big block hot start issue Timing?
July 25th, 2014, 07:50 PM
#1
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Join Date: Apr 2012
Location: terre haute IN
Posts: 119
big block hot start issue Timing?
Ok been trying to get all the bug out of my big block this summer. Its about 11:1 street strip cam head work etc. I have a new battery high torque starter. Fires right up when cold. Doesnt wanna start when hot. Now before everyone gives the basics. Starter spins well even when hot. Gas lines are clear of heat. Carb has a nitrous plate under so i dont think its a heat in carb problem. It is reliable im not gonna get stranded but i have to floor pedal when hot starting. I have checked and rechecked carb everything is as it should be. I have my vacuum advance hooked to manifold vacuum(hei). 18* dist advance. soooooooo here my question im thinking of getting a box with maybe some timing control. I am a little confused on if a timing retard at start up will help the problem.
July 26th, 2014, 06:28 AM
#4
Connoisseur d'Junque
Join Date: Sep 2010
Location: The Hudson Valley
Posts: 21,183
Are you saying that your actual symptom is needing to floor the pedal while cranking to get it to start when hot?
If so, then, yes, it may be flooding, but, more importantly, this is not that unusual - there are cars you need to floor in order to start, either hot or cold, and yours, being highly modified, is unlikely to start just like a stock setup.
If it cranks freely and does start reliably when flooring it, then what's the problem?
If you want to play, then just retard the timing by about 5° then next time you run it, and see if it starts easier when hot. If so, then you need to retard the timing at idle, while increasing it while running, which is to say that you have to increase the span of the mechanical advance. This generally entails replacing or modifying the weights and cross piece, and / or the springs.
- Eric
If so, then, yes, it may be flooding, but, more importantly, this is not that unusual - there are cars you need to floor in order to start, either hot or cold, and yours, being highly modified, is unlikely to start just like a stock setup.
If it cranks freely and does start reliably when flooring it, then what's the problem?
If you want to play, then just retard the timing by about 5° then next time you run it, and see if it starts easier when hot. If so, then you need to retard the timing at idle, while increasing it while running, which is to say that you have to increase the span of the mechanical advance. This generally entails replacing or modifying the weights and cross piece, and / or the springs.
- Eric
July 26th, 2014, 07:11 AM
#5
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,477
July 28th, 2014, 04:18 PM
#10
Administrator
Join Date: Oct 2009
Location: Poteau, Ok
Posts: 40,635
If you want to try retarding your timing you can just temporarily do it and save the expense of the box. You stated that your advance is connected to manifold in your first post. Did you check to see if the carb was dripping fuel? Did you check that the carb is spraying fuel if you pump the throttle when it's hot?
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