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Distributor drive question


521dad71

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Hi!  I am new here.  i hope you can help me.  I have a 71 521 with a L16.  I had it running a while back just enough to get it in and out of the garage. Recently when i went to check the timing with my light, I could not even see the timing marks.  I looked at the distributor to find the hold down bolt was completely out of the adjustment area. I found top dead center on #1 and removed the distributor. I have read many forums here with timing issues. From what i gather, #1 should be closest to the front of the truck but my #1 is towards the back of the truck.  I also read that the distributor drive should be at 11 and 25 but mine seems to be at 1 and 35.  How do I fix this situation so I can set the timing and adjust the carb? Any help would be appreciated.  Thanks

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Are you sure you are on the compression stroke? There are two TDC positions on a 4 stroke engine.

 

The position of the rotor really does not matter as long as you have enough adjustment to set the timing to 12 degrees... or whatever the L16 is for that year.  The 11:28 position is where it was set at the factory and handy for telling others how to set up their distributor.  Just a way of having everyone on the same page. Again..... as long as you can set timing it doesn't matter where the rotor points... THAT is number one..

 

Someone may have had this engine apart and the distributor drive spindle was put in a different position than the factory is all.

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Are you sure you are on the compression stroke? There are two TDC positions on a 4 stroke engine.

 

The position of the rotor really does not matter as long as you have enough adjustment to set the timing to 12 degrees... or whatever the L16 is for that year.  The 11:28 position is where it was set at the factory and handy for telling others how to set up their distributor.  Just a way of having everyone on the same page. Again..... as long as you can set timing it doesn't matter where the rotor points... THAT is number one..

 

Someone may have had this engine apart and the distributor drive spindle was put in a different position than the factory is all.

 

You have a PM.

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There are 2 adjustments on the dizzy like Banzai noted. One up top that is a 10mm wrench and one underneath (it goes up toward you) that is 8mm. Between those two you get a lot of adjustment. If it isn't enough rotate the sparkplug wires. I believe the rotor spins counterclockwise so rotating the wires 1 prong/plug clockwise will advance your timing and if you went 1 prong/plug counterclockwise it will retard your timing. It is a 4 cylinder engine so rotating the wires will advance or retard by 90º. If you or the previous owner had installed the spindle correctly during engine build/oil pump replacement then the plugs might be orientated the way you're reading. I know I don't do it properly because I don't want to dick around with fishing a spindle up through the front cover trying to mesh it with gears. Then again, I'm a lazy piece of shit so what do I know?

 

The only time not doing it correctly really becomes a major problem is when you end up right in between adjustment. You can't retard it enough with the 2 adjustment points but if you rotate the wires all of a sudden you're too far retarded and can't advance enough. Obviously this becomes less of a problem with a 6cyl dizzy where rotating the wires is 60º rather than 90º and with a V8 it's 45º for each rotation. The direct and improper solution would be to cut out the slots on the bottom plate (one with the 8mm) so you can rotate it as much as you want and then use a washer or a stepped washer that's actually meant to be used as a hold down and tighten the 8mm down so the washer grips. You could do that for the top 10mm adjustment but even I, the laziest of lazy, want that little adjustment plate on the dizzy that shows how advance or retarded you are, to be relatively accurate; meaning if I cut the hold down slot out on the 10mm sure I can twist the dizzy around all I want but that adjustment plate will be way off.

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By the time you have messed around with enlarging the adjustment slot, getting a special washer, and being able to almost get the timing close, you could have dropped the oil pump, and spindle, and put the spindle back in where you need it.

 

There are 20 teeth on the spindle.  Moving the spindle one tooth advances or retards the distributor cap rotor 18 Degrees, two teeth is 36 degrees and three teeth is 54 degrees.  Since the distributor fires every 90 degrees, moving the spindle 54 degrees is more than half way to the next plug wire tower on the distributor cap.

