Packard Forum Index » Pre-War (1899-1942)

Howdy everyone,

I recently finished a lengthy drive with my 726, and though it was great fun there were a couple of hills that the car seemed to just barely able to climb. Some of them weren't terribly steep, but approaching them from a slow speed (say, after coming out of a turn) I found that third gear wasn't quite enough. Now, typically, I find the third gear to be powerful enough to do almost anything. These cars have so much torque that I can slow down to 5 mph or less and still pull away in third gear. On at least one hill I had to stop completely, drop it into first (I actually used the stump puller, low-low gear) and start again.

I've been suspicious that the car is running slightly lean (when engine breaking from high speed, say 40-45, there seems to be a bit of burping, like very slight backfires through the carb, but not loud, gunshot like backfires through the exhaust, and it stalled once or twice when parking) but I don't think it was so lean as to cause a loss of power when going uphill. Or could it be?

What do you do when approaching a hill? Do you need to drop it into a lower gear, or do you find enough power and torque in third gear? What kind of speeds can you usually maintain going uphill?

Based on your description of hill climbing as compared to my '34 with essentially the same engine, I'd question if you have a high speed rear axle? The smaller Eights with high speed axles can be real dogs on hills.

My '34 has the stock 4.69 and I climb all but the steepest hills in high gear. Obviously the price I pay for that performance is a lower comfortable sustained highway speed.

So, what's your rear axle ratio, and what body style or weight?

I don't know if you are aware of this but it may be part of your problem. If you are still running the 726 vacuum tank fuel supply you must realise that if you hold the throttle fully depressed when climbing continuing grades, then you do not develop vacuum and you will start to run out of gas after about half/ three quarter of a mile of uphill grade. You should depress the throttle almost fully , if necessary, and back it off slightly so that you can still hear a distinct sucking sound through the carby. This will ensure that you are developing vacuum to refill your vacuum tank. A very similar situation to vacuum wiper systems on cars which do not have a vacuum pump. PT

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To be honest, I'm not totally sure what the rear end ratio is, but I don't think it's a high speed ratio as the car feels like it's topping out at 45 mph. Besides that, it's the stand 726 sedan, at hair over 4200 lb. (as I recall).

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That actually sounds like it may be what I ran into. On one particularly steep grade the car came chugging to a stop and actually stalled. I had to pull the handbrake, start the car again, then drop into the low-low gear to start moving again.

Lemuel, I have toured extensively with two different 633's each with 4.33 :1 rear axles, they both performed strongly on hills. It took quite a steep hill to need second then they would climb anything. They both cruised at up to 50 mph , any more than that and they were revving too hard, if that happens to yours at 45 mph it suggest yours has the 4.69 axle which should allow excellent climbing. Maybe your engine tune is not optimal, timing or mixture.
I have never eperienced the vacuum tank emptying as described by Peter despite have climbed some long steep hills, the vacuum tank on our Packard has a particularly large reserve capacity. I have experienced vapour lock under those conditions but your description does not fit that problem.
In answer to your question, I have never selected second gear approaching a hill and can usually maintain speed in top gear over all but steep hills.

Maybe your spark is retarded or as you say it's running lean but it is capable of much better.

O.D., What sort of up hill speed do you usually maintain with your '34 4.69:1 ?, and what sort of comfortable highway speed do you experience ? As you may recognize, this is TomB with the '34 1101 2-4 coupe, and I'd like to know what to expect when I finally get it on the road ! Rear-end/axle same as yours.
Thanks,
Tom

With the exception of unusually steep hills, I climb hills in 3rd gear and maintain whatever speed I wish to, and can generally accelerate on the hill if desired. For sustained highway driving I find 45-50 mph to be a very comfortable cruising speed and try not to exceed 50 mph except when absolutely necessary.

In case you didn't see Fred's response on your tail lights, yes when you put your car into Reverse your brake lights should come on as an alert to those behind you that you are backing up. Pretty much a standard feature on better cars of the era.

O.D., As always, a heap of "Thanks" for this response and following up again with the back-up light issue.
I'm in California and do not look forward to having to pull onto one of our InterState highways where the 18 wheelers blow your handles off at 70 !!. I noticed you said you avoid it whenever possible....hope I find those "alternate routes too !
Thanks again,
TomB

Tom, just as I have, I'm sure with little help from Bing Maps ar similar, you'll find State and County highways to be pleasant alternatives. About the only time I have to use Interstates is to cross the Hudson river to New York, or similar.

👍 😊