Wrong Distributor

[henda]

Hello,
After being advised on the forum to go to the Distributor Doctor to replace my distributor rotor arm. I received the new rotor, however it was nothing like mine. Spoke to the Distributor Doctor and sent photos. It turns out the distributor on my cay is off a xj6. Does anyone else have this on there car and if so is it ok to run with it? My original problem was that it was cutting out after a short drive, if you waited 10-15 minutes it would start again.

Paul.

[malcolm]

It could of course mean that various different parts of your ignition system have been modified. If it was me, (and I'm not a purist), I'd get a 123 dizzie and return the rest of the ignition system to standard (not expensive other than the dizzie)

[MarekH]

I presume your car has been running perfectly well with an xj6 distributor for many years.

The only two relevant facts about the distributor from one xk engine versus another are 1/ what centrifugal (mechanical) advance does it give and 2/ what vacuum advance does it give? Neither are related to something cutting out after 15 minutes.

So does the distributor doctor say that his rotor arm is compatible with your distributor cap?

kind regards
Marek

[henda]

Morning,

The car is a 1970 series 2 4.2 Roadster

The conundrum that I have is, my uncle bought the car a year ago from the son of the bloke who built the car up who had died. Unfortunately my uncle then passed away and all that I can presume is that it was running when he bought it. He then had some body work done on it and apparently after it came back it has this problem cutting out after 15 - 20 mins. The Distributor Doctor advised that it is a post 1974, probably an XJ6 distributor and that it may or not be calibrated for my engine. It looks as though the Coil has been changed as there is an old one in the spares box i got with the car. The car seem to run really well, like I say after 15-20 mins of driving it just losses all power in the throttle and when you pull over it cuts out. It wont restart immediately, however if you leave it 10-15 mins it starts and runs. Any help or advise would be appreciated.

[malcolm]

Could be fuel starvation? Not enough feed so eventually fuel in bowls gets too low. After sitting, they refill and off you go?
Maybe check the fuel filter, and disconnect the fuel line to see how much petrol is being pumped out? (obviously with engine off but ignition on)

[henda]

Hello Malcolm,
Do you know if the tank would have a breather on it and if so could you point me in the right direction to look for it.

[Jack the lad]

Just leave the fuel filler cap off and go for a drive, if it's OK beyond 20 mins then is the time to locate the tank breathers. If it cuts out as before then the tank breathers are not at fault. My guess would be the condenser and/or the coil, best sorted by substitution. cheers John.

[JerryL770]

That could be a failing coil, could it not?

[MarekH]

However well or poorly the distributor is matched to the engine is a red herring - it's still that well calibrated 20 minutes later. An xk engine clearly works over quite a range of answers and the engine doesn't know what car it is connected to.

You have a spare coil (albeit of unknown quality), so run the car around the block until it fails and then take the spare coil and swap it in for the one currently fitted. Even if you can only hold it on for thirty seconds with duct tape, see if the engine fires up straight away. If it does, that rules out fuel and will help you focus on the ignition.

The fuel cap on or fuel cap off starvation thing can be finessed in seconds by trying to remove the fuel cap just after you cut out. If the fuel tank breather is clogged then the cap will be hard to pull off and you'll hear a woosh as the air is admitted to the tank.

As others have suggested, the likely culprit is the coil (or lack of ballast if you were supposed to have one), especially since you already know the coil has been replaced once. Not having a ballast when you should have one will mean the coil is charging at too high a voltage and so it'd be unsurprising that it overheats. Using a replacement coil of too low an ohmage value would have the same effect - it'd also draw too much current and get hot that way. That's why swapping in a cold coil just to see whether it can fire back up is suggested.

You still need to decide whether the distributor cap is good with this rotor.

Another simple test you can do is to rest a spare plugged in spark plug on the metal of the engine block just to verify you have no spark just after you fail. If you have no spark, then that's progress; if you have spark, then you can't conclude anything.

kind regards
Marek

[SimonBrown]

I did have a very similar problem with my Series 2. Ran fine for 15-20 mins, then a misfire, followed with cutting out but would restart after a short wait. It progressively worsened until I had to be recovered.
Turned out to be a faulty modern rotor arm. A replacement from the Distributor Doctor fixed it.
Simon

[henda]

Thanks for all the advise. I have just ordered a a full new distributor and coil recommended by the Distributor Doctor. Ill get it fitted and report back. I did take the fuel cap off when it cut out, but there was no intake of air that was noticeable.