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Grab distributor and twist it clockwise... it needs more initial. If the engine picks up RPM when you do that THE ENGINE WANTS THE TIMING, PERIOD!

Put 16 on it at idle, turn the idle speed down to 850-900, reset mix screws to highest vacuum and see what it does. You'll have to change the mechanical. been through this before, read the other post you started. Don't drive it until you alter the mechanical advance.

IMO, Total timing method is a rotten method for timing a street driven car.

Only time I have a tune up on a car like what you currently have is if it needs to be smogged!

Positive you don't have vacuum leak issues?



Thank you for informing me my way of timing is "rotten".

So I set the timing at 18 Initial, with no regard for total timing, turn down the idle and go for a cruise, and find the car has enough spark knock to melt holes in the tops of the pistons when you get on it. Yep that sure works.

Unless you have a race motor with big cam and lots of duration and overlap (low idle vacuum), the motor does not need 18 degrees initial.

Excessive initial timing can cause the engine to run hot as well. Not a problem on a rich race motor which uses the excess fuel to help cool it, but not what you want on a street motor.

Why not let the distributor do what it is designed to do? The problem of idle speed drop in gear will not change with more initial timing. The mechanical advance is still dropping timing when the car is put under load (neutral to drive), so the idle speed will still drop excessively.

I still say to set the total timing at an RPM that has the mechanical advance "all in", usually by 3000 RPM. Then IF the motor really needs more initial timing to stay running after setting the total timing, you then modify the distributor advance.

The springs for the mechanical advance need to be strong enough to prevent movement until the motor is rev'ed above the idle speed. There should be NO mechanical advance in at idle speed. With the 2500 converter, the motor will rev up easily enough to prevent excessive loading of the motor until the timing starts to advance.

To determine if this is indeed the original Posters problem, you can check the timing at idle in neutral, and again in gear. If it is the same both times, there are likely other issues such as a vacuum leak. It they are different, then the problem is the advance springs, regardless of the initial timing. .



He already knows he needs to limit the distributor advance to get his total in line. Much of what you wrote has been hashed out in prior threads. He says it's NOT dropping timing.

I better run out and take the initial on my 340 down from 22* to something safe because it might run hot... NOPE. It runs cool in ANY weather including the 115-120* days we have in my area. Mine have never run hotter with more initial and they sure don't gas people out because of nasty carb settings required by retarded initial timing settings. I don't pick an initial timing number willy-nilly, I let the engine tell me what it wants. My cars don't crank on the starter either, you bump the key and they fire RIGHT NOW! I was at spring fling and heard plenty of cars cranking on the starter for extended periods, or having to crack the throttle to start... wanna guess what a major cause of that is?

It's my OPINION that total method is rotten for street cars. Again, MY OPINION, It's the lazy way to do it. If idle quality doesn't matter, have at it with total method. Just like you think my method is less than ideal. More than one way to skin a cat. One MAJOR issue about total method, how much mechanical advance is in the distributor. Is mechanical 28* or 14* or 22* or 16*... you get the idea. Idle quality varies greatly with a range like that. I sure am glad that MSD includes those useless mechanical advance limiter bushings with their distributors, cause according to some, they just don't matter (total timing group).

One thing you can't argue with, if the engine picks up rpm as you advance the timing at idle, it's running more efficiently. Same as using a vacuum gauge to set initial, picks up vacuum, the engine wants it.

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For the OP, there is a set screw which you need to access from the bottom to open/close the secondaries of the carb. Lots of times the secondary arm is actually seated on your baseplate, not the set screw. A cheat is to get some feeler gauges and shim it from the top. Once you get it close you can remove the carb and turn the screw up so it holds the secondaries open a bit more, close the primaries down.

If you have only 7" of vacuum at idle, that cam is pretty dang big with lots of overlap.

Good luck with it.