Thread: Ignition timing woes. Help please

The most likely problem is that the timing marks are incorrect. You can check this fairly easily.

Remove all the plugs so the engine can be easily turned and will stay wherever you leave it, and remove the rocker cover so you can see what the valves are doing.

Turnit until the No.1 cylinder has both valves closed and is coming up (should be able to feel the air coming out of the plug hole), and use a 'feeler' such as a thin wooden skewer to feel the top of the piston, and by moving the fan back and forth set the piston to exact TDC.

Then check where the timing marks are. It should have a single groove in the crankshaft pulley, opposite a three pronged pointer. The manual tells you which point is TDC.

If it is incorrect, the key locating the pulley on the crankshaft is probably sheared.

If this is correct, look for the timing chain having slipped, but I think this is unlikely. You can check this by comparing the valve movement with the timing figures in the manual.

Hope this helps,

John

G'day Preso,

Welcome to the Landrover series forum.

Some basic info needed:

Landrover engine 2.25Lt 4 cylinder or 2.6 Ltr 6 cylinder?
or maybe Holden 6 or other?

Type of carburetor? either Zenith or Solex or other.

Original distributor type number Lucas 25/29 45D or Ducellier?


However, from your test description in my opinion there is nothing wrong with the timing and only needs to be set up properly using static/ dynamic timing. Your electronic ignition instructions should tell you how to do this. You could refit the original distributor and static time it. Those pulley timing marks are for static timing not dynamic timing. You need a timing wheel fitted for dynamic timing.

What you are seeing is the centrifugal advance (and maybe some vacuum advance as well) operating as it should. From my Excel sheet timing chart for the 45D, 20 degrees BTDC the RPM will be between 1200 to 1800 depending on the static timing setup. Does this correspond to your RPM when you were testing?
I would also check the timing marks are correct on the crank pulley. Check the TDC.

Because the vehicle has been sitting for 10 years the carby is probably clogged up with dirt and stale petrol. It will need a rebuild.

Just noticed John replied whilst I was looking for my timing charts. All good.


Chris

Thanks for the prompt replies. The vehicle in question has the 4 cylinder petrol engine. I thought it was 2.4 litre but it is probably the 2.25 litre as suggested by Chris. It did have the Lucas 25D distributor until we changed it out for the Accuspark unit. The carburettor has been changed to a Holden Stromberg unit and it has not been overhauled however prior to the ignition timing problems the engine was starting and running perfectly. I should mention that the fuel tank has been out of the vehicle and some leaks were patched. I did suspect that there may have been a fuel blockage but we also fitted a new fuel filter prior to refitting the tank in case some debris got carried over into the carby.
John, we did check the timing mark was correct by finding TDC on #1 cylinder during the compression stroke and verifying that the pulley mark was where it should be. When we can get the engine running we can verify that the vacuum advance is working although as I said it seems that the timing mark is around 20 degrees from where it should be when using a dynamic (strobe) timing light.
My next test is going to be to remove and earth all the plugs and then try turning the engine with the crank handle, slowly, so we can see if the sparks are happening at TDC on all cylinders. It might be difficult to see with any certainty if the timing is right or wrong but I am running out of ideas and patience. My friend has had a mechanic (who normally maintains equipment for the golf club) look at the vehicle since I saw it last and he has told me that the engine is starting and running well with the old Lucas distributor but the distributor is not where it should be or at least not where it was before all these problems showed up. That is to say it appears to be rotated around 15 degrees clockwise using the axis of the vacuum advance as a reference. Before our little jaunt down the hill the engine was running with the distributor vacuum advance axis parallel to the side of the engine. I told my mate this morning that the next step might have to involve removing the timing chain cover to make sure nothing has slipped or stripped but honestly, I don't want to go there!
Still mystified.

Regards,
Preso

G'day Preso,

Gee your almost back on the road. Before we talk about valve timing can you advise the engine number.

The 25d is a single step centrifugal advance dizzy. The vacuum advance is 12 degrees of crank.

The 45D is a better one with 2 step advance.

Chris

G'day Preso,

Gee your almost back on the road. Before we talk about valve timing can you advise the engine number.

The 25d is a single step centrifugal advance dizzy. The vacuum advance is 12 degrees of crank.

The 45D is a better one with 2 step advance.

Chris

'The distributor has the offset key drive so it can only go one way into the engine'
As long as the bottom part was put the right way round !!!!
It can be put in 180 out as Its not off set.
1 3 4 2 is firing order, with rotor pointing at No 1 cylinder. Anit clockwise viewed from top

whitehillbilly

Chris,
I only work on the rover once a week but I will check the engine number on Tuesday.
Whitehillbilly64,
My understanding was that the bottom key was offset. I have tried to turn it 180 degrees but it will not go into the drive shaft from the cam. I did consider that this might be the problem so I did also check with the manual I got from the Accuspark vendor. It stated that the drive was offset and that it could only be inserted one way. Still none the wiser!

Regards,
Preso

The distributor drive coupling which sits on top of the oil pump drive shaft, has an off set on the top side, to which the distributor off set sits into,
but the bottom side is central, so can be off set by 180 deg.
Tried to find a pic to explain, but cant find one as yet.

whitehillbilly