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Matt Conlan

Matt Conlan

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Been working on '70 Newport Custom 2bbl 383, new electronic ignition, for a while, and I'm stumped. Might be time to get to a pro, but I figured I'd ask the forums for help one more time. Car starts great, idles fine, feels really strong. I take it out on the road, and it runs great for about a mile, then loses power. It feels and sounds like it loses it in steps, I have to floor it to get enough power to get home and keep it from dying. I let off the gas and it dies. Try to start it, nothing. Everything looks fine under the hood. If I set the timing way off, like 30 degrees BTDC, I can get it to start, and then adjust it down to about 12 degrees, and it runs great and sounds fine. I take it out on the road and the whole thing happens again. I don't even know where to look anymore. Thanks in advance for any ideas.
 
If this were my engine, I would be checking the basics: Is the timing mark on the balancer set at true TDC? Is the rotor phased correctly with the terminals in the distributor cap? Has the timing chain Jumped? Others may have more or better ideas, but this is where I would start. LC.
 
Have you verified TDC marks on the balancer coincide with the crank keyway position?

Have you driven it with the 30 degrees BTDC base timing? Lots of clatter from too much advance? Quick re-starts at that setting? Extended crank time at 12 degrees BTDC? Is ALL of this happening as the engine warms up from cold or after everything is fully warmed up?

When you say you try to re-start it and "nothing", does that mean "no elec power to turn the starter" or that it cranks over and will not start?

My suspicions are that if it is mechanical in nature, the timing chain might come into play, but as the issue is after it's run for a while, that can bring "spark", "ignition", and "fuel" into play.

Just some thoughts,
CBODY67
 
Timing chain and gear was replaced last year. Worked fine after that. I have not driven it at the 30 deg. BTDC, it sounds really nasty. When I start it and then bring it back down to about 12 deg. It starts right up. Sounds real good. By "nothing," I mean it won't turn over. The starter cranks and it gets gas but won't fire. I don't see how it can go "out" of timing. It is a new distributor. Can that be slipping?
 
It's happening with a warm engine. I let it idle in the driveway, and it sounds fine. Even when I rev it up. I have to drive it for a while for it to have the problem
 
Presuming that you have the distributor snugged down rather than not? Without it being "locked-down" after adjustment, I usually set it snug enough to be able to turn/tweak the housing with a decent amount of force, with no issues. FWIW

For good measure, have you cleaned the battery terminal posts and the inside of the cable ends with a wire brush post cleaner? From my one experience after I installed a MP kit in my '67 Newport 383, it started fine for 4 consequtive times, but on the 5th try, no power getting to the starter. New relay didn't change things, either. Cleaned the terminals that looked ok, but had a thin layer of gunk on the posts and cable ends. All was well again.

Thanks for the replies and updates,
CBODY67
 
Yeah, I loosen the distributor enough to turn then tighten down about a half turn from there. Its getting power and gas. I feel it's got to be timing, but I don't understand how it can be good and then all of a sudden not. Unless I have a bad part. I guess maybe I do need to put the old one back in. Ive even got the old points one somewhere...
 
If it takes 30 degrees BTDC to get it to start and then "goes away" as things heat up under the hood, it could be a control module or what triggers that module that is effectively retarding the spark curve. Presuming the ign system is getting a full 12+ volts to operate on during all of these events?

Thanks,
CBODY67
 
Yep, all the voltage tests out fine. Same with the coil and ballast resistor. I already replaced the ECM once. To be clear, the problem happens after I set it back to about 12 BTDC, and runs fine for a couple of miles. I can't, of course, test the voltage when it happens, because I'm driving it. Not trying to be a smart ***, its just that everything seems fine in my driveway, but then I can't drive it.
 
Presuming you have checked the voltages with the car stopped after it stops running? With an inductive self-powered timing light to check ignition function on the re-start events?

Just curious,
CBODY67
 
"Self-powered" means it just has an internal battery and an inductive pickup that goes around the plug wire, not needing car battery voltage to power it. Just mentioned that to keep battery voltage out of the mix, IF that might be an issue. If not an issue, then the normal car battery powered light should work fine.

Take care,
CBODY67
 
When the pickup coil in my distributor failed it acted like what you describe... fine cold, but when driving things got hot enough that it ceased to deliver spark and the car died and would not start until it had cooled off enough that the pickup coil was "happy" again.

Replaced the pick up coil and solved the problem.

Hope this is helpful.
 
I wonder if its not the carb. Its getting gas, and I blew everything out with compressed air, but I've got the original 2bbl Holley on it that nobody likes. Maybe just time to replace?
 
See if it has spark as soon as it dies, suspecting a pickup coil has all the symptoms like mentioned above.
 
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