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Distributor questions
https://slantsix.org/forum/viewtopic.php?t=15663		 Page 1 of 2
Author:  Reed [ Fri Jan 06, 2006 8:23 pm ]
Post subject:  Distributor questions
I am going to bite the bullet and dump the lean burn computer on my van.

In preparation I have been assembling a new ignition system form spare pats in the garge.

I have a good condition distributor and I was wondering if anyone could tell me what its original application was, and hopefully some advice about its advance curve and how it will work in a van.

The part number on the tag is 3874876.

It has 10R stamped on the vacuum pod arm.

It has small slots on the governor.


It has one small green spring and one heavy spring.

I tried searching for past posts about distributor re-curving but there have been so many that it is alot of material to sort through. Whatever happened to the plans for a tech article?
Author:  Reed [ Sat Jan 07, 2006 11:11 pm ]
Post subject: 
No one can tell me where this dist. came from originally?
Author:  Eric W [ Sat Jan 07, 2006 11:32 pm ]
Post subject: 
Don't know Reed. If you search for my comments on recurving my distributer it might help you out since you have a heavy vehicle also. If I remember right I used a light yellow spring (heavier than the green) and a thick spring with a tighter loop that goes around the post on the weight. It has a 9.5 governor...can't remember the number on the vacuum pod, probably a 10 like yours. I adjusted it for the vacuum to come on a little later (3/32nd allan wrench, turned counter-clockwise). Timing set to 5* (of course, it will be different for your hydraulic lifter engine). This set up gives good acceleration and really good high speed driving . I surprised myself the other day when I got it up to 90 passing a cluster of semi trucks and moron drivers on the express lanes. Gas milage isn't great (around 18mpg), but its a small engine moving alot of weight around.
Author:  Reed [ Sun Jan 08, 2006 8:24 am ]
Post subject: 
Hey, 18 sounds better than 12! If I could get this van to 65 I would be happy.

I guess I will just make the switch and start fiddling with it.

Thanks for the response Eric!
Author:  Slant6Ram [ Sun Jan 08, 2006 11:22 am ]
Post subject: 
This is my posting from Sept 17 when I took an entire day to compile some distributor info. I've been very distracted from this forum since then due to job changes, but I haven't forgotten. Hopefully, this will help renew some interest from other members. I can't do it all by myself.
Quote:
It's been a long time in the making, but I had another board member hound me about dist curving today, and I finally put together the first 16 pages! today.

I really need some clear photos of distributor internals. Can you help with that in any way? even links to other peoples photos would be nice, but I can't seem to find much of anything. I can't use copy written materials without permission, so keep that in mind.

I already know it's too long and badly organized, but if you have any other comments, I'll try to add them in or correct them.

http://www.potentialtech.com/pmoran/dist-9-22-05.pdf

Thanks,
Paul
The short answer is exactly as Eric offered. It will work for a start, but you might have to retard it from the 'factory' idle setting to stay out of ping with your heavy van.

I suggest you install it, connect up a dial back timing light and set the total advance to around 30* at about 3000 rpm. Take note of where this sets the initial timing in case want to fool around in the future.

Next, drive it around without the vacuum advance. Try 2nd gear up a big hill and listen for ping. If it pings, retard the timing by just a few degrees and try again. Repeat until ping is gone.

Now hook up the vacuum advance. Go find the same big hill and see what happens. If it pings now, don't adjust the timing. Use the allen wrench to adjust the vacuum pod as Eric mentioned.

Once you've got the vacuum pod out of ping, drive it around for a week and see if you get acceptable mileage and performance. Keep us informed and then you can deceide if you want to build a custom distrubutor curve. Good luck.
Author:  Valianator [ Sun Jan 08, 2006 12:23 pm ]
Post subject: 
Great article, /6Ram. I saved it, and printed out a copy for further study in the "reading room" :D .
Author:  Reed [ Sun Jan 08, 2006 12:44 pm ]
Post subject: 
WoW! Good article! I scanned it as I was printing it out and I will efinitely be reading it more in depth.

