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Classic/Antique Car Repair/Classic Car hard starting when engine is warm


I have a 1978 Ford LTD Landau with a 460 c.I. engine.  Car starts very well every time when engine is cold.  Car runs beautifully; smooth, even and is a shear delight to drive.  When engine is warm and I turn engine off and attempt to restart within ten seconds, it generally will restart.  If I wait for a minute to ten minutes, engine doesn't want to turn over.  It's as if battery is weak, but it is not.  Battery is strong.  I can attempt to start it two to four times and the engine barely turns over, but then will catch and turn over strong as if nothing is or has been wrong.  Again, when engine is cold I could crank and crank on the engine and the battery will show no weakness.

While the engine was warm, I removed the coil-to-distributor wire and engine turns well.  Not lethargic.  Battery is good.  Battery posts clean.  Ground and positive wire contacts clean and making good contact.  New quality spark plug wires.  New plugs.  Clean distributor cap, rotor, stator and armature.

I'm at a loss to know where to look to effect a repair. It has been suggested to me to check a heat riser valve on the exhaust manifold.  Does this engine have one?  Could this be malfunctioning, causing engine resistance and thus my problem?  If so, where is this valve?  How might I check it?  And are there other possible causes?  

I see no indication of a weak starter.  I'm stumped.  Please help.

Your problem is pretty unusual. However, once the starter bushings
kicks in, they turn the starter and flywheel at normal speed. However,
their is a little known problem that you are describing that occurs when
a battery to starter cable(hot/red cable) is going bad. When cold its sends a full
12 volts to the starter solenoid, but when hot, it will send much less that 12 volts.
This gives the impression that the battery is weak, when it's just a weak cable that
can't carry 12 volts to the starter solenoid. Try replacing cable first. A very cheap change.

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Vern Bullock


I can answer most questions about autos built in the 1920 through 1990. Mechanical issues and technical questions are my expertise. I also have a general knowledge of most older automobiles. Keep in mind, I can only provide answers if the questions are very specific and complete. Without details, I can only speculate and that's not good for solving your problem.


I have owned and maintained Silver Shadows for over 10 years now. I find most mechanics and even Rolls Royce mechanics have very little knowledge about these automobiles. I have researched these cars in quite a bit of detail and can pretty much tell you what is wrong, if you can describe the behavior in detail. I have saved quite a few RR owners a lot of money and aggravation due to improper diagnosis. I am the owner of Classy Transportation, LLC a luxury limousine service specializing in antique cars, classic cars, vintage cars and exotic cars.

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