Engine Prolems - I need help!

Post by **Luxobarge** » Sat Jan 17, 2009 11:56 am

Whether or not it's new, it might still be faulty. Be aware that there are a LOT of faulty ignition components on the market at the moment, of very poor quality made in China, orrespective of what "brand" they may carry. This is especially true of condersors and rotor arms, apparently.

Normally, if you replace a component for a new one, you can be pretty sure that that has eliminated it from the equation, but this is most definately not the case with these items.

To eliminate the rotor arm, check for a spark from the king lead, not the normal plug leads.

In the case of a condensor, you may have to try many new ones, or better still, "borrow" a known good working one from someone else, or another vehicle.

If you get stuck, you can get high quality components from this guy, who is the industry "guru" for classic ignition components:

http://www.distributordoctor.com/

Hope this helps!

Post by **nslocomotive2** » Sat Jan 17, 2009 11:59 am

To check the king ignition lead do I disconnect it from the dissy end or the coil end to check for a spark, sorry I am a newbie to classic ignition

Post by **Luxobarge** » Sat Jan 17, 2009 12:24 pm

nslocomotive2 wrote:To check the king ignition lead do I disconnect it from the dissy end or the coil end to check for a spark, sorry I am a newbie to classic ignition

Disconnect it from the dizzy end, so you have the thick "king" lead coming out of the coil, and hold or clamp the other end of this so that the metal end on it is 1/8 to 1/4 inch away from an earth on the body - a nut on the cylinder head is ideal. Then spin the engine with ignition on, and you should see a nice fat spark between the end of the king lead and earth. It can be difficult to see the spark in bright sunlight, the darker the conditions the easier it is to see.

Note - if you hold the king lead with your hand, beware that you might get quite a jolt from it, so either use a tool, wedge or clamp to hold it in place while you're testing it, or wear thick gloves. The jolt isn't dangerous to your health, but is quite unpleasant!

All the best!

Post by **aupickup** » Sat Jan 17, 2009 12:30 pm

i like the jolt

should be ok so long as no other part of your body is touching the car

Post by **nslocomotive2** » Sat Jan 17, 2009 12:44 pm

No spark from main HT lead from the coil so I asume its power to coil as this is a brand new one?

Post by **Luxobarge** » Sat Jan 17, 2009 1:27 pm

nslocomotive2 wrote:No spark from main HT lead from the coil so I asume its power to coil as this is a brand new one?

OK, so that rules out the distributor cap, rotor arm and plug leads.

Yes, next check, it's worth checking you have power to the coil - use a meter or a test lamp. You should see a constant 12 volts on one side of the coil - the +ve side if your car is negative-earth, and vice-versa if it's positive earth.

One thing - have you changed the points recently, or since this fault occurred?

Let us know how you get on!

Post by **nslocomotive2** » Sat Jan 17, 2009 1:34 pm

ok I have power to the coil its a positive earth car so should that be different, I'm gonna get a new set of HT leads, as I think the cable between the cap and the new coil is suspect, the points I have left alone, as I don't know much about them, I don't have the tools to gap them right, should I look at replacing those as well, seen as there is no spark from the main HT lead from the coil I don't know if the points would affect that?

Im learning lots today so thanks for the advice please keep it coming, I need this car to run

Post by **Luxobarge** » Sat Jan 17, 2009 1:41 pm

Well, replace those items by all means, but we've already discounted them as you don't have a spark from the king lead, so I doubt they are the reason the car won't run.

OK, you haven't touched the points - you really need to check the gap on them - you only need a screwdriver and a feeler guage. The gap should be 15 thou - if you don't have a feller guage then two thicknesses of a fag packet, or one thickness of an average cereal box will be close enough to get it running. If you can, clean the points surface up before setting the gap.

To set the gap, take the dizzy cap off, then rotate the engine (you can usually do this by grabbing the fan and belt) until the four-lobed cam in the distributor has opened the points to their maximum. Then, with the "peak" of the cam holding the points to their maximum, set the gap to approx 15 thou.

It's a bit fiddly as access isn't great, you will probably end up with a little back-ache! Also, a bright light down there is good so you can see what you're doing.

If the points aren't opening at all (i.e. the gap is too small) then you will get no spark, and the coil will end up getting quite hot, as current is flowing through it continuously.

Hope this helps - keep in touch!

Post by **nslocomotive2** » Sat Jan 17, 2009 2:00 pm

OK,

the gap is set, using the cereal packet option, I may pick up some feeler gauges latter when I get the leads and rotor arm. the points are clean and the open and close as I crack the car round, but still no start. or spark.

what else is there to go wrong? hmm perplexed indeed

BTW im getting 12 volts to both sides of the coil is this right?

Post by **Luxobarge** » Sat Jan 17, 2009 2:14 pm

nslocomotive2 wrote:BTW im getting 12 volts to both sides of the coil is this right?

Yes, but on one side of the coil it should be a more-or-less constant 12 volts and on the other it should be around 12v with the points open, but more-or-less zero with the points closed.

Can you hold a meter or test bulb on the +ve side of the coil (as yours is a +ve earth car) and rotate the engine slowly? The bulb should flash on and off, (or meter fluctuate bewteen roughly 12v and zero) as the points open and close - if it doesn't do this, then that narrows down the fault a lot!

