Mallory Comp S/S Dist Help

[1969GTS340]

Hey guys I just finished breaking in my 340 drag dedicated build and I'm trying to dial in the advance timing with a Mallory distributor. This model has two springs that are enterchangable for a desired curve and keys (which are basically plastic feeler gages) to mechanically set the total advance. My only experience with distributors dates back to setting points gap and dwell, so this is all new to me.

In the pictures below are the instructions and the distributor. Seems pretty straight forward but I don't know how to remove the reluctor and other parts to gain access to the springs and advance plate adjustment.

I'd appreciate some help with how to disassemble this correctl y. Thanks in advance

 

[HSDemon]

Your going to have to use a small gear puller to pull the center reluctor out of the distributor to gain access to the advance mechanism. Do not try to pry the reluctor out with a screwdriver, you will damage the advance mechanism and the bearings on the distributor. I am not sure if you can just use a punch and push the pin out of the reluctor and let it fall inside the distributor, and then remove the reluctor, no idea if there is enough room for the pin to go down deep enough, a puller would be much safer on the distributor.

 

[Ironracer]

@halifaxhops

 

[1969GTS340]

Your going to have to use a small gear puller to pull the center reluctor out of the distributor to gain access to the advance mechanism. Do not try to pry the reluctor out with a screwdriver, you will damage the advance mechanism and the bearings on the distributor. I am not sure if you can just use a punch and push the pin out of the reluctor and let it fall inside the distributor, and then remove the reluctor, no idea if there is enough room for the pin to go down deep enough, a puller would be much safer on the distributor.

Thank you for confirming my suspician. I was hoping the process wasn't going intale minor surgery lol. I just watched a video that TrailBeast posted that demonstrates the disassembly. It looks like something that I hope to nail the first-time avoid having to take it apart repeatedly to get the right set up.

 

[RustyRatRod]

Use a flat blade screwdriver under each opposite side of the reluctor and simply pry it off. Very simple. You will want to mark it though, so that you can reinstall it exactly as it is. Also be very careful and don't lose that roll pin.

 

[Rat Bastid]

As Rusty said, use a screw driver. I use so and they come right off.

Don’t trust the curves Mallory published. Or anything MSD published either. There is too much tolerance stacking to trust that stuff. Verify what you have. It’s better (easier) on a distributor machine but you can do it with a timing light.

Also, the all in by 2500 (or less) is most likely wrong for you application. That’s because it’s wrong for most every application.

FYI

 

[halifaxhops]

@halifaxhops

You do not pull the reluctor. Great disyributor by the wat, Mopar Peformance actually cloned that design for a few years.
OK here we go
Use the two screwdrives as stated above thn take he pick up plate out.
There are two hex head screws you loosen a bit do not take them out! and then you use that larger hole to put the key into to set it. Turn the shaft do the other side which should be close. Then re tighten the screws. Really easy but hard to explain. Hope it helps.

 

[1969GTS340]

You do not pull the reluctor. Great disyributor by the wat, Mopar Peformance actually cloned that design for a few years.
OK here we go
Use the two screwdrives as stated above thn take he pick up plate out.
There are two hex head screws you loosen a bit do not take them out! and then you use that larger hole to put the key into to set it. Turn the shaft do the other side which should be close. Then re tighten the screws. Really easy but hard to explain. Hope it helps.

Sounds clear and simple to me now. Thank you.

I'm expecting to see the current setting off the chart. When i set my initial at 10* my total jumped to 60* around 3500. From what i have read, my target should be in the 32 to 36 range. What is your opinion on that?

By the way, Thanks to FABO I got a great deal on this distributor still in the box. I matched it up to a Mallory HyFire VI with programmable 2 step.

 

[halifaxhops]

So thats 50ish total mechanical, prob the slots are wide open. They usually are set up for drag racing out of the box. Re set it and go fom there. 35-38 sounnds like what your engine wants. Use that chart they included with the keys to set the advance rate up. Remember no vacuum advance.

 

[1969GTS340]

So thats 50ish total mechanical, prob the slots are wide open. They usually are set up for drag racing out of the box. Re set it and go fom there. 35-38 sounnds like what your engine wants. Use that chart they included with the keys to set the advance rate up. Remember no vacuum advance.

This is strictly a drag car and I was not only surprised to see that much advance, but that the engine responded well with it too. Just seems a little.much and don't want to damage anything.

