Total Timing?

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Shane

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Hey,

I have read a few different RPM's that total timing should be checked at.

I dont know if it makes a difference, but its a 340, purple cam, headers, 600DP Holley..

I just want to clarify what I should do to properly check and set my total timing:

First, warm up the motor.

Then unplug vaccum advance from the distributor?

Then set the rpms to 2000 or 3500??

Then turn my dial on the timing light, til the mark on the balancer is at 0, then whatever the dial on the light is reading is the total timing???

And I want it to be at 35 or 36 or 37 degrees??

Thanks,

Shane
 
I just set mine by followed an article from an old Mopar Muscle issue.
Set your idle, unplug vacuum line from port and plug with golf tee. Have someone raise the RPM to 3500, timing should be about 36*. Return to curb idle and rehook vacuum line to port at carb. Timing should not be far above 15*. With vacuum attached, raise RPM to 3500, now timing should be between 50 & 55 degrees.

My total timing is 52* at 3500 RPM and initial is about 12* at 850 RPM.
 
Total timing is the SECOND piece of the puzzle.

Basic explanation: total timing = Initial + mechanical in dist.

You need to have the initial timing set first before moving to total timing.

The bad thing about setting total is this. If the distributor has 28* of mechanical advance and you set total at say 34*, you don't have enough initial advance (6*). The engine would not run well at idle with so little initial advance.

My guess, you'll need 14-20 of initial timing and about 16-20 in the distributor.
 
Oh I think I finally get it!

Thanks guys,

When I first set up my car , I was at around 12*. And thecar ran great. Then I kept hearing a rattling when I got on the gas hard. I even made a post on hearing asking about it.. Turned out it was pinging I was hearing... I turned the timing right back, and the rattle/ pinging went almost away... Just a little when I jump on it..but my inital is at about 4. I havebeen having an issue with a backfire lately that I thought was bad gas from storing..

So if I do actually get it now, I must have to much mehicanical advance in my distributor...

It's a mopar performane distributor, so do I have to learn how to change the springs in it to give me less advance???

Thanks
Shane!
 
you should have 14-16* initial (at idle) and 34* total (no vacuum) mechanical. 4* is not near enough initial.
 
I had 12 intial, vaccum from distributor disconneted. It was good off the line, but the car pinged.

Does this mean I have to change the amount of advance in the distributor??
 
388dart said:
you should have 14-16* initial (at idle) and 34* total (no vacuum) mechanical.
Click to expand...

That's exactly how I have mine set up. I have mopar distributor and I can't hook the vacuum advance up! I try to but when I'm at cruising speed say like 55mph I have a stubble. I pull over unplug the dist and plug the carb it goes back to running smooth again.
 
Shane said:
Oh I think I finally get it!

Thanks guys,

When I first set up my car , I was at around 12*. And thecar ran great. Then I kept hearing a rattling when I got on the gas hard. I even made a post on hearing asking about it.. Turned out it was pinging I was hearing... I turned the timing right back, and the rattle/ pinging went almost away... Just a little when I jump on it..but my inital is at about 4. I havebeen having an issue with a backfire lately that I thought was bad gas from storing..

So if I do actually get it now, I must have to much mehicanical advance in my distributor...

It's a mopar performane distributor, so do I have to learn how to change the springs in it to give me less advance???

Thanks
Shane!
Click to expand...

And right there you have the winning statement!
----------------------------------------------

12* isn't enough with a 484 cam IMO.

You can set the initial with a vacuum gauge too. Feed the engine timing, keeping idle constant, until vacuum stops increasing, then back it off 1" and take a timing reading. That's a really good place for your initial advance.

Then you have to limit the mechanical to hit your desired total advance. Some MP distributors have a mallory style advance system, others need to have the advance slots shortened. Easy to do.
 
Again thanks alot!!!, I have been struggling with this for almost a year in the back of my head...lol,

I have been reading over the link from 70duster440... it seems do able...just get the damper degress from Mopar, read it ten more times, ask a few questions, and dive right in...
 
crackedback, the distributor I am using came with the car and the old motor that was in it. I was told it was mp performance from the mid ninties...

How can I tell if it's mallory style or how much I need to shorten the advance slots?

I like the easy to do part...
 
Shane

That a good article..lots of good info.

In a nut shell...your mechanical timing is coming in way to soon which is causing your ping. Your initial should be close to 20* with your set up. Vaccum advance will not cause ping.

I sent my dizzy out to Dave at FBO in Calgary. Got it back within a week. Never looked back. Cost...$100.00. He will test it on a distributor machine and will provide a print out of results.

Also, never trust a 40 year balancer when setting initial. Using a vacuum guage may be the way to go.

Jim
 
mullinax95 said:
That's exactly how I have mine set up. I have mopar distributor and I can't hook the vacuum advance up! I try to but when I'm at cruising speed say like 55mph I have a stubble. I pull over unplug the dist and plug the carb it goes back to running smooth again.
Click to expand...

I have the M/P electronic ignition convertion on my '69 340. When I bought it, the guys at Monicatti said DO NOT run the vacuum advance. I still had problems with the distributor so I had it "curved" by a pro. I found out that the timing was at 36* @ 2400, but it would advance to 45* over 4000rpm. So now the TOTAL advance is 36*. Period. This comes in at 2500rpm. I set my intitial to about 15*. I still have the vacuum hose attached, but it is plugged with a ball bearing, so it looks stock.
 