This morning I went and took a look at the governor and it has a 9 stamped in it. A few years ago I bought a NOS Crane Cams distributor re-curve kit for a big-block Mopar distributor. I bought it just fr the springs in it. The kit included instructions which were generic for slant sixes to hemis, so I followed the recommendation and used the "orange" spring for heavy vehicles. This spring looks like the stock "heavy" spring but it has a longer loop on one end. I'll try that for starters.

So right now the distributor has a 9 governor, a 10 vacuum can, the stock "light" spring, and the Crane Cams recommended spring for heavy vehicles (trucks, vans). I will try running this setup first and dial in from there. The Crane kit also had several other springs so I will be able to play around a bit.

If anyone is intereted I would be happy to post pictures of the internals of this distributor and the differences in the springs.

I don't have a dial-back timing gun but I am bidding on on on e-bay right now. I am also going to install a tach, vacuum guage, and air/fuel meter since my van has the factory 02 sensor.

The next step for me is to take the plunge and rip out the Spark Control computer and feedback carb. I am waiting for some parts to get her ein the mail ad then I am going to just swap straight to a BBD Super Six setup at the same time. The ignition system will be interesting- HEI control, recurved distributor, and an old Mallory Magspark coil.
Author:  DusterIdiot [ Sun Jan 08, 2006 1:42 pm ]
Post subject:  Dist..
Quote:
3874876
That's a stock super six distributor from 1978...

If you have a 9R gov. and a 10 vac. can...leave the springs as is, and see how it does, it should be OK up to 12BTDC initial...but being a heavy vehicle you may want to start with less initial and figure out what it likes, and you may have to swap in a heavier spring to slow the advance a bit.

Getting all the accessories listed will help dial it in better, hope you get a good price on the timing light Harbor Freight has an OK one for less $$$.

-D.idiot
Author:  Reed [ Sun Jan 08, 2006 1:52 pm ]
Post subject: 
Right now the timing light is listed for $5 with $6 sipping to me. My max bid is $14, so I won't pay more than $20 if I win. If it goes over $20 I am going to Harbor Freight.

A stock Super Six dist eh? Thats cool. I don't even remember where this distributor came from. The only 78 Super Six car I have ever owned was my very first car ever- my safety purple Volare station wagon. I will swap back to the factory spring then and try that for starters.

I can't wait to do this swap. It should be fun! I know that 5300+ pounds is quite a bit for a little slant six to push around, but it does have 3.54 rear axle gears and I will be switching to a BBD so it should at least perform better. Thanks for the help and tips guys!
Author:  Reed [ Wed Jan 11, 2006 10:12 am ]
Post subject: 
8) I got a dial back timing light for $14 including shipping. :D 8) now to scrounge for the cheapest guages and mounting pod I can find...
Author:  Eric W [ Wed Jan 11, 2006 12:17 pm ]
Post subject: 
Sounds like a good deal Reed. I got my Sun dial back from a pawn shop for 25 bucks after my Craftsman light went south.....great tuning tools.
Author:  Slant6Ram [ Sat Jan 14, 2006 2:45 pm ]
Post subject:  Making it better
Yes, I would like clear pictures of distributor internals and I will add them into the document.

As for the dial back timing light, I figured out a little trick a while back and I will share it here for everyone.

Start by aligning the crank so that the timing mark is right at the top dead center on the timing tab. Now, turn the crank counter clockwise so that the timing mark is at 10 BTDC (before top dead center). Scratch a mark on the damper with a screwdriver or use a paint marker to mark the current 0 position. turn the new 0 mark to 10 BTDC and make 1 more mark at the current 0.

