Re: Harmonic balancer info

Posted by Ross On 2014/4/8 19:27:06

In 1951 Packard issued a service bulletin about a vibration sometimes encountered in Ultramatic cars between 80 and 90 mph. The problem was addressed with a brace on the bellhousing. Apparently some folks expected to drive that fast and Packard agreed.

With the normal 3.54 axle in the models mentioned that is cranking 3900 rpm. 4250 if it had the 3.9 axle some of the early cars had. I think you might be underestimating those old engineers. All of those engines had a high class fluid suspension damper in two different sizes. Oddly, the nine main bearing engines had the big one. I'm sure they knew that most folks would not rev them near the rating, but that doesn't mean they didn't design to sustain the rating.

The later L8s were all rated at 4000. That doesn't mean they couldn't turn faster--the breathing on an L head becomes so poor that the power falls off after that.