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I'm sure you already know this, just eliminating the scenario...since you mentioned GM...just confirming that you are aware that cylinder number 1 on a ford is right front and not left front like a GM...
I'm sure you already know this, just eliminating the scenario...since you mentioned GM...just confirming that you are aware that cylinder number 1 on a ford is right front and not left front like a GM...
In that case it must be something like dl suggested or you're simply not pointing it at the right wire.
Here’s a sanity check. I moved the distributor one cam gear notch counterclockwise from it’s original position when I reinstalled it. I kept the rotor pointing at #1. That shouldn’t affect timing, should it?
Mixed success today. I discovered this engine likes lots of initial. First I double checked (again) to be sure I was at TDC. Set the timing on the balancer at 12*, made sure the rotor was exactly on the #1 post, fired it off and checked timing: 45*. So I started retarding the distributor. As it was turned the idle speed fell from around 900 to around 750 at 12*. Throttling up from there it backfired around 2000 RPM. I increased initial to 14, then 16 and finally 18* to get a nice curve that’s all-in at 3000 RPM with 36*. Great! Except… when the vacuum advance is connected (ported) it will not run above an idle. It bogs terribly with any throttle input at all. That’s where I left it for tonight. My next plan of attack is to reduce initial a couple of degrees to see if that has any affect.
No clue whatsoever why my initial static 12* on the balancer turns into 45* with a light. There has to be a logical explanation.
It dont work that way. You cant set the pointer to 12 on the balancer and then line up the rotor to #1 and rely on that being accurate number to set your timing . That type of setting gets you close enough with some twisting of the dizzy to get it started. Then the only way to accurately set it would be the light. Your curve sounded ok with the initial set at the 12-16 range with light all in 36 at 3k.
Agreed. none of this makes sense . whatever your problem is it's not going to be adjusted out if your description of the events is being relayed properly. you have something screwed up.
I would check everything. voltage to the coil. firing order. try a different ECM. try a different light if it's a dial back. try everything whether is seems logical or not because it will probably be something you didn't suspect.
1. First I double checked (again) to be sure I was at TDC. Set the timing on the balancer at 12*, made sure the rotor was exactly on the #1 post, fired it off and checked timing: 45*.
2. So I started retarding the distributor. As it was turned the idle speed fell from around 900 to around 750 at 12*.
3. I increased initial to 14, then 16 and finally 18* to get a nice curve that’s all-in at 3000 RPM with 36*.
4. No clue whatsoever why my initial static 12* on the balancer turns into 45* with a light. There has to be a logical explanation.
With regard to point 1, two 18L limiters + an initial of +/-12* would = +/- 48*, IF the weights were fully opening at idle.
You already verified that the weights are not opening at idle, so 45* is incorrect (as you already know).
With regard to point 2, the drop in rpms as the dizzy is retarded is the correct behaviour, but it would not remain at a static 12*. The timing would be retarding !
With regard to point 3, if your initial was 18*, and the total was 36*, that would reflect a curve of 18*. Does two 18L limiters provide an 18* curve ?
Which brings us to point 4, and that sort of problem has been around since post 1.
Is the timing light connected to the HT lead closest to the t/stat, (I.E. HT lead number 1) ? (I assume yes from your comments with dlburch)
Is the connector on that HT lead facing the right way ?
If yes to those questions, then one has to question the accuracy of the actual timing light.
If you can borrow one that is known to be accurate, then borrow it.
If not, buy a new basic cheapish one, which doesn't have to be a dial back, and try it.
As far as I can tell, the only thing you did was remove the dizzy, change a few things, and reinstalled it.
So, assuming you put everything back together correctly, and didn't f$$k anything up, the only valid reason for the 'weird' observations is a faulty timing light.
It's the reluctor square on the pick-up that is the only true measure not the rotor pointed to #1.
Exactly. This is the illustration I saw to set the rotor, and centered the reluctor post closest to the rotor pointer (the post immediately to the left in this picture) to the pickup. Interestingly, as you can see the rotor and corresponding pick-up in the cap is offset from the reluctor pickup slightly.
With regard to point 1, two 18L limiters + an initial of +/-12* would = +/- 48*, IF the weights were fully opening at idle.
You already verified that the weights are not opening at idle, so 45* is incorrect (as you already know).
