Packard Forum Index » Modification Discussion

Ross, does the service bulliten day what caused the vibration at 80-90? Also do you have any horsepower or torque figures from Packard dealing with the later L8 engines? All the literature I have been able to find has those engines peaking at around 2000 RPM for both torque and horsepower. The internet being what it is I'm not sure I was reading correct information. I will be doing something that rhymes with racing with my engine so I would really like to get some good information on what the engines could sustainability handle stock so I know what needs to be addressed.

The problem in that case seemed to be a slight droop occurring at the bell housing on the Ultramatic cars only. It is a long way from the front mounts to the rear mounts and I surmise some sort of harmonic vibration was set up by the flex plate. The fix, described as for early production cars only where the complaint was noted, was two little braces between the oil pan rail and the bottom of the bellhousing. Apparently they took care of the root problem with a casting or machining change as those braces were not used again till the 359 of 1954 with Ultramatic which all got them.

I have run my roadster which has 288 and Ultra to slightly over 100 with no problems noted.

A darned handy thing to have is an old Motors repair manual as it lists detailed specs for each car with out having to look very far. Worth every penny at a flea market or fleabay.

Most of the eights had their torque peak at 2000 until 1954 when they advanced the cam 5 degrees so that torque peaked at 2200. The 288 already had their torque peak at 2200 as they had less air to move through the same size ports as the bigger engines.

Peak horsepower was at 3600 rpm for all the two barrel cars because of breathing limitations, and rated at 4000 rpm for the 4 bbl cars as they did not start gasping for breath so soon.

Very nice performance gains are available with relatively modest porting efforts. That is why every L8 I do gets a quick and dirty port job; not only are they quicker, but with the stock carb they seem to get better gas mileage.

Ross I think we need to be friends You say you have done 100 in your roadster what are the specs of the car weight and gearing and how much more did it have in it at 100 mph? Also what RPM were you at at 100? I really want to take mine to the track but as noted I don't want to blow it up and I would like to make a decent showing, I now it will never be as fast for as little money as a modern engine but I really want to know what it can do.

Now that she's 4 years old some details are slipping. I think I have a 3.23 in that one. The weight is greatly reduced from the sedan it was made from, it is something like 2700 if I recall.

The wind blast in the face and the poor balance of my left rear tire did not leave me at 100 very long but it seemed to have more. Should have bought better tires.

IS the engine mostly stock with the mentioned port work or do you have other modifications as well?

It is a 51 288 bored iirc .040 over, ported and lightly relieved. I use 1954 heads whenever I can as Packard finessed those heads every year and 54 was the latest and best. The combustion chamber contours represent a lot of research on turbulence and flame propagation that I don't imagine I am going to improve. I merely polish out the sand-cast roughness to minimize heat transfer. I am not a big fan of heavy head milling to raise compression: as you do so you loose flow path over the top of the intake valve which is counterproductive. Plus the engines become harsh and fussy about their fuel. This car spends most of its time on back roads.

The crank was very nice, as they usually are, so I left it alone. The replacement pistons were all within a couple grams of each other so I left them alone. I did smooth off the rods of their forging marks and then brought them within a few grams of each other.

The cam is stock and very tractable--it will pull up a steep hill at 20 with the torque convertor locked. On other cars I have had Crane grind me a warmer cam (I know just about nothing about cam grinds) which were still quite tractable but gave a noticeable performance boost. Knowing what I know now, I probably would have installed a 54 cam gear if I could find one to bump the cam timing--that or make a stepped key to advance the cam to 54 specs.

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It seems like a very simple straight forward build noting exotic, I like that and the car is gorgeous. Are you running the aluminum head or a cast iron piece? If you have it available would you be able to upload the cam card from the comp regrind?

Look in Hemmings for a Harmonic Balancer rebuilder. I know there is a company that does that. Can't remember the name. They would be the experts and could possibly rebuild yours to meet your requirements. At least they should have the resources to direct you to someone knowledgeable.

Jim Chrisner, Western, PA.

Here is one place a few on the forum have used to have their dampers repaired or revulcanized if the replacement turns out to be not satisfactory.http://www.damperdudes.net Of course by the time freight from Australia is factored in it would probably be cheaper to have the new one made there. There was a another recommended place but he was part time and his link currently seems to be NLA. Maybe he went into another line.

Although it would probably be uneconomic for me to ship to/from the US, for packard1984 and others in the US it looks like a viable option. I see they have 2 Packard dampers listed on their Website.