Thread: Swapped Distributor problems

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I've searched around the forums, but have yet to find anything that really answers my questions so here is my specific problem.

I have a 1964 Chevy C10 which has a 1978 350 Small Block in it. When the 350 was installed a lot of the old equipment off of the 283 went along for the ride including the distributor.

This weekend I went to change out the old points system with a new electronic one (Pentronix Flamethrower II). I bought the entire distributor assembled and with the matching coil, rahter than a conversion kit as all the old parts were well worn. I made the swap and the motor is running, but not well. It will idle fine, but on acceleration it misses and it doesn't run well when timed anywhere between 6 and 12 degrees.


Here's what I did:

Wwhen I removed the old distributor I lined up my timing marks on the balancer to 6 degrees BTDC (what the motor was timed at. I removed the old cap and the rotor was pointed just before the #1 plug. (Actually pointed directly at the notch on the distributor cap where it lines up with the housing to seat properly.)

My first question is: Does the notch on the distributor cap always designate which plug contact is suppossed to be #1 or does it matter which wire you plug into as #1 as long as you have your firing order set properly? If it matters then I know what I did wrong

I ask this because that notch was on the front of the old distributor and about 3 or 4 plugs down on the new distributor. If that is the case then I know my problem becuase I ignored the notch and just lined up my rotor with the first contact to the front of the distributor. And that's basically what I did. The distributor dropped in and seated without a problem. Engine cranked fine, but the timing was WAY off. The timing mark was all the way on the other side from where the marks are. I rotated it back to 6 degrees and it idled fine, but runs like crap. Tried everything between 6 and 16 degrees and it does not run well. If it's low in gear and you go to accelarate it will pop and jump and it just has a knock to it like a plug is fouled (althought they are not).

Where did I go wrong and what is the best way to make this right. If I return the motor to TDC start my plug wires with #1 being at the notch on the cap and set my rotor to point to that contact and follow firing order will this rememdy my issues?

All help is greatly appreciated in advance...

Sounds like you may have it set at #6 TDC instead of #1. Don't worry about the notch. Pull the cap off the distributor. Take the #1 spark plug out. Rotate the engine by hand until you feel the compression push your finger off the hole. Line up the pointer with the timing mark. Put the cap loosely back on the distributor. Make a mark on the distributor housing at the #1 terminal. Remove the cap. Rotate the housing until the rotor points directly at that mark. Snug the retainer bolt lightly so the the distributor won't move on its own, but you can still rotate it by hand. Put the cap back on. Wire the spark plugs 18436572 clockwise.

Did you re-do the wiring when you put in the new system?

Some of the old points systems started on 12 volts but ran on 6 volts ( this can be dtected by a wire running to the start side of the starter solinoid) And Maybe the Pertronics needs a constant 12 volts....If it's like this it will do exactly what you say...sufficient spark for idle but not much more...

Simple fix is to run a new 12volt wire from the ignition circuit

GM used a ballast resistor (little white porcelian block) and they used resistor wire to step down the voltage....might want to check that out....I would be sure the new distributor requires a full 12 volts and it's not getting it....

buddychiefguy, if you've got your timimg light hooked to #1 wire and you can see 10 degrees at the timing mark then you're in time, unless the mark has slipped, but you should be able to move the dist around a little one way or the other to see if the motor clears up. you need to find out about the 12 volts going to the dist. like dr_bowtie said, could be something to that, but other wise if you're on #1 wire and you setting it at 10 degrees then you can forget about the time and look for something else wrong. it dont make no dif. where #1 wire is in the cap, as long as you know where its at, and wire your motor from there.

Happy to hear about the #1 being anywhere I want on the cap. I got into a long debate over this and thought I was right, by putting it wherever I wanted

Ok, so I am timing my motor properly, sensor coming off of the #1 plug and it is at 10 degrees as we speak, so that should do it for timing the motor right?

The wiring from the starter had been redone recently. As for the voltage coming into the coil it is 12 volts steady at idle. I just hooked my volt meter to the top of the positive coil contact. That should give me the accurate reading of volts coming to the distributor, right?

So at this point I feel like yanking the distributor returning cylinder 1 to TDC and giving it another go. Should I do this, or would it be an excercise in futility since the engine is coming in timed at 10 degress and somewhat running. Should I look for other problems? I just can't understand why when I pulled the old distributor and installed the new one just about in the same rotor position as the old and it came out about 20-30 degrees off and it ran fine at idle through that whole curve of adjusting it back down to 10 degrees.

Oh and as far as testing the timing out. The motor idles fine anywhere from 6 degrees to 25 degrees. I tested 6 degrees and when you take off it is really sluggish and knocks. At 15 it starts to miss on accelartion. At 8 it is a little of both. Weird. I think I'm going to pull all the wires and plugs just to triple check there is not a problem there, although I have done this before.

Being straight out of the box, I put faith in the distributor being set properly. That is another thing to check, I suppose.

Ok, so I am timing my motor properly, sensor coming off of the #1 plug and it is at 10 degrees as we speak, so that should do it for timing the motor right?


if you have the light hooked to #1 wire and the light is showing 10 gegrees then you dist. is right. make sure the plug wires are in the right order then the dist. shoud be in time. sounds like you might have some plug wires crossed. sometimes at idle its hard to tell its missing.

To answer your specific question wich I see no one else did. Yes it matters what your #1 is designated. #1 has to be at #1 #1 on the cap is at the notch. If you have it there and still runs poorly then you are of a couple of teeth when you set the distributor. Probly have the timing retarded a little pick up your dist. and move it cunterclockwise looking at the motor. If that dont do it move it clockwise a couple of teeth.

