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Discussion Starter #1
I am breaking in the Ford 460 in my jet boat. Runing a new cam, lifters and exhaust so I am breaking the motor in on the trailer. MSD wise I have MSD 6M-2 High Performance Marine Ignition, Blaster Coil, and the 83506 ford MSD distributor.
The motor fired right up and ran well for about 60 seconds, and then just died, stopped. A little investigation and I had no spark. Pulled the coil wire, put close to a ground, turned over motor, and no spark. I tried the jumper wire to the distributor plug and I do have spark (per MSD's suggestion).
Where is my problem??? And what would cause me to lose the spark while the motor is running? It is dark when I get home so I can't do much until the weekend, but would a ground coming loose or not be connected be what possibly did this? Any help please! Thanks!
 

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You can double check the box by diconnecting the dizzy plug, and grounding the white wire from the box. Every time you grond the white wire, it should spark. If ok, double and triple check the connection from the box to the dizzy. Make certain the FACTORY plug has them like this. Black/org from the dizzy to the violet on the box and the black/violet from the dizzy to the green on the box The factory has had a really hard time getting this right lately.

If still nothing, check the ohms thru the pickup. You'll need a multu tester. check it like this, and it should read between 500 and 700 ohms.

LINK: checking MSD pickup



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Man I have lost count on how many posts I have seen where an MSD (might spark daily) has failed. If you have an old factory distributor handy then get the cam broke in, then worry about the MSD. we have all seen enough cam failure issues come thru the boards. The last thing you want to do is try to break-in a new cam with an ignition problem that might require crank here-crank again-and again-and again. Question! was the MSD in prior and ran great or is an add on at the same time as the cam change? M
 

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Man I have lost count on how many posts I have seen where an MSD (might spark daily) has failed. If you have an old factory distributor handy then get the cam broke in, then worry about the MSD. we have all seen enough cam failure issues come thru the boards. The last thing you want to do is try to break-in a new cam with an ignition problem that might require crank here-crank again-and again-and again. Question! was the MSD in prior and ran great or is an add on at the same time as the cam change? M
Although I will agree Ol guy, that MSD have failed, so have HEIs and mags. Trust me, we are about 50/50 MSD to mag failures in the GN class, and there is about an equal number of each.

The problem with MSD right now seems to be them getting the wires crossed in the connectors of the marine units. I think this is a new install. You may be correct that a stock points and condenser would be more reliable, but who whats to go thru the install this, remove that, now install this. Its pretty simple to tell if the MSD fires before you ever start the motor. But I have seen brand new induction/points condenser ignitions fail a brand new coil before. Nothing is failsafe. Maybe it explains the FAA's reasoning behind redundent ignitions. Including the fail proof mags. Ya think



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One day i had a ford engine engine shut down like you have posted here, and it turned out to have sheared the roll pin on the dist shaft.
Just something to check. good luck
 

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One day i had a ford engine engine shut down like you have posted here, and it turned out to have sheared the roll pin on the dist shaft.
Just something to check. good luck
Just what i was going to suggest. I have seen this many times with a 460 Ford. Small diameter roll pin.
 

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Discussion Starter #8
Thanks for all the input guys. I am going to get back on it tomorrow when I have some day light. I will be pulling the distributor first, if nothing else to prime the motor and make sure the distributor is still in one piece. The current MSD set up I have was on the motor prior to puting the cam in, all the connections are correct, nothing backwards. I am going to go through the voltage checks, ohms checks, etc. and see if I can figure it out. It just bugs the #%@! out of me that something like this has to fail 60 seconds in to breaking in a new cam! Hopefully tomorrow I can send a post with successful news of an ignition working and a succesful cam break in! I'll keep you posted! View attachment 99279
 

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I was able to find this from Lakes Only on another site. He posted a diagram on PB once before, but I can't seem to locate it.

But if you shearing gear pins, you should read this.

