It seems as if my advance isn't working on my distributor. Whether I check the timing with the vacuum hooked up or unhooked, the timing doesn't really seem to move at all no matter how high I rev the motor. If I remember correctly, on other cars it's always changed with the revs, isn't is supposed too? Last time I had the distributor out (4 months ago) I checked all the mechanical advances and they all seemed to move freely and I threw just a little lube on them just for insurance.

Is there anything I can do to fix this, or am I just better off going with a new Accel or Mallory distributor or something? This one is pretty old.....

-Brandon

 

could be that the vac advance canister on the distributor is no longer holding the vacuum.. that happens from time to time (i have gone through 2 of those and had the same problem you have) Although I am even very tempted to get a new accel or mallory disty.. just so everything is new and shiney and i know it should all work flawlessly.. working with a disty that is over 25 years old in my case is a PITA, especially since no one around me sells the mechanical advance weights/springs

 

I had that problem recently and it was the vac advance cannister. Replaced it and she runs like a dream now!!

 

The centrifugal advance mechanism should be advancing the timing when it revs, not the vacuum advance can.

 

So chances are it's the weights/springs inside. What could I do to fix this? I just checked those not too long ago and they seemed okay, but I guess they're not. A new Mallory unit is looking pretty tempting right now, and like someone else mentioned, it's probably gonna be hard to find parts for it.

 

i just bought a mallory dist. not to long ago, and it came cap, rotor, springs, and a 50K coil for $140! summit has the part # in wrong or something because they charged me the price of the no-coil one . call them and find out. you may be able to take advantage if they didnt realize their mistake yet

 

Not sure what I'm going to do. One question though, what's preferred, mechanical or vacuum advance? Also, how do I set the advance? It says adjustable, but where do I adjust it and how do I know when it's where it should be?

This is the distributor I was looking at is this one: JEGS High Performance - Mallory HEI Distributors

Good choice if I do choose to go new, or are there better, similiarly priced options?

 

Why wouldn't it be the vacuum canister? Is there anyway to test if it is or not? If the distributor won't work, then I really don't feel like dumping another $30 for a vacuum canister and then just end up getting the Mallory one anyways. But if just a vacuum canister will solve my problems, then I'm all for changing it out.

 

The vacuum canister moves the pickup coil around on the housing. It's possible for that surface to freeze up, from corrosion or the funk of the ages or whatever.

So, it DEFINITELY is possible, for the vacuum can to be "good", and the vac adv to still not work.

Of course, it's usually not too hard to unfreeze that, so even if it has that problem, the dist isn't necessarily toast.

Trafe-off: risk & extra work, vs extra money. You get to take your pick.

 

Part of his complaint though was that he gets no advance with increasing RPM. While the vacuum advance could be stuck, it sounds to me like there's a problem with the centrifugal advance too.

 

The centrifugal part has a similar situation; it moves the rotating star part around on the shaft, and it too can get frozen and gunked up.

Rust is a common cause of BOTH things getting stuck. The dist getting wet and then sitting around for a few months, would have that effect.

 

The car is run quite reguraly. It honestly seems like too much trouble and trial/error to try to find out what's wrong, and even then It's still not gonna be perfect. I think I'm just gonna go with that Mallory one I linked too. That look good to you guys? If there's one that'll give me better performance for a similair price please let me know.

 

Not really much trouble to find out what's wrong, just take the cap and rotor off and have a look. They're simple enough to clean up and rebuild, but if you don't feel like it then an aftermarket piece is a great way to go too, and not all that expensive, really.

 

What is it I'm supposed to look for though, and if I find this problem, how do I fix it?

 

Look for rust or corrosion or any kind of goo binding the mechanism up. The weights and springs should move freely, and you should be able to move the vacuum advance mechanism against its spring with some resistance.

There's pictures and more information on a more complete rebuild at Ignition 2 HEI

 

that was some good reading.. however. i have a question. as you are very knowledgable.. what could cause an irratic miss in the ignition? (ruled everything else out except the igntion) Would a bad reluctor cause it? I am going to try a cap and rotor tommorow to see if that helps.. they look ok.. but they are a litle old.. could to much initail timing cause it? and so on.. also it only seems to really miss bad once the car is at operating temp....

 

Could be plugs, wires, coil, cap, rotor, pickup, and/or ignition module.

 

That is a good read. Do you think I'll be able to do most of this with the distributor in the car though? I don't really wanna mess with it out of the car and then go through the hassle of putting it back in. I'll probably get to this tonight. If the centrifigul advance is sticking, what should I do about it? Should I free them up and put some silicone grease on them or what? On the vacuum I take it I half to replace it if I discover it's not working right?

 

if the vac advance is not working and you hvae a street driven motor it would probably be a good idea.. gas milage and unless you deal with the centrafugal stuff it probbly will be a little rough.

 

Allright, think I'll tackle this tonight, hopefully I can figure out what's up with this thing, not sure if I wanna dump anymore money into this distributor, however if I can narrow it down to the EXACT problem, and it's not too much to fix, then I have no problem doing that.

 

Well, I ended up finally doing this tonight. I pulled the cap, and the mechanical advance weights/springs, etc all seem to be perfect, no gunk or anything on them and moving freely. I didn't get to check the vacuum caniseter since the previous owner of the car stripped out a screw to get the hole canister/arm out, does anyone know a way to check it with the whole unit on the distributor? Or can I just narrow it down to being the vacuum advance?

Also, is it possible that maybe my adavnce is just coming on at idle and that's why it's not moving as I rev it?

For a way to make sure that the centrifigul advnace isn't working, could I simply uhook the dist from the carb, and then plug the vacuum canister, and then go to WOT, since that's when the centrifigul advance is working anyways? And if the timing moved like it should then could I assume that the centrifigul is fine? Or will that test/theory not work?

 

Whether the vacuum line is connected to the dizzy or not - the timing should advance way beyond the marks on the timing tab with acceleration (from the centrifigal/weighted/mechanical (whatever you want to call it) advance. At 2500rpms, you should see the mark way out there with a timing light- like 2 inches beyond the last mark on the timing tab (about what would be 36* if the tab went that far).

Just unplug the vacuum line, and plug the vacuum port on the carb (to ensure no vacuum leak) - no need to plug the vacuum can on the dizzy.

 

I've already done this and plugged the vacuum port on the carb, didn't work at all.

 

Well I bit the bullet and bought a new Mallory Distributor. Should be here Friday.