1949 Cad high speed operation

[kentz]

Has anyone ever experienced problems with acceleration above 60 mph?  The engine seems to run fine and accelerates good until about 55-60 mph.  Do not seem to get very good response after and car seems to slightly hesitate and these speeds.    

[Otto Skorzeny]

First thing to check is your distributor advance. I assume '49 is vacuum operated.

Does this happen when engine is cold? hot? doesn't matter?

[35-709]

Fuel pump failing, possibly not supplying adequate fuel under higher demand?
Fuel filter dirty?
Geoff N.

[Jay Friedman]

'49s have both centrifugal and vacuum spark advance.  As Otto suggests, you should check these. 

The vacuum advance unit's diaphragm could be bad or the vacuum line from the base of the carburetor could be clogged or its rod is hanging up inside the distributor, etc. 

The centrifugal weights are under the breaker plate.  Remove the distributor from the engine and take out the breaker plate.  Make sure the weights are free to move when you rotate the cam and that none of the springs are broken.  Tthen put a drop of oil on each pivot point. 

Another possibility is merely that the distributor contact points are too close together.  Set these to the proper gap.  I don't have my manual handy but I think it should be .018 inch or so.

[Ken Z]

Hi Jay,
The vacuum advance seems to hold vacuum and move freely.  I also spray cleaned out the line.  Have not visually checked the centrifugal weights, but the vehicle does accelerate good to 60 mph.  I have pertronix, ignition so no points.   Have had alot of vapor lock problems, so I installed a electric fuel pump parallel with the mech pump fuel line.  A one way check valve keeps the E Pump from pumping back into mech pump.  Fuel lines are clean and tank has been cleaned.  Car has automatic transmission.   Thanks to all,  Ken Zitzmann     

[Otto Skorzeny]

Maybe the coil is breaking down under load?

[carguyblack]

I concur with what Forrest says about the coil. My 56 had an electronic distributor like yours and the coil went bad. It was a back and forth thing for quite some time as the bad coil eventually messed up the electronic distributor. Had the same symptoms as yours and I went through the whole fuel system thinking it was a fuel starve issue. Turned out to be a weak or intermittent coil. Put regular points and a new coil and the things purrs and roars as it should. In the process I also got a $300 gas tank overhaul and a whole lot of hours chasing an elusive rabbit. I don't even like rabbit.

[Otto Skorzeny]

What's that saying?

Ninety percent of all fuel problems are electrical? Something like that.

[Jay Friedman]

This may be heretical, but I suggest you experiment by temporarily switching your ignition from the Pertronix system back to points and see what happens.  I once tried Pertronix ignition in my '49 and only had so-so results, perhaps due to its electrical system being the stock 6 volts and (in spite of the manufacturer's claim otherwise) Pertronix really being designed for 12 volts.  I went back to the original points system and the car has run perfectly ever since.  Yes, you have to replace the points every so often, but they are widely available and not expensive.

[Ken Z]

Dropped in a rebuilt OEM distributor with points.  Worked like a champ!  I will put the other one back together to its original configuration and try it out some day.  Everything looked good inside, so maybe it is the Pertronix.  Always good to have a spare one. Thanks for help      

[Bill Podany #19567]

Hello Members,

I want to add an accendote regarding a 49 Cadillac having restrictions at higher speeds.  My father bought a new 49 Cadillac sedanette when I was a youngster.  He was a fast driver.  My father took our family from Minneapolis to San Fransciso in that car, and recall him driving 100 MPH through many parts of North Dakota, Montana, Utah, etc.  He loved that car's high end performance.  The car peformed flawlessly at these speeds for the total trip to and from Minneapolis.  He had a bag of water that he tied to the front bumper filled with water, just in case of cooling system problems going through the desert.  Such fond memories I have of that Cadillac as a youngster. 

Bill Podany
Knoxville, TN