Re: Powerful 46-47 Supers/Custom Supers

Posted by su8overdrive On 2012/3/2 17:15:34

Regarding the Nash twin-ignition, ohv, nine-main-bearing inline 8 mentioned three posts above, some things sound better on paper. Don't know about the earlier, larger version, but the 1935-41 260-ci version of the above Nash engine (the final year '42 didn't have twin ignition), because of its relative shortness, had very small main bearings, which quickly wore and lost oil pressure.

Sometimes, as with the five-main-bearing Packard One-Twenty 282-ci and Hudson five-main 254-ci inline eights, five large mains are better. The 420-ci Duesenberg J elected to go with only five instead of the nine in era Packard, Pierce, Chrysler straight eights, all of which had the same 3 1/2 bore/5-inch stroke, 385 cid. But the Duesenberg's five mains were huge. Off the topic, but often wondered if Fred Duesenberg decided to use only five to reduce friction losses in what was more a performance engine than luxury plant. Don't forget that 10th grade high school dropout former car salesman, stock market marauder E. L. Cord ballyhooed 265hp for the Model J simply as he wanted to advertise "the most powerful car in the world," and at that time, there was an extremely limited-production Mercedes SSK boasting 250hp. DOHC or not, there's only so much you can extract from 5.2:1 compression (5.75:1 optional). Road & Track's John Bond, a degreed engineer, visited the Lycoming plant in 1950, saw the dynamometer reports of four Model J engines, the best of which showed a peak 208 hp.

Further afield, but since Monsignor Randerson brought it up, Duesenberg's own test of a Model J gave 116 mph, and that was obviously a well-tweaked example, likely with the 5:75 compression and tallest of the four axles, 3.8:1 (The later 3:1 was ONLY in the Cooper/Gable bobtail speedsters, and Ab Jenskins' Bonneville edition). Maurice Hendry and others in the know cite a real world 105 mph or so for most Model Js in road trim, which makes sense, since each 1931-33 ohv Marmon V-16, with 6.25:1 compression and another 71 cubic inches, 3:78:1 rear end, lapped the Indy brickyard at 105 before delivery, and this was confirmed, not a case of E. L. Cord having dash plaques inscribed with an arbitrary figure just over 100 mph slapped on each 1935-36 Auburn 851-852 boattail speedster.

Chrysler Imperials in road trim could hit an honest 95 mph. Period Packards, as we know, suffered from stumpier rear axles, as we know from Col. Vincent's longer legged speedster.

The professional and much missed Special Interest Autos (Hemmings Classic Car is not in the same league) did a DriveReport of a 1931-33 Chrysler Imperial years ago entitled "Better Than a Duesy?" Adjust for price, a good question. A longtime Packard collector with experience with all three 385-ci straight eights, said the Pierce had the best manifolding, if he had to pick the best engine.

BTW, in 1940, Augie Duesenberg was offering a marine version of the 254-ci Hudson splash-oiled straight 8. I always wondered why Packard sold marine versions only of the 245-ci six and 356-ci Su8, but never the 282-ci One-Twenty engine. A 3M engineer in Texas i bought some parts from for my '40 120 in 1975 told me they were still using Packard 120 engines working 24/7 irrigation pumps down there, governors set at 1800 or 2000 rpm.

Meanwhile, the question remains unanswered here as it was when i asked a year or two ago on the CCCA Forum:

Does anyone have any observed, AAA- or otherwise sanctioned top speeds for 1940-47 Buick Century/Roadmasters, likely with the rare, no cost optional 3.6:1 "economy" rear axle, and 1940-47 overdrive Packard 160 and their 1942-47 Super Clipper versions?

?

?