kalli

i have advance mhooked to manifold vacuum from day 1 I have that 302. the engine builder had it that way so i asked and everyone agreed that this seems a better idea.
However I had to retard intial idle back to 8 degrees (vacuum disconnected and plugged). it was low on power and jerky and jittery when cruising. especially in cruis when throttle position didn't change.
I'll check if the balancer is correct (slip?) next time. i still have a feeling I should retard a bit more. Unfortunately I'm deaf to engine pinging for some weird reason so I can't go by that. but that 8 degrees was a lot of fun to drive. still lacking a bit of power (should be quicker). so i'll keep looking

kalli

8 was a lot better than 14. can anyone tell me where "real timing" should be when the vacuum as plugged to advance? I'll measure tonight, but I have a feeling that even with the 8 degrees I'm a bit early. I'll check with a piston stop to make sure the timing marks are actually correct

scootchu

Bringing back an April thread to ask where you finally wound up with this tuning.
It's like chasing your tail isn't it?

kalli

heheheee :-) it's still crap. The piston stop verified TDC

currently:
-----------------
8 degrees initial
16 deg max by vacuum advance hooked to ported vacuum
26 deg max by mechanical advance (adding to 34 at 3400)
the mechanical advance doesn't kick in until 1500 rpm. used 2 medium springs
-----------------

you can imagine it's far from good.

My problems are:
1. can't adjust the vacuum advance (pertronix II flamethrower billet distr). Contacted pertronix, no reply yet.

2. Can't find the packet with the original springs and flaps for holding the centrifugal advance. so I can't mess around really.

What I would love to do (at least try) is:
- have initial at 14
- vacuum advance reduced to 12 or even 10 max
- manifold pickup for vacuum
- keep both medium springs in advance but use flaps to reduce to 20 max advance of centrifugal.

So I now have 2 options:
- get a new adjustkit for the pertronix, but that won't solve my vacuum advance problem
- install the Mallory distributor that came with the engine.
It would have a CD box and rev limiter, but would put my Rally Pac out of action (at least until I get a rpm converter for that).

Since getting the ignition right is more important I'm going to change over to the Mallory I have next week ...

scootchu

In my thread I posted that I have a way I can limit the maximum vacuum with a mechanical stop placed on the breaker plate.
https://mustangforums.com/forum/clas...and-wow-3.html
It's in the ballpark of what you are shooting for. Don't know if I like it or not.

tx65coupe

I agree with hooking up the advance to the manifold vacuum.

Kali,

I have a very similar setup to yours as well as the same distributor with Edelbrock 650 AVS and I have the vacuum advance connected to the manifold vacuum port on the driver side of the Edelbrock carb instead of the ported vacuum on the passenger side.

The timing is set at 15 BTDC and I think mine runs nearly perfect.

My engine builder recommended this setup.

kalli

my engine builder had it the same way. he said time initial to 14, hook to manifold vacuum. job done.
But since I have another distributor in there my car will idle at 31 degrees ... (as the vacuum pulls already 16).
That causes my car to jitter a lot when I'm driving at very low revs (in idle downhill, just off idle uphill...)

So for the fun of it I'll just set to 14 again, plug the advance and see how she goes.
If it's running good at WOT, i might just try to restrict the vacuum
If all that doesn't work the Mallory will go in, which will hapopen sooner or later anyway. I'm just too lazy to hook up the box and coil and whatever cablecrap is with it ...

Kalli

kalli

hmm .. was home during lunch and hooked it up to manifold vacuum, with idle at 14 (total at idle 28).
changed one of the medium springs back to heavier and no complaints since. sounds better at part throttle and drives better. WOT is still lacking power but that might be A/F related. it's plenty down low (2500-4000) but seesm to loose the bark at 5000+
i have done a lot of modifications to carb (changed from holley 570 to this one), maybe that's why it's more relaxed now.

I'm getting a A/F meter start of next week and see from there, until then I'll leave it like that.

scootchu

What is your total timing with 15 being your initial?

kalli

I second that question :-)
what is your total (without advance)? (i have 34ish)
what is your timing at idle (with advance hooked up)? (i have 28 with and 14 without)
what is the very total (with vacuum revving when standing in neutral at 3000?) (mine is 48)