• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Help with timing

hunt2elk

FBBO Gold Member
FBBO Gold Member
Local time
3:14 AM
Joined
Jul 15, 2009
Messages
10,544
Reaction score
11,694
Location
WI
I'm hoping one of you engine guys can help me figure out why the timing reads high on my car. Ever since the motor was rebuilt I have had extremely high readings, but the car runs great. I noticed that the #1 plug wire on the distributer is pointing to the front of the vehicle. The vac. advance is pointing towards the battery (which is normal, I think). My other car and others I have looked at all have the #1 of dist. pointing to the front of the passenger side valve cover. This positioning makes mine 2 holes off. Can the rotor-dist. shaft relationship be changed, and would this change the readings? Also what is the easiest way to find top dead center on a motor that is all put together? I did buy a comp cams tdc tool that screws into the #1 plug hole. I am thinking the shop that rebuilt the motor did something not quite right when aligning everything up.
 
Your talking about your 383 right?

Just have your buddy place his finger covering the #1 spark plug hole and when it gets blown off you should be very close to tdc at the #1 ...A 383 has the same firing order as a chevy 18436572 and it goes counter clockwise
 
Forgot to mention that this is a 383. If the dist. gear is off a tooth, what is the easiest way to check?
 
if you put the mark on the harmonic balancer to ( O ) that will be the long line on the balancer take the cap off and it should be on #1 or #8 .....Artie
 
What are your timing readings? It really doesn't matter where your distributor is placed so long as your initial timing can be set. The advance mechanism is what controls your total but the more initial you have the more total it'll have. If it's running great, it seems to like it. Is it pinging? What's the compression ratio? Lower compression engines usually like more timing....
 
Timing

Dosent make any differance wich hole the # 1 wire is in as long as it alines with the rotor when your engine is at TDC and you have enough room around the vac advance for fine tunning the timing.
 
Good advice so far. If it runs good and the timing light is showing you an odd reading, it is possible that the balancer's outer ring is slipping. That happens fairly often when they get old.
You could find tdc like described above and make some marks or stick some timing tape around the balancer.
 
Hey,
I have seen readings very high before, and it turned out to be the reluctor installed incorrectly in the dist.
If your running a stock electronic dist, and someone had it apart, make sure the reluctor is installed using the correct role pin location. Putting it in using the small block location will cause a high adv reading for the engine to run correctly!I have done this experiment on my engine and had these very results.
 
I'm using the mopar ignition kit that comes with the orange box, distributer, ballast resister, and wire harness. It was new when the motor was rebuilt. 9.5 compression ratio. My initial timing is 31 and was checked with 2 different lights. At 2000 rpm the timing is 44. With the vac. advance hooked up @ 2000 reads past 60 which is where my light stops. I have been playing with this for 2 years and keep advancing the timing. It keeps running stronger and I have not got it to ping yet. I do think I am getting close to perfect though. It starts very good cold or hot. I just want it to read correctly which it is not doing now. Could it be as simple as the distributer being installed off?
 
This is a nice article out of one my mopar books:::::Mopar Timing
The purpose of this document is to describe the precise way to set timing on your Mopar engine. It applies to non-computer controlled engines only.

