dizzy cap, rotor arm wear...

[slowcoach]

Hi,
ive got some ignition problems, and just been inside the dizzy to look at the rotor arm and bits. they were quite black, which ive now scraped clean (still got problems, but not able to get down it it at the moment). i was just wondering, how much black 'depositing' is normal? these were new parts about 3 months ago, and were obviously squeaky clean. can the rate/speed of blackening tell anything about the engine? (timing?)

thanks!

[slowcoach]

anyone? hoping to get this worked out at the weekend!

[BOXY]

The deposits inside the dizzie cap can't really give an indication about the timing. They're caused by the spark jumping from the rotor arm tip to the post that attaches to each spark plug lead. I've never really given much thought to what would effect the amount of build up? I suppose if the "air" inside the dizzie was particularly oily that might effect the rate of build up, or if the spark was weak maybe the carbon builds up instead of being vaporised?

If you've got a fat, healthy looking spark at the spark plug then the deposits in the dizzie aren't the problem.

[slowcoach]

thanks boxy-
pretty sure the sparks are good coming out of the coil, have yet to check each plug end though. might just be this cold weather causing me probs! will look into it this weekend when im back with the van.

cheers!

[kevtherev]

Hi,
ive got some ignition problems,

You still haven't said what the "problems" are

[slowcoach]

You still haven't said what the "problems" are

thanks kev-
well, what i thought started as a hot start problem seems to have developed into a general 'all weather/temp' starting problem.

from any temp, it suddenly takes a LOT more cranking to fire up. its always been a quick starter. ive been doing it by nudging the pedal up and down while cranking, which finaly fires up. the starter turns at a good speed (as fast as it ever has in the year ive had it), and battery is good. after a long run, i can pull up on the drive, turn off, try to turn it on again and it wont go. and now it seems it does this from cold

seems to have all started when the weather went cold, but i doubt thats connected now as its not that cold anymore.

its a fuel injection DH - im not sure if any pedal pressing while cranking does anything to help? its a new temp2 sender (, been in for a couple of months and seemed fine at the time (was a precautionary swap to help a non steady idle, but fine actually).

im working away so havnt had the chance to do any real testing to improve things. going to give the battery a good charge and try and see whats what. any initial thoughts, beyond checking sparking? the fuel pump primes, and it runs great and sounds nice once started.

PS i changed all fuel lines in early october, but havnt tracked down new injector seals (the little ones) yet so using the old ones, which werent mint, but werent entirely crumbled either. it all seemed good after the process was complete and has ran fine until this current problem! theyre on the list to get...

[kevtherev]

You still haven't said what the "problems" are

from any temp, it suddenly takes a LOT more cranking to fire up.

Ok
sudden things do suggest an electrical failure so I can see now why you're looking at the cap.
because of the non steady idle, I would certainly be looking in these areas too:-
plug gap.
timing.
mixture.
air leak

basics really then move on the other things

[Red Westie]

Hi,
ive got some ignition problems, and just been inside the dizzy to look at the rotor arm and bits. they were quite black, which ive now scraped clean (still got problems, but not able to get down it it at the moment). i was just wondering, how much black 'depositing' is normal? these were new parts about 3 months ago, and were obviously squeaky clean. can the rate/speed of blackening tell anything about the engine? (timing?)

thanks!

As far as the distibutor cap and rotor arm are concerned, you have fallen for the common misconception that the errosion on the tip of the rotor arm and distributor cap segments is in some way a bad thing!
Unlike a tradional electrical contact that needs to be clean to make a resistance free connection the critical thing with rotor arms and caps is the 'air gap is kept to a minimum. The black 'build up' is highly conductive and is normal, by scraping it off clean you have actually increased the air gap between the rotor tip and it's alotted segment. In effect, the coil will have to work much harder to jump the increased distance you have created by scraping.
For the record...errosion build up should never be scraped off as you are doing more damage than good.

Martin

[slowcoach]

thankyou kev, ill check some of those things out. i cant do an airlock check myself (or maybe something about putting my thumb over a spark plug hole while turning the engine? sounds quite basic!). embarassingly, i never have had the spark plugs out on the van, in virtually a year. ive done about 6000 miles in it since owning, and i think new plugs were installed 16 months ago from the receipts i have. is this a really daft oversight, being that it does seem to run well once started??

and thanks martin- very interesting! an old dizzy cap i replaced had quite a groove in one of the 4 contacts inside, which looked pretty bad to me. ill not worry about the black stuff now though

[Cruz]

I had been getting hesitation in 1st and 2nd on LPG. Looked in the dizzy cap and two of the contacts had fairly deep slots worn/burnt into them meaning the spark had further to jump. Now runs nice and smooth

[Nicola&Tony]

. . . embarassingly, i never have had the spark plugs out on the van, in virtually a year. ive done about 6000 miles in it since owning, and i think new plugs were installed 16 months ago from the receipts i have. is this a really daft oversight, being that it does seem to run well once started??

Give your van some love and treat it to a new set of plugs!

Tony

[kevtherev]

Oversight?.... yeah right.

get some plugs you tight wad

[slowcoach]

heee!

set them to .7mm - if you havnt got a shim thing- what do you use?

[BOXY]

You buy some feeler gauges.

[kevtherev]

yeah... tightwad