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hard start after running for long periods
https://slantsix.org/forum/viewtopic.php?t=55825		 Page 1 of 2
Author:  John Deville [ Mon Jul 21, 2014 6:16 am ]
Post subject:  hard start after running for long periods
Hey guys,
Havent had any problems in a long while. But now I am having a hard start after long periods of run time. If the motor has time to cool, it does start. Replaced cap and rotor, and have a Pertronix. 1361A. In place, also, have Pertronix flame thrower 3.0 ohm coil, all was new two years ago. Could the coil go bad so soon?

Also sometime ago I read here I should run through the valve train at around ten thousand miles. Which is where I am at. And am going to do. But would that cause a hard start after long run times. Suggestions? / thanks much in advance
Author:  nm9stheham [ Mon Jul 21, 2014 9:28 am ]
Post subject: 
So is it right to assume that the engine cranks over when hot but does not fire? Does it not fire at all, or just fire erratically and not 'catch'? Sometimes small details can give good clues. Assuming it does crank... and this is the '71....

With the higher resistance coil, is the ballast resistor out of the circuit? Per Pertonix, the ballast can be bypased with a resistance of 3 ohms or higher. (For a the model 1161 at least; I can't find the 1361A instructions in 2 tries.....)

Some things to check/try:

1) Is the brown wire that used to go to the ballast from the firewall connector also connected to the blue wire feeding ths coil? (This assumes the ballast resistor is not there anymore.) You need both; the brown wire feedss +12v to the ignition when the key is in START and the blue feed the +12V to the ignition when the key is in RUN.

2) The coil could indeed be starting to fail; heat is not their friend! Do you have the old coil and ballast to substitute as a test?

3) If the ballast is bypassed, I would check the voltage at the coil + and see if it is around 9 v or higher when cranking. That is an educated guess at what it will be with the ususal voltage drops.
Author:  6inarow-makemego [ Mon Jul 21, 2014 10:03 am ]
Post subject: 
Could it be heat soak/vapor lock? How long is it sitting before restarting is hard?
Author:  Aggressive Ted [ Mon Jul 21, 2014 10:42 am ]
Post subject: 
Heat soak and vapor locking is quite common on a stock SL6 during the summer months.

Better ventilation under the hood helps like electric fans that engage after shut off along with heat diverters or heat shields, cooler ram air, higher initial timing (10 degrees or more), etc.....
Author:  John Deville [ Mon Jul 21, 2014 10:57 am ]
Post subject: 
I'm running through valves then going to re check timing. The resistor is in place. All wires still connected. Always ran well. Coil does seem warm after considered drivin. Dont think vapor lock, have run hard fuel line well above and away from block and valve cover. Coil the only? ? After timing and I have help
Author:  Aggressive Ted [ Mon Jul 21, 2014 12:22 pm ]
Post subject: 
John,
Quote:
The resistor is in place.
With a 3 ohm coil you do not run the resistor!!!!!! The key benefit or reason for running a 3 ohm coil is to delete the ballast resistor.

You want to have a full 12 volts going to the coil and the Pertronix unit for it to run properly.

Delete the resistor and wire the two sides together to provide a full 12 volts.

Click on the red link below my name to view pictures of this mod.....
Author:  John Deville [ Mon Jul 21, 2014 3:37 pm ]
Post subject: 
Ok , final thoughts. Weak fuel pump, and bad vacuum advance. Corrected, 6 to 12 volt. With jumper. Advanced timing til V.A. comes in. Went through valves. Highly suggest for everyone, cause it needed it. Thanks to all, car after mechanical overhaul from three years ago, runs and is the daily driver still, I have tried to follow all the advice. Best wishes, til it has another problem
Author:  Reed [ Mon Jul 21, 2014 3:56 pm ]
Post subject: 
Quote:
Advanced timing til V.A. comes in.
:?:

That is not how vacuum advance is supposed to work. Put your timing back to the stock timing specification and hook the vacuum advance hose up to the ported vacuum nipple on the carb.
Author:  John Deville [ Mon Jul 21, 2014 4:04 pm ]
Post subject: 
Plugged advance til new one arrives.
Author:  John Deville [ Wed Jul 23, 2014 8:55 am ]
Post subject: 
Ok, here goes, have new vac. advance, saw Dans thread asked for a vc. 93. They send me a 161. New number? Arm states it as a 6.5x doesnt match the 93. Pulled the 93 number from sl6 parts list here. Dont want to pull the distributor without knowing, thanks
Author:  John Deville [ Fri Jul 25, 2014 6:30 am ]
Post subject:  Vacuum advance for 71 Duster
Ok, hoping to get a reply. Could I get a part number for a V.A. with the set up I currently have. I know I dont want to pull that distributor til I know for sure what I put in is appropriate.Please and thanks
Author:  64 Convert [ Fri Jul 25, 2014 6:42 am ]
Post subject: 
One problem I had with my '73 318 pickup. The starter turned normally, but it took forever for it to fire when hot...sometimes it killed the battery. After all the fuel related ideas were exhausted, I decided to change the starter. Now it fires on the first turn every time, hot or cold.

Apparently when the engine was warm, the hot starter was drawing enough to kill the ignition, yet gave no indication of being bad.
Author:  nm9stheham [ Fri Jul 25, 2014 7:21 am ]
Post subject: 
Wish I could help you on the V.A. number.
Author:  John Deville [ Fri Jul 25, 2014 11:51 am ]
Post subject: 
Thanks guys but I know the v.a. is bad.
Author:  John Deville [ Fri Jul 25, 2014 11:51 am ]
Post subject: 
Thanks guys but I know the v.a. is bad.
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