Tools Needed Timing Light
Vacuum Gauge Vacuum pump (hand held) Vibration Damper Timing Tape Allen Wrench (if car has vacuum advance distributor) Tachometer (hand held or a helper if dash mounted) Distributor Hold Down Wrench
Ignition Timing Theory Timing is the point, measured in crankshaft degrees, that the distributor fires each respective spark plug. The measurement is established on the number 1 cylinder of all Mopar engines. Once the timing is set the distributor fires each consecutive spark plug at the same number of degrees. The crankshaft is divided into 360 degrees, a perfect circle. The point of reference is 0 (Top Dead Center {TDC}). Timing is measured After Top Dead Center (ATDC) or Before Top Dead Center (BTDC). The 0 reference means the number 1 cylinder piston is on the compression stroke at the maximum point of travel before beginning to move away from the head on its power stroke. All engines include a timing mark on the vibration damper and a gauge usually attached to the timing gear cover. The gauge usually measures from 0 to about 12 Before Top Dead Center (BTDC). BTDC is also called advanced timing because firing occurs before the crankshaft reaches the 0 point in rotation. ATDC is called retarded timing because firing occurs after the crankshaft reaches the 0 point in rotation.
The objective is to establish the minimum timing and the maximum timing of an engine. The maximum timing is the most critical from a performance standpoint. An engine needs less timing (fewer degrees of advance) at low RPM and more at increased RPM. The increase in BTDC degrees occurs over a smooth line as engine RPM increases. The line may be linear or exponential depending on the type of equipment added to control timing.
1
Components That Affect Timing
Distributor – the primary device, which is adjusted to establish minimum timing. Vacuum Advance – a device that increases or decreases the timing by moving the distributor plate. It is controlled by the amount of vacuum the engine produces. The source of the vacuum is a ported opening in the carburetor. Mechanical Advance- consists of weights attached to the distributor shaft, controlled by coil springs attached to the distributor plate. Centrifugal force created by the speed of the turning distributor shaft is transferred to the weights attached to it.
Total timing is determined by measuring Initial timing (distributor setting) + Vacuum Advance (the setting of the small diaphragm can attached to the distributor) + Mechanical Timing, the advance caused by the weights attached to the distributor plate and controlled by the strength of the springs.
Correct adjustment of timing affects the quickness of the engine starting, gas mileage, amount of horsepower, rod bearing life, valve ping, and idle quality. Timing that is set outside the parameters of the capability of the engine may cause severe damage to the engine.
PROCEDURE
Step One Determine the base line of the settings that affect timing and write them down.
Initial timing -Start with a COLD non-running engine. Find the timing mark on the vibration damper (the big round wheel about 1 inch thick behind the belt pulleys at the very bottom front of the engine). It is a perpendicular mark that is cut into the damper. Clean the mark with an appropriate shop cleaner such as WD40 so it is clearly visible. If it is not clearly visible after cleaning it use an artists brush with white paint to paint a thin line on the mark. -Attach Mopar timing tape or measure and mark degree increments on the vibration damper to about 40 BTDC. (Note 1 inch equals 16 and 2 1⁄4 inches equals 36. -Find the degree gauge usually attached to the timing cover and visible from the top of the engine. Clean it also, so the numbers and marks are clearly visible. -Find the distributor hold-down clamp and bolt. Loosen bolt then tighten very slightly.
2
-Find and disconnect the vacuum line to the distributor. Connect the vacuum gauge to the line. -START ENGINE, outside of garage, and run until Engine operating temperature is reached and choke is completely off, transmission in Park.
-Determine your vehicle’s ideal idle speed in RPM; usually 600-800 RPM. If you have a high performance cam it may be as much as 1100 RPM. -Connect tachometer to determine idle rpm (SEE DRAWING No. 1). -Adjust carburetor idle screw to achieve desired rpm.
-TURN ENGINE OFF.
-Connect Timing Light
-START ENGINE and point timing light at mark on damper.
Record the timing reading and the vacuum reading.
-Disconnect the vacuum gauge.
-Re-connect the vacuum line to the distributor.
-Run the engine up to 3000 RPM, point timing light as above. - Record the timing reading.
-TURN ENGINE OFF
You have now established the theoretical minimum and maximum timing. Mopar performance recommends a maximum (total) of 35 BTDC for street engines. The following step will identify and quantify the source of timing which exceeds the minimum (initial) timing.
Step Two -Disconnect the vacuum line to the distributor. -Connect a vacuum gauge to the end of the vacuum tube you disconnected. -START ENGINE, RUN UP TO 3000 RPM, repeat with timing light as above. Record the timing reading and the Vacuum gauge reading. -Subtract the first maximum timing reading from the second maximum timing reading. The difference is the number of degrees of advance timing the vacuum system is adding. -Subtract the minimum (initial) timing (step 1) from the maximum timing as recorded in step two. The difference is the number of degrees of advance timing the Mechanical advance system is adding.
Now lets look at an example, which will help you decide the next steps. Lets say the minimum timing is set at 8 BTDC, the vacuum advance provides an additional 13, and the mechanical advance provides 21 at 3000 RPM. 8+13+21=42. This is too much advance timing. We have 3 choices:
3
1) Reduce the minimum timing (initial) to a point that 35 is achieved by the above tests. Set up the minimum timing procedure and retard the distributor to a number less than 8, then re-measure everything again. Keep adjusting and measuring until the number is achieved. OR;
2) Reduce the Vacuum advance to a point that 35 is achieved. This done by removing the vacuum line at the canister on the distributor and inserting the 3/32 inch Hex head Allen wrench, through the hole where the line was connected, into the set screw (inside the canister) and turn the screw to the right (in) to reduce the amount of advance (or left to increase). Turn the screw one (1) turn and record the amount “1 turn right”. Re-connect the vacuum line, run the engine back to 3000 RPM and check the timing again. If still too high turn to the right and record the number of turns (or partial turns). Check timing again. Continue to adjust until the 35 is achieved.
-Alternately you may use the hand held vacuum pump and the reading for vacuum from the first and second step instead of running the engine up to 3000 RPM. OR;
3) Change the springs on the distributor plate and check timing in the same manner at 3000 RPM. This is a fairly complex process and beyond the scope of this document.
You may have to use some combination of all three to achieve the desirable results which include; easy start, good idle, power throughout the RPM range, and no valve pinging.
Disconnect all equipment and replace hoses. Happy motoring!!!!
The EPA prefers low BTDC settings to reduce emissions. Unfortunately, this is counter to a high performance engine.
If you don’t have the above equipment and/or do not want to go through the involved process, there is a fairly simple procedure to use, which will produce, desirable but not optimum performance.
Steps
-Loosen the distributor hold-down clamp bolt. -Start the engine and turn the distributor a small amount in the direction that the engine speeds up. This is advancing the timing. -Tighten the bolt without moving the distributor. -Turn engine off, and then re-start. It should turn over without hesitation and start quickly. If not reduce timing slightly. -Test drive the vehicle. From cruising speed (about 50 MPH) accelerate slightly and listen for valve noise from under the hood. Accelerate fully and observe valve noise and vehicle performance.
4
If no valve noise, repeat the entire process. When valve pinging is heard reduce the advance by turning the distributor slightly in the opposite direction from above. Re-test and adjust if needed. Once this state is achieved your engine is handling all the advance timing it can take.
600-800 rpm
Tachometer
Connect Ground lead to a good source of ground. Connect other lead to the Negative (-) side of the coil
+
-
Coil
GROUND
Drawing No. 1
5
Timing Light
Drawing No. 2
No. 1 Cylinder Spark Plug Wire
Pos
Neg.
Battery
6
 
