Packard Forum Index » Modification Discussion

I would be very curious to hear other opinions from experienced operators of 320 8 cyl. engines on max. sustained rpm.

I guess I qualify as an "experienced operator", having driven my 1934 Eight (1100) about 45,000 miles over the years. That's the 320 engine with babbitted rods, also the first year with oil cooler and finned connecting rods. Car weight is 4640 dry weight so about 5000 lbs or a little more with a full load of 25 gallons of gasoline, water, driver and passenger. To that weight must be added the weight of the optional 6th wheel and trunk rack and trunk. 55 mph is about the maximum comfortable speed, 45-50 mph more comfortable. As a closed car it has the standard rear axle gearing of 4.69. I've driven one of the lighter open cars, an 1101 with a 4.07 and a few closed cars with the aftermarket 3.98 or so; they aren't as nice to drive, you're in lower gears more around town and on the highway require more frequent downshifting on upgrades. For my type of driving the factory 4.36 rear would probably be my choice. Available ratios in 34 ran from 4.07 to 5.08.

To keep all this in perspective, we need to remember than in 1934 the majority of roads in the U.S.A. were not yet paved and there weren't many opportunities to exceed 50 mph.

O_D,

I have never found information specific to recommended sustained cruise rpm. I think theoretically the 35 and latter inserted engines would be a bit higher than the earlier babbited engines. The nature of these engines is obviously in the realm of torque.

The question of an actual sustainable rpm number may be difficult as few cars equipped with 320's would have had tachs. The magic in all this is figuring out what gearing v. what torque and hp, and what is the sustainable engine rpm all working happily together to yield the best clip of road speed. In my case, I have a very unique set of circumstances. 39 was the only year a 320 could be had with overdrive. The 39 Super 8 came in at 3930 dry weight, and is fairly aerodynamic. I am pretty convinced that a happy medium between reasonable rpm / cruise speed can be obtained (best of both worlds).

Jim

I have not heard of high speed gear sets for other than the '27 and later big cars and the similar vintage Standard Eights, but that does not mean they don't exist.

Since both Packard and 9 inch Ford are "third member" ( variously termed "meat ball" and "pumpkin" by gear heads) rear axles, I wonder how practical it would be to adapt a nine inch 3.25:1 "pumpkin" to the 526 housing. This of course would require some axle spline magic.

Having a retirement machine shop with seriously large equipment, I would not mind playing around with this idea.

Here is a nine inch housing I did that was written up in Street Rodder Magazine in the nineties.

John Oder

http://img.photobucket.com/albums/v337/johnoder/Ford9/01.jpg

For a period-correct tachometer, I'd look for one of the old Stewart-Warner mechanical tachometers from a diesel application. Most of these were 0-3500 RPMs and that would be plenty for your engine. It shouldn't spend any time above that anyway.

Here's a couplehttp://cgi.ebay.com/RARE-STEWART-WARNER-WHITE-FACED-TACH-HOT-ROD-TACHOMETER_W0QQitemZ280298154432QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item280298154432&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A3|39%3A1|240%3A1318

http://cgi.ebay.com/Stewart-Warner-4-6-Cylinder-Race-Car-Hot-Rod-25K-Tach_W0QQitemZ200300542552QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item200300542552&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A3|39%3A1|240%3A1318

FWIW, today's better oils are the best friend babbitt bearings ever had.

thnx, jack vines

Another source perhaps for a period tachometer would be the sites that cater to vintage small boats, almost all inboard types had mechanical tachometers.

John,
I would think the 9" third member would require quite an adapter to fit to the Packard housing. How about machining a Ford ring and pinion to fit the Packard pieces?
Ron

"How about machining a Ford ring and pinion to fit the Packard pieces?"

Unlikely that the Hypoid offset (how much lower the pinion centerline is than the axle centerline) would be the same.

There is also the problem of physical size. The Ford has a 9" OD ring gear and the Packard is larger.

These two considerations makes getting the Ford pinion in the right place in the Packard housing difficult to say the least.

John Oder

On edit:

I just scaled the 7th/8th Series rear axle breakdown on page 113 of the parts book. I know the straight part of the axle shaft is 1.750" because I have a 740/745 axle in the shop.

Using this figure I find the ring gear to be 12 1/2" OD or thereabouts.

I would not of thought it was quite that large.

JO