stumped!!

Posted By: buck440

stumped!! - 04/12/14 01:30 AM

hi guy's recently rebuilt my buddys 440. basic rebuild with ported 516s 509 cam etc... we got it all together went to fire it off for cam break in and it runs for bout 5mins and dies like someone turn the switch off. wont restart unles it sits for a few mins. any ideas changed coil carb is good n cool full of fuel 7psi fuel pressure. could the msd be takin a dump?

Posted By: AAR-B4

Re: stumped!! - 04/12/14 02:44 AM

Distributor pick-up coil? Sounds like something electrical is getting hot.
Good luck

Posted By: JD Dart

Re: stumped!! - 04/12/14 02:54 AM

Ballast resistor

Posted By: gregsdart

Re: stumped!! - 04/12/14 12:42 PM

If it is a stock early wiring harness, it could be the wiring at the firewall feed through. Run a hot wire directly to your ignition for test.

Posted By: buck440

Re: stumped!! - 04/12/14 09:14 PM

ok guys update changed msd pickup cap rotor. started it ran for almost 4mins n shut down ? I believe its wired to the relay hot on the firewall or are you talkin bout the one to the ignition switch?

Posted By: MR_P_BODY

Re: stumped!! - 04/12/14 09:39 PM

Quote:

ok guys update changed msd pickup cap rotor. started it ran for almost 4mins n shut down ? I believe its wired to the relay hot on the firewall or are you talkin bout the one to the ignition switch?

MSD says you should run the BIG red wire to the hot
battery... but I've never had any issue doing it to
the hot side of the relay... the small red goes to hot
ignition.... BUT since your having a problem run a
jumper from the hot battery to the big red just to
eliminate any possible issues... I would think more
like the dist pick up is bad.. so if you have another
dist try it... your having a thermo issue on the electronics

Posted By: buck440

Re: stumped!! - 04/12/14 09:50 PM

that's what I was thinkin distrib. pick up was changed this morning does the msd 6al have thermal breakers in it? cause I give it five mins and bam it has fire again.

Posted By: MR_P_BODY

Re: stumped!! - 04/12/14 10:01 PM

Quote:

that's what I was thinkin distrib. pick up was changed this morning does the msd 6al have thermal breakers in it? cause I give it five mins and bam it has fire again.

I dont know of any thermo switch in a 6al... you might
need to measure the voltage going to the MSD as soon
as it quits... both wires
EDIT
also check the ground when it quits

Posted By: therocks

Re: stumped!! - 04/13/14 12:41 AM

My big red and black both go to the battery.Rocky

Posted By: dogdays

Re: stumped!! - 04/13/14 01:26 AM

So do mine. I think I used 12 gauge.

Looking into my used MSD6 before I installed it I didn't see anything that looks like a circuit breaker.

R.

Posted By: buck440

Re: stumped!! - 04/13/14 05:48 AM

update new msd box runs like a champ just hope all the startin n stopping. didn't mess the 509 break in up that n rings n bearings!!