Originally posted by Gary Brown
To answer your specific question wich I see no one else did. Yes it matters what your #1 is designated. #1 has to be at #1 #1 on the cap is at the notch. If you have it there and still runs poorly then you are of a couple of teeth when you set the distributor. Probly have the timing retarded a little pick up your dist. and move it cunterclockwise looking at the motor. If that dont do it move it clockwise a couple of teeth.

if you can set the timing with the light, then the dist cant be off. it dont make no dif. where #1 is in the cap if you wire it from there.

Yes it matters where the number one plug lead is on the cap,,,because of the amount of rotation of the distributor while adjusting advancing or retarding will be affected,,usualy if you have it wrong your vaccume advance unit will prevent rotation of the distributor on some motors when it hits the intake.
Do this:
When you align your rotor with the #1 on the cap and hold it there,,,,then make sure you have got your #1 cylinder at TDC,or just a couple of degrees before.,,then install your distributor,,,,,sometimes it may help to hold the rotor slightly anticlockwise to #1 and as you install the distributor,, the rotor ( if everything is in alignment ) will want to turn clockwise to the #1 position.
thats when you know you've got it right........that is of course if your timing chain is installed correctly.
And dont forget to disconnect the vaccume advance line while using the timing light,,,and then connect it when you have finished.

(You said: Here's what I did:

Wwhen I removed the old distributor I lined up my timing marks on the balancer to 6 degrees BTDC (what the motor was timed at. I removed the old cap and the rotor was pointed just before the #1 plug. (Actually pointed directly at the notch on the distributor cap where it lines up with the housing to seat properly.)

My first question is: Does the notch on the distributor cap always designate which plug contact is suppossed to be #1 or does it matter which wire you plug into as #1 as long as you have your firing order set properly? If it matters then I know what I did wrong )

I would do as another suggested and CHECK to make sure you have FULL 12 volt to the dist. not going through a ballast resistor. I just did what you did and changed over a motor from a 305 to a 350 and changed all the parts over and the truck missed and ran badly. I ordered a new dist that is in the garage know. The truck is new to me and I found the alternator was nto wired correctly and not charging and as w worked on the new motor the voltage dropped and the truck was missing and I thought we had a bad spark. ordered the dist. When I fixed the alt problem the voltage went up to near 14 volt and the truck is not missing any longer. Do as the other fellow said run dist to bat 12 volt source with a good wire size 12 or bigger wire. Ed ke6bnl

Thunderbucket you need to read the post before speaking. i said if you could set the timing with a light then it didnt make no dif. where #1 wire was. then you come along and says

lt1 quote if you can set the timing with the light, then the dist cant be off. it dont make no dif. where #1 is in the cap if you wire it from there

Thunderbucket quote " Yes it matters where the number one plug lead is on the cap,,,because of the amount of rotation of the distributor while adjusting advancing or retarding will be affected,,usualy if you have it wrong your vaccume advance unit will prevent rotation of the distributor on some motors when it hits the intake."

if something prevents the rotation of the dist. then you wouldnt be able to set the timing, so i still say it dont make no dif. where #1 wire is in the cap as long as you can set the timing.

If you read 'Buddychiefguy's' post, it sounds like he dropped his distributor in while losing his reference point on the distributor body ( usualy indicates where to start from ) and now it sounds like he has the timing 180* out,,,he can get it running but cant adjust the distributor enough to get it to run well,,,which is usualy because the vaccume advance module will prevent further rotation.
If he had the distributor in correctly, then the #1 on the cap when mounted (on the notch,) would align with his rotor.

It is good practice to scratch a mark on the distributor shaft casing and the hole in the casting,,,that will give a reference point to start from,,,and once this is done most of the distributor caps will have a mark signifying #1 leed position.
all things being equal,,,as you install the distributor at the scribed mark, and when the motor is just shy of TDC, the rotor will point to the #1 position.
And yes you are right,,,IF,,,,,,he could get it on the propper degree mark with a timing light, he would already have the rotor in alignment with the number 1 leed.

buddychiefguy quote- Oh and as far as testing the timing out. The motor idles fine anywhere from 6 degrees to 25 degrees. I tested 6 degrees and when you take off it is really sluggish and knocks. At 15 it starts to miss on accelartion. At 8 it is a little of both. Weird.

Thunderbucket quote - If you read 'Buddychiefguy's' post, it sounds like he dropped his distributor in while losing his reference point on the distributor body ( usualy indicates where to start from ) and now it sounds like he has the timing 180* out,,,he can get it running but cant adjust the distributor enough to get it to run well,,,which is usualy because the vaccume advance module will prevent further rotation.
If he had the distributor in correctly, then the #1 on the cap when mounted (on the notch,) would align with his rotor.
And yes you are right,,,IF,,,,,,he could get it on the propper degree mark with a timing light, he would already have the rotor in alignment with the number 1 leed.

LT1- i read his post and it he was using a timing light to check the dif. degree settings. i don't know how much more room he needs. so im gonna say it again, if you can set the timing with the timing light(i would think the right timing should be somewhere between 6 and 25 degrees) it dont make no dif. where #1 is in the cap.

One more time,,,and i quote,,,,,, "The distributor dropped in and seated without a problem. Engine cranked fine, but the timing was WAY off. The timing mark was all the way on the other side from where the marks are. I rotated it back to 6 degrees and it idled fine, but runs like crap. Tried everything between 6 and 16 degrees and it does not run well. If it's low in gear and you go to accelarate it will pop and jump and it just has a knock to it like a plug is fouled (althought they are not).