If it does flash on and off, then next find the non-earthed side of the points (this will be the bit that the curved spring is attached to) and do the same test - this should also cause the bulb to flash (or the meter to register up and down) as this part of the points is directly connected to the side of the coil you've just tested.

Easy to do all of this with the dizzy cap off, of course.

Cheers

Post by **nslocomotive2** » Sat Jan 17, 2009 2:33 pm

ok testing from the +ve and the fusebox the volts stay constant 12 as the points open and close, if testing from the spring and the +ve constant zero as the points open and close, i did get a spark when i slipped with one of the needles on the testmeter.

Post by **Luxobarge** » Sat Jan 17, 2009 2:50 pm

OK, so you're saying that both sides of the coil show a constant 12v but the spring on the points shows a constant zero?

If so, then the wire between the points and the "CB" or "+ve" side of the coil is broken. I deduce that you're using a meter rather than a test bulb, so put the meter on "ohms" - the lowest range it has, test that the meter registers close to zero ohms when you touch the two probes together, then put one probe on the +ve side of the coil and one on the spring, and you should get a dead short, or less than one ohm anyway. If you don't then this is definately the problem and you need to check that wire for breaks/damage, especially where it connects to the points assembly, it may be broken or loose there. Also check where it goes through the distirbutor body, and the little wire on the inside of the distibutor body that connects to the points themselves.

Do all this with ignition off, as you want the circuit passive for resistance and continuity checking.

By the way, the thin wire exiting the side of the distributer is the one that goes to the coil, you should see that it is the same colour code as the one on the CB or +ve side of teh coil that you are testing, as it's the other end of the same wire. Just had a look at the manual - it should be white and black in colour.

Fun this, isn't it?

Post by **Luxobarge** » Sat Jan 17, 2009 2:59 pm

Just had a thought - a wiring diagram would be useful for you here, so you can see what you're looking at.

In case you don't have one, I've sent you a link to a download via PM, it's well worth having this on your PC for reference - I printed mine out too!

Cheers.

Post by **nslocomotive2** » Sat Jan 17, 2009 3:02 pm

Yea its fun but frustrating

your deductions are correct I have been using a multi meter, I set it to ohms and touching the probes together reads 7 when testing from spring to +ve I get 9

the wire is wire is white and black and looks to be in good condition. Ignition off ...

now im starting to get depressed

Post by **Luxobarge** » Sat Jan 17, 2009 3:14 pm

Hey, don't get depressed, can't be that far away from fixing it! (famous last words......)

That's odd - 2 ohms isn't great, it should be less than one really, so you might want to investigate that wire, especially the part of it that's inside the dizzy. It's only a short run from the points to the coil, I'd expect a dead short to be showing on the meter between the two ends of this wire.

It would be easier to zero your meter so that it reads correctly too, BTW!

I just want to be clear on one thing:

When testing the coil while rotating the engine, can you confirm for sure that on one side (the -ve side) you get a constant 12 volts, and also a constant 12 volts on the +ve side too?

Also confirm: while rotating the engine you also get a constant zero volts on the points "spring"?

If so, there MUST be a break in continuity here somewhere! If not, please confirm to me what you are getting at these places.

Hopefully that workshop manual will be of use - the wiring diagram is on page N23, the wire we're talking about is labelled "16".

Cheers

Post by **nslocomotive2** » Sat Jan 17, 2009 3:15 pm

sorry should have written .7 and .9

Post by **Luxobarge** » Sat Jan 17, 2009 3:17 pm

nslocomotive2 wrote:sorry should have written .7 and .9

Ah, right, that's a dead short in my book, as it should be. Digital meter eh? Good!

Now, if that's a dead short, then you CANNOT have a constant 12v at one end and a constant zero at the other end, so can you confirm or re-test as per above post?

Cheers!

Post by **nslocomotive2** » Sat Jan 17, 2009 3:34 pm

yea I have re-tested

# can you confirm for sure that on one side (the -ve side) you get a constant 12 volts, and also a constant 12 volts on the +ve side too?
- yes i get constant 12 volts on both sides, taking the reading from engine block to coil, and from the box terminal marked E to the coil.

# Also confirm: while rotating the engine you also get a constant zero volts on the points "spring"?
- yes im taking the reading from the coil to the spring on both sides same result.

is it possible as this car has an alternator I have inadvertently got the +ve and -ve cables on the coil the wrong way round???

thanks Nigel.

Post by **Luxobarge** » Sat Jan 17, 2009 3:44 pm

Right, I think I'm getting confused here because you are taking various points as a reference when measuring voltages!

When measuring thee voltages, the positive lead of your meter needs to be on a body earth (e.g. engine block) for every measurement.

Doing all the measurements in the same way, i.e. with one side of the meter on a body earth without moving it, can you again confirm the result while the engine is rotating, with ignition on?

Sorry to be a pain, we'll get there though!

I'm thinking that if you get a constant 12 volts on both sides of the coil and also at the points "spring" then the points are not switching the coil. In this case, you might want to also check the braided copper wire that connects the points base-plate to earth - you might have to take the base-plate out to see this, I can't remember, although you could temporarily jumper the base-plate to earth with croc clips or whatever, and see if this makes a difference. I hope you follow that!

Post by **nslocomotive2** » Sat Jan 17, 2009 4:29 pm

hmm this is interesting, I did the same thing again this time keeping the positive lead of the meter on the engine block, got 12 volts on both sides of the ciold and 12 with the points closed, with the points open i got 0.

I did this few times to confirm,