Rotor Arm Melted

[Jamiep]

On the way to Stafford on Saturday the car started to splutter whilst doing about 70...ish, stopped at services for about 30mins with the bonnet off as i thought it was over heating (no temp gauge) had a coffee etc and set off again but a bit slower around 60mph (gps) and got to the show no probs, if a bit later then planned.

 

On the way home we were stop start in traffic for a few miles and it all started again with miss fires and loss of power, after pulling to the services I didn't think the engine was that hot but left it to cool for an hour whilst we had some food and again set off. Didn't get too far before it started again, every time I tried to accelerate it would pop and bang and loose power, then started cutting out.

 

Anyway ended up in a pub carpark just off A1(M) N dead as a dodo waiting for recovery.

 

A quick look by the very knowledgeable recovery guy (and builder of at least 3 hoods plus other kits) went straight to the problem, the rotor arm was burnt away.

 

My question (eventually) is what would cause this? the cap looks very clean and newish (cars done less then 1k miles in approx 4 yrs) the points are spotless and the leads and plugs look new too.

 

is the timing out? the cars ran fine this summer since i've had it.

 

thanks in advance,

 

Jay

[Big Jim]

I would be looking at the state of the dizzy, are the bearings knackered? it may be time to get it reconditioned.

[Jamiep]

I don't know anything about these, so forgive the stupid questions but, would this cause some scoring on the inside of the cap? i noticed some fresh marks but assumed it was caused after the melting arm. also should i be able to move the arm by hand, rotates maybe 5deg then springs back?

 

what sort of cost is involved/ where would do recon dizzys?

[Longboarder]

Can you post pics of the arm and inside of the cap? And yes it should advance and spring back. Thats the centrifugal advance mechanism consisting of two bob weights and springs that take care of ignition timing advance dependant on revs.

 

Nigel

[Jamiep]

photos as requested

 

 

 

[miikae]

I looks to me like the connector that the lonely bullet terminal connects into has burt out completly, where there any bits of it knocking about in there by any chance?

 

Mike

[Longboarder]

Cap looks fairly new and its terminals don't look too bad. Central carbon contact still in place. Rotor is ? resistor type with conduction from centre to tip via embedded link. Tip would have been small crescent mounted in the plastic. I suspect faulty part, tips fallen off and its been sparking from the link to the posts and fried the plastic end of the rotor. Can it jump that far? Alternative could be wrong rotor, too big a gap, hefty spark that has overheated the rotor tip and the copper has fallen off.

Either way I would just try a new rotor and cap. Check resistance of plug leads (about 5Kohms per foot) and check the plugs. Run it and keep an eye on it after every run for a while.

 

Nigel

[Jamiep]

thanks for the replys, will renew and keep an eye on it.