Ignition Timing

From Holdenpaedia

Page created by T April 9th 2012:

Blue/Black Timing Marks. Note the Timing Mark on the Harmonic Balancer bisects the Bolt Hole and rectangular arc on the Balancer Boss. This is the correct position for a Blue/Black Harmonic Balancer in good condition. A failed one may have the outer part of the Balancer rotated anticlockwise from the correct position. Click to Enlargen. Photo by Jesse_Madden.

1 Ignition Timing:

[edit] Ignition Timing:

This Page provides info on how toTime the Ignition of Holden Engines as well as the Firing Order.

[edit] Firing Order Holden V8 and 6:

When setting the ignition timing on any Holden engine it is important that Cylinder number 1 be at the timing mark on the firing stroke and both the inlet and exhaust valves for Cylinder number 1 are closed. This position is slightly before Top Dead Centre (TDC). Note there is a second and unwanted timing position which occurs at the end of the exhaust stroke. When this position is present both the inlet and exhaust valves will be "on the rock" i.e the exhaust valve will be closing and the inlet valve opening. "On the rock" is also known as "Valve Overlap" because both valves are partly open at the same time or overlapping. Setting the ignition timing to the Valve Overlap position will cause backfiring out of the carburettor and the engine will fail to start. This is because the plug will spark while the valves are open instead of them both being shut.

Timing Mark for red Six Engines from EH - HG. The long Mark is for 5 degrees of advance and the graduations in 2 degrees. Photo by Vuss57. Click to Enlargen.

173, 202 and LJ 138 Timing Marks. Photo by Jacks. Click to Enlargen.

[edit] Holden V8 Firing Order:

1-2-7-8-4-5-6-3

[edit] Holden V8 Breaker Point Distributor Position and Timing:

[edit] Holden V8 HEI Distributor Position and Timing:

[edit] Holden V8 Cylinder Positions:

The cylinder positions are sometimes written on the inlet manifold.

Engine Front Left	Engine Front Right

2	1
4	3
6	5
8	7

[edit] L34 Single and Dual Coil Distributors:

[edit] Holden Red/Blue and Black EFI VK 6 Cylinder Firing Order:

1-5-3-6-2-4

The arrow shows the rotational direction of the Harmonic Balancer when viewed from above. In other words the Engine rotates clockwise when viewed from the front.

The Alignment Mark for the Rotor Button and the correct position for the Distributor Body at TDC of Piston 1. Photo by HQ_SS. Click to Enlargen.

[edit] Further Timing Red/Blue/Back Six Cylinder Engine Details:

The Crankshaft must have the Harmonic Balancer Timing Mark in the correct position. The Timing Mark on the Harmonic Balancer may be in the wrong place or the outer part of the Balancer may have spun in the anticlockwise direction on the Balancer centre so check the images at this page to be sure the marks are in the correct position for your model Holden Engine. There are 2 broad categories.

All Red engines use the Red Harmonic Balancer.

All Blue/Black engines use the Blue/Black Harmonic Balancer.

1. First set the Crankshaft to the correct position by removing the Oil Filler Cap from the Rocker Cover and watching the frontmost Valve (the Number 1 Inlet Valve) as you rotate the Crankshaft. You can rotate the Crankshaft by putting a 1/2 " Spanner on the a Water Pump Bolt if you have Thermo Fans. Pressing down on the Fan Belt on the side nearest the Fuel Pump as you turn the Spanner will make the Fan Belt grip better.

2. When the Inlet Valve starts to open, the Number 1 Piston is beginning to descend on the Intake Stroke. When the Inlet Valve shuts the Number 1 Piston is on the Compression Stroke.

Note that there is a second Top Dead Centre at the end of the Exhaust Stroke sometimes called "On the Rock" or "Valve Overlap". This occurs as the Exhaust Valve is closing. This is the brief period where both Valve are paritally open. The Timing Mark will also line up here, but this is not the TDC position you need.

3. Keep rotating the Crankshaft until the Harmonic Balancer Timing Mark lines up with the 6 degree mark on the Timing Cover. Now you have the Crankshaft set at 6 degrees before Top Dead Centre set on the Number 1 Compression Stroke set accurately.

4. Now position the Rotor Button, Distributor Body and Number 1 Spark Plug Lead all to line up as per the 6 cylinder Diagram at this page. Note that the Distributor Shaft will turn anticlockwise as you lower the Distributor into the Engine. That means that you will have to position the

Distributor Shaft further Clockwise than in the photos so that it will rotate into the proper position as you lower it into place.

