218 timing

[jchalk1949]

Hi, I just rebuilt a 1949 218 and have a question about timing. Does anyone know if timimg with a timing light, the vaccuum line is capped or hooked up to the distributor? I timed it with it disconnected and after it was hooked up the timing changed. None of my manuals say anything about this. Help.

I also put this under another heading, and am not sure if it should be there.

[Joe Flanagan]

I also have a 1949 with a 218. On my engine, you cannot move the distributor unless you disconnect the vacuum line.

[Jim Saraceno]

Does anyone know if timing with a timing light, the vacuum line is capped or hooked up to the distributor?

The vacuum should be hooked up to the distributor for timing. Make sure you set the idle speed first and a change in speed will change the advance.

On my engine, you cannot move the distributor unless you disconnect the vacuum line.

Then how do you adjust your timing? There should be enough give in the vacuum line to move the distributor for timing.

[greg g]

Keep in mind the factory setting was calculated using fuel available then. Today's petro chemical brew is vastly diffenten in terms of btu's, flame front characteristics,detonation resistance, and many other variables. while using the factory spec is fine for setting up a newly rebuilt engine, or even getting an old one resurected ( I know it's Lent and this could be construed as a religious comment, It not) many of us have found that using a vacuum gauge to set the timing takes into account all the variables present with in each particular engine.

Attach the gauge to the windshield wiper vacuum fitting (or other access on the intake manifold) then with the engine warm and running at idle speed, rotate the distributor to gyield the highest steady vacuum reading. Then snug the distributor, readjust the idle speed if necessary and road test. If you get a spark knock upon acceleration of sustained load like climbing a hill at moderate speed, retard the spark by rotating the dist counter clockwise in small increments, till the knock disappears. Now fully tighten the dist.

If you want you can check with the timing light, my guess is that depending upon your engines condition you will be in the 3 to 6 degrees BTC neighborhood.

Timing can be checked and set with the advance vacuum line attached, since it is attached to ported (carb vacuum) which should be 0 at idle.

Based upon the above, if you just want to use a light and set the timing that way start at about 5 degees BTC and do the road test procedure.

Either way you will probably end up in the same zip code.

Edited March 15, 2011 by greg g

[Frank Ollian]

I have a listing of distributors used from 40 to 46, in those distributors centrifigal advance starts at 370 rpm with one degree of advance and by 400 rpm its three degrees. Vacume advance starts around 5 1/2 inches of vacume. Your 49 distributor may be different but probably not much.

[Joe Flanagan]

Then how do you adjust your timing? There should be enough give in the vacuum line to move the distributor for timing.

For a nice, clean look, I ran the vacuum advance line close to the head. Looks nice, neat, and streamlined. The price for that little move is not being able to move my distributor when the line is connected. I was under the impression--mistaken, apparently--that you could adjust your timing without the vacuum line attached. One more little bug I have to work out.

[Jim Saraceno]

For a nice, clean look, I ran the vacuum advance line close to the head. Looks nice, neat, and streamlined. The price for that little move is not being able to move my distributor when the line is connected. I was under the impression--mistaken, apparently--that you could adjust your timing without the vacuum line attached. One more little bug I have to work out.

I added a short section of rubber tube at the distributor for easier movement.

[Don Coatney]

I originally plumbed my vacuum advance line hard and added a loop so it looked nice and pretty. Did not work as planned. So like Jim I used rubber for the final.

[greg g]

I have used a modern product which is a stiff but flexible piece. This is routed between the head and water pump, and slips over 4inch long pieces of the origial metal line at both the carb and at the dizzy. Allows for quite a bit of dist movement.

[Joe Flanagan]

I was looking closely at your pictures, Don, and I've caught you. I discovered the little secret you didn't want anybody to know: You smoke Kools.

[Don Coatney]

You smoke Kools.

I smoked Kools as in past tense. Smoked them for longer than I care to admit. About 5 years ago I gave up the Kools and switched to a pipe.

[jchalk1949]

Thanks. I think I will try the vacuum guage.