Broken down - tow - rotor arm!

[Wolvesboy]

Hi I all,
I was just cruising (60ish) & engine just stopped. Tried to start x2 in vain & managed to turn into a slip road before I rolled to a stop.
Cranked but no catch.
Aaaahhh - sounds just like the inertia switch again. Checked, no change
Looked for any obvious disconnections. No change
Checked for spark at main/ king HT lead. Spark, so good there. No change though.
Now I’m thinking 100amp fuse but cranking over so not that.
Fuel pump priming.
Getting stuck now.......... ended up being towed home & thoroughly peed off as twice in two weeks.
(First time hit a pot hole and inertia switch disabled fuel).

At home I tried spark again at the plugs - zero spark! Did this across another 2 plugs and the same so suspected the distributor side. The distributor was also loose and could be rotated quite easily which shocked me.
Both the rotor arm and dizzie cap were brand new less than a thousand kms ago so surely couldn’t be them? I removed cap and seemed good. Couldn’t get rotor arm off as stuck tight but eventually got it off using two screwdrivers as levers underneath each end. I inspected the outside of the rotor arm & it looked fine. Tried a continuity test and zero - then looking closer inside there was a large hole halfway up the metal tab opposite the plastic key way. I gently pulled the tab with pliers and it came apart as in the photo below.



I cannot believe this has failed so early.

Also, the top of my dizzie arm looks rusty and certainly not as clean and conductive as I think it should be.



Lesson learnt - have a spare dizzie cap & rotor arm for every eventuality! Also check tightness of dizzie stuff as engine vibration has loosened this over time. An Unbelievable turn of events that could so easily have been sorted at the side of the road.

[hoofa]

Another reason people dump the dizzy and go aftermarket ecu

[Steve_D]

Wolvesboy said:

………..Now I’m thinking 100amp fuse but cranking over so not that.

This fuse is only in the charging circuit so would not be relevant in this case.

Wolvesboy said:

………..Tried a continuity test and zero - then looking closer inside there was a large hole halfway up the metal tab opposite the plastic key way. I gently pulled the tab with pliers and it came apart ………..

Where were you continuity testing? It sounds like you were expecting continuity between the brass plate on the top of the arm down to the clip in the base. The two should not have continuity otherwise your spark would go straight to earth rather than jumping across to each spark plug in turn.

The metal tab is a spring clip and can be pulled out with pliers. Its only function is to hold the rotor arm in place.

Wolvesboy said:

………..Also, the top of my dizzie arm looks rusty and certainly not as clean and conductive as I think it should be.………..

It does not need to be conductive as there is no electrical circuit through it.

Steve

[Wolvesboy]

Thanks Steve.
Oh ok - so having misinterpreted the rotor arm process, it may not be that in the end? I could have another underlying issue then.

[rev-erend]

Did you check the carbon button in the dizzy cap?

[Steve_D]

Wolvesboy said:

Thanks Steve.
Oh ok - so having misinterpreted the rotor arm process, it may not be that in the end? I could have another underlying issue then.

That's what I thought.
So to follow the process. The coil produces the high tension electrical pulse (lets call it the 'Spark' for now). The spark travels down the lead from the coil to the centre of the dizzy cap this lead is known as the 'King lead'. Inside the cap the spark passes through a carbon contact which is spring loaded so you need to check it moves in and out of its housing freely and is not jammed up inside. The carbon contact sits on the brass plate in the top of the rotor arm. As the rotor goes around the spark jumps the gap between the tip of the rotor arm brass plate and the contacts for each plug lead. At the spark plug the high tension again jumps across the spark plug contacts creating the spark which sets fire to the fuel/air mix.

So back to your problem you need to first check you have a spark. Remove the king lead from the dizzy and lay it on top of the plenum (or anything metal) so that there is a few MM gap for the spark to jump across.

