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I haven't stirred up any thing here in a while so today seems like a good time!
The shop that originally freshend my DE block several years ago mainly works on drag and circle-track V-8's, with a few monster street cars mixed in. The owner is from New York but retired to the Georgia countryside a few years ago. His son now runs the shop but he's still active in the business.
He's a bit of a ride from my house but I was on a trip last week that took me by the shop. I stopped and picked his brain for a while. He's in his 70's and he's been doing this a long time.
I asked him if he'd had any experience comparing half-weight vs fully counter-weighted crankshafts. He said he'd worked on a number of 4 cylinder engines for various uses and that he had experimented. He said he was never able to identify any differences in horsepower or vibration levels between the two on the dyno. He did say that he found that checking the balance in two planes (weights up/down and side-to-side), just like a V-8, does improve the balance on a 4-cylinder engine. He said that you can also tune to certain RPM ranges by adjusting the "bobweight percentage" values. He said he'd explain it when I bring him one to balance....,
I also asked him about his experience with harmonic balancers. He said that they can make more horsepower but they have a natural tune that favors certain RPM's and that you need to understand that when selecting one. He said that is true for both rubber/poly and viscous balancers. I asked him about the TCI "rattler" balancers (the ones with bob-weights inside). He said that they were patterned after aircraft engines that had the crank weights attached to the cranks on a pivot so that they could swing and help absorb the acceleration/deceleration forces. He said that they do work well over a wider range than the others.
TCI's website says that the rattler works "at any RPM". I don't necessarily believe that, but I've researched the physics behind them and they do cover a wider range than rubber/poly or viscous balancers. I mentioned that TCI builds one for a Pontiac 4-cylinder but not for a Nissan. He said that from a balancing standpoint it would work on any similar 4-cylinder if you made your own hub adaptor and the pulley grooves were compatible.
<flame suit on>
The shop that originally freshend my DE block several years ago mainly works on drag and circle-track V-8's, with a few monster street cars mixed in. The owner is from New York but retired to the Georgia countryside a few years ago. His son now runs the shop but he's still active in the business.
He's a bit of a ride from my house but I was on a trip last week that took me by the shop. I stopped and picked his brain for a while. He's in his 70's and he's been doing this a long time.
I asked him if he'd had any experience comparing half-weight vs fully counter-weighted crankshafts. He said he'd worked on a number of 4 cylinder engines for various uses and that he had experimented. He said he was never able to identify any differences in horsepower or vibration levels between the two on the dyno. He did say that he found that checking the balance in two planes (weights up/down and side-to-side), just like a V-8, does improve the balance on a 4-cylinder engine. He said that you can also tune to certain RPM ranges by adjusting the "bobweight percentage" values. He said he'd explain it when I bring him one to balance....,
I also asked him about his experience with harmonic balancers. He said that they can make more horsepower but they have a natural tune that favors certain RPM's and that you need to understand that when selecting one. He said that is true for both rubber/poly and viscous balancers. I asked him about the TCI "rattler" balancers (the ones with bob-weights inside). He said that they were patterned after aircraft engines that had the crank weights attached to the cranks on a pivot so that they could swing and help absorb the acceleration/deceleration forces. He said that they do work well over a wider range than the others.
TCI's website says that the rattler works "at any RPM". I don't necessarily believe that, but I've researched the physics behind them and they do cover a wider range than rubber/poly or viscous balancers. I mentioned that TCI builds one for a Pontiac 4-cylinder but not for a Nissan. He said that from a balancing standpoint it would work on any similar 4-cylinder if you made your own hub adaptor and the pulley grooves were compatible.
<flame suit on>
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