rough running...really rough

[MiketheBike]

Whats all that about then.

 

I drive to work in the morning...the ferret runs nice and smooth.

 

I drive home in the evening and it starts to run as rough as hell half way home...about 5 miles into the journey. I use the same roads, with the same amount of stop/start and traffic.

 

I have already renewed all the HT and LT leads, and put a NOS distributor in. All new plugs also.

I don't think its fuel, although I could be wrong.

 

It idles fine, and at low revs it is also fine. Its when it gets above 2000rpm that it all goes pear shape. It splutters, pops/backfires and feels like its cutting out.

 

My next guess is maybe the coil is on its way out? Maybe because its been hot from the morning run?

How do you test a coil? Are they easy to source?

 

Cheers

 

Mick

[Marmite!!]

Try a new condenser :-D

 

Have a read of this http://www.hmvf.co.uk/pdf/TESTINGCONDENSERSRW.pdf

[sirhc]

Or fit the electronic ignition kit?

[TooTallMike]

Try a new condenser :-D

 

Have a read of this http://www.hmvf.co.uk/pdf/TESTINGCONDENSERSRW.pdf

 

Agreed, that sounds very much like a condenser beginning to fail.

[Richard Farrant]

Mick,

 

A good sign of failing condensers, is burnt contacts, so if you have a new distributor fitted then the points should be in good order, if not then 10 to 1 its condenser.

 

As Clive will tell you, brand new condensers off the shelf, can be suspect, especially if they are old stock types. It is quite a common problem, with older vehicles were the new spares stock can have been a good number of years on the shelf.

[fv1609]

If you send me a SAE I can test your condensers. Or it might be easier just to buy another 0.2 mfd one eg from a series 2 or 3 Land Rover, bend the lug & it will fit in. There are degrees of condenser failing. A condenser may leak only a bit & hold a charge for a short while & not have been in this state long enough to show pitting than can be noticed. The limitations will be shown when you are trying to get max performance from the engine.

 

Check your plugs are they all sooted up? New plugs they may be, but plugs easily soot up especially RSN13P, Rover ones RSN12Y seem less prone to this. I never use the choke I have disconnected it. Just two pumps with accelerator (hand prime if not used the engine for a day or so). Foot off & keep it off, then start up til it fires. Keep foot off for a good half minute, then away you go.

 

Now I do have electronic ignition, but this is the starting procedure advocated for pigs in NI, which obviously had the original ignition.

 

I recently saw a rotor arm them was recently supplied. It was the cleanest, shiniest & nicest rotor arm I had ever seen. But measuring the leakage from the end to chassis there was a leakage due to a resistance of 100megohms. Now a tatty secondhand one on a stall nearby had double the resistance ie half the leakage. Now why was that?

 

I tested my two spares I had with me, they were better still but still leaked. I tested the one on my vehicle & that was nearly infinitely ie a near "perfect" resistance.

 

Now this leakage can be measured from the ht electrode of the arm to the distributor shaft, but it virtually the same as the leakage to the overspeed earthing collar. So the rotor arms can be tested not necessarily in situ but just by themselves. Removing the earthing pin where it contacts the shaft makes virtually no difference to the electrode to shaft leakage.

 

My theory is that moisture is the problem. I doubt that the lovely NOS condenser has been stored in a heated & moisture controlled environment. But the old one on the stall had been baking in the sun.

 

I found another rotor arm in my workshop which is a bit damp. Similar reading to the NOS one. Put it in the sun after an hour the resistance had doubled. After another 2 hours it had doubled again.

 

Whether this leakage in not recently used rotor arms is significant, I do not know. But it certainly won't help. Off hand the figures I quoted are comparative, I can't quite recall the calibration of the megger, figures may be 10 or 100 times greater. These readings could not be detected on 250/500v meggers. It was only using a 1000v megger that this showed up.

 

Anyone had similar suspicions or experiences of damp rotor arms?

