Re: Redline/Maximum Continuous Operating RPM - Packard 6 Cylinder Engines

Posted by Owen_Dyneto On 2016/2/24 11:29:06

A good question to ask yourself when you think about what sustained speeds the cars of the 30s were designed for, is what percentage of the nation's roads were paved! And of those (probably less than 50%), what speeds were they consistent with?

I recall reading of two tests that Packard conducted at their Proving Grounds in the 30s; as I recall an Eight with poured bearings was run at full throttle and retired with engine failure at 5000 miles. A few years later after the adoption of thin shell insert bearings the test was repeated; the test ended at 25,000 miles though I don't recall if it was just terminated or the engine failed.

If you can find it, locate the article about the high speed drive to celebrate the opening of the new Pennsylvania Turnpike, mostly Buicks and Packards and quite a few engine failures during the high speed run from end to end. If someone can locate and post that story I'd be interested in reading it again.

I have a friend with a '38 Eight (a/k/a 120) without overdrive, when he does Interstate highways it's happy enough at 60 mph but it may have the more advantageous rear axle gearing; 4.54 standard but 4.36 and 4.70 available in the 120s of that era. My '48 Custom 8 was quite happy at 60-65 without using the overdrive; as I recall it had a 4.09 rear axle (3.92 w/o overdrive).

Another thing to consider when driving these older cars at speeds higher than those typical for its era is that engine isn't the only consideration; brakes, suspension, lights all have limitations. And though uncommon, just plain old metal fatique can rear its head.