Distributor

[Andrew77]

Hi,

Please can any one help...
Would it be possible to accidentally put the distributor on the wrong way round by 180 degrees?

If you did, what would happen to the engine? Would the engine still start?

I think I may have done this, but not sure! I don't want to turn it around if it is correctly positioned.

The piston is at the top of the cylinder, the top dead centre marks are in line with the engine case, but the rotor arm is 180 degrees out.

The engine is turning over, and I have spark at the plugs, but it is not firing.
I have checked the carbs and the timing, and seems fine.

Any suggestion would be much appreciated.

Andrew

[peter leinberge]

yo.
The distributor gear slot is offset slightly to one side.
It needs to be "clocked" for lack of a better term.
Put cyl 1 (on right side of engine furthest away from you unless it's a 914)
at TDC. Make sure crank pulley slot lines up with mark on case.
remove dist. cap, see if mark on dist lines up with plug wire going to cyl. #1 or at least is in close proximity, close enough that you can turn the dist. one way or the other to get it lined up.
That should tell you if the gear is properly positioned and go from there.

[WFBowen]

Andrew
Make certain that you’re at TDC on the compression stroke. Bring cyl. 1 to your current TDC setting. Now pull your pass. side rocker cover, grab the 2 rocker arms for cyl 1 and make sure both have slack and are both closed and are visually in the same position. If not, rotate the crankshaft another 360deg. and see if you are now at TDC on the ignition stroke.
Bill

[tatch10]

Andrew, I did this once. The oil rubber gasket was so tight, that even though I was 180* out, I still got occasional action. Solution- I took off the distributer cap, grabbed the rotor, and forcefully rotated it 180*, took the rotor off, then used a rubber Mallot on top of the rotor drive shaft ( gently), and then watched as the distributer dropped into it’s natural position. I am assuming it ran successfully before eliminating the possibility that the distributer drive gear missed a notch. Never heard of this happening 180*
Ben

[wkrtsm]

If you ensure the following three things are correct, you should resolve any issue surrounding the potential for the distributor to be off 180 degrees:

First, make sure the ignition key is out (you don't want the engine to start). Then remove the left and right valve covers, and distributor cap.

1. Align the crankshaft pulley so the two hash marks at top dead center (TDC) are aligned with the TDC groove on the engine casing. (i use a large wrench on the generator nut to turn the crank)

2. Confirm that there is slack on both rocker arms (for intake and exhaust valves) on cylinder 1. To do this grab each rocker arm (intake, exhaust) and try to wiggle them. When cylinder 1 is at TDC, there will be no force on the valves from the push rods as they will be fully closed, resulting in slack in the rocker arms. When a valve is open (even slightly) there will be no slack in the respective rocker arm since it will be under force, or tension).

3. Look at where the rotor is pointing on the distributor. When the crank is at TDC for cylinder 1, the rotor will be pointing to the right rear tail light, or your right shoulder when facing the engine.

Once the above three criteria are met, just make sure the spark plug wires trace to their respective cylinders. After this there should be no problems.

Note that the TDC mark on the crankshaft pulley will be at the TDC position twice during the firing order sequence (1-4-3-2), once when cylinder 1 is at TDC and once when cylinder 3 is at TDC. The reason you removed the left valve cover for cylinders 3 & 4, is to confirm cylinder 3 is not at TDC when the crank pulley TDC marks are not aligned with the TDC mark on the casing. Because when cylinder 3 is at TDC, BOTH its rocker arms for intake and exhaust will have slack. However, you will know when cyl 1 is TDC when BOTH its rocker arms have slack and the crank pulley is upright at TDC.

(a rule of thumb when doing anything related to removing the distributor is to mark on the engine casing with a sharpee where the rotor is pointing before pulling the distributor, and then don't move the crank shaft. If you drop the distributor back in the casing with the rotor pointing to where the sharpee mark is, there will be no problems. you have to go through the TDC steps above because it sounds like you did not follow this rule)

See the pic below to see where the distributor rotor should be pointing when cylinder 1 is at TDC. The spark plug wires must also trace from the position on the cap to each of their respective cylinders.