Hey gang. I need help. I have a 270 gmc in my box truck that I need running so I can move it to the front of the house. Ive been trying to start it for a couple of days. Its been sitting for 2 years. After I changed so many condenser,coils,etc it fires but won't run.. Im hoping I can get a list of where to get good reliable parts for this thing,,found out that all stores have cheaply made parts..of if someone has a rebuilt distributor/carb i could buy. That would be great.. Thanks in advance
Does your ignition system wiring include a ballast resistor? Does the engine stop running just as soon as you release the ignition switch? If so you may a bad connection or a failed ballast resistor (open) that's not allowing current flow to the ignition when the switch is returned to the to "run" position. https://www.jalopyjournal.com/forum/threads/hot-rod-technical-library-basic-ignition-systems.983424/ This might help with troubleshooting if you have an electrical problem.
Measure volts at the coil, Ignition on and also when cranking. Run a little fine sandaper between the contacts on the points. Also make sure you are switching the negative on the coil with the points, for neg ground system. The coil can work wired backward, but not very well.
Thanks guys..it was running great then it won't..I ***ume I wired it correctly it should start after I replace those parts.... I need to buy a new voltmeter they keep burning up on me...at this rate I just want to replace the running gear with a 350/700... Ill try again after work.
What you got for compression ? Have you adjusted the valves ? If it was running with corn gas when parked, make sure all 12 valves still go up & down ... In order to get rid of all that ballast stuff, put an internal resistor coil on it - the "big blue Bosch" was my favorite. And hunt up some 50 year old points & condenser - new stuff no longer means anything but trouble ...
Absolutely as you don't need or want a ballast resistor with 6 volt. With 12 volt you have to have a resistor byp*** when go to crank it to start and that may be his issue. I haven't seen it lately but in the 70's when I lived in Texas we would have cars show up at the shop that someone had changed to 12 volt and put the resistor in but didn't install a byp*** wire. Or on something like that box truck forgot to hook it up when they worked on the rig. With several years of 12 volt Chevys you don't have power from the switch to the coil when you are cranking as the power is supposed to be supplied by the byp*** wire. Now that I just ordered more I have one of these test lights with a digital volt meter for every one of my rigs. They dropped the price a bunch and at 10 bucks a test light that shows voltage is seriously handy to have. Great for playing the "why the hell is my right taillight dimmer than my left taillight and seeing a voltage drop. Still things like a dirty coil top will drain of power to the coil. Not getting full voltage is the normal issue if you don't have a weak coil to begin with.
Are you sure it's the spark? If sitting for 2 years, there is a good chance the gas has gone bad. I had a snowblower that sat over summer, would not start in the fall. Finally out of desperation I dumped out the gas and put fresh stuff in it. It started right away with the new gas.
Well that looks like it could be a handy little bit of kit there, doesn't it. Don't see how you could go wrong at that price!
When I was in the Air Force years ago, we borrowed a fork truck that had just been tuned up by the motor pool. It would run for a short time, then die. The guy who got it was ranting and raving like Donald Duck; I ignored his "you aren't authorized to work on that" at***ude and removed the distributor cap. Whoever installed the points forgot to set the gap, which I fixed using a borrowed screwdriver and matchbook cover. It ran great after that!
That might be my issue... im not a mechanic but I lve been lucky getting stuff to run by feel...ill givebthat a try
New resistor,condenser,coil,points,gapped them,same issue fires but wont keep running. Does this sound like carb issue? https://youtube.com/shorts/_UNGLQ1wpH4?si=3JWzt2QgtwFzi9Ar
Spray some brake cleaner or starting fluid while it's started. If it continues to run with the spritzing of fluid then it's a fuel problem (carb,bad gas or poss. pump), oxygenated fuel around here goes bad a lot sooner then old regular gas. As for tune up parts, I always lookup the old part numbers for quality brands and hit eBay for 90s and below (Made in USA). Also I have a few old USA coils (new and used) and Bosch blue (made in Brazil or Germany ONLY). You might get lucky and find NOS parts for cheap also.......the big secret is you need to know part numbers not just application. It's a total time waster this way, but it's better then getting **** parts.
What ever you do, don't spray brake cleaner into the motor. If it burns, it will put off a poison gas. If the motor starts, runs a bit, then quits, its probably a gas problem. How long does it run after it starts? 2 seconds? 2 minutes? Are you moving the throttle when it dies? Today's gas can turn to **** in 6 months to a year, often when it gets old, it won't even burn. If it runs 2 minutes or longer before it dies, it could be a problem with the carb, not the points or the gas.. Does it slowly die, or just abruptly quit with no warning? How long it stays running after it starts, is important. What it does when it dies is important. If there is gas in the carb when it dies is important. Without these answers, we are just guessing.
Thanks for all the replies.. If hard to tell in the video but it fires with the key ignition and the starter spinning the flywheel it dies after.. At this point i think im going to pull it with one of the trucks all the way fwd and out of the way which i know its going to be a mayor pita since its so heavy..then after the pavers are done,then ill just swap the engine for a running one
Hook a jump wire from battery to + side of coil & fire it ... if you have a key start ignition switch, they can come apart inside.
I noticed that when i hit the starter with the key,i wasnt getting power to the ballast resistor,so i hooked 12v directy to the battery..still nothing.. Im going to try fresh gas tomorrow. I also bought a compression tester
I am always reluctant to replace the condenser, unless you know that it is the problem and are confident of the quality of the replacement condenser. Simply because the new ones don’t seem to have the quality of days gone by. I would try it with the old one put back in.
Don’t know how your wiring is set up but usually when you’re on the starter circuit you get 12v directly to the coil and the ballast resistor is byp***ed. Did you hook the 12v from the battery to the coil or the ballast resistor?
For grins, head to the AP store or order online, a spark tester. I’ve seen some fancy inline ones as well as the inexpensive HF ones that work.
If it fires when you crank, and dies the second you release the key to the run position, it's a bad ballast resistor. Like said, run a wire from the battery to the + on the coil and try to start it. If all the above is correct it should start.
*******GREAT SUCCESS******* I decided to give it a last go before a deep tissue m***age appointment... Put another rotor from another 6 inline,a set of new spark plugs i had laying around,new hei spark plug wires i had from the same kit,, new points and it fired right up with the new coil,condenser and old resistor... The fuel pump might be stuck solid with old gas but i have a couple laying around...thanks for all input.
Glad you got it running. Since you changed so many things at once you will never know what the problem really was.
Thank you guys.. Some times the little guy wins..running on its own. https://youtube.com/shorts/gBXmL7XnsMA?si=35zU2n_EQJH6r_OO
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