First let me say I have followed this procedure before, but don't know it I was doing it properly. Awesome information, by the way!!

Lars below I have copied your timing paper and have made it specific to my 81 with no computer. I have broken it down it steps.....Am I doing this correctly? (I am not trying to rewrite the paper, but trying to put it in a format that I easily understand).

I am going to recheck timing, as the last time my rpm's were way to high....... My questions are in bold......

Q 1: Should I bring the rpms at idle down to 700 or 800 first? If so, do I do it with the throttle screw, or the idle mixture screws? (EB 1411 carb)?

Here's your paper...

Step 1:
Remove your distributor cap and rotor. Remove the 2 centrifugal advance springs. Install the rotor and the cap (without the springs).

Step 2: (this is where I get confused reading between HEI and not)
Disconnect the vacuum advance.

<deleted info. relative to HEI>

Step 3
Start the engine. It may kick back a little due to the advance coming in immediately without the springs. If you’re using an adjustable timing light, set the light to 36 degrees advanced.

Step 4
Now rev the engine just a little while observing the timing marks with the light. It shouldn’t take much rpm to peg out the advance without the springs installed. With an adjustable light set at 36 degrees, align the stock timing marks with “0” when the timing is “pegged out.” With the non-adjustable light, align your new 36-degree mark with “0.” Rev the engine a little to make sure the timing will not advance any further.

Step 5
Shut it down. Pop the cap and rotor and re-install the springs. Put everything back together, but leave the vacuum disconnected.

Q: Which springs? Softest, or ones it shipped with, or does it matter?

Step 6
Start it up. For future reference, make a note of the timing setting at idle. This is your new curb idle timing spec.

Step 7
Now give the engine a few quick rev’s past 3,000 rpm and verify that the full timing (36 degrees) is coming in. If it’s not, you need to change to a softer set of springs until you get full 36-degree advance before 3000 rpm. (NOTE: A stock set of springs will usually not allow full centrifugal advance to come in before redline rpm. If you have stock springs installed, don’t rev the engine beyond its limits to try to force full advance in.)

Step 8
Shut it down and hook up the vacuum. Now do a road test.

Q: When I hookup the vacuum I get a considerable jump in rpm and timing. How do you allow for this additional rpm increase coming in?

The 36-degree 2500 rpm advance curve is optimum for performance, but may require premium fuel. Lug the car around, and punch the throttle at low rpm while listening for detonation (“engine knock”). If you’re getting any audible knock, you MUST retard the timing. Retard the timing in 2-degree increments until engine knock stops. Engine knock will seriously damage engine components if not corrected. If you get no knock, you may see slightly improved performance at 38 degrees total timing. This is particularly true if you’re running at high altitude.

If you have no engine knock under acceleration, but the car “chugs” or “jerks” at cruising speed (light throttle application), you are getting too much vacuum advance on top of the mechanical advance. You may need to change out the vacuum advance diaphragm with an adjustable unit available from aftermarket sources. Adjust these units so that you get the most vacuum advance possible without any “chugging” or “jerking” at cruise speed. Your timing is now set for best possible performance.

Make note of the new setting, and use this for your future tune-up work.

Questions, Comments & Technical Assistance If you have questions or comments regarding this article, or if you notice any errors that need to be corrected (which is quite possible since I’m writing this from memory…), please feel free to drop me an e-mail. Also, if you need any technical assistance or advice regarding this process, or other maintenance issues, feel free to contact me: lars.grimsrud@lmco.com

 

Q. What kind of distributor are you using???

 

What type of distributor do you have?

 

Hey Page -
That's pretty funny - notice the time stamps on our posts: exactly the same time and exactly the same post...

 

 

Well...I've tried to learn from you. I guess a little bit is finally starting to sink in!

 

MSD #8360 distrib. w/ mech. and vac. advance......

 

MsVette -
Let me give you the basic easy setup procedure for the MSD-type distributor. Let me first answer your questions directly:

Never set idle speed with the idle mixture screws. Idle speed should only be set with the idle speed screw. Set up your idle speed to whatever idle speed you normally use. Adjust idle mixture to produce best quality idle. Idle speed setup is irrelevant for the purposes of setting the total timing.

I'd recommend installing the softest springs you have for the purposes of checking total timing. This will limit the maximum rpm you have to rev the engine to when checking total timing. This keeps things a little safer.

Re-set your idle speed.


