Distributor removal
Discussion
You need to mark the position of the rotor arm before and after removal as well as the distributor body to the engine block.
As you draw the dizzy out the rotor arm will rotate by 15-20 deg. so its important to mark rotor arm position before and after as you are drawing up a spiral gear.
Page 66 of the bible for reference
As you draw the dizzy out the rotor arm will rotate by 15-20 deg. so its important to mark rotor arm position before and after as you are drawing up a spiral gear.
Page 66 of the bible for reference
Thanks. So the problem is just getting the timing right?
In the past I've guessed the dizzy position and replaced it, then got an 'assistant' to crank the engine while I advance the distributor by hand until the engine fires, then set it up properly with a strobe. Was going to be a bit more careful with my Griff though...
In the past I've guessed the dizzy position and replaced it, then got an 'assistant' to crank the engine while I advance the distributor by hand until the engine fires, then set it up properly with a strobe. Was going to be a bit more careful with my Griff though...
The skew drive on the distributor will turn the rotor arm as you remove the dizzy, and turn it back as you refit it, so not completely trivial. But you've got the basic idea. However, you need to be very accurate in order to get the ignition timing back in exactly the same place, and ideally you would re-time it afterwards. You are looking at accuracy of one degree, and as you will see there is not much access to see what is going on at the base of the dizzy. Personally I prefer to measure the distance between a reference mark on the body of the dizzy, and a known point on the front of the odd cylinder head. The more accurately you manage this the less important it is to retime the ignition afterwards, but at least for the first couple of times you do this I suggest you should retime the ignition. But your mileage may vary.
I assume you either know how to reconnect the HT leads in the right order, or at least know well enough to leave them alone.
Just out of curiosity, why do you want to remove the dizzy? It's not something that you would normally need to remove.
I assume you either know how to reconnect the HT leads in the right order, or at least know well enough to leave them alone.
Just out of curiosity, why do you want to remove the dizzy? It's not something that you would normally need to remove.
Thanks again both.
I need to remove the dizzy because I'm still tracing an intermittent misfire - and more recently (though it's only done it once) sudden cut out. The plan is to replace the vac. advance unit and swap the base-plate and pick-up. I want to mod. the pick up to ignition module wires to earth-shield them and remote-locate the ignition module. All far easier with the dizzy out I think...
I need to remove the dizzy because I'm still tracing an intermittent misfire - and more recently (though it's only done it once) sudden cut out. The plan is to replace the vac. advance unit and swap the base-plate and pick-up. I want to mod. the pick up to ignition module wires to earth-shield them and remote-locate the ignition module. All far easier with the dizzy out I think...
Vac advance module is a five minute job with an allan key, definitely don't take the dizzy off for that. You can change the pickup without removing the base plate, it is just held down by a couple of nuts. I don't see any reason why you'd want to remove the base plate but if so you are basically dismantling the guts of the dizzy and you'd need to remove it first.
GreenV8S said:
Vac advance module is a five minute job with an allan key, definitely don't take the dizzy off for that. You can change the pickup without removing the base plate, it is just held down by a couple of nuts. I don't see any reason why you'd want to remove the base plate but if so you are basically dismantling the guts of the dizzy and you'd need to remove it first.
Ah that's useful - I'd assumed I'd need to take the guts out to disconnect the vac. advance actuating arm. Is it just a pin through a hole then? Which I can lift off to withdraw the vac advance unit?
If you're running without vac advance you need to leave the advance capsule fitted (but with the vac port disconnected) otherwise the base plate will be free to wander around. The vac advance unit just hooks on to the base plate, just make sure it has hooked on properly when refitting otherwise the base plate will be free to move again.
One of my theories prompting the dizzy overhaul and restoration of the vac. advance is that on a part throttle there is is insufficient advance, incomplete combustion, and eventually the plugs foul to the point of misfiring. I could be way out but I'm down to clutching at straws now. Anyway that's why I'm thinking of putting the vac. advance back, and swapping the pick-up at the same time as at least one other PHer has cured a similar problem the latter way.
When you say 'replace the vac advance unit' do you mean you're currently running with the unit completely removed? Is the base plate locked? The combination of these two would mean you could have completely random ignition timing which can change as you are diving along. It wouldn't account for the fouled plugs (various other possible reasons for that) but could give highly variable performance including the risk of severe damage due to over-advance under power.
GreenV8S said:
When you say 'replace the vac advance unit' do you mean you're currently running with the unit completely removed?
No, sorry - I meant replace it with a new one, and 'put back' the vac. pipe. I still wonder whether the existing vac. unit with a holed diaphragm isn't worn or otherwise naughty and allowing the baseplate to wander a bit with the result you describe though.
griffter said:
One of my theories prompting the dizzy overhaul and restoration of the vac. advance is that on a part throttle there is is insufficient advance, incomplete combustion, and eventually the plugs foul to the point of misfiring. I could be way out but I'm down to clutching at straws now. Anyway that's why I'm thinking of putting the vac. advance back, and swapping the pick-up at the same time as at least one other PHer has cured a similar problem the latter way.
Griffter, are you absolutely sure that you haven't got an HT problem? You should rule that one out before doing all this.
Just a thought on your theory about the problem being due to insufficient advance. As you know, your ignition dynamic advance is achieved by both, mechanical weights in the Dizzy (advance proportional to engine speed), and also vacuum where advance is proportional to engine load - but not at all times. This is something I learned on my Griff whereby I originally expected the ignition to advance immediately when the throttle was opened due to the change in pressure in the Plenum (just upstream of the Plenum actually). Not so! My car is fitted with a restrictor in the vacuum pipe which prevents the vacuum advance working immediately, the intention is that the vacuum advance works very sluggishly such that the ignition is only advanced when cruising on constant throttle - as soon as you close the throttle the advance is removed because the restrictor allows a fast pressure equalisation in the opposite direction (a bit like a one way valve).
Not all cars have this restrictor I know, and I'm not sure what conditions these other cars ignition advance works under, but it might be useful to investigate how your car is supposed to be set-up before dis-assembling a poor innocent dizzy. I have read on here in months gone by that some folk have removed this restrictor from their cars. There is a chance you have one of their cars.
Test your vacuum unit by sucking bl**dy hard on the inlet - making sure there's no restriction like the one mentioned above in the pipe, and watch the dizzy plate move. If this is working, then it's highly unlikely that there is anything wrong with the dizzy.
That description of the delay valve isn't quite right, but if in any doubt replace it with a plain pipe.
What plugs do you have fitted? How do the plugs look after they have been running but before the misfire developes? Do you have any reason to assume that the ignition system is all working perfectly? This doesn't sound like a dizzy or vac advance problem to me.
What plugs do you have fitted? How do the plugs look after they have been running but before the misfire developes? Do you have any reason to assume that the ignition system is all working perfectly? This doesn't sound like a dizzy or vac advance problem to me.
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