Hot start nightmare!

Phil, is your coil compatible with the new ignition system? Does the new system call for a ballast resistor and, if so, is it properly connected. My thought is that you're putting 12 volts into a coil that's spec'd at 6 volts. This could cause the coil to over heat and cause a hot start problem . . . maybe. Also, are your plug wires at the distributor and at the plugs got a good solid connection. Any looseness, particularly at the plugs, could cause increased resistance and, consequently, more heat and less spark to the electrode.

Just some possibilities that are easy to check.

Bill

 

I don't think its a problem with a Crane XR3000 setup, which works quite well in a Dino in my experience. Sounds like vapor lock to me or an issue with the carbs.
What happens if you switch on the ignition, wait for a minute or two so the fuel pump cycles a bit of fuel through the carbs (ideally getting rid of the bubbles/air) and then try to start, is that approach working better?

 

But he said it never happened before, so unlikely to be vapor lock

Failing ignition when hot is a classic sign of a bad coil.
Did you replace the coil?
If not, I agree it is likely not the right coil for your setup. Check the website for the ignition system and see what coil they recommend for 6 cylinder street use. Is that what you have?

If not, get one. Coils are cheap.

 

I agree with Pantdino.

Your mechanic's analysis is too simplistic. Now the question is "Why is the spark too weak?" Since you didn't have this hot start problem before the conversion to the Crane system (correct?), something has changed probably related to that conversion. I have the Crane XR700 system on my Dino and it runs to the coil thru a ballast resistor. I believe the XR3000 does not require that resistor. If that's true, be sure you're not connected to the coil thru a ballast. Also, if you're using the XR3000, Crane recommends using their PS91 E-Coil (P/N 730-0091). So, if you're going to replace the coil and you don't care about having the "original look," go with the recommended coil. My favorite saying: When all else fails, re-read the instructions.

In any case, good luck!

Bill

 

The Crane PS50 cannister coil has the correct specs for the XR3000 and looks relatively original, no need to go for an e-core coil in this setup.

If the problems result from a (broken) coil heating up (which it shouldn't do in a correct setup), then Phil should notice this already while driving (engine running rough, some misfires) and not only on a hotstart condition.

Phil, did your mechanic measure the voltage to the Crane unit to make sure its not a wiring problem inbetween the +12V supply and the Crane unit? Is the battery fully charged?

 

PS60 is the nickel plated version of the PS50 coil, which is painted matte black. Both coils are identical except the finish, for the sake of originality i would recommend the PS50 coil.

 

Phil,

Also, are your ignition wires from coil-to-distributor and distributor-to-plugs in good condition and have a solid connection at the plugs? Any looseness, particularly at the plugs, could cause increased resistance and, consequently, more heat and less spark to the plug. Look for discoloration at the plug connection point. If you're using OEM type wires (red color, simple slip-on connection), any brown or black discoloration would indicate overheating. The attached pix shows a few of my wires that contributed to my hot start problem. New wires with "re-engineered" connections from T. Rutlands helped solve my hot start problem. The wires look exactly like OEM but really grab the plug tight with a spring clip.
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