I have a eletronic ign. dist. out of a 1980 Cordoba that I plan on using in my 60 Val and I disassembled it today to figure out what needs to be done to get my timing at 32 degrees.This is what I found;

vacumn can marked 11R--- this means 22 degrees advance,right?

mech.advance plate was marked 9R--this means 18 degrees mech. advance right?

one light spring and one heavy spring

From what I have read here all this means that if I set my initial advance to 10btdc which will give me 28 degrees total advance+22 degrees vac advance=50 degrees overall advance.
Also from what Ive learned here ,I really need to have 30 to 32 dgrees total advance which means that I need to elongate the mech. advance slots........am I on the right track???
What I need to know is about how much should I open the slots or is this pure trial and error stuff?I just dont want to cut to much from the slot.
I also remember reading here that the total timing needs to be all in at about 2000 to 2200 rpm ,for this I plan on replacing the heavy spring wth a lighter spring out of another dist.
Do you think I am on the right track or am I about FUBAR SOMTHING??
Any suggestions would be greatly appreciated,thanks in advance(no pun intended).
HyperValiant

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1960 Hyper-Pac Valiant(rolling test-bed)
1963 Valiant V2OO(Son's summer project,- he just turned 15 )
1972 Valiant 4dr(Daughter Kelly's repair in progress)
1974 Valiant (v8) daughter Kelly's work in progress

You are correct.

Cecil and I have posted a couple times with either pics or specs on what to 'do'.

You'll have to grind a smidge out of the slots. The MP distributor has an 11R governor in it and all the remanfs are 9R, and remanfs for small and big blocks seem to have 13R in them. Been trying to find a source where we just buy a set of 11R's so the performance minded just have to swap a spring and a governor and all is well...


You'll need to whittle the slot open a bit with a small die grinder rasp. So far the best recipe for 'in at 2300' has been pull the large spring and grab the medium (sometimes 'blue' painted) spring out of a small/big block distributor. (I'm also trying to find a source for these springs too, then maybe I can 'cobble' some MP clones together for our group, for the 'plug and play' crowd...)

If it all goes well you can go 10 initial, 22 mechanical (in by 2300), and have the vacuum pod yard in another 22 (or you can also buy a new one that's only a '10' for 20...)...

Each build is a bit different, and as you change the timing you will also have to change your carburation/check the plugs too...my recurve currently varies between 5 and 8 BTDC initial depending on how bad the gas is here in Salem, if I get a good batch of Super I can run 10BTDC with no problems...

-D.Idiot

Where are you deriving that 11R = 22, etc? Is this distributor degrees versus crank degrees? Not saying you are wrong, I just want to know where this info comes from. I have always assumed that "11R" would indicate 11 deg advance, right hand (as opposed to "L" for left), but I must admit, I have never verified that.

My technique with all motors has always been to set for total timing and pretty much go with where the initial falls, unless the car exhibits poor behavior off idle and at low RPM, in which case I will swap to a point cam/reluctor shaft (or modify) with longer or shorter slots, depending on the situation. Once I set the total, if I experience a surge or ping at high speed/high vacuum, I adjust the tension and/or epoxy shim(s) under the shoulder of the arm on the advance diaphragm until it is just satisfactory with max advance.

The springs are another matter. On mostly stock applications, I leave them alone, but I am still sorting out the advance curve on my Duster. I will keep in mind your advice, above. I sure do wish I had a distributor machine! It's a bitch removing the distributor, changing springs, reinstalling, checking etc. Pure hit or miss.

D/W

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If it ain't broke, fix it!

You have the same distributor I had from the factory in my 1980 Aspen. Your distributor has 18 degrees mechanical and your vacuum advance has 22 degrees, as you have said. This is what I would do:

Use the distributor the way it is. The only modification I would do is to quicken the mechanical advance using a lighter spring(s). Set your initial timing to 10 - 12 degrees. The vacuum advance unit should be adjustable. Using the correct allen key, turn the adjusting screw in the vacuum port fully counterclockwise. This will give you the slowest advance. Drive the car and gradually adjust the screw to bring the vacuum advance in quicker. Too much advance here will give you preignition at part throttle and cruise.

I am currently using a modified distributor I built that gives 14 degrees mechanical and 16 degrees vacuum. To get this, I welded up part of the advance slots. Using more initial timing with less mechanical advance gives you improved low speed and part throttle performance.

There have been others who have posted detailed outlines on how to do this. Doug Dutra has written a 'how to' article on this.

Mitch

My advice is to leave it right where it is and try it first. Ask most of the racers and they'll tell you that 30 deg is even on the high side for full timing advance. I run my street/strip motors around 26-30 for best performance, and you can easily tolerate 10-14 deg at idle, especially with a hotter cam.

The 11 deg vac advance canister is nice for hwy mileage too.

Lou

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Home of Slant6-powered fun machines since 1988

Not to steal this topic but, what I'd like to know is what is the final at what the totasl timing is and at what rpm? i.e. ??*@???rpm

DI, once again,thanks for a insightful and educational reply

Dennis,my info on the 9=18 actually came from this board ,maybe some with more experience than myself could shed more light on this.

Lou and Mitch,I think I will try the dist stock right now only with the afformentioned lighter spring and if I need more I know how to get it.

