ignition timing ?

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DART66GT

DART66GT

62 Lancer GT - B Body 8 3/4
FABO Gold Member
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Hi everyone - I rebuilt my distributor with new springs,vac. can and 13 degree mechanical advance. When I set my initial to 0 deg. then run up my rpms to 2100 I show 35 deg. on my dialback timing light. When I set the initial to 10 deg. I show 45 deg. at 2100. I checked the balancer and it is off by only 1 degree. I checked the length of the slots and they are exactly the length they should be for 13 degrees. everything moves freely and all this is with the vacuum advance off and the carb plugged. Shouldn't I be getting 26 deg. with initial at 0? Thanks........
 
You should be but the question is why not? What length are the slots? I'm assuming it's a factory dist. If not correct me please. I just did the same thing to an extra factory dist. I have but due to surgery haven't been able to get it installed yet to test it. According to the chart I have your slots should be .445 long to give you 13 degrees of mechanical advance at the dist. which is 26 crank degrees.
 
That is the measurement I used (.445)and they were on within one thousanth. I don't know what else could cause this. Any help I could get would be greatly appreciated...Thanks....
 
DART66GT said:
That is the measurement I used (.445)and they were on within one thousanth. I don't know what else could cause this. Any help I could get would be greatly appreciated...Thanks....
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Wow that's odd. I'm sorry but I don't know what to say since my experience is limited. Hopefully next week I'll be able to get mine in and test it and I'll let you know how it turns out so we can compare things.

Maybe Chief is right. Was everything good and tight or kinda sloppy?
 
I rebuilt my slant six dist. the same way and it ran fine. 26 Degrees exactly. The Dist. is real tight its from a 32,000 mile motor it looks and feels like new.
 
I just read on another sight that if youre wires to th pickup coil are reversed it could make it look like you have 10 - 15 degrees more timing than you actually have. Has anyone ever heard this. If so would this be true with my HEI?
 
No that's not possible at all. The pickup in not polarized. The only that I can think of that would affect the ammount of centrifugal advance is the slot length and slop in the dist.
 
Damn, it sure would be nice to have a Sun distributor machine to diagnose this. I wish I had the money back in the day when they closed our school auto shop.
 
ramcharger said:
Damn, it sure would be nice to have a Sun distributor machine to diagnose this. I wish I had the money back in the day when they closed our school auto shop.
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Wouldn't it though. Back when I was a kid a guy down the street from me had one and wanted $150 for it. I couldn't afford that and If I remember right about a year later his roof started leaking on it and he didn't do anything with it but let it set and rust up then finally through it in the scrap. What a shame.
 
fishy68 said:
Wouldn't it though. Back when I was a kid a guy down the street from me had one and wanted $150 for it. I couldn't afford that and If I remember right about a year later his roof started leaking on it and he didn't do anything with it but let it set and rust up then finally through it in the scrap. What a shame.
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IIRC, they only wanted a $100, but you could buy a running car for $100 back then, lol!

Back to the subject at hand, I think it's possible to install the reluctor 180 off. I may be wrong on this, but I'm pretty sure it's only supposed to go in one way.
 
I know what you mean Joe about the price. Back then If I had a $150 I would have felt rich.

It is possible to install the reluctor wrong since there is 2 slots in it but it shouldn't affect the timing advance. It will affect the phasing though. The one I just did isn't really in phase good on either of the slots I tried it on. Their's a multi slot reluctor on E-bay to correctly phase your dist. but I haven't been able to twist my arm enough to shell out $40 bucks for it.
 
I can't comment on the accuracy of the number you used and the amount of advance it would give you but the one time I modified a stock distributor I didn't bother with a measurement.

I removed the point/pickup plate, then glued a 39 cent protractor to an old rotor so the center of the protractor was centered over the center of distributor shaft hole. I put the rotor/protractor combo on the distributor with a wire taped to the housing to use as a pointer and advanced the distributor to 1/2 the number of degrees I wanted on the crank (distributor degrees are 1/2 crank because the distributor rotates at 1/2 speed) and skribbed a line. I then welded the slots to that point and fine tuned it by measuring with the protractor to where I wanted it with a file.

When I put the distributor back in the engine and measured the timing on the timing tape it was dead on.
 
Just bumping this up to see if anyone had any new thoughts. I disassembled the dist. again and checked everything everything seems good. Hooked it up and the same problem. with timing set at 0 and advanced plugged. when I rev the engine I get 37 degrees of total with only a 13 degree mechanical advance. I even removed the vac. advance completely. Still 37 degrees. Im using a dial back from craftsman could it be off? I tried my friends standard light and they seemed about the same at 0. Im running 10 btdc now and the engine runs good 17.5 inches vacuum at 750 rpm. But it is not real responsive. With the vacuum advance hooked up I get over 65 degrees that is what worry's me. When Im set at 10 deg. btdc initial my total is around 48 deg. with no vac. advance. any thoughts I hope this wasn't to confusing. (I am using HEI). By the way this is a 75 318 stock with oerformer manifold and 4 barrel.
 
Did you actually lock the vac advance plate or is it loose? I think the vac advance plate may be adding the extra.
 
I did not lock the plate while the can was out. Didnt think of it. But when I put the vac. can back in I had the exact same reading.
 
I'm sorry to confuse you. As long as the vac advance arm and hookup are still there it should be o.k. if you have it plugged. In my case I completely removed the vacuum advance assembly.
 
I just had one other thought. When you welded up the slots to .445" was that the total length of the slots in the cam without the weight pins sticking through or did you have things assembled and .445 is how far the weight pins can travel?

Hopefully that question is at least a little clearer than mud!! If not I can take some pics of mine and post what I'm saying with pics.

I never did get around to installing mine. Seems like one thing then another happens and throws me off.
 
I didn't weld mine. I found a factory 13 degree arm. And I measured the slot itself without the pins in it.
 
A 13 degree stamped arm gives you 26 degrees of advance measured at the crank. You would only need another 5 degrees in the distributor to get to the 37 number you are seeing with the timing light.

I would try the protractor trick I mentioned earlier and measure the actual advance in the distributor. If you are mixing and matching parts from different distributors there could very well be some other changes that would make the "13" stamp on the arm invalid.

BTW, if I undeterstand you correctly you have a stock 318 and the only thing you have done is add a 4bbl. If that is the case why are you messing with the advance? There would be no reason to change the amount of advance in the distributor, just put in some lighter springs.
 
The motor really runs good on 8-10 degrees of advance. I was hoping with the 26 degrees of mechanical and the 8-10 of initial to be approx. 36 deg. total. At least that is what the plan was. It does have lighter Ford springs its all in by 2200 right now
 
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