You have now set the Static Timing to 6 degrees.

The Distributor is in the incorrect position. It has been rotated too far anti-clockwise making timing adjustment and Vacuum Hose connection very difficult to achieve. Click to Enlargen. Image by Red Seat.

[edit] Practical Timing With Cap Priming:

If you watch this Link you'll see the first step taken is to Cap Prime the Engine .... 202 First Start.

They place the Fuel Can away from Engine which is very advisable since Exhaust Flame soon becomes evident.

The Engine's problem is likely Plug Leads in the wrong location because you see Backfire come out the Carburettor.

Also the sound the Engine makes indicates misfiring of some Cylinders.

At 10 seconds they retard the Spark Timing by rotating the Distributor clockwise, but rotate it too far then try to compensate by rotating anticlockwise, but too far. On the Next Start the Engine kicks back under Cranking because it is too far advanced.

They address the Timing issue but by then there is no Fuel left in the Inlet Manifold and another Cap Prime should be done.

You'll note they are running out of Battery which is why Cap Priming is so important.

Finally heavy Backfire from the Exhaust occurs when they adjust the Distributor with the Engine running. This is because one or more Plugs is sparking while its Cylinders Exhaust Valve is open.

[edit] Checking the Static Timing With the Engine Running:

Once the Static Timing is set, remove the Vacuum Advance Line from the Distributor and plug it off. This makes sure that no Vacuum gets to the Distributor and that there is no Air Leak in the Fuel System.

Connect a Timing Light and start the Engine. You now aim to make the Ignition Timing and the Idle Speed agree. They will interact with each other.

If there is too much advance, the Idle Speed will be too high.

If there is too little advance, the Idle Speed will be too low.

You may need to adjust the Ignition Timing to 6 degrees first, then check the Tachometer.

Adjust the Timing and Throttle Stop until the Idle Speed and Timing are correct.

Once done, reconnect the Vacuum Advance Line to the Distributor.

The Bosch HEI page has timing from scratch details

3.3 engine (Blue/Black) Harmonic Balancer. Note the Red Arrow. For a Visual Check, note the Timing Mark bisects the upper Bolt hole pointed to by the Crankshaft Keyway and the rectangular Gap in the Balancer. Image by Jacks. Click to enlargen.

Despite being black in colour, the item on the right is a Red Engine Harmonic Balancer. Note the Red Arrow. The Timing Mark is at the clockwise end of the rectangular arc immediately anticlockwise from the Crankshaft Keyway. Click to Enlargen. Image by Mark Berner.

[edit] Grey Motor (132, 138, 6 CYL) Firing Order:

1-5-3-6-2-4

The arrow shows the rotational direction of the Flywheel when viewed from above. In other words the Engine rotates clockwise when viewed from the front.

[edit] Finding Grey Motor Cyl 1 TDC Firing Stroke:

Remove the Oil Filler Cap and note the position of the Cyl 3 Inlet Valve Rocker Arm which is to the front of the Oil Filler Hole.

Rotate the Crankshaft until the TDC mark on the Flywheel has aligned on the Cyl 1 Firing Stroke and Cyl 3's Inlet Valve is open (the Rocker Arm will be down on the Manifold Side).

This tells you the TDC mark has lined up for Cyl 1 correctly and saves removing the Rocker Cover to identify the Cyl 1 Valve Positions.

Grey 138 cu in Holden Six Cylinder Engine. Note the Vacuum Advance Diaphragm axis is parallel to the Engine. Click to Enlargen. Photo by Stock EJ.

Grey Holden Six Cylinder Engine Distributor. Click to Enlargen. Photo by 1962_EJ.

Grey Holden Six Cylinder Engine. The Timing Mark is behind the Thumb Tab at the Bell Housing near the Distributor. Same for all Grey Sixes. Click to enlargen. Photo by Qute.

[edit] Chevrolet V8 Firing Order:

1-8-4-3-6-5-7-2

[edit] Chevrolet V8 Cylinder Positions:

The cylinder positions are sometimes written on the inlet manifold.

Engine Front Left	Engine Front Right

1	2
3	4
5	6
7	8

The Rotor Button will have to be in this position before installing the Distributor into the Engine. This is because it will rotate anticlockwise as the Distributor enters the Engine. Photo by HQSS. Click to Enlargen.

173 with Bosch HEI Conversion. Note the Distributor Body needs to be rotated anti-clockwise by one Plug Lead Position to permit Timing and allow for connection/disconnection of the Vacuum Advance Line. Photo by Red Seat. Click to Enlargen.