Im sure that the 170 hyper-pac will time a little different than a 225 but I was just trying to ballpark it somwhat for the initial start up and break in.

Thanks again everyone.
HyperValiant

I got dispatched back to employment today, so DusterIdiot's infamous quick reply network only works after 8pm....

Anyhow,
I'm pretty tired, but in a nutshell Dennis has got the goods...cam companies have 'cheat sheets' on some of their profiles and they even print on them crank degrees divided by 2 = cam degrees....

And I can agree on being tired of running the mill up to TDC then swapping in a new distributor and retiming things, checking the specs via tach, vacuum pump, and dial back timing light, then taking a test drive and going hmmm...

Also hypervaliant, none of this is all set in stone, timing changes and carb/mixture changes go hand in hand, you'll tweak one then have to dial the other back in, your mill may like something that other build won't.

What I ended up doing was starting my build with a remanf distributor with the 18 advance and it did ok and got ok mileage, I then bought a second one to modify, and make changes to (that way I wasn't 'stuck' for a bad change). I spent a few afternoons changing springs and vacuum pods, I eventually opened up the slots in the mod distributor a bit, timed it, ran it, repeated the proceedure until I was happy with what I got out of it on the street...at the drags this will be a bit different.... Gratefully I had lots of time to do this, but I'm sure the $150 on the local performance shop's Sun machine would've been cheaper.


Luckily a few months back I got to get my hands on one of the MP distributors (Thanks, 66DART), since he was having some bad mileage and idle stability issues, pulled it apart to swap in one spring and got to record the contents for future builders since the price on these no longer offered peices has skyrocketed....

Good post guys, lots of info here.

more later,

-D.Idiot

Hey Mitch, just an FYI to compare your curve to say the Feather Duster curve here are the specs (Thanks CRAlt), from a Feb. 23 1976 TSB

P/N 3874795 (I have two of these distributors and the specs are right on)

All in 'distributor degrees':

Centrifugal- 1.5 to 3.5 @ 650rpm
3.5 to 5.5 @ 2300rpm

Vacuum - 2.0 to 7.0 @ 7"
9.0 to 12.0 @ 8.5"

Per the sticker on the car, Initial timing set at 12BTDC....

Whoops, I missed the part about it being a 170. You will definitely need a different curve than a 225, but can start with what you have.

Lou

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Home of Slant6-powered fun machines since 1988

I was milling this problem around.... Heavier weights would make the advance come in sooner if lighter springs are hard to find. Weights never wear out, and are easier to modify/duplicate than springs.

If there's no room for a bigger/heavier weight, the spring mount could be moved closer to the fulcrum. A 'blank' oversize could be cast, and holes drilled to lighten it as necessary. I'm surprised we can't easily find kit's with different springs and weights, with advance curves being so important, but there's no reason we can't make our own.

I'm no expert. I've barely looked at the inside of my distributor, so don't be afraid to tell me I'm dreaming.

I have a whole plastic tote, full of stripped distributors. The funny part is the weights are the same from 60's+ in the slant six ones, and oddly some small and big block distributors had the same casting number on their weights too... Drilling a wiehgt and adding metal would add the weight, it's pretty tight in there.

With springs, the only kits available assume you're going out for strictly drag and only provide the lightest springs you'll ever see...if you put one of those in and remove the heavy spring from a distributor you get full advance at 1200, put two springs in from those kits and it all comes in at 800....

FYI,

-D.Idiot

It is sad that "recurve kits" are no longer available, years ago, Crane had a pretty nice one which included an adjustable vacuum pod and some different springs. (and decent instructions)
http://www.dutra.org/doug/draft-webpage ... ibutor.htm

Note: the mounting posts for the advance springs are adjustable to allow for some fine tuning. The early distributors had tabs that you would bend, the later units had a post with an eccentric base, rotating the post moved it "in & out".

My work with SL6 distributor "curves" show that you should use a primary and a secondary spring, the secondary spring has a loop on one end.
The trick is to have a light primary spring that starts bringing-in advance right off idle, say at 1000 RPM and gives you 10-12 degrees pretty fast, by 1800-2000 RPM. At that point the second spring start working and slows down the rate for the next 8-10 degrees.
DD

Instructions, what a concept!!!

I still have some ideas for mods, but I'm feeling much more prepared to tune that preignition knock out without getting crazy.

If only very light springs are available, then drill holes until the weights are matched to the lighter springs, right? The closer the hole is to the fulcrum, the less effect it will have, so start far away and work closer for your fine adjustments.

I feel like I'm explaining things you racers already have worked out, so I'll stop. Thanks for the link!, Very helpful.

Literally they are paper thin.. you'd have to remove a lot of weight before those became as effective as the medium versions...

-D.Idiot

Next time you're at a Schuck's/ Kragen's, they might have Mr. Gasket set for the chevy HEI on their 'performance' section (along with all the neon convolute tubing, etc..). It's about $3.50 for a package... the chevy kit is the same as the mopar kit, but they give you different instructions inside...

I got a new distributor for my /6 at eBay for $42.90 or something. Is a complete unit, 8.5 vacuum unit, primary and secondary springs (the secondary is the weakest of the strong ones I've ever saw). Brand new unit, (repro, but nice quality) the only thing it was missing was... ... the rubber seals anyway, the axis has the eccentric round screw holder (not tabs) Hope to be of any help at all.