[valiant67]

Some of the smog era cars used like 12º or 15º BTDC. Even on those cars the scale on the engine only went 10º BTDC to 10º ATDC so you had to either use a timing light with an adjustable advance built into it or put a timing tape set on the balancer.

I would strongly suggest getting rid of the points. If the dwell is not set properly on the points first, you can't properly set timing. Plus the points require more frequent maintenance than an electronic ignition would. So you want to set dwell, set RPM then set timing with vacuum disconnected.

There are really three factors to consider when setting timing:
1) Base timing - this is what you are setting with the timing light.
2) Vacuum advance - On a stock distributor this is a fixed function, but on the Mopar conversion kit the vacuum advance is adjustable so you can dial in more or less. You want ported vacuum, like at the base of the carb where there's no vacuum signal at idle and vacuum present when RPMs increase. Normal engine vacuum is the opposite.
3) Mechanical advance - The distributor will advance timing as the RPMs increase. This is why you must set RPM speed before setting base timing. This advance is fixed based on distributor design but can be modified by changing the springs in the distributor.

You may want to verify that timing is advancing as it should when RPMs increase and when vacuum is applied to the vacuum canister on the distributor. I've seen old distributors where the advance is frozen and they will backfire under throttle.

If the engine is stock, I'd tune it to the 1971 specs. If it's modified, the best way I've heard it explained is to set timing so that with mechanical and vacuum advances you have a certain advance at a certain RPM. I can't recommend the best for your combo because I generally have only ran stock engines.

 

[stpltn250r]

I was told to set the rpms this way.

Take the hose off @ the carb for the vacuum advance. Take a light weight piece of paper and adjust rpms until the price of paper falls off the vacuum port. This is where you should start. Then adjust timing (initial) to where the motor acts best. Then put hose back on carb.


Sound about rite?? Its all stock except for the intake / carb set up.

 

[dana44]

Popping through the carb is an indication of too much advance to start with, being the fuel is being sparked before the valve is closing all the way, and/or the secondaries in the carb are too soft and opening too much and you go lean. The Holley carbs have a secondary spring kit that will adjust the speed of them opening according to a color code. So, if you jab the throttle at idle and you see the secondaries move more than just a hair, spring is too soft. Additionally, the squirter, if too small a number, or if the accelerator pump is too loose (that little arm that goes from the throttle shaft forward and operates a little arm on the underside of the carb bowl, there is a 3/8ths (I believe) bolt, spring and nut. It should be adjusted so there is zero play, but no pressure when touching the arms at all locations.

Just to check here, you say 318, but is the intake manifold a 318 intake? They do make them, the 340 and 360 intakes have a difficult time sealing properly if at all because the ports themselves are too small for the gasket of the 360 and vice versa. The gasket kits have both gaskets, a comparison is noticeable and can cause some of these idle problems, work their way to throttle stabbing stumbles and popping, too.

The distributor, as others have said, would be best converted to electronic ignition, it is much better than points, you may have a worn bushing that is also allowing the points to bounce and change as you stab the gas, altering the points setting. You can pop the cap and see if you can push and pull gently side to side on the rotor to alter the points setting to verify this slop, there are several companies that offer aftermarket electronic ignition systems. Inside the distributor, under the points plate, are the mechanical advance counterweights and springs. Too soft of springs will advance too fast, there are spring kits to adjust them, and then the vacuum advance canister may have an adjustment to it, I believe it is the vacuum advance canister that has a hex on the end of it, not just a round cone. If it does have the hex, you can stick a long allen wrench that fits into it and crank up or down the amount/speed of vacuum advance. clockwise should reduce it, counterclockwise should increase the amount.

A lot of adjustments and checks, but start with 8degrees BTDC, pinging and popping is an indication of too much advance, not too little, and too much advance is not necessarily a good thing. Once everything is dialed in, a simple two degrees of too much advance can drop gas mileage by two miles per gallon, and hurt performance. The key is the mechanical advance tuning to get it correct.

Keep us informed of the results and findings.