:? Was just trying to figure this out yesterday on the Demon. I'm still reading and will try some more today.
 
I do have a vaccum gage, so tomorow on my day off I will set my intial with the vaccum gage hooked up....

Nicefisheh, there is no chance of leaving the vaccum advance plugged helping with the ping?
 
Shane said:
I do have a vaccum gage, so tomorow on my day off I will set my intial with the vaccum gage hooked up....

Nicefisheh, there is no chance of leaving the vaccum advance plugged helping with the ping?
Click to expand...

Shane

The vacuum only functions beyond the mechanical top limit. Has no influence on the ping issue. Just gas milage.

If it pingged at 12* and you use a vacuum guage to set initial....yeah, it will idle higher and smoothen out, but your initial will go even high...exacerbating your ping problem.

You need to slow down how fast the mechanical is coming with different springs and slots in the dizzy.

Jim
 
I understand...

I just called Mopar performance, and they said there curve adjustment kit only works for MP distributors from 2004 and on.

Mine is from the motor that was in the car from mid 1990's...

Any suggestions where to get a kit for mine?
 
Shane said:
I understand...

I just called Mopar performance, and they said there curve adjustment kit only works for MP distributors from 2004 and on.

Mine is from the motor that was in the car from mid 1990's...

Any suggestions where to get a kit for mine?
Click to expand...
\


Mine is from the mid-90's as well. The shop that curved mine welded up the advance weight slots and then filed them to stop advance at 36*. Cost was $65. Cheaper and less aggravation then buying a kit and experimenting with pulling the distributor in-and-out until you get it where you want it.
 
Do you know how much mechanical advance is in the distributor? If so you can use a little math to figure out how much to shorten the slots, based on movement and degrees.

Total - initial = Mechanical. Get that number and when you bust into the distributor, you can shorten the slots yourself.

I've used JB weld to shorten the slots too. Easier to file than wire welded.

This is from a magazine article a while back.
----------------------------------------
dist. degrees X 2 + initial= total


dist. degrees / slot length
6.............. .340
7............... .355
8............... .375
9............... .390
10.............. .405
11.5 ........... .420
12.............. .435
13.............. .445
14.............. .460
15.............. .475
16.............. .490
17.............. .505
18.............. .520
--------------------------------

Based on what you have I'd guess the slot length would need to be about .350"-.380"

Make sure you know where all the clips are located in the distributor before you tear into it. Get a copy of the factory service manual illustration if possible. I gave someone that "KNEW" what they were doing a 70 340 dual point distributor and it came back a bent useless mess, they missed the clip that hold the rotor standoff on the main shaft. They were prying on the thing and bent the plates.

It's easy to do.
 
Thanks Crackedback,

Tomorrow is my day off, I'll set the intial to were it needs to be.
Then I will check what the total is.
Then I will use the info in your last post to shorten the slots...

When I get the numbers, I will put them here first, then go for it!

Thanks, again
Shane
 
I have been talking about my distributor all day at work here, and I was informed of a local shop that will set it up for 60 bucks on a dist. machine for me.

I will drop it off to them tomorrow...Anything special I need to tell them?
Or just set for 36* total timing and give them my initial timing ?

again, thanks for all the good info in helping me get this issue to make sense for me!!

Shane
 
Shane said:
I have been talking about my distributor all day at work here, and I was informed of a local shop that will set it up for 60 bucks on a dist. machine for me.

I will drop it off to them tomorrow...Anything special I need to tell them?
Or just set for 36* total timing and give them my initial timing ?

again, thanks for all the good info in helping me get this issue to make sense for me!!

Shane
Click to expand...

Shane,

Just tell them you want 36* total advance by 2500rpm. Your initial timing has nothing to do with what they are doing.
 
alright sounds good. Thats what I will tell them!

Just for my learning curve, why is it at 2500?
 
Here's some more information on ignition tuning - starting at page 5

http://www.dippy.org/upgrade/ignition.pdf

NOTE: These are the instructions that come with MP distributors. MP distributors are known to have very light springs so the mechanical starts (too) early and is all in at a relatively low RPM (around 2000). The key to using this timing technique is to know the specs or your distributor. Using this technique without knowing the specs or your distributor is a total crap shoot. The springs will determine at what RPM mechanical advance starts and how fast and at what point RPM it reaches the total.

So, if you follow GTS Registry's suggestion for the advance curve and the shop sets it to those specs, then you would drop your dizzy back in, run the car up to 2500 RPM and turn the dizzy till you get 36 degrees with the timing light and you're done. When you set the idle back down the initial will be wherever it is. It would be a good idea to run the RPMs up beyond the 2500 to make sure the shop did it right and it doesn't continue to advance.

You can then move on to the vacuum advance adjustments. There's nothing wrong with running vacuum advance on a street car.

FWIW, I had Don at FBO recurve my MP distributor based on engine, cam, intake, rear, etc. It came back with specs of 16 initial with 34 total all in by 3400 RPM! I may change the springs so that my total is all in at a lower RPM.
 
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