Thanks Pops, but I understand and have done everything from that article. I am thinking something is not letting me corrospond the actual timing reading to my measured timing. I had some time today and think I found tdc with the comp tool I had. It looks like the timimg mark on the dampener is almost 3" off from tdc. Is it possible there would be that much movement?
 
You should set your initial timing with the vacum advance capped off. then hook it up. If you have the advance hooked up to too much vacum then it is maxing the dist. out at idle. The advance should be hooked up to a port that has no vacum at idle but pulls harder as you accelorate.
 
You should set your initial timing with the vacum advance capped off. then hook it up. If you have the advance hooked up to too much vacum then it is maxing the dist. out at idle. The advance should be hooked up to a port that has no vacum at idle but pulls harder as you accelorate.

This is how I have set it up.
 
TDC is what you need tto determin. If your mark on the balancer is not lined up with the timing tab0 deg mark, then determin if the timing cover is wrong, or did the outer ring spin on the inner hub. If you have determined that the balancer is good, put a new mark on the balancer to line up with the timing tab zero and adj timing from this mark. Is this a new balancer? Is the timing cover from the engine or not? Was it a cast crank engine converted to a steel crank? I don't know if the timing cover timing tabs are the same or not, but something is up...
 
The motor is a #'s matching in a 69 RR. As far as I know everything was original. I didn't realize it was possible for the balancer to spin. If it did move already, what would stop it from going farther? This would make sense though. I am going to try to find another to compare. If I end up having to buy a new one, is one better than another?
 
O.K. guys, update on what I have done. Pulled the crank bolt out and compared my harmonic balancer with 2 others. They are all the same with the keyway 90 degrees from the timimg mark. So my balancer has not slipped. When I put the timing mark on the "0" on the tab, it looks like the rotor is a little past the #1 plug of the cap. I pulled my distributer and moved the oil pump gear first a tooth one way and then a tooth the other way. After moving the distributer to get it started and idling good, I still had the 31 degrees initial timimg reading no matter where the pump gear was located. So would my next step be to pull the timing cover to make sure the dots are aligned? Would the motor run as good as it does if the marks are off? If I do this how do I tell exactly where top dead center is? Thanks for any help as this is driving me crazy.
 
You could pull the dist and move the drive gear a tooth at a time untill you have made a complete circle, and it wont change a dang thing... One tooth off is IMPOSSIBLE....
I still say you should pull the dist cap and check to make sure the reluctor is in the correct location. One role pin location is for a small block and the other is big block. the little arrow points in the direction of rotation for both types. I have seen readings such as yours with this in the wrong position. I put mine together in the wrong location, because the last one I had apart was a small block, and I was thinking of it during assembly. It had the same timing as yours, and wouldn't run worth a **** below that setting. I too thought,,,"wow, how could I have something wrong when it runs this good at such a high degree of advance"? I pulled the timing cover off twice checking and double checking the timing! I made a new degree wheel too, just to be sure I was getting good readings!
It wasn't untill I changed the dist to a Mallory did I realize it was actualy a problem in the dist itself. After further inspection, I realized what I had done and shook my head with an under the breath, "You dumb ***!"... LOL! Of course I know better than to do this, but sometimes you get your thoughts mixed up a bit....
Anyhow,,, just do yourself a favor and have a look....
Good luck!
 
This is how I have set it up.

BTW,,, The vac adv should be hooked up to "ported vacuum" not "manifold vacuum". Ported is typicaly any port located above the throttle plates on a carb.
If you think differently just look at a PDF online from different manufactures. Manufactures like Holley point out ports with comments such as "Vacuum advance port".
 
Auto Transport Service
Back
Top