I swear I know how but this thing is making me feel ignorant, so I would love some advice. I royally hate trying to do timing or valve adjustments on automatic transmission cars. How would YOU go about setting ignition timing on an engine if the distributor had been pulled and all reference points lost? 305 SBC with stock ‘70s HEI distributor with vacuum can. Street Demon carb, dizzy can hooked to ported vacuum. I replaced the intake gaskets and f’d up pulling the dizzy, didn’t make marks in the appropriate spots. Explain this to me like I’ve never seen an internal combustion engine before, maybe it will help me figure out what I’m missing before I completely burn all my facial hair off. Thank you in advance.
Sometimes the oil pump drive will turn and prevent the distributor from pointing at the #1 cyl I’ve had to turn it a couple times.
Oh...from the beginning.... First thing you have to do is get the engine in position for the #1 plug to fire, which means the #1 valves are both closed, and the timing pointer is just before Top Dead Center. There are two ways to make sure the valves are closed on #1. The safest way is to remove the valve cover on the driver side (that's the left valve cover, as you're sitting in the driver seat). See if either of the #1 rockers are pushing the valves open a little bit, or not. Use a 5/8" socket and breaker bar to turn the bolt that holds the damper to the crankshaft, turn it clockwise and watch the rockers to see if they're moving. Turn clockwise until the rockers are still, and the timing pointer indicates about 10 degrees Before Top Dead Center. The dangerous way is to hold your finger over a spark plug hole while cranking the engine, to see when it's on the compression stroke. More dangerous on older Fords, which have big enough spark plug holes to let your finger get ****ed in, then crushed. Now you're ready to install the distributor, but first you need to figure out where #1 plug wire is on the cap. Follow the wire from the #1 plug (front, driver side) to the cap. Fit the cap onto the distributor, and make a mark with a sharpie, or put some tape on the distributor near where the cap fits, in line with the #1 terminal on the cap. Also figure out where the #1 wire will be in relation to the engine...usually it's at the front, to one side or the other of center. You're going to have to set the distributor in place so that it's oriented properly, but this is a little different on each engine. The important thing is that the vacuum advance clears the intake manifold, and that you have enough adjustment (turning the distributor housing) to be able to get the timing right. So, it might take a couple tries to get it just right, be patient. Drop the distributor in place, and you'll see that as you get it the last little bit, the rotor turns a little bit. You need to get the contact on the rotor to be pointed at the #1 plug terminal mark you made, after the distributor is fully seated. You'll also find that it won't fit down all the way, most likely, because the oil drive shaft Anthony mentioned will stop it. I take the distributor out and turn the shaft as needed with a long screwdriver, to get it so the tang will line up as I drop in the distributor. Once you get the distributor in all the way, with the rotor pointing at #1, and the shaft seated all the way on the oil pump drive, then you can set the initial timing. If it's a point distributor, life is easy, you can turn the housing back and forth and watch the points open and close. When you turn the housing slowly counterclockwise, when the points just start to open, is where you want to clamp the distributor in place. With electronic ignition, it's tricky to see where it actually fires. One way to do it is to connect a plug wire to a spark plug, and to the coil, and lay it on the engine. Turn on the ignition, and turn the distributor housing back and forth. As you turn it counterclockwise slowly, it should spark...that is where you clamp it in place. Put the cap back on, make sure the wires are all as they should be, and see if it starts. It's a good idea to have the air cleaner in place on the carb, in case you got the timing wrong, and it backfires--this could prevent it catching on fire! Something I learned long ago. Now use a timing light to set the timing. If you know for sure what the initial timing should be (for example you have a completely stock engine and distributor), set it at idle, to the specification, with vacuum advance disconnected. But if you're like most situations, you don't really know what the initial timing should be, you'll need to set "total timing". This is the advance at higher RPM, with vacuum disconnected. Usually around 34 degrees total timing works on most small blocks. To do this you'll need a way to see what 34 degrees is, either a timing tape on the damper, or a "dial back" timing light that will let you program in the advance, and you line up the timing marks to TDC.
OK, in simple terms as you asked- Anthony got you to a good start. If the engine is together with the just the dizzy pulled- take off the valve cover on the right side and pull the #1 spark plug. Slowly rotate the crankshaft clockwise watching the #1-cylinder rocker arms. Once the intake valve closes, stick a piece of wire into the #1 cylinder and feel for the piston coming up as you continue to rotate the crankshaft. With the piston up top, see if there are any timing marks on the balancer. If not install align the rotor and #1 cap position on the dizzy. Back the rotor pointer up counterclockwise about 1" and install the dizzy. The rotor should rotate clockwise as it installs. Align the rotor with the #1 plug on the cap. Then rotate the distributor counterclockwise about 1/4" and lock it down.
This works for points ignition; I don't know about electronic ignitions because I don't use them, but I don't see why it wouldn't work with one. I am ***uming that you have the number one cylinder at TDC and the distributor "stabbed" correctly as has been covered by others here. Turn the engine until the timing mark lines up with the pointer. Take the number one plug wire off of the plug and hold it near the block. Having the distributor loose enough to turn manually, turn it back and forth slowly until you get a spark. Needless to say, the ignition has to be "ON". Tighten the distributor and recheck the timing. Done.
