Re: Driving comparisons between the Packard Six and 120.
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Forum Ambassador
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More information please, re: 3.54 gearset 50 Custom 8 into "earlier" housing...
Posted on: 2012/7/7 7:04
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Re: Driving comparisons between the Packard Six and 120.
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Home away from home
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Once upon a time a fellow wrote to the engineering department at Studebaker asking which equipment to buy to get the very best gas mileage. The reply in essence was to order the transmission and axle ratio that would keep the engine as close as possible to its peak torque rpm at the intended driving speed.
Peak torque represents the engine's most efficient breathing and combustion scenario, so this makes sense. I took this advice and set up a 62 Lark six and overdrive with of all things a 4.3(?) axle as its torque peak comes rather high. This was a most satisfactory combination that gave great flexibility and performance well beyond what one would expect for a little 170. Oh, and the mileage was outstanding.
Posted on: 2012/7/7 9:07
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Re: Driving comparisons between the Packard Six and 120.
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Home away from home
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Here is a little followup: Most of the postwar inliners had their peak torque at 2000 rpm. The 54s has it a 2200 because of the cam timing change.
So, if I want to spend a lot of time at 60, and my tires are 28" in diameter, I am looking for a 2.78 overall final drive. With overdrive, that means the axle would ideally be a 3.85, or lets say 3.9, which is readily available. Packard usually provided a 4.1 with overdrive which puts the optimum speed clustered around 57 or so. (Remember this is all very fuzzy stuff with many variables entering). And the moral of the story is that the Packard engineers were pretty clever in their choice of ratios given the types of driving that predominated then. In cars without overdrive they necessarily chose with an eye to flexibility and hill climbing. The vast majority of cars seldom saw sustained high speeds--certainly not around here as there was no place to do it.
Posted on: 2012/7/7 9:24
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Re: Driving comparisons between the Packard Six and 120.
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Home away from home
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Flack Attack, don't recall details, but believe you need to replace the entire pumpkin, not just the ring and pinion.
Ross, good points. Sportsfans, see my last post, which i just revised, added to. That cleans me out. Let us know what you come up with; corroborated, vetted information please. Broken Hill, you've got a slick little Packard. Just remember, Bendix hydraulic drums that were good for the '40s, even '50s, are NO match for today's power four-wheel discs with ABS. The mechanic i mention above hit a 40-lb. jackrabbit in his '53 Hudson Hornet at 80 mph. Imagine a goodsized roo'd do a number on that pretty snout.
Posted on: 2012/7/7 17:58
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Re: Driving comparisons between the Packard Six and 120.
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Home away from home
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Thanks guys, this has turned out to be great read!
Anyone know where I can find the hp and torque curves for the Six (& 120 for that matter) engine?
Posted on: 2012/7/7 18:19
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1963 Morris Cooper 997
1969 Austin 1800 |
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Re: Driving comparisons between the Packard Six and 120.
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Home away from home
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Hi all, I would urge everyone to consider the use of some form of anti-valve recession agent ( upper cylinder lube) in the unleaded fuel. I believe this is particularly important when numerically low rear axle ratios and overdrives are used, as the duty cycle ( loading up) of the engine is increased. To me this means higher exhaust valve temps and greater risk of exhaust valve seat recession without the previous protection of lead. This is not so much of a problem if the engine uses a bit of oil, but watch out if it is a "brand new" engine. I also run 7 thou inlet and 10 thou Exhaust tappet clearances instead of the normal 4 and 7 thou, to keep the valve on the seat a few micro-seconds more, to help cool the valves. In the past, I have burnt out a few exhaust valves running lean mixtures and high compression in Packards so I write from experience. Best regards Peter Toet
Posted on: 2012/7/16 18:27
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I like people, Packards and old motorbikes
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