If you are shearing pins in your Ford dizzy, it is MUCH more likely due to improper distributor thrust clearance than anything else in the world. Not likely thick oil, oil pump loading, etc. like many people seem to think, meaning that while lesser pumps or thinner oil may alleviate the problem, the culprit of the problem probably has not been addressed (but should be).

There is a distributor shaft end play spec of .020" and an installed clearance spec of less than .010" between the bottom of the dizzy gear and the block's dizzy gear thrust boss (the pad that the dizzy gear rides on once the distributor is installed). Few people understand Ford's reasoning behind the obscure specification and therefore dismiss it.

The reason for these spec is because as the distributor is turned by the cam gear, it is thrust downward against the dizzy's thrust boss in the block. If the shaft end play and boss clearance are out of spec (too much boss clearance/not enough end play), the dizzy gear does not ride on the boss but instead is floating in mid air all the while being thrust downward by the turning of the gear.

Eventually, the dizzy gear roll pin shears downward because the spec's were not set by properly measuring/installing the dizzy gear and/or shimming the underside of the dizzy gear to take up the slack between the boss and gear.

To say that the Ford engines randomly shear pins rotationally is a fallacy which is assumed by those that are not familiar with the detailed workings and necessary specifications of these engines. Their fix is usually to drill oversize and put in a bigger pin though the gear. :roll: The joke about such an approach is that this is a band-aid fix that may or may not end the pin shearing, because more than likely the root of the problem has not been corrected.

Here is a picture of the dizzy gear thrust boss in the block:
http://home.earthlink.net/~highflowdynamics/sitebuildercontent/sitebuilderpictures/dizgrjet9ba.jpg

If you look in the mirror's reflection in the above photo, you will see just the lightest wear (from the bottom of the dizzy gear) against the top of the boss. This is exactly how the wear pattern should look. If you have more wear, the block gets chewed up; if you have NO wear, the gear is floating and you are shearing pins. Paul




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Discussion Starter #11
Thanks for all the help and assistance. I am not shearing pins, the plugs are all clean and well intact, I do get a low voltage spark when puting a jumper on the distributor plug per MSD, I have plenty of power (11 volts) at the Ignition power wire, I think it was 560 Ohms at the distributor (within spec range), the distributor turns as it should, and all contacts in the ditributor look clean. I am at a loss, and with the fresh cam and lifters I think my only choice is to send the ignition into MSD for a check. I am always up to anymore good suggestions! Let's see if MSD customer service beats me down n this one!
 

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Thanks for all the help and assistance. I am not shearing pins, the plugs are all clean and well intact, I do get a low voltage spark when puting a jumper on the distributor plug per MSD, I have plenty of power (11 volts) at the Ignition power wire, I think it was 560 Ohms at the distributor (within spec range), the distributor turns as it should, and all contacts in the ditributor look clean. I am at a loss, and with the fresh cam and lifters I think my only choice is to send the ignition into MSD for a check. I am always up to anymore good suggestions! Let's see if MSD customer service beats me down n this one!
11 volts IS NOT plenty of power. Although it is enough to fire the motor, it way below what should be at the box. If you crank the motor over at 11 volts, the box is seeing way less than that while cranking. This is what blows the internal fuse in the box. You battery should read better than 12 cranking, and over 14 when running.



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Discussion Starter #13
11 volts IS NOT plenty of power. Although it is enough to fire the motor, it way below what should be at the box. If you crank the motor over at 11 volts, the box is seeing way less than that while cranking. This is what blows the internal fuse in the box. You battery should read better than 12 cranking, and over 14 when running.
MSD told me that I needed to read at least 8 volts on the ignition power wire going to the MSD box? That's why I figured 11 was plenty? I have a brand new Optima Battery turning this somewhat high compression motor over very easily. That 11 volts is what it reads while just siting there, not cranking it. Maybe the fuse in the box is blown because of this all. I am waiting on MSD now.
 
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