Sorry, I made a mistake in my last post. You are not "Done" when you have the initial timing set correctly. Getting the engine started and idling well is the minor part of the process. Most of the time, you are driving the car at varying speeds and under varying loads. Just about all ignitions have some sort of advance mechanism to allow the spark to occur earlier in the combustion cycle. This can be a lever on the steering column (like on a Model "A"), a centrifugal and/or vacuum advance mechanism inside the distributor, up through a computerized system. Unless the advance is working as it should, the vehicle will not operate properly. On the vehicles we are concerned with here, the total advance and even the rate of advance should be addressed after the initial is set. This requires either an advance timing light or a distributor setup machine to do the. There are plenty of threads on this forum and others on how this is done, so I will not address it here. A case in point. In the early nineties, I built what I considered to be the "ultimate flathead" for my '36 3 window. A 276 Merc with heads 'n carbs, an Isky cam, and the latest MSD ignition there was. The car ALWAYS ran hot and was never what I expected it to be. I finally tracked it down to the distributor. The MSD ignition had an advance more suited for an SBC (36 degrees total) rather than a flathead (low twenties total). I had installed the distributor ***uming that the advance was working and correct for the engine. Don't make the mistake I did; you're not done until you check and verify the advance curve.
With the timing dots lined up, this is the start of the combustion cycle, the rotor at that point would be 180 degrees from the no 1 plug wire
Squirrel explained it well .......my suggestion is that when you are rotating the engine with a socket and strong arm on the bolt in the crankshaft, watch for the intake valve to open and then close. That will be the end of the intake and compression strokes. Thats the place where you need to be when you send a spark to light the fire. If you do the same thing but are looking at the exhaust rocker arm, you will be 180 degrees out of rotation. Simply look at your intake and/or exhaust port location to tell which valve is the intake or exhaust, as the valve will be inline with that port.
The exhaust is closing, the intake is opening, when the crank is in the "wrong" place....but neither one is moving while it's in the "right" place. That's why I said to look for the timing mark to line up when both of the #1 rockers are still.
Anthony, that will get you 180 out at the distributor. That is timing set ***embly purpose reference. 12 o’clock 12 o’clock dots is what you want to drop distributor to get rotor to where GM pointed rotor with out rolling crank around to feel for compression at #1 cly.
Mostly covered in the replies already. @WashBear2 Pull the p***enger side rocker cover off as well and observe # 6 while trying to get #1 at TDC The exhaust and intake should be "on the rock" as # 1 is at TDC [on the rock means exhaust closing as intake is opening , rocking like a chair] My 2 cents is [especially with electronic /HEI ignitions ] is once you have established true TDC on # 1 cylinder BUY some timing tape for the balancer [$5.00 now will save a lot of grief later] You can get the distributor rotor pointing approx in the correct position , it will start and run [then time it on the fly with a timing light] Use a sharpie and mark on the distributor body adjacent to where # 1 plug lead is.
here's how a shop does it... put a compression gauge in the hole..(being safe) soon as it start to show compression... look at the timing mark, and slowly bring the marks together... thats top dead center... drop the distributor in... even if it doesn't go all the way. if the wires are on the distributor look where #1 is , looking at the pin for the cap..notice where # 1 is on the cap... and point the rotor to that spot on the distributor... doesn't matter if it drops all the way...it's in the cam gear.... if it doesn't drop... bump the starter till it drops in the oil pump slot... tighten the distributor HOLD DOWN TO WHERE ITS SNUG... BUT YOU CAN STILL TURN IT... hook up timing light... start the engine, and set the timing to engine specs... if its cranking to hard... turn it slightly till its cranking correct.. once it starts... set the timing with the light...done
I run with scissors, so here... hold my beer... I stick my finger down by the plug hole... I'l tell you to bump the starter till the # 1 hole is getting compression... soon as I feel the compression.. I stop and have you bump the starter till the timing marks line up... done... don't stick your finger in the hole like it's a prom queen...you just wanna cover the hole a little to feel it fart...
When the dots on timing set are lined up next each other, that's actually TDC (firing) for cylinder 6. Cylinder 1 at that same position is on exhaust. The balancer timing mark is also lined up. But remember in a 4 cycle engine it takes 2 revolutions (720 degrees, firing every 90 degrees x 8 cylinders equals 720 degrees) to come around to firing. Firing order is 1843 6572, I deliberately put space to show that 1 and 6 are separated by 1 full revolution. BTW, you can also use cylinder 6 for timing light due to the same features as described in paragraph above.
Better pic? kinda glad this came up cause the HEI vs points dizzy comment engaged a brain cell that hasn’t been activated in decades I better get my ancient Chiltons out
I find it best to only look at the timing sprocket dots while I'm installing the timing chain. Then I look at rocker arms to install the distributor. Otherwise, it gets confusing.
I’v never dropped a distributor in before going thru the valve’s. Let alone do it with the timing cover off.
After a while you get good at making sure the engine is ready to install the distributor, by always leaving it in #1 firing position after putting it together. Or before you take stuff off of it, if it's still in the car.
This is the typical position of the distributor when installed. The vacuum advance will point toward #6 and the points window will be fairly straight ahead. This is around 10-15 BTDC. Moving it clockwise will back off timing. Pulling the vacuum advance forward will advance timing. Took a bit to find a HAMB friendly engine.
Thank you everybody. It’s humbling get hung up on simple ceap like this. I actually didn’t even think about just wiggling the dizzy to find out where it actually fires. I’ve mainly fooled with points cars. My silly little motorbikes mostly have electronic but they’re single cylinder 2ts, much easier. I can make it start now, but it still refuses to idle. I’m going on a hunt for air leaks in the morning.
Don't let your finger get ****ed in the spark plug hole ......is that like the ooffee cup warning , contents may be hot ? Probably more like an old friend of mine , after I welded a part for him , he grabbed it out of the vice ....
The Jalopy Journal
