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What is considered redline for a 320 cci engine

G'day inews,
See you've been a PackardInfo member for a loooong time but first post so,

Can't answer your question directly, but members more familiar with those engines may be able to do so. Though I do remember there were some threads a while ago about "safe" speeds for babbit bearing engined Packards. Use of the search function may find those for you.

However I invite you to include your babbit bearing engined Packard/s, and/or other Packard/s in the Packard Owner's Registry here on PackardInfo!

I see you are new, so welcome indeed. I am taking a bit of liberty answering in this manner, so please understand the 320 engine takes a bit of a beating on this forum. My answer is if you have to ask, you are asking for trouble. Slow it down if you want it to live.

Doing an advanced search, using "babbit" as the keyword, found this thread, among many. There are a couple of posts where owners give their MPH recommendation for touring speeds, does this help?

To access the [advanced search] function go to the foot of this page and click on [advanced search]. From there use keywords and paramaters for your particular search requirements.

Of course, by driving your Packard as hard and fast as you can you'll find the red-line is the point that is just before a rod exits the block!

I would suggest 3,000 rpm as momentary redline for a 320 engine. I would suggest 2,500 rpm maximum sustained on top gear( 50 -55 mph on standard 4.69 rear axle gearing), 2,800 maximum for an upchange going up a grade. You may be able to top 65 mph for a "burst" but anything sustained over 2,500 and you are giving the poured bearings a "pounding". My recommendation if you really want not to speed stress your 320 bearings is to get a rear end change to 4.1 to 1 and sit on 60 mph within your 2,500 rpm envelope. Hook up a 12V Tacho from a flea market which works fine on a 6V coil ( cost around $10) and check what revs you are currently using. Best regards Peter Toet

As always, Peter speaks the unvarnished truth. These are not rpm engines, but cammed for effortless tractability on the winding two-lane "highways" of the day. A friend had a beautifully rebuilt '35 Eight Model 1201 coupe-roadster with such an engine, everything according to Hoyle, or East Grand. It also had the ridiculous 4.69:1 rear axle. I drove the car a spell and it was a paragon of smoothness, refinement, as you'd expect. Once we took it to a Packard meet and he cruised for a couple miles on the freeway at 65, even touching 70. It was testimony to Packard engineering that even at those speeds, the sound from under the hood was a loud, confident hum, not harsh roar.

I assumed it had a 4.41 axle. When i discovered it was nearly the same stump puller as the earlier L-29 Cord (4.7:1 in high) i was horrified. The first-generation Cords were infamous for being saddled with an absolute top speed of only 78mph, despite their racy looks, and they have lower, reduced frontal area compared with a Packard. This is the absolute limit for a razor-tuned MG-TA/B/C with a tail wind.
Back in the '30s there was the expression, "Going like 60," which meant you were really peeling the wind.

Absolutely. Listen to Peter. Scout out a 4.1 rear cog, and/or an aftermarket overdrive. There's an informative article about gearing, long stroke engines, bearings, Down to the Interstate in Ships: Modern Speed in Vintage Iron,
in the late, great Special Interest Autos, Issue #144, Nov/Dec., '94, which may still be available through Hemmings.

Remember, the 319.2 engine came out in the late 1920s,
was never as husky as Packard's 384, not that that similarly five-inch-stroked mill likes high rpm any better.

My knowledge of the 319 engine is entirely second-hand, but if you keep road speed down and/or install taller final drive, keep oil and water in it, and don't insist on driving it in modern traffic and expecting it to perform with no more fuss than a late-model Camry or Taurus, it'll reward you with smooth running for years. This last adviso is something well remembered by drivers of ALL Packards, and vintage/Classic cars in general. In the day,
people pulled over at roadside stands, had a cup of coffee,
and never suffered the hellish traffic inevitable with today's domestic population of nearly a third of a BILLION.

Even in my '47 Super Clipper, despite its nine-mained, hydraulic-liftered 356 being rebuilt, balanced and having 7.5:1 compression, i set the period 4,500-rpm Stewart-Warner tachometer's redline at 2,500, rarely exceeding this other than momentarily during acceleration.

Peter Packard gives sound advice in his above post. His rpm numbers are spot on. Note that this question and Peter Packards answer of 2500 to 3000 RPM is not a Packard specific rpm range. Those rpm figures are mostly par for just about ANY engine of the prewar era and engines prior to the HP revolution of 1955. OF course there mite be an exception or two. Only one i can think of off the top of my head is maybe the Crosley 4 cylinder capable of very high rpm. A good rule of thumb is if an engine is flat head AND compression ratio under 8:1 then its a 2500 rpm engine. I don't care who made it, where or when.

Bottom line: it's a 2500 rpm engine with occasional room to breath for passing and a bit of hot rodding up to a momentary 3K rpm.

FOr interstate highway use for sustained speeds above 55 mph then an overdrive and maybe a very long ratio rear axle are a must.

My complete support for Peter Packard's and Su8Overdrive's comments is based on almost 50 years and 45,000 miles of touring in my 34 Eight, 320 engine and 4.69 rear with 7:00 x 17 tires. I find 45-50 mph to be the "comfort zone" which is probably consistent with what most roads and highways of the time were built for. I've done a bit faster at times, but only for short intervals.

I consider the engine life I got to be very satisfactory, finally getting a slight rod knock at about 83,000 miles at which time I went for a full rebuild and stayed with babbitt bearings. A thorough valve job was done at about 45,000 miles and other than that, never an engine issue. Actually, only one breakdown in all those years and miles, a broken rear axle in 1999.

Frankly, there is something restful, you might even say therapeutic, about driving non-Interstates at these speeds which are consistent with the rest of the vehicles mechanical capabilities like brakes, lights, suspension and steering. These cars are absolutely delightful to drive, though the front beam axle can keep your reflexes sharp and alert on lousy pavement.

Although my car has the 282 and a 4:36 rear end and 28" tall tires. I have the R11 OD and at 2500 RPM I do 66 MPH but comfortable highway cruising is about 60 MPH

Technically there isn't one given the motor is free wheeling. In an interference engine going past redline can result in the valves hitting the pistons.

That said, the service letters indicate maximum speed for the eights in the 4200-4400 rpm range.

Given the proving grounds opened in 1929 the standard axle ratios no doubt were chosen for highest top speed.

In 34 they ran a V-12 wide open for 6300 miles when it blew up. Later with insert bearings they ran an Eight 15,000 miles wide open and found the bearings still within tolerance. However, those crankshafts wear out so running those motors like that today will blow them up.