What is your timing curve?

[68 Sport Satellite]

Like someone else said, every engine is different. My 451 low deck B motor with flat top pistons 015" below deck, Edelbrock Performer RPM heads with .037" Cometic gaskets (any thicker and I'd lose quench) and Lunati Voodoo 60302 mild cam (475 lift, 220/226 @ .050, 112 LSA) is 10.1:1 compression. The most total timing i can run without detonation is 32 degrees. I selected my pistons before my cam and should have done the opposite so I could be down around 9.6:1 and have less worries and run more timing. I have my initial set at 15 and am running a Firecore distributor. So 15 initial and 17 mechanical locked in with the adjustable slots gives 32 total. I'm running the medium blue firecore springs and I'm all in on total timing by 2500 rpm. But guess what? It runs well on the street and has consistently run high 12's in the 1/4 with a best of 12.80 @ 108 mph. So whatever works.

I do not have vacuum advance hooked up. I've tried to run it with the advance rate dialed all the way back, but it pings. So I need to open it up and wrap a wire stop to limit the amount of vacuum advance and then I can hook that up and have better off throttle performance (just need to get around to it). Of course fuel octane matters too. Here in California the normal high octane is only 91. Two stations within an hour of me sell 110 octane, but it's super expensive.

 

[Jonas Nordstrom]

38 is too much for my engine also.
Mine is happiest at 34 total mech and I had to adjust down the vac adv a bit to get away from pinging.
16 initial adding 18 mech, low comp engine, iron heads.

I found a new set of the Mr gasket springs in the garage, so will try to change out the heavy spring.
(I also have extra stock springs, so that is also an option.)
I would like to come in with total around 2500.

 

[Kern Dog]

Man, I looked and looked for the plastic gauges I had that came from either Mallory or Accel. I could not find them anywhere. These were used as spacers to set the amount of total advance these Mopar Performance distributors can have. Here is a tip: If the distributor shaft looks like it is made from brass:

..instead of a standard steel color...

...it could be the MP unit with the light weights and springs.
Regarding total timing...I have read that an efficient combustion chamber doesn't need nor respond to as much timing as an inefficient design.
Reading that a larger bore needs more lead is interesting. I may have read that before but I'm not sure.
I still need the wife's help to plot the curve. She has been too busy with work to help. She finishes for the day tired and annoyed and often just wants to relax.
I don't want to interrupt her relaxation time.

 

[HALIFAXHOPS]

I use the fast idle cam to do it alone. Hey if you have not noticed some one welded up the slots they started at 15 dist degrees.

 

[Jonas Nordstrom]

I use the fast idle cam to do it alone. Hey if you have not noticed some one welded up the slots they started at 15 dist degrees.

Hah, great tip!
The fast idle cam is super easy to adjust and reach on a TQ.

 

[Kern Dog]

I use the fast idle cam to do it alone. Hey if you have not noticed some one welded up the slots they started at 15 dist degrees.

Thanks. The fast idle cam doesn't have 500 rpm increments.
I wanted to plot a graph at 1000, 1500, 2000, 2500 and 3000 rpms.

Sort of like this:

 

[HALIFAXHOPS]

Just adjust the screw to get the RPM you want.

 

[Kern Dog]

I suppose that I could.
I'm embarrassed...I didn't think of that. I'm not even drunk.
Thanks for the suggestion!

 

[moparedtn]

Fairly stock 440 (a little lumpy, but not much on the 484 purpleshaft).
"All in" is 35 at 2300 in a stock distributor, leaving about 12-14 at idle.
Determined by judicious use of a vacuum gauge and confirmed by smoothness of engine -
it'll tell you what it wants if you listen.

No, I've never bothered to dial in the vacuum advance - all three stock electronic distributors
I have stutter and jitter with it connected, meaning I need to do the tiny allen wrench tuning
on the diaphragm - which I've never done.
Guilty as charged.

