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Home » Public Forums » GMCnet » Re: [GMCnet] Harnomic balancer/timing chain
Re: [GMCnet] Harnomic balancer/timing chain [message #343363] Wed, 15 May 2019 23:56 Go to previous message
BobDunahugh is currently offline  BobDunahugh   United States
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
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Senior Member
Skip. ( If your interested. I have a new one on hand cheeper then you can get one anywhere. )
That part is mostly an harmonic dampener. As about all internal combustion engine have RPM points. That cause damaging harmonics to build up in the crankshaft. And can break the crankshaft if unchecked. That's why the outside part is riding on rubber. I've made modifications to engine that change the original harmonic levels. And the RPM points. That's part of the reason some people break their crank.
And it's also a part of the balancing system. That's why it has an unusual shape.
The double roller will last a long time. ( But so will the stock chain. ) They where developed for higher RPMs, and heavier loads brought on by more aggressive cam lob profiles. As then with the more aggressive cam lobes. You then need higher valve spring pressures. Then it comes down to the fact that we don't have any of these conditions that the double roller chain was designed for to start with. Kind of negates the reason to install one. I replaced the original chain in a friends 78 Royale. That had about 150,000 miles on it. Chain was fine. The aluminum/plastic cam gear was the issue. Stuck with GM stock. Some builds put in the roller chains, High volume oil pumps, high strength rod bolts, and some Mondello high performance parts. Sounds like great upgrades. So if these items are great improvements. Why didn't the GM engineering department put these parts in to start with? GM built these engines to do a task. And we use them just as GM meant for them to be used as. And put a warranty on. I've built GMC engines just as GM did. I've build some GM engines that can run at 8,000 RPM's all day. Put out more then double the HP/torque that GM ever even dreamed of. These engines must have upgrades because of these extreme demands. This is in upgrade territory. Not in, as built for designed operation. Face it. GM knows more about their engines then anyone. If these so called upgrades were needed. GM would have used them in their build. I know enough to know that I'm NOT smarter then the GM engine engineering department. Bob Dunahugh
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