 

[stpltn250r]

Now tht you say it, may dad ordered the intake, he got one for a 340 or a 360. We were told to get one for the size of motor. Though the only difference between them was internals... very well could be a problem.. Might spray some brake clean around intake to see if we have any sealing issues.

I will look down in the dist. to see if any of the springs are broke or weak. And will check the points to make sure they are solid..

 

[stpltn250r]

Well. some more info here. After checking everything, my brother went and bought the electronic ignition kit it. I will be checking everything tonight. If the battery is still charged up.

If it will fire up I will check total timing with vacum canister plugged and set it at 34* At 3k rpm. I will then let it idle at around 800-900 rpms and see where it is. I will then set the initial timing to 12-14* and re-check total timing at 3k rpms. To see what the actual mechanical advance is.

With just a carb and intake im guessing I want it to be a slow curve rather than a snappy curve to total timing.

Does this all sound correct?

When I set the total timing first, and let it come back down to idle, If it idles high do I reset the idle screw first or do I go ahead and change initial timing?



Forgot to add that this is a 65 Plymouth Sport Fury but with a 71 318 motor...

 

[dana44]

Lower the idle at the idle screw. Small blocks like faster advance than big blocks, but, if you want to have that much initial timing, slower would be better to prevent pinging.

 

[TWX]

stupid question, but you mentioned some difficulty originally getting the timing set on... Are you sure that it's on correctly? If the valvetrain is retarded then you might find yourself having to advance the ignition timing relative to the crank to get it in line with the cam...

 

[stpltn250r]

You know I was just reading another timing thread on a guys 383 that dana helped him with and Im thinking back when the timing set was put on and I did notice the dots were not lined up. I put everything back the way it was b/c it ran like that for years so I assumed it was correct.

Now its got me thinking like you are saying TWX, with the cam out of time to the crank Im in fact needing to give it more advance to make up the difference. Look like I will be taking the everything off to double check.

When I go to reset the timing set. Should i set it to have the timing marks line up at crank dot at 12 o'clock and cam dot at 6 o'clock?

Or make sure the crank is a tdc and the cam is set with both intake and ex valve closed, but make the cam set after the intake valve has just closed.


Sorry to sound stupid, but Im used to working on two stroke atv's and not car motors.


And this is the ignition that was put in the car.

http://www.summitracing.com/parts/PRO-66991/

Thanks for your help guys.

 

[dana44]

The cam sprocket (the big one on top) can be at 12 or 6), the crank (small bottom sprocket) at 12, period. It is best and easiest when the top is at 6 and the bottom is at 12, and then at this point when you stab the distributor, on a V8, place it where the number 6 cylinder sparkplug wire is, not the number one (trust me, took 30 years to realize this one), and if nothing has been turned over, when you turn the key on and rotate the distributor, turn it the opposite direction or rotation (shown on all intake manifolds), and your timing will be really close to be able to start first time she turns over.

 

[stpltn250r]

Dont want to sound like Im questioning you. But why is the motor able to fire with #1 cyl at tdc with timing marks lined up and you have the rotor fire at #6 cyl?

Can you explain that a little more or maybe shoot me in the direction of where you have already?


You think at this time would be a good time for a cam swap? Like the comp cams XE262H cam and lifter package. This is not going to be a strret/strip car, Just an every now and again driver. A tinker car if you will.

 

[68RT]

Firing order is 1-8-4-3-6-5-7-2.
#1 piston is at the top at both 1 and 6 when firing because the cam/distributor turns at half speed. You do have to make sure that the rotor is pointing at the cylinder that is under compression rather than the cylinder that is changing from exhaust to intake.

 

[dana44]

When the marks are lined up at six and 12, the normal way marks are lined up and shown in all and every single setting the timing marks, number one is actually getting ready to go exhaust clear, not compression building ready to fire on number 1. I will put any amount of money that 180 degrees from the number one cylinder is going to be the next one to fire (it really works). I finally figured it out with a little bit of confirmation from another person after about the 30th engine I set up with the marks lined up on the timing chain and stabbing the distributor, just to find out it was 180 degrees out, each and every 30 times.

 

[stpltn250r]

okie dokie