If you do have a spark it is possible the loose dizzy spun around and the timing is now so far out it will not start but I'm not confident on this one as I would expext it to pop and fart but not start in which case you would have included that in your description of the issue.

Best we wait and see if you have a spark.

Steve

PS do you want to pay for me to come out and fix it for you?

[wuckfitracing]

I think I would be looking at what was under all that red insulation tape.

[VerySideways]

hoofa said:

Another reason people dump the dizzy and go aftermarket ecu

That and the fact that so many dizzy caps and rotor arms these days are of very poor quality.

[spikep]

I’ve had 2 rotor arms and 1 cap just die. Fortunately when the 1st arm died, the recovery driver was old school and diagnosed the arm by getting the engine to kick with it. I still got recovered home and think I’ve now got 3 rotor arms and 1 cap permanently in the boot.

[swisstoni]

There’s a place I’ve used called Distributor Doctor.
They attempt to supply parts that are a bit better than the typically poor modern bits.

[asd2001]

I’ve used distributor doctor too - so far so good (but keep old ‘good’ bits in the boot just in case!)

[indigochim]

Another happy DD customer. From memory it's worth getting together with a mate and ordering a couple or more.

[jr6yam]

wuckfitracing said:

I think I would be looking at what was under all that red insulation tape.

Definitely

[Wolvesboy]

I have replaced the rotor arm - fired up straight away!

Checked the dizzy cap and looks good with carbon tip moving and springing like it should. Im now going to reset the timing when I have a chance.

Red insulation tape is me just tidying up some of the wires that were all over the place and too close to the belt for my liking. Yet to sort properly.

I will definitely have spares in the boot in future as that was a PITA. I am gradually writing a checklist in my brain of certain things to look for when the car dies and this has been added to it.

HT Leads
Inertia switch
100A fuse
relays
Rotor arm
Dizzy cap etc ...in no particular order!! No doubt there are many more that others will gladly add!

[Classic Chim]

Wolvesboy said:

I have replaced the rotor arm - fired up straight away!

Checked the dizzy cap and looks good with carbon tip moving and springing like it should. Im now going to reset the timing when I have a chance.

Red insulation tape is me just tidying up some of the wires that were all over the place and too close to the belt for my liking. Yet to sort properly.

I will definitely have spares in the boot in future as that was a PITA. I am gradually writing a checklist in my brain of certain things to look for when the car dies and this has been added to it.

HT Leads
Inertia switch
100A fuse
relays
Rotor arm
Dizzy cap etc ...in no particular order!! No doubt there are many more that others will gladly add!

That’s a very good idea.

[SMB]

Classic Chim said:

Wolvesboy said:

I have replaced the rotor arm - fired up straight away!

Checked the dizzy cap and looks good with carbon tip moving and springing like it should. Im now going to reset the timing when I have a chance.

Red insulation tape is me just tidying up some of the wires that were all over the place and too close to the belt for my liking. Yet to sort properly.

I will definitely have spares in the boot in future as that was a PITA. I am gradually writing a checklist in my brain of certain things to look for when the car dies and this has been added to it.

HT Leads
Inertia switch
100A fuse
relays
Rotor arm
Dizzy cap etc ...in no particular order!! No doubt there are many more that others will gladly add!

That’s a very good idea.

Whilst carrying some spares is not a bad idea, regular checks and maintenance will be better. Eg replace the 100amp fuse with a midi fuse, check leads are clear of manifolds etc. Then add an ignition amp, and pre made fly leads to your spares kit.that way you. An overcome failed otter switches etc.

[Wolvesboy]

Oh, I check stuff regularly - however, my rotor arm looked brand new and was only 6 months old and....... had less than 2k kms on it! That is beyond "checkable" and should not be an issue. I will always have certain items in my boot from now on. The boot will be like a "pick - a - part" store! I hate being stranded and unable to fix stuff.

[Mazinbrum]

http://www.distributordoctor.com/rotor_arms.html