 

[68 Sport Satellite]

Just adjust the screw to get the RPM you want.

is it also possible to use a remote tach hooked up to the wire at the carb so it's easy to view underhood instead of the one at the dash?

 

[Jonas Nordstrom]

is it also possible to use a remote tach hooked up to the wire at the carb so it's easy to view underhood instead of the one at the dash?

I got a timing light that displays rpm, very handy.

 

[RJRENTON]

Man, I looked and looked for the plastic gauges I had that came from either Mallory or Accel. I could not find them anywhere. These were used as spacers to set the amount of total advance these Mopar Performance distributors can have. Here is a tip: If the distributor shaft looks like it is made from brass:

View attachment 1645158

..instead of a standard steel color...

View attachment 1645159

...it could be the MP unit with the light weights and springs.
Regarding total timing...I have read that an efficient combustion chamber doesn't need nor respond to as much timing as an inefficient design.
Reading that a larger bore needs more lead is interesting. I may have read that before but I'm not sure.
I still need the wife's help to plot the curve. She has been too busy with work to help. She finishes for the day tired and annoyed and often just wants to relax.
I don't want to interrupt her relaxation time.

With regard to the comment about the shaft being brass....it is very possible that it either: brass plated, steel that is zinc dichromate plated but not brass, as there are several types of brass, the most common bring 80%-20% copper-tin or 70%-30% copper-tin. Color is not the determination of a material's composition......just FYI....
BOB RENTON

 

[68 Sport Satellite]

I got a timing light that displays rpm, very handy.

Didn't know they had those. Time to order one! Can you recommend a brand you like?

 

[RemCharger]

I really like this one, very solid

 

[Jonas Nordstrom]

I got this one. Feels very plastic but does the job.

 

[Kern Dog]

I've been satisfied with mine since I bought it 20+ years ago but the ones with the tachometer readout are interesting.

 

[lewtot184]

anybody here old enough to remember when all we had was a simple light (no inductive) and we'd put a safety pin in the #1 plug wire (and keep it there) at the distributor?

if you're trying to measure distributor degrees each .0154" of travel in the slot is one distributor degree. i use number drills to measure that distance and divide by .0154. vacuum advance is different and i have to admit i've never got it exact but around .011" of movement is one distributor degree.

 

[68 Sport Satellite]

anybody here old enough to remember when all we had was a simple light (no inductive) and we'd put a safety pin in the #1 plug wire (and keep it there) at the distributor?

if you're trying to measure distributor degrees each .0154" of travel in the slot is one distributor degree. i use number drills to measure that distance and divide by .0154. vacuum advance is different and i have to admit i've never got it exact but around .011" of movement is one distributor degree.

thanks. I have a note somewhere about installing a .027" - .032" wire shim in the Vacuum Advance can to limit the max travel to where I want it to be. I was planning to use an appropriately sized paper clip wrapped around the Vacuum Advance lever arm. I used to think that the adjustment hex screw limits the total advance, but it turns out it only limits the rate at which it is applied. I need to shim mine to be able to hook it up.

 

[lewtot184]

thanks. I have a note somewhere about installing a .027" - .032" wire shim in the Vacuum Advance can to limit the max travel to where I want it to be. I was planning to use an appropriately sized paper clip wrapped around the Vacuum Advance lever arm. I used to think that the adjustment hex screw limits the total advance, but it turns out it only limits the rate at which it is applied. I need to shim mine to be able to hook it up.

I use small .030" thick washers with a small dab of ultra Grey rtv.

 

[Kern Dog]

Lookie what I found!

These are for adjusting the advance on a Mopar Performance unit.
The Gauges are from 14 degrees to 28. Who the heck needs 28 degrees of advance???
If you’re at 12 degrees of initial, that puts you at 40 degrees total.

From this angle you can see the difference in thicknesses for them.

The spring kit is sparse.

Okay. Now onto plotting the existing curve. Once I pull this MP distributor, I’ll check the new Hi-Rev unit.