Jump to content

48 Packard Questions


Recommended Posts

Mine is a 48 Packard. Three questions: 1) Is it possible to cold adjust the 288 valves to .070 intake and .010 exhaust to get a start point for the engine to run? 2) How do I now if they are solid or hydraulic lifters and 3) my car has no voltage regulator. Is that correct and how will switching from the 6 volt to 12 volt impact the electrics in the car (radio, lights, generator, starter etc). Many thanks!

48 packard3.jpg

Link to post
Share on other sites

Since the manual recommends a final warm adjustment of .007 for the intake and .010 for the exhaust on engines with mechanical lifters I would start with having them a bit closer to the final value if doing a preliminary adjustment on a cold engine.   A mechanical lifter will have what looks like two hex shaped nuts at the top which are visible below the valve stem while the hydraulic lifter will have a round plunger with a spiral spring affair wrapped around it.  There is no adjustment with hydraulic lifters except at initial valve installation or if they have been ground and seats resurfaced after being in service.   A special tool is needed to temporarily substitute for the lifter so the valve stem end can be ground to have a specific length clearance to the tool.  That value is generally between .030 and .070 which provides the necessary clearance so the lifter is able to compensate once those are back in the tappet.  If you want to go to www.packardinfo.com you can freely download a complete 46-50 service manual or just a pertinent section.  Since the 288 was new to the line in 48 and served Packard until 54 it is better covered in the engine section of the 51-4 manual which is also available for download.

 

Most 6v alternators available for retrofit need no external regulator since it is all done internally.  In that case the original regulators are bypassed and sometimes removed.  If you still have the generator and no regulator then you will need to find one but if an alternator has been substituted for the generator then maybe not.  Be aware that if your car is an early 48 and has the R9 overdrive there is another black box which looks much like a voltage regulator also on the firewall and positioned a few inches away from the regulator.  The regulator will have 3 or possibly 4 wires, the black box R9 relay will have 6.  Later 48s with the R11 OD have a relay with 4 wires and is usually silver or natural metal color.

 

Doing a 12v conversion has lots of steps and several components have to be changed or methods added to provide the still needed 6v to those items that cannot be replaced.  Instruments, OD solenoid, and radio are a few that need to stay 6v.  Light bulbs and the starter solenoid need to be changed and the generator/regulator or alternator will also need to be changed.  Heater blower motor needs at the minimum an added resistor or a 12v version found.  While a few 6v items will work adequately at 12v there is a considerable amount of stress added to them which frequently results in damage or a shortened life.  The starter motor is a prime example.  The added speed and torque provided by 12v has resulted in a few broken castings because of the pinion slamming into the end stop.  

 

 

Edited by HH56 (see edit history)
  • Like 1
Link to post
Share on other sites

I would add that usually, people convert to 12V because it's "more reliable" or "starts better". Most reliability problems with a 6V system can be traced to worn components or undersized wiring. With big battery cables, good soldered connections, and a good battery, she'll run just fine on 6V! Nice looking car, and good luck!

  • Like 2
Link to post
Share on other sites

I've had three cars show up this week with either a 6- to 12-volt swap or an "upgrade" to an alternator. Two of them arrived with failed electrical systems, either bad alternators or something worse, but they're not charging at all. One is a bad alternator and the other is an unknown at this point. The third seems operational but has a bunch of junior-grade wiring in the engine bay that looks like a child did it.

 

Meanwhile, my 1941 Buick with a 1941 generator and a 1941 6-volt electrical system started every single morning last December and January when I had to drive it daily because my modern car was in the shop. Then, after sitting outside in freezing temperatures all day, it started instantly and I drove it home with the headlights on.

 

Tell me again how switching to 12 volts or using an alternator is better? I seem to have missed the point.

  • Like 2
Link to post
Share on other sites
5 hours ago, HH56 said:

A special tool is needed to temporarily substitute for the lifter so the valve stem end can be ground to have a specific length clearance to the tool.  That value is generally between .030 and .070 which provides the necessary clearance so the lifter is able to compensate once those are back in the tappet.

The same *kind* of tool, and same range (0.030 to 0.070), apply to 1937-48 flathead Cadillac V8s.  The Cadillac tool number was J-1055 which was finally reproduced a few years ago.  It was merely a piece of bar stock with a knurled handle attached at a 90* angle.  But a Cad collector / professional machinist taught me to to use two inside micrometers as "go" / "no go."  Measure the length of a *collapsed* hydraulic lifter (for Cad, a hair over 3.0 inches) which becomes 'x.'  One mic is set at x+0.030 and the other mic at x+0.070.  Consider the 0.040 difference between the two values as the allowable pump-up range of the hydraulic lifter.  You grind the end of each valve stem accurately until the gap between the stem and the heel of the cam lobe is within the "go" / "no go" range.  This is usually done ONLY in conjunction with a valve job where the seats are ground, causing the stem to be a tad too long.

  • Like 1
Link to post
Share on other sites
  • 1 month later...

Stick with your original 6-Volt system,

just do all appropriate tune-up items and adjustements,

use #0, or 2-Aught batte3y cables, and clean all ground contact areas down to bare metal-

you'll be better off in the long run

 

Good luck 

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...