With regard to point 2, the drop in rpms as the dizzy is retarded is the correct behaviour, but it would not remain at a static 12*. The timing would be retarding ! - I get why idle speed drops, but it doesn’t seem right it will even cold-start at such a high measured initial (45) and so much retarding is needed from the starting point. I don’t understand your reference to static 12* and retarding.
With regard to point 3, if your initial was 18*, and the total was 36*, that would reflect a curve of 18*. Does two 18L limiters provide an 18* curve ? - Good point and on that’s been bothering me. From the little I think I know an 18L limiter should provide 36* total mechanical advance. So if that’s correct I should see all-in at 36* plus initial, in this case another 18, for a total of 54*? High.
Which brings us to point 4, and that sort of problem has been around since post 1.
Is the timing light connected to the HT lead closest to the t/stat, (I.E. HT lead number 1) ? (I assume yes from your comments with dlburch) -Positively yes
Is the connector on that HT lead facing the right way ? - I didn’t know there is a right or wrong way for the connector to face. Can you elaborate?
If yes to those questions, then one has to question the accuracy of the actual timing light.
If you can borrow one that is known to be accurate, then borrow it.
If not, buy a new basic cheapish one, which doesn't have to be a dial back, and try it.
As far as I can tell, the only thing you did was remove the dizzy, change a few things, and reinstalled it.
So, assuming you put everything back together correctly, and didn't f$$k anything up, the only valid reason for the 'weird' observations is a faulty timing light.
I hope it's as simple as that !
6 by 8, you bring up some interesting observations and questions. I responded to some of them in the body of your quote, above. I have another cheap non-dial back light. The thought my dial back might be bad hadn’t occurred to me. I’ll test one against the other. I can also check both lights against a known ignition system on another car.
I just used the soft springs and the little limiter bushing from the kit (was M-G kit, but I forget the part number) in the slot which limits total cintrifugal advance, then my advance is all in before 2,000. Since it's already advancing at high idle, I just set total advance at 35* above 2,000 or maybe 2,500 ... after it's no longer changing with increased revs. Lock it down, remove old fashion timing light, reconnect vaccum to canister. Done. I have no idea what "initial timing" is before the cintrifugal starts in. 351M, cam (like Summitt # 2162) at 0* now, Edelbrock P-400 intake and 1405 carb, I did add marks to H-B up to 45* in 5* increments with short scribe marks.
First I double checked (again) to be sure I was at TDC. Set the timing on the balancer at 12*, made sure the rotor was exactly on the #1 post, fired it off and checked timing: 45*. So I started retarding the distributor. As it was turned the idle speed fell from around 900 to around 750 at 12*.
When I read the above, I got the impression that you started at 12*, retarded the dizzy, observed a drop in rpms, and ended up still at 12*.
If you meant that you started at 45* and ended up at 12*, I understand, but I don't trust the 45* starting point.
LMAO @ ''From the little I think I know ''. ( I can totally relate. )
Yes, I would also expect 54* at idle.
On my basic timing light, in the block shaped section that slides over, and locks to, the HT lead, one of the rectangular surfaces has 'this side must face the plug' moulded into the surface, and that's what I mean by facing the right way.
I'm pleased that you have a second timing light and another engine to use to verify their accuracy.
When I read the above, I got the impression that you started at 12*, retarded the dizzy, observed a drop in rpms, and ended up still at 12*.
If you meant that you started at 45* and ended up at 12*, I understand, but I don't trust the 45* starting point.
LMAO @ ''From the little I think I know ''. ( I can totally relate. )
Yes, I would also expect 54* at idle.
On my basic timing light, in the block shaped section that slides over, and locks to, the HT lead, one of the rectangular surfaces has 'this side must face the plug' moulded into the surface, and that's what I mean by facing the right way.
I'm pleased that you have a second timing light and another engine to use to verify their accuracy.
I’m pretty sure you meant 54* all-in or total, not idle. Given that, and from what I recall from a couple places I’ve read, is to aim for 38-42 total on this engine (351/400M) but that seems low given the advance will give 36. Limit advance to provide ability for more initial? Suggested higher total? Comments?
I’ve never noticed anything on my timing light clamp. Interesting, I will look. And thanks for brainstorming with me.
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