10L distributor swap (not a carburetor question!!!)

Since my other thread regarding the 10L swap was taken over by carburetor enthusiasts I figured I would let them have that thread and start another discussing the 10L swap...

What kind of benefits should I expect from swapping to 10L?

I would guess that if the advance curve starts earlier, I would essentially pick up some low RPM torque, which would help improve my takeoff with my stock convertor

 

Well, I got into the distributor and found that mine doesn't have 10L and 15L, but 18L and 13L and it is already set on 13L...

This is a fairly new distributor that I got from Autozone or similar about 3 years ago, and I am guessing that the newer one have different plates...

 

I apologize that your thread went south.
I hope you understand that I was called ignorant in your thread, not the other. Therefore defense of myself in the proper thread would have made no sense as the comment was not posted there.

Again, sorry.

I would like to hear details of this mod too.
You seem to know more than I do.
Where do I find the numbers in the distributor?
What do they mean?


Edit:
Fwiw, you can delete the other thread.
All you do is delete the first post, then the entire thread goes away.
This only works for the creator of the thread as he is the only one who can delete the first post.

 

I will delete the thread and those guys can revive the original carb thread or start their own to argue on. I am not upset about it, that stuff happens, but I don't want someone in the future to do a search on 10L and get that information that is not at all relevant.

If you take the plate out of the distributor that has points mounted to it, underneath you will find the advance weights and springs, and on each arm of the weight is the number...

 

From Derek5oComet. Only on-topic response from the thread I deleted.

 

Is this only for points distributors?
I have a stack of Ford distributors, all but one are DS.
The one points style is a 351c. That probably doesn't matter though as the shaft is the only difference on Ford distributors...

What I would like to build is a DS distributor with a single vacuum line canister, and adjustable canister at that.
Sounds like I could go a step further and use the plates.
So I will follow this thread with great interest.

Oops, forgot about the stock distributor in my Sprint.
It is points, but probably doesn't have anything performance about it.

 

This is a Duraspark distributor in the picture (I think). Mine had points but I swapped to Pertronix.

 

So what is your question concerning the 10L slot? The different size slots control how much total mechanical advance is in the distributor. 10L means there is 10* of distributor advance which equals 20* crankshaft advance. Each .013" of exposed slot from the post to the edge of the slot equals 1 crankshaft degree. If you need a little more advance you can grind the slot, if you need less advance you can put pieces of vacuum tubing over the post.

The slot does not affect when mechanical advance starts or how quick it reaches max advance, it only affects total degrees. You need play around with the spring tensions and spring posts to set the curve. Bending the spring attaching posts helps "fine tune" the spring tensions. I like to have advance start about 300 rpm above idle and reach max at about 2800 rpm. With my cam I run 18* initial so to get 34* total I need 16* in the distributor. My distributor has a 13L slot so I have a piece of vacuum tubing and a piece of heat shrink over the stop post to get what I need.

 

You can plot your timing curve by writting down the advance start rpm and recording the advance degrees in 500 rpm increments up until you reach max advance. I like the curve to be more or less linear from start to finish. Of course, all of this is done with any vacuum advance disconnected and plugged.

 

Okay, so now you confused me with this comment. (not too hard to do)

So do you figure this in distributor degrees, or crank degrees?

 

Oh, I thought that this is what it was doing...starting the curve earlier (beginning to advance at a lower rpm).

I will try to do a "curve" today.

Is there some place where I can find a list of "optimal" curve and degrees that my setup needs?

I would like to find out what initial and final degrees I need and when it should start to advance. Is there a list or is it just "what feels right" and found out by tuning at the track?

 

I did it kinda backwards, it was easier for me to adjust the engine speed using the idle adjustment, and watch the timing marks at 5* increments.

700rpm (idle) approx 14*
1400 - 20*
1600 - 25*
2000 - 30*
final reading was 32 degrees and hit it at 2500 rpm. Wouldn't go any higher than that with more rpms.

With the advance hose hooked up it went all the way up to 48-50* total timing.

Any suggestions based on these numbers?

I am not very knowledgeable about timing, but it seems like it is kicking in nice and early, and maybe has too much total timing...

 

32° total is about right. Maybe a little more like 34°-36° max. Initial advance should be about as far as you can get it without pinging, especially if you have a cam that bleeds off a little low end power. It may be a good idea to "phase" the rotor when you're done. Take an old dist. cap, drill a 1/2" hole in the top of it between the coil wire terminal and one of the plug wire terimals. Hook up a timing light to that cylinder's plug wire and start it up...watch to see where the rotor is in relation to when the spark occurs. Sometimes you have to bend the vacuum advance actuator rod a little to get the rotor to line up with the terminal. Ideally you'd want it to be perfectly lined up. I did this on my Mustang when I had it, and it did make a noticeable difference. But, then again, I did it on all 8 cylinders. Had 8 holes in the cap and I bent the reluctor tabs rather than just bending the advance arm. Took forever to get it all right, but it did make a difference. You'd be surprised how far out of phase it was.....

But you're on the right track with what you're doing now. You don't necessarily need the vacuum advance hooked up but if your engine runs a little better and is more responsive with it attatched, then use it. I always had problems with them & took them off completely.

 

I have run it without the hose and it ran fine, but runs much better with it. Also, I ran it for a while before I swapped the heads with the hose going into the other port on the front of the carb that pulls vacuum all the time, ran even better then, but had 36 advanced at idle...

Not sure how that would work with this little "stronger" setup.

 

The distributor (and cam) spins at half the crank speed, each cylinder fires one time for every two crank rotations (4-cycle engine).

Timing is always expressed in crankshaft degrees.