Changing the distributor

[youngb506]

I've just received an original, unused distributor from the club spares and I see in the manual that I'm supposed to turn the engine till the rotor arm is pointing at no 1 cylinder before removing the distributor. Trouble is that the cam on my old distributor doesn't move at all. Can I achieve the same setting by sticking a long screwdriver down no 1 cylinder, through the plug hole, and feeling when it's at the top of its stroke?

[dalebrignall]

i would use a drinking straw just to stop possiable damage to the bores its probally over the top but good to be safe .

[mogbob]

Note the relative position of the old distributor in situ. You can take a photo , scratch a mark on the old distributor body and the clamp holding it in the engine with an old screwdriver.
With rocker cover off , line up TDC on the pulley / pointer attached to the engine. Check Number 1 cylinder ( by radiator end ) valves are both fully closed. Turning over the engine by hand will be easier if you remove all the spark plugs first. Once the cylinder is at the top you should be OK to remove the old distributor. Clean away all the oil and crud away from the base with a degreasant and a rag / paper towel , so that no dirt goes into the engine.

Make sure , when you compare old with new , that all the old distributor has come out. If any metal bits have come adrift you
will have to go " fishing " with a small magnetic pick up stick in the hole.
Once cleaned up , mark the replacement distributor on a strip of masking tape on the side , with a rough mark equivalent to the scratch on the old one. It will give you a starting point.
Another double check is to look down the hole and see which side the offset slot for the key to engage in , sits. If you line up the new shaft , in correct orientation , does the rotor arm point to the No 1 cylinder ? Lightly oil the bottom of the shaft to ease it into the hole
You will have to rotate the distributor to tune the engine for best tickover so just tighten the clamp to allow "some " movement but not too loose.When you're happy , tighten up the clamp finally.
Good luck with it.
Bob ( Old.. probably too old for my own good ! )

[simmitc]

Have you already removed the old distributo? If no, then the cam won't move because it is engaged with the engine, you have to turn the engine in order to rotate the cam. I have never known a distributor to seize in such a way that it stops the engine from turning over.

However, it is not necessary to have the distributor in any set position to remove and refit as long as the drive shaft has not been removed. Since the shaft of the dizzy will locate in the drive shaft in only one poisition, then it must end up in that position in order to fit. It is still worth noting where the rotor arm is pointing before removing the old unit because you can set the new one in the same position and then feel it in as you fit the new unit.

You will need to set the timing using No. 1, but that's a slightly different matter. Your new unit should be a good investment.

[youngb506]

Thanks for that. The engine rotates fine, it's just the cam that's not moving.( I suspect it's lost contact with the drive gear in the distributor because the screw in the middle of the cam was loose.) So, the end that sticks out of the bottom of the distributor will only go in one way, so no need to find tdc on cylinder 1 anyway. That's very helpful to know.

[bmcecosse]

Of course you need to know- so you can position the contact in the cap opposite the rotor arm when the piston is at TDC on the firing stroke.......

[youngb506]

Confused again if the distributor will only fit in one way. How can you position the contact in the cap anywhere when the contacts in the cap are fixed?

Is this really complicated?. Can anyone point to an article where this is fully explained? I've been driving this car nearly every day for 20 years and I've been able to fix just about everything if I can find full details of how to do it but none of the four different manuals I have explain how to put in a new distributor when the old one's cam won't turn. Hoping to drive to Norfolk in a week.

[dalebrignall]

its easy , just make sure cylinder 1 is at top dead center check that the rotor arm is pointing to cylinder 1 if it is loosen the clamp and the 2 studs that hold dizzy in place , take out old dizzy . replace with the new one making sure the rotor arm is pointing the same way , put in the 2 studs ,start engine , rotate dizzy till you get the best idle tighten up clamp and away you go .

[simmitc]

Correct that the end that sticks out will fit only one way round. If the cap remains connected to the plugs then nothing is going to get moved anywhere. Swapping the distributor is not a major operation.

[iconic]

I understand the OP confusion....as Vicky Pollard would say.

Yes.....the dizzy shaft can only fit one way...

but...

No ...the dizzies 'outside' can be twisted so that lead number one could be 90' or 180' degrees out.

....its difficult to put into words...a eureka moment will happen and it all drops into place, good luck.

[liammonty]

Just remove the old distributor and replace it with the new one. Make sure that the slotted end engages in the offset driveshaft by rotating the rotor arm until it slots into position as you push the body of the distributor down. Make sure that the body of the dizzy is in the same rough position as the one you took out - just gauge it with the position of the vacuum advance unit. As long as the position is similar, it will be fine.

Now the new dizzy that rotates is in position, it will be easier to find TDC, which you'll need to do for the timing. Get cylinder to the top of its stroke, and check that the rotor arm is pointing in the general direction of the contact in the cap that goes to HT lead number 1. If it is 180 degrees out, you'll need to turn the engine over 1 complete revolution to get it right. You can then set the engine according to the timing mark to 5 degrees before TDC. Then, with the ignition on, move the body is f the distributor slowly backwards and forwards - you will hear a close click as the points open. That position is very roughly the correct timing. The car will then be fine to drive, and you can tweak the timing according to a bit of road testing.

This might sound complicated, but it is really pretty simple and I am sure you will get it sorted in time to go to Norfolk.

[iconic]

Excellent explanation...cant go wrong with that.

PS To OP where in Norfolk are you off to?

[youngb506]

Thanks for all the advice in changing the distributor which I did today feeling quite confident. Number 1 cylinder at the top of its stroke and rotor arm pointing to no 1 contact in distributor cap. However, no spark at the plug. Changed the contact breakers and condenser in the distributor to new ones from distributor doctor and still absolutely no spark at the plug. Made sure I'd reconnected low tension cable. Must be something else that happened when the old distributor broke? Am I missing something? The coil was getting quite warm while I was fiddling, is this a sign? Lucas rotor arm that came with the distributor in unused condition.
What's the next step without a volt meter?

[liammonty]

You can check for power at the points. When they are closed, you can carefully flick them open with a screwdriver, with the ignition on. Hopefully you'll see a spark. That may give an idea of where the issue is. Regarding the coil, whether to worry or not depends on how hot it got.

[youngb506]

No spark at points when I flick them open with ignition on.
Coil was quite warm, not burning hot. Maybe because I'd left the ignition on.

[bmcecosse]

Obviously the coil is heating because there is power flowing through it all the time ! The points etc must be wrongly assembled to cause the short. As you pull the lead off the dizzy - do you see a spark then ? It is a white wire going to the coil - and then a white/black wire going to the dizzy from the coil ??

[youngb506]

You mean the low tension lead? Should that spark as I touch it against the dizzy body? Can two sets of points go wrong? The first set were the ones ready fitted so I don't think it's the way they're assembled.

[youngb506]

There's a spark when I touch the low tension lead on the outside of the distributor so, I imagine, there must be a fault inside the distributor. Must be the ponts? (Also the ones pre fitted?) there's no break in the LT wire inside. Can't figure it out. Grr!

[youngb506]

Making progress? There was continuity across the points when open in both the distributor doctor set and the original set that were both of the two separate parts style, rather than the all of one piece modern ones. I think there's supposed to be a fine washer between the two parts where they fit over the brass locating pin in the distributer. There's now a spark when I open the points with the ignition on. Having a break for breakfast before the next stage.

[youngb506]

Engine fires! Now to work out how to time it.