 

[halifaxhops]

Drag car? Anything else I should know. Have any idea what is aftermarket in the motor? Cam etc?
High 40's low 50's might be where it wants. Now to get the spring rate right. Did it ping at all when it was high RPM?

 

[1969GTS340]

Drag car? Anything else I should know. Have any idea what is aftermarket in the motor? Cam etc?

I built it myself so I do have data. Nothing too crazy.

1971 340 block, factory forged crank and rods balanced. +.060 KB hyp. pistons. Oregon cam grinders 572/569 252/258 @50. 104*, EQ Magnum heads reworked by Hughes. Crane 1.6 roller rockers. Air Gap with Holley 750 DPDF. Hooker super comp headers. 727 Cheetah valve body and 4500 converter. 4:88 on a spool.

 

[halifaxhops]

Can you change the springs out to say the medium curve Mallory has in the instructions?

 

[1969GTS340]

I could. There are a number of spring/curve examples. Two stage, single stage matched springs and Single stage paired springs. Which would you suggest?

 

[1969GTS340]

I removed the reluctor and pick up. There are two hex screws that appear to be holding the pick up wires in place. I only loosened them and moved the wires to see if the slit you referenced was there, and no. PIC 1.
I then removed those two screws and the "C" clip that held in the cover for vacuum advance. This Leaves a plate that turns but isn't lifting out. PIC 2. Is there any special way to remove it? It turns but seems stuck when trying to lift it out.

 

[halifaxhops]

Usually they have a hole in that plate to adjust them. Take that out you should have acess to the advance then. Honestly I have never seen that Mallory

 

[1969GTS340]

I found two additional set screws on the side of the housing that ride inside of a groove of the plate. After backing these out the plate comes out easy and the springs and mechanical adjust are there.

 

[crackedback]

Drag car with that camshaft, I'd lock it out.

If you MUST have a curve, I'd go somewhere in the 22*-26 Initial and 10-16 mechanical advance depending on what the engine will tolerate and provide best MPH.. As long as the all in number is below the converter stall, you should be good to go. As long as it cranks OK with the 22-26 advance run it and dial in total.


I was going to mention the lock screw on outside for cover plate, one by the edge of your hand in first picture (right side).

Nice going on diving into this. Ignition/distributor advance has always been one of the voodoo things with most hobbyist.

 

[1969GTS340]

With the help from you guys, you made.me look like I knew what I was doing lol.
There were a lot of curve choices but I went with the middle.of the road (2 Grey springs) which I felt would have around 10* initial and 34 all in. I chose this because she cranks hard when. The initial is 12 and up.

I just reassembled everything and has happy to see it start right away. Adjusted the timing to 12* at idle But she still wantrd more when I gave it gas. I kept advancing until I heard the response and rpms sound good and the advance looked like 38-40*. When it returned to idle the initial was 14-15*. After a cool down she turned over slow but started. It looks like I'm not quite there yet. But to answere the lock out idea, I don't think she would start with 34*

Another note, the mechanical advance keys o ly for up to 28* Based on my gut more than experience, I think it needs more like 45plus with initial around 10 for easy starting. Not sure if I can achieve that combination.

 

[halifaxhops]

I was thinking the earlier? Mallory style. I do not think you can get even near 40 if it has the same advance plate.

 

[Rat Bastid]

With the help from you guys, you made.me look like I knew what I was doing lol.
There were a lot of curve choices but I went with the middle.of the road (2 Grey springs) which I felt would have around 10* initial and 34 all in. I chose this because she cranks hard when. The initial is 12 and up.

I just reassembled everything and has happy to see it start right away. Adjusted the timing to 12* at idle But she still wantrd more when I gave it gas. I kept advancing until I heard the response and rpms sound good and the advance looked like 38-40*. When it returned to idle the initial was 14-15*. After a cool down she turned over slow but started. It looks like I'm not quite there yet. But to answere the lock out idea, I don't think she would start with 34*

Another note, the mechanical advance keys o ly for up to 28* Based on my gut more than experience, I think it needs more like 45plus with initial around 10 for easy starting. Not sure if I can achieve that combination.

They will start with 35 on them. It’s not a Chevy.

If it was me I’d set it up so you had 28 initial and 8 mechanical. Or better yet (if you can get it) 30 initial and don’t be afraid to let it go as high as 40 at your highest RPM.