This will give you 20 extra degrees of reading so you can more accurately gauge your advance. Instead of 1 mark, you will have 3 which are each 10 degrees apart. When reading your new marks, should understand that when the second extra mark is aligned with 10 Btdc, the total timing would be 30 degrees advanced. This is a great improvement because most slant sixes only have 10 or 20 degree marks on the timing tab which makes it very difficult to check total timing without a dial back light.

I'd like to take some pictures to better illustrate, but I think this is clear enough to be useful to many of you. I've got all of my dampers marked in this way and it's much easier than fumbling with the dial and I can easily make due with any cheap strobe light. :idea:
Author:  Reed [ Sat Jan 14, 2006 3:47 pm ]
Post subject: 
I agree. I will take pictures of the distributor before I install it and show all the various parts. I also plan on marking the damper out 30 degrees. A little extra tip on marking the damper is to put a 1, a 2, and a 3 next to the marks so you can quickly tell 10, 20, and 30 degrees advance.


Also, if I understand the literature regarding slant six preferred timing and the measurements of the components, with a 9 governor, and a 10 vacuum pod, to achieve 32 degrees total timing I need to set my base timing to 12 degrees BTDC, right? 18 crank degrees mechanical advance, and 20 crank degrees vacuum advance, that should work out to 12 BTDC right?
Author:  Slant6Ram [ Sun Jan 22, 2006 11:42 am ]
Post subject:  Yep but there's more
Quote:
Also, if I understand the literature regarding slant six preferred timing and the measurements of the components, with a 9 governor, and a 10 vacuum pod, to achieve 32 degrees total timing I need to set my base timing to 12 degrees BTDC, right? 18 crank degrees mechanical advance, and 20 crank degrees vacuum advance, that should work out to 12 BTDC right?
Yes, your final answer is correct, but you didn't figure it out by the right method.

In regard to vacuum advance, you don't need to think about vacuum advance while calculating your initial timing and total timing.

total timing = total mechanical advance + initial timing.

In your case, you have correctly doubled the governor number for 18 crank degrees of mechanical. Using an ideal total timing number of 30, you subtract to get a suggested initial setting of 12 BTDC. The vacuum pod is not considered in this calculation. Some vehicles will dial in with slightly higher or lower optimal total timing numbers. I suspect that as much as 4 degrees in either direction based on suggestions from many forum members. You'll have to use some trial and error.

Only during light load and part throttle operation does the vacuum pod take effect for greater economy. Because optimal advance might be greater or less than 30 degrees depending on engine load and rpm. This is the part of tuning a new curve that gets rather complex. With mechanical + total + initail you might want 22 degrees at 2000 rpm under a heavy load but 38 degrees at same rpm on a down hill grade with a tail wind. Getting it all dialed in will require vacuum pod adjustment and carburator adjustment in my experience as you get closer to the perfect tune.

The first step is getting a good initial and total timing with the vacuum pod disconnected and getting the springs right so that the engine performs strong and without ping. Later, you should connect the vac pod and start adjusting or replacing the pod for improved mileage without adding ping back into the mix. You can't really tune the mechanical and vacuum curves at the same time. :idea:

Here is the final 'curve ball' for all you slanters searching for the nirvana that comes with a perfect recurve. The day after you've spent all summer tuning it in, it will get cold and rain and you'll get a particurally bad tank of gas. Now that the planets have aligned differently, your perfect curve could ping and sputter! That's why chrysler went to computers.
Author:  Reed [ Sun Jan 22, 2006 12:09 pm ]
Post subject:  Re: Yep but there's more
Quote:
Here is the final 'curve ball' for all you slanters searching for the nirvana that comes with a perfect recurve. The day after you've spent all summer tuning it in, it will get cold and rain and you'll get a particurally bad tank of gas. Now that the planets have aligned differently, your perfect curve could ping and sputter! That's why chrysler went to computers.

Ah, sounds like it might be worth it (if you are really anal and/or bored) to set up a "Summer" and "Winter" distributor to deal with climate and gas formulation changes.
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