Now, on your MSD:
To set your total timing, pull the vacuum advance hose off the distributor. Install the softest springs you have with the tuning kit that came with the distributor. Start the engine. Set your adjustable timing light to 36 degrees. Using the timing light, rev the engine and observe the timing advancing. Increase engine rpm until the timing does not advance any further. This should occur at about 2500-3000 rpm. When the timing pegs out, and with your timing light set at 36 degrees, the line on the balancer should line up with "0" on the timing tab. Rotate the dstributor as required to make this happen.

Tighten the distributor clamp down and re-check the total timing - verify it pegs out at 36 degrees.

Re-attach the vacuum advance hose. Re-adjust idle speed as required.

Done.

 

Above post edited after I saw that you're running the MSD distributor. Instructions in the post are now correct for your system.
Lars

 

Thanks Lars!! It takes a little while for this to sink in, but I'm grasping the importance of getting all the total timing in! Thanks for the clarifications.........

 

MsV -
Trick is to not make it more complicated than it is: Simply set the timing light to 36, yank the hose off, and rev the engine briefly by flicking the throttle to peg out the timing. Tweak the distributor and do it again until it hits the timing mark. Re-connect hose and set idle speed. The whole process takes about 37 seconds.

The MSD distributors are supplied "stock" with very stiff springs and a slow advance curve - MSD keeps it conservative... Yank those stiff springs off and install the lightest ones as your frst order of business - no point in even checking the timing with the big stiff stock springs. You can use the stock MSD springs as front springs in your suspension.

 

lol on the stock springs!! We found that out the first time we were using your system! We did it the first time with now springs and worked up.......


Is there a simple timing check for when you have the vacuum hooked up? Should time at idle be in a certain range so you know you have everything hooked up properly?

 

there's allso two ports on that carb to hook up the distributor, one pulls all the time and one only pull when you hit the gas. make sure your use'n the port you need.

 

With a correct advance curve length and 36 degrees total, timing at idle (with the hose disconnected) should be 16-22 degrees, or anywhere in that area. I like to target about 18 initial, but you can run anything from 8 to mid-20's. The vacuum advance should pull in an additional 16 degrees, but this will depend on the vacuum advance control unit that's being used - most pull in a bit more. 16 degrees vacuum advance is optimum with a 36-degree total mechanical curve.

No, there is no simple timing check for when the vacuum is hooked up and the engine is at idle, because the timing range in this configuration is pretty wide. And it's irrelevant.

 

Lars-
What about the spacers that come with the MSD? The instructions recommend using specific springs with the proper spacer to ensure correct timeing. Any recommendations?

 

The spacers control the length of the advance curve. The springs control how fast that curve comes in. For a performance application, you want a fairly short curve (allowing about 18 degrees initial advance while not exceeding 36 total), and you want it to come in quickly. So to set it up, install the softest springs so the curve comes in quick. Set up the 36 total as descibed above, and see what the initial ends up being. If the initial is less than 18 degrees, install a fatter spacer to shorten the advance curve - this will allow more initial timing while maintaining 36 total.

 

Lars,
Still a bit confused. What is the advantage of running so much initial advance. I thought most V8 run around 8 to 12 initial for proper performance.

 

Thanks Lars! We nailed it this evening..........Had to do 3 different spring swaps of different sizes, but we got it!! It was backfiring early (it was propped up on jackstands from the rear for a week) with the softest springs.... got her set at 17 initial, 36 at full advance around 2900 rpm, and steady 800 rpm at idle........sounds sweet........no test drive yet! (See other post why).

Thanks again for making it simple......next up is test drive and vacuum advance settings.....oh yea!!

 

Depends on what you mean by "proper performance." If "proper performance" means that you are meeting the emissions requirements for your vehicle, then you need to run 8 degrees initial. If "proper performance" means you have decided to buy stock in a tire company because you're shredding tires from excessive torque, you need to run 18 initial. Any performance engine will produce much better throttle response with 16-22 degrees of intial advance at idle, with 18 being the target number for some great low-end torque and instant response. On my 357 '64, I run 20 intial with a 16-degree vacuum advance unit plugged into manifold vacuum to produce 36 degrees timing at idle. When I get on it, the 16 vacuum drops out to produce 20 base, but the 36 total comes all in by 2000, so I'm right back up to 36 degrees within a second of hitting the throttle off idle. As long as you don't get low-rpm detonation or kick-back upon startup, run as much timing as you can without exceeding 36 total (your engine will run cooler, too..)

MsV -
The numbers look great: 17 initial with 36 total will work great. The vacuum advance control unit on the MSD distributors is a 16-degree unit, so just plug it into a manifold vacuum source and go have some fun!

 

your PM box is full there MSvetteman.