The Stovebolt Site Forums The Shop Area Engine Shop First attempt to tune my 216

First let me say that I am a rookie when it comes to tune ups. But I need to start somewhere, so armed with a shop manual, a tach, and a timing light, I figured I couldn't go wrong with something as simple as the 216 in my truck, which probably doesn't need a tuneup to begin with. Half a day later, I have several questions that need some answers from the experts.
(1) Manual says the #1 plug wire attaches to the distributor at the point farthest from the block. Now I always thought that the #1 cylinder was at the front end of the motor, but darn if the wire that runs to the front cylinder doesn't come from the point CLOSEST to the block. From there, all of the wires are in proper firing sequence.
(2) When I hook up the timing light to the rear plug (which I thought was #6), she times perfectly, although I'm supposed to be connected to #1.
(3) Manual says to set the idle at 450-500 RPM. She runs like a top at about 800 RPM but lower than that the motor tends to stall. Carb was just rebuilt. Should I really be trying to make this work at 450-500 RPM or is 800 good enough. Will that upset any other part of the timing process?
(4) Finally, with today's fuels, where should the octane selector end up? Don't think my ear is trained enough to set it based on relative degrees of pinging which is what the manual calls for.
Thanks for answering all or part.

(1)#1 plug is at the front of the engine.
(2) Sounds like the distributor might be set wrong. To check remove all spark plugs. Hold your finger over the front plug hole and turn the engine by hand. When your finger is blown off the hole by the pressure, you are near the top dead center for #1. Your timing ball should be close to the pointer in the hole, and if you remove the distributor cap the rotor should be pointing the #1 spark plug hole.
(3) Sounds like a vacuum leak. Could be either a loose hose or a manifold leak. How did the engine idle before you rebuilt the carb?
(4) Don't worry about it. Todays gasoline probably won't ping in one of these old gals.

I would recommend you get a vacuum gauge. Great tool for diagnostics, I hook it up to the manifold tap for the wipers. Cost is around $15. Follow the link for instructions Vacuum gauge tuning
There should also be instructions with the gauge, but the webpage is nice. When tuning one of the stock sixes, I don't even mess with a timing light, I set the timing with the vacuum gauge. And even if your distributor is not correctly positioned, the gauge doesn't care. Then you don't have to change the distributor.

Thanks Fred T. I know that my questions seem rather elementary but thought I would ask for expert advice before doing something really stupid.
The carb was rebuilt because it was all stopped up with crud -- so a before and after comparison is not a very good measure of success. Some "helper" had taken the guts out of my fuel filter. It is running better now than in years. Thanks for the hint on timing by vacuum. I'll give it a try sometime and if I figure it out, will pitch the timing light. In the meantime, should the vacuum advance be disconnected when checking the timing. Timing light manual says YES, truck manual doesn't mention that step.

One more question for the stupid category: If the engine is running fine with the distributor 180 degrees out of position, how did I get to this status? Can I loosen the clamp and rotate the distributor body half a turn to put the #1 wire where it belongs?

Sorry to be so longwinded. --Steve

Steve - You have to plug the vacuum line to the distributor to check the timing. And if the distributor is not set properly, it has to be pulled out of the engine to be corrected. To check this you need to find where number 1 is at the end of the compression stroke by using your finger over the plug hole. Then turn the engine to align the timing mark, it shouldn't take much. At this point the rotor should be pointing at the #1 plug hole. This is where #1 plug wire should be connected to the distributor cap, too.

Also, these engines can usually be turned by hand. With the wheels chocked and the tranny in neutral, you can usually turn the engine with the fan blade, even with the spark plugs in, if the belt is set a little tight.

Personally, if the engine is running good, I would leave the distributor alone. And don't pitch the timing light, one day you might need it when you upgrade your engine.

From my mistake, which side of the motor are you using to time from?
Ignore the hole on the drivers side

I'm using the passenger side. I guess I am quite surprised that the engine runs so well with the distributor installed wrong. THe timing mark (ball) lines up perfectly with the pointer when the timing light is connected to the #6 plug. Old axiom must apply: "If it ain't broke, don't **** with it."

OK guys - correct me on this:

47ranchtruck seems to be having success in timing using the spark from #6 cylinder.

153624 is the sequence for a 216's firing order (I memorized 28 years ago - same for 236 and 261). The crank rotates two times for each firing cycle. Thus, halfway through the cycle, number 6 cylinder is firing.

That is why 47ranchtruck is getting a good timing setting. Am I right or was this so obvious that no one commented on it?

Tim

Don't pull the dist. If 6 is now 1 just switch the wires around and check the others while you are at it. Yes it will run pretty good if you are using 6 for 1, other wires must be ok but check anyway. I've done that in the misty past.

If you have already pulled the dist in flustration things get ugly.
Tim

800 rpm is way over normal idle speed .
If it wont idle at 450 - 500 them there is still a little bit of that crud in the idle circuit.
The dist is easy to fit up 180 deg out , 'cause the oil pump drive is a slot. If it starts ok , just leave it . So what if the wires are in a funny place .