But that takes some heavy springs and I don’t know if the Mallory springs will do that.

They want a curve and the advance should gain with RPM. There may be some gains in using a high speed retard when you drop into high gear and then slope the advance back in. That takes a ton of testing but I can make some ET and MPH.

 

[1969GTS340]

I can certainly try setting the initial at 30 and set the advance at 40. It just seems to crank harder with a higher initial and not start easily or at all. When I first installed the distributor I set initial at 10 and it started easily. The advance was hitting the 60* mark. Now the initial is at 10 and i adjusted the mechanical at 24 (34 total). I also changed the spring to get there sooner. By ear and minimal experience I'd say it's not as smooth or responsive as the original setting. Maybe I shouldn't have made both changes at once? With that said, is it recommended to dial in a desired intail and advance first, then make curve spring adjustments?

 

[Rat Bastid]

I can certainly try setting the initial at 30 and set the advance at 40. It just seems to crank harder with a higher initial and not start easily or at all. When I first installed the distributor I set initial at 10 and it started easily. The advance was hitting the 60* mark. Now the initial is at 10 and i adjusted the mechanical at 24 (34 total). I also changed the spring to get there sooner. By ear and minimal experience I'd say it's not as smooth or responsive as the original setting. Maybe I shouldn't have made both changes at once? With that said, is it recommended to dial in a desired intail and advance first, then make curve spring adjustments?

Yes. Get your initial set and then deal with the springs.

In his engine book, Jenkins covered timing curves. I agree that the curve should always gain advance with RPM. I always thought is was strange he was using points for so long when “better” stuff hit the market.

Then I learned about slew rates and then it made sense. He was using points so he didn’t have to deal with timing retard from an ignition box. When the box starts retarding the timing (and they all do) you have to figure for that unless you want some high RPM retard.

The issue is no two boxes start to retard at the same RPM and no two boxes retard the same amount.

So you have to account for that if you are running anything other than points.

 

[Rat Bastid]

I should add my mentor told me a great story about timing retard and timing lights.

He had a shop with two other guys and they were tuning up a Modified Eliminator car for a local guy. This is when the first CD boxes hit the market.

So they get this guy a box and hook it up. He takes the car to the track and it’s a couple of tenths slow. So he brings the car back and says WTF? Why did it slow down?? So my mentor (who didn’t do the original tune up, he did just the carb) grabs HIS a timing light and the timing is off. By about 4 degrees. So he sets the timing where it should be and sends it.

And the car is still slow. So it’s back in the shop and the third guy grabs his light and guess what?? The timing is off. Again. So he corrects the timing (he thinks he is but that wasn’t THE issue, but it was AN issue) and says who was the idiot who sent this thing out with the wrong timing?

So the finger pointing starts and it gets pretty heated. Then they came to their senses and realized that none of them were idiots. There had to be an answer.

They all grabbed their timing lights and hooked them up. All three lights said something different!!! So no one set the timing “wrong”. It was a matter of all three lights showing different numbers. And that’s because all three lights had a different SLEW RATE!!!

Because the timing light is an electronic device it will have a slew rate. That’s just the way it is. That’s why you should always use the same light when timing your engine or you can get in the weeds right quick if you borrow a light and they read differently.

So that cleared up the different timing issues, but the car was still slow. Someone had the light go off in their head that if the timing lights could have different slew rates, maybe the box had an issue with slew rate and the timing was changed.

They got the car on a chassis dyno and drew straws to see which one of them was going to sit on the fender while they made a pull to watch the timing.

My mentor drew the short straw. They were stunned when the box was retarding something like 8 degrees at 8k. And it was starting to retard at something like 4500.

Once they found that, he recurved the distributor to deal with the RPM retard of the box and it went out and went much quicker than it did with points.

The moral of the story is that all engines like a curve. All ignition boxes have a slew rate. And none of them are the same. If you don’t know how much retard you have you have no way of knowing what your exact timing is.

And, all timing lights have a slew rate. Use the same light every time of you can get lost right quick.

 

[1969GTS340]

That's both interesting and frustrating to hear lol. It's amazing how many variables need to be taken into account and that does answere a question why I thought I had the initial set with my middle of the road light and my buddy came over with his that had dial in advance feature and displayed different timing. All in all it sounds like I won't know the exact timing but I'll have a standard reference if I use the same light, that's hopefully consistent.