain but couldn't get the exact words. But if the frictional force couldn't hold it you would still have the keys.

The multikeyed sprockets won't hurt even though they have more material removed. Cool stuff.

I have heard of some people having trouble with super modified motors. The frictional force just couldn't do it.