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This was a well-documented and witnessed exhibition for the annual Dealer's meeting at the Masonic Temple in Detroit. You many find some details in the Kimes or Turnquist book but as I remember they took a stock Eight sedan at random and ran it on their test track at wide-open throttle for 25,000 miles with only stops for drivers, gas, oil and tires and after the test the engine was dismantled and inspected with no significant wear apparent. It was to demonstrate the superiority of the new copper/lead and steel backed bearings.

P-V8,

I think I have determined some rpm and gearing combinations that will work. It looks like 3.92 final ratio with overdrive would put me around 2400 at 75 mph. That is definitely sustainable. I have modern thick shell insert bearings, so I am not terribly concerned about bearing failure at this point. As far as the rod itself, the rod cap leaves a bit to be desired, kind of spindly, but adequate.

I also share some skepticism about gearing and actual engine rpm during the 25,000 mi endurance run O_D mentioned. I only say this because Packard accreted that a 39 Super 8 would do 105 mph when equipped with overdrive. The standard overdrive axle ratio was 4.69 : 1 So doing the math says it may have achieved 105 but with standard gearing this would have been around 3975 rpm's. I am not even sure this engine is capable of breathing enough to achieve 3975, no less not slinging parts into the stratosphere. It is far more likely they had a 4.09, or even a 3.92 axle.

O_D & P-V8

This has been good food for thought. I appreciate your feedback. I think I will see how this gearing works out. Should be interesting. I think the outcome will be a very relaxed comfortable cruise speed with a relatively comfortable cruising rpm.

Mornin' all,

While this discussion has gone entirely over my poor little head I will attempt to add something resembling an intellectual comment.

While I have no idea about the gear ratio on my car, I will tell you that the progressive modifications to my motor, (forced upon me by necessity and the need for total reliability, in all weathers, night and day), have allowed the motor to breath, fire and charge better. In particular, I replaced the totally worn out carb (EE33?) with a carb supplied by Max Merritt. I will see if I can find a make on it but I can tell you it is totally rebuilt and looked like new. (I think I remember it was from some aircraft engine, could be wrong. Anyway, it really opened the motor up, improving acceleration and pulling power. The electronic ignition provides fat sparks with no problems such as points breaking down or bouncing at high rpm. The 12v alternator connected to a heavy- duty battery keeps the ignition happy. An electric fuel pump was also an important addition to the 'performance package', when this was added the rpm really settled down from barely ticking over to high rpm.

While I do have other totally standard vintage American cars, the Packard was in a poor state when I got it, hence the need for, ultimately reversible, modifications.

Pat.

39 super8 writes:
"It looks like 3.92 final ratio with overdrive would put me around 2400 at 75 mph. That is definitely sustainable."

Yes, that sounds excellent to me. Some of the 8 experts will hopefully confirm or refute.

Remark:

i'm guessing that Compression ratio of the engine is probably 6:1 or thereabout. That's relatively low CR. The 5ive inch stroke means extremely fast PISTON speed.
All of that is ok but just be aware that the sustained high piston speed at the higher rpm range mite wear piston rings rather fast. I'm guessing a ring job every 25K miles under these condiotions. Still ok since doing a ring job on the flat heads is fairly ez, fast and cheap.

The low CR coupled with low compression due to ring wear may become evident when hard starting or sluggishness under load is experienced.
But this problem is off in the future and ez enuf to service given that it's the flat head engine.

super8 writes:
"As far as the rod itself, the rod cap leaves a bit to be desired, kind of spindly, but adequate."

I wouldn't worry about that much either at the 2400 rpm range. Probably even ok for short passing bursts up to 2800 rpm under comfortable passing conditions.


Remark:
I doubt that u will experience any problems at the 2400 rpm range. If something should happen that u hear the engine trying to let loose then do NOT back off of the accellerator real fast. Back off gradually like stopping for a stop sign. Release the accelerator gradually and smoothly over 3 to 4 seconds.

"25,000 mi endurance run .... Packard accreted that a 39 Super 8 would do 105 mph when equipped with overdrive."

Does the Endurance Run article indicate an AVERAGE speed over the entire test run???? I would be MOST AMAZED if 105 mph was the AVERAGE over the entire test run. That rivals the Packard V8 test run performed in 55-56 by PMCC as well as several later V8's.

My motor is fitted with a High Compression head. (stamped on the head) Was this an optional extra or fitted for some other reason?

P-V8,

You are certainly correct about piston speed. If the math is correct, with a 5 inch stroke and 11 inch long connecting rod, 1.2:1 rod ratio, this engine is at 1450 feet/second @ 3750. This actually seems kind of low for such a long stroke. Fortunately, the Egge pistons I installed utilize modern Hastings rings, replacing the double one-piece oil control ring with one multi-piece oil control ring.

As far as the endurance test and flat out speed run for 1939, they were definitely two different runs, about 4 years apart. I have never heard top speed cited in the endurance run. Conversely, I have never heard how many miles the 1939 top-speed run was. O_D will probably be the best person to answer this question. I am in no way trying to discredit either of these marketing demonstrations, but do believe there were some deviations from standard equipment (i.e. gearing).

Pat,

I am totally intrigued by the work done to your engine. I would love to have a high compression head! You really have some fantastic sounding modifications. I think you and Turbopackman have horsepower at heart. Sounds like with the modifications your engine has, you are probably generating a good bit more torque and horsepower than my engine. Again, I really appreciate the information you have provided. It is most unusual for an early 320 to be used in daily service, no less in a professional car. Good for you!

" 5 inch stroke and 11 inch long connecting rod, 1.2:1 rod ratio, this engine is at 1450 feet/second @ 3750"

That's not what i get.

ONE revolution of the engine moves the piston 10 inches. 5" down + 5 inches up for one rev.

10" x 3750 rev/min = 37500 inches/min. 37500in/min//12in/foot = 3125 ft/min. 3125//60 sec/min = 52 feet/second.

One of us is wrong. Probably me.

Anyway, compare that to a relatively common or average post war stroke of about 3.5 inches. I get 36 feet/second. About 30% reduction from the 5" stroke.


Keep us posted on the sucess of your project. When will make the first test run????

P-V8,

I am positive you are correct. My calculated piston speed seemed to low. It will probably be a month or two before I can install the 3.92's. I am really excited to see how this works out.