 

[Chrisg]

We had a similar problem with a champ popping/backfiring flame out of the exhaust

change points & condenser which cured the problem

 

Chris

[Chappers]

I had a very similar problem with a jeep but reversed to yours,would run very rough until warm,then run fine tried all the usual checked everything was in order,it turned out to be the coil,the coil had a broken wire in the base,when the windings of the coil got hot and expanded it would make a good connection. I stripped the coil down and examined it was a bit of a bugger getting it opened but found the problem.Instralled a new coil and it's been fine.

 

I've also installed electronic ignition on all my vehicles from Frank Jolly (Not so Jolly) engineering.

Had one of his units fail after 5 miles causing me to get my GMC recovered :evil:He would only send another out after testing the original first and I'd brought 4 units for different MV's of him previously No refund on my postage either .

They are still worth the electronic alteration and have made my MV's much better to start and run.( I carry the old distributor parts with me just in case of a problem).

 

Hope you get it sorted .

 

regards

 

Steve

 

 

 

 

 

[haybaggerman]

same here,

 

 

Ferret was popping away, lots of flames out the exhaust when decelerating. It went suddenly down hill in the middle of a carnival. New points and condenser went along way to curing it. Changing the fuel mixture did the rest.

 

Paul

 

[MiketheBike]

Thanks guys. I had changed the condenser, and the new distributor came fitted with another new one...but thinking about it now, I did swap that out for the one I had before...if you see what I mean.

The condenser seems the easiest/cheapest quick check.

I will also check out the rotor arm (I may need to print and read your instructions on that ;-) ).

 

Starting is on the button...it hardly needs turning over without choke over the past few days, and the exhaust is clean. I am running the carb idle as slow as possible with it running smooth.

 

I'll see if I can get a condenser on teh way home today.

 

Cheers

 

Mick

 

I just had a thought after reading up on timing. If the condenser is flakey, would that cause the ignition to be artificially retarded?

To have the engine running smooth, the distributor is turned almost all the way anti-clockwise against the bolts holding the distributor....so as advanced as it can go.

A stupid question, but what position...roughly...should the distributor be in....kinda parallel to the engine (the straight sides of the dist housing parallel to engine)?

 

 

[fv1609]

 

To have the engine running smooth, the distributor is turned almost all the way anti-clockwise against the bolts holding the distributor....so as advanced as it can go.

 

That's where mine ened up.

 

I would also take out the plugs & sandblast them clean. Although they are fairly new they could well have carboned up by now.

[polecat paul]

I had exactly the same problems as you've described and i changed the condenser and points .....jobs done works great :-)

[MiketheBike]

Thanks guys...looks very much like it could be that then.

I got a couple of .2mf condensers from Unity Motors (33710), so I'll see how it goes.

 

Mick

[MiketheBike]

OK, new condenser fitted, also replaced the rotor arm (the original appeared to have a small part missing...a small curved bit of metal retained by two springs on the top of the rotor arm), plugs cleaned up (they did look OK).

 

Paul...when you say adjusting the fuel mixture, is that the two idling jets? I have opened those up just enough to have the engine idling smoothly.

 

Only thing left would appear to be the coil? Is it just a standard coil that slots into the ignition coil housing?

 

Cheers

 

Mick

[Tony B]

I've fitted one of Jolley enginnerings electronic kits. Very easy to fit and Oh Boy does it make a difference. http://www.classicheads.com/ About twenty minutes to fit to a dodge, 10 minutes spent 'cause I lost the screwdriver. Just started straight away after wards.

[MiketheBike]

Tony,

 

I keep thinking about that, but I just bought a new engine and the missus might divorce me if I spend any more money.

I will be trying to get the engine in before Beltring...I must be nuts! I am not sure if I can manage it before the event, but I'll try!!!!

 

Mick

[R Cubed]

Check your plugs are they all sooted up? New plugs they may be, but plugs easily soot up especially RSN13P, Rover ones RSN12Y seem less prone to this. I never use the choke I have disconnected it. Just two pumps with accelerator (hand prime if not used the engine for a day or so). Foot off & keep it off, then start up till it fires