Broke the distributor pin - and can't get her timed! No start. Why?
05-19-2018, 04:28 PM
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Broke the distributor pin - and can't get her timed! No start. Why?
Alright boys....I'm invoking the higher powers and asking for your input here.....
A close buddy of mine has an '85 F150 with the 300 six. Manual tranny, 4x4. Pretty bare bones truck, but has been a real workhorse. Starts every single time. Until a few days ago....
He was driving along the road when she just......died. Dead in the water. He pulled over, poked around a bit, and found that the rotor just turned freely. Broken dizzy pin.
No problem; got a new pin, installed it - but now we CANNOT get it timed right. He's been wrenching on it for a few days - with no luck at all! What are we doing wrong?
We tried setting #1 to TDC, then installing the distributor. She'll start, but just coughs/bucks/backfires/surges - then dies. Cannot keep her running to save our lives.
It's a bone stock, one barrel carb inline six. This should not be rocket science here, but we cannot get it to fire. We need your help.
What are we doing wrong?
I can post some pics later today hopefully....
A close buddy of mine has an '85 F150 with the 300 six. Manual tranny, 4x4. Pretty bare bones truck, but has been a real workhorse. Starts every single time. Until a few days ago....
He was driving along the road when she just......died. Dead in the water. He pulled over, poked around a bit, and found that the rotor just turned freely. Broken dizzy pin.
No problem; got a new pin, installed it - but now we CANNOT get it timed right. He's been wrenching on it for a few days - with no luck at all! What are we doing wrong?
We tried setting #1 to TDC, then installing the distributor. She'll start, but just coughs/bucks/backfires/surges - then dies. Cannot keep her running to save our lives.
It's a bone stock, one barrel carb inline six. This should not be rocket science here, but we cannot get it to fire. We need your help.
What are we doing wrong?
I can post some pics later today hopefully....
05-20-2018, 05:07 PM
#2
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The bottom of this caption explains how to stab a distributor:
(phone app link)
But that pin didn't just break from age or miles - mine has ~860Kmi. Something caused it to break, and that MIGHT be the same thing keeping it from running right, even if the distributor is stabbed correctly. A common problem with that carb is that its accelerator pump diaphragm is VERY sensitive to backfires. Even one can rupture it, causing an intermittent rich condition.
(phone app link)
So once you're sure the dist is stabbed right, diagnose it as if there was never any dist problem.
(phone app link)
But that pin didn't just break from age or miles - mine has ~860Kmi. Something caused it to break, and that MIGHT be the same thing keeping it from running right, even if the distributor is stabbed correctly. A common problem with that carb is that its accelerator pump diaphragm is VERY sensitive to backfires. Even one can rupture it, causing an intermittent rich condition.
(phone app link)
So once you're sure the dist is stabbed right, diagnose it as if there was never any dist problem.
05-20-2018, 06:25 PM
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So we realigned everything - EVERYTHING - and stabbed the dizzy dead nuts on. I mean perfect - the timing marks are on, the number one cylinder is TDC (using a straw to verify), and the rotor is pointed directly at the number one tower on the distributor cap. It's gotta be right as far as dizzy location.
Now, it tries to start, but only runs for just a second - then coughs and dies, backfiring up and out of the carb.
When it's running (even for the one or two seconds she's running) it's PURRING. I mean SMOOTH! But then a cough, backfire, and dies. Every time.
Could all of this be an accelerator pump diaphragm tear/puncture? Would that cause this kind of behavior?
The timing has to be right. Everything indicates it's right where it should be. But still not running...
Now, it tries to start, but only runs for just a second - then coughs and dies, backfiring up and out of the carb.
When it's running (even for the one or two seconds she's running) it's PURRING. I mean SMOOTH! But then a cough, backfire, and dies. Every time.
Could all of this be an accelerator pump diaphragm tear/puncture? Would that cause this kind of behavior?
The timing has to be right. Everything indicates it's right where it should be. But still not running...
05-20-2018, 07:42 PM
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Here's something to add to the mix:
When my buddy discovered the broken dizzy pin, the gear on the distributor was setting down in the distributor shaft area. He tried to tease it out, but it got knocked down into the oil pan sump area. No big deal; once she's back running, we'll do an oil change and drop the pan, put on a new oil pan gasket, and grab the gear. Not a deal breaker at all.
SO - while he was at the parts store, he gets the replacement pin AND a replacement gear for the distributor. However - when he was back at the truck, working on the distributor, he said getting the new gear on the dizzy shaft was SUPER tight. Really tight. Had to nudge it pretty hard to get it installed, then it took a vise and some channel locks to rotate it around into position to drive in the pin.
Could he have the wrong gear? How many different gears might an inline Ford 300 distributor have? Can't be that many different options can there?
This is getting frustrating....should be a simple job here....but it's getting the best of me!
Any what about the distributor itself - is there something inside that could have gone bad? Broken? Something that would allow it to sort of/kind of run - but not really? Some sort of electronic spark unit that would somewhat function - but only enough to start the truck? Not enough to keep it running?
When my buddy discovered the broken dizzy pin, the gear on the distributor was setting down in the distributor shaft area. He tried to tease it out, but it got knocked down into the oil pan sump area. No big deal; once she's back running, we'll do an oil change and drop the pan, put on a new oil pan gasket, and grab the gear. Not a deal breaker at all.
SO - while he was at the parts store, he gets the replacement pin AND a replacement gear for the distributor. However - when he was back at the truck, working on the distributor, he said getting the new gear on the dizzy shaft was SUPER tight. Really tight. Had to nudge it pretty hard to get it installed, then it took a vise and some channel locks to rotate it around into position to drive in the pin.
Could he have the wrong gear? How many different gears might an inline Ford 300 distributor have? Can't be that many different options can there?
This is getting frustrating....should be a simple job here....but it's getting the best of me!
Any what about the distributor itself - is there something inside that could have gone bad? Broken? Something that would allow it to sort of/kind of run - but not really? Some sort of electronic spark unit that would somewhat function - but only enough to start the truck? Not enough to keep it running?
05-20-2018, 11:36 PM
#6
Senior Member
But that pin didn't just break from age or miles - mine has ~860Kmi. Something caused it to break, and that MIGHT be the same thing keeping it from running right, even if the distributor is stabbed correctly. A common problem with that carb is that its accelerator pump diaphragm is VERY sensitive to backfires. Even one can rupture it, causing an intermittent rich condition.
So once you're sure the dist is stabbed right, diagnose it as if there was never any dist problem.
So once you're sure the dist is stabbed right, diagnose it as if there was never any dist problem.
05-23-2018, 11:49 AM
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Forget about the distributor - move on. Yes, the gear is an interference fit (VERY tight). There are SEVERAL other known problems with that carb, including its 2 mounting studs & thick,soft gasket allowing it to rock & create vacuum leaks & intermittent lean conditions; and the unequal-leg intake manifold preventing all cylinders from getting the same mixture.