 

There is a dot on the side of the spindle gear, and an arrow mark on the oil pump.  Put the engine at TDC, number one, align the dot on the spindle with the arrow mark, and put the oil pump with the spindle on the engine.  That should make every thing line up.  You only need one bolt to hold the oil pump temporarily.  Put the distributor on the engine and check rotor position, and timing adjustment.  If good, put the other three bolts in the oil pump.  If not good, mark what way the rotor needs to go, drop the oil pump, and turn the spindle that way.  Remember, you have 18, 36 or 54 degrees to move the spindle.

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Hi!  I am new here.  i hope you can help me.  I have a 71 521 with a L16.  I had it running a while back just enough to get it in and out of the garage. Recently when i went to check the timing with my light, I could not even see the timing marks.  I looked at the distributor to find the hold down bolt was completely out of the adjustment area. I found top dead center on #1 and removed the distributor. I have read many forums here with timing issues. From what i gather, #1 should be closest to the front of the truck but my #1 is towards the back of the truck.  I also read that the distributor drive should be at 11 and 25 but mine seems to be at 1 and 35.  How do I fix this situation so I can set the timing and adjust the carb? Any help would be appreciated.  Thanks

 

 

Well it runs so can't be too far out.

 

Don't know how TDC was set if he couldn't find the timing marks.... Right??? What method used and how accurate was it? Just looking at cam lobes??

 

Doesn't really matter too much where the rotor points right now. This could simply be an adjustment as he hasn't said what his timing is because he couldn't find the marks. Maybe looking on wrong side.  Keep in mind that it runs... can't be out too damn far.

 

Then........... never comes back.

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By the time you have messed around with enlarging the adjustment slot, getting a special washer, and being able to almost get the timing close, you could have dropped the oil pump, and spindle, and put the spindle back in where you need it.

 

There are 20 teeth on the spindle.  Moving the spindle one tooth advances or retards the distributor cap rotor 18 Degrees, two teeth is 36 degrees and three teeth is 54 degrees.  Since the distributor fires every 90 degrees, moving the spindle 54 degrees is more than half way to the next plug wire tower on the distributor cap.

 

There is a dot on the side of the spindle gear, and an arrow mark on the oil pump.  Put the engine at TDC, number one, align the dot on the spindle with the arrow mark, and put the oil pump with the spindle on the engine.  That should make every thing line up.  You only need one bolt to hold the oil pump temporarily.  Put the distributor on the engine and check rotor position, and timing adjustment.  If good, put the other three bolts in the oil pump.  If not good, mark what way the rotor needs to go, drop the oil pump, and turn the spindle that way.  Remember, you have 18, 36 or 54 degrees to move the spindle.

 

 

 

 

Thanks for the help. I did exactly as you suggested. I finally got it running and timed correctly. The distributor drive was way off. I could not get the rotor to point directly at an electrode and with the way someone had jerry rigged the distributor with a big washer and had both adjustments maxed out to barely get it to run. I finally figured out how to take the oil pump off and reset the drive. After watching a video on youtube that explained where the oil pump was and how to remove it. I had to stab it three of four times but I finally got it.  I first set both adjustment bolts on the distributor to the middle and just kept making adjustments to the drive until it pointed directly to the original #1position as you suggested.  It was very far advanced so all timing marks were out of sight when the timing light was used. The timing gear is also on the third adjustment but all timing marks such as the V mark and small black mark on the head was alligned as per timing specs.  Someone has been thru this before with all the scribe marks and punch marks on the timing gear. The timing marks were not hard to find once it was half way in time. They are on the passenger side of the engine where the freaking pointer is.  SO evidently it does matter where the rotor points and NOT just any where if you can't adjust the distributor far enough to even get close to proper timing.     I will start today trying to get the 32/36 weber adjusted. I messed with all the adjustment screws thinking it was a carburetor issue originally causing the poor performance.  I will back everything out again to some place close to the original and start over again.  I think it will go much smoother with the new carb adjustment this time.  I bet the timing issue was the reason it was in the junk yard to start with.    Ill get a photo account set up so I can share pictures ASAP.  Thanks Daniel C your the man

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