302 Prestolite Distributor

[bianchija]

Can anyone educate me as to how I would check the mechanical advancement of the distributor. I was told to check the springs and weights, but I'm not sure how and I don't want to ruin things while teaching myself. Is it an easy process? Thanks for the help.

 

[achris]

Re: 302 Prestolite Distributor

Easiest way to test is to run the engine and use a timing light to see the advance, then check against the advance curve in the service manual. If you need a copy of the curve I can e-mail it to you.

 

[bianchija]

Re: 302 Prestolite Distributor

I could really use a service manual. Thanks for the help. I'm worried it's not advancing properly. One thing I found last night is that there is only 7.8 volts of power going into the coil and 5.2 coming out to the distributor. If I pull the power line from the ballast off the coil it reads 12 volts, so I'm not sure why it's dropping. Is that normal?

 

[achris]

Re: 302 Prestolite Distributor

The 7.8 volts going into the coil is correct. They have a 'resistance wire' on the battery side of the coil. Not sure what you mean by "coming out of the distributor". Why do you think the timing is not advancing?

 

[bianchija]

Re: 302 Prestolite Distributor

If your looking at the distributor there are two terminals, one on the right and one on the left. The one on the right is connected to the ballast resistor and reads 7.8 volts. The one on the left, which appears to go two places, one of which is the distributor has a voltage of 5.2 while the key is in start position, and 4.8 volts while running in idle. The reason I'm worried about the timing is that I set it the other day and it hasn't held that setting. It seems to be advanced and I'm not sure if it's the mechanical advancement in the distributor or something else. Someone told me to throw a new distributor in there, but they're $250 and he was speculating. I wanted to verify that it wasn't working correctly before I spent the money. Since then I have run into the issue with the coil and am hoping that's my problem.

 

[achris]

Re: 302 Prestolite Distributor

Hi Joe,<br /><br />Sorry about the delay in getting back to you. Had a bit of a think overnight and it occurs to me that you may have a broken spring or sticky weight in the distributor. Since it's a Ford engine and the dissy is mounted up front it shouldn't require the removal of the dissy to check the weights and springs, just remove the wire going to the points, then remove the 2 screws holding the breaker plate down and lift it out. Check for free movement and that it returns fully to the 'rest' position. <br /><br />Let us know how you go.<br /><br />Chris........<br /><br />Chris

 

[Boatin Bob]

Re: 302 Prestolite Distributor

If your looking at the distributor there are two terminals, one on the right and one on the left

Joe....I'm assuming you mean the coil and not distributor?<br />Is this an OMC or Merc? You could have up to 5 wires (not including the high tension) on the coil, on the plus side 1 resistor wire, live while key is "on", 1 from ignition switch, live while key is "start". On the negative side, 1 from points, 1 from ESA or interupt switch and 1 going to tach. As Chris said, take out points plate and check springs and weights for broken or seized up, you can grab the rotor and turn it a bit the opposite way to see the plates move and then the springs pull it back together.

 

[bianchija]

Re: 302 Prestolite Distributor

I checked the springs and weights and they all seem to be moving freely. I cleaned them, but then made what appears to be a mistake. The guy at the local marine store told me to put an electronic ignition in after I pulled the points. I went ahead and had problems. Looking at other forums I have learned that this is a problem if you have and ESA module, which I do. I bought the parts from Radioshack to build the circuit for fixing it but I haven't had the time to put it together. I hoping to do this tonight.<br /><br />Also, in response to Bob, I have an OMC. There were three wires on the coil. One from the resistor on the + terminal, and two on the - terminal, which are connected to the breaker and to the ESA module. <br /><br />If there is still no luck with the electronic ignition I am planning on putting the points breaker back in.<br /><br />Any thoughts?

 

[Boatin Bob]

Re: 302 Prestolite Distributor

Joe....I'm surprised you only have 1 wire on the positive, the wiring diagram clearly shows 2. Are you doing this because of hard starting? There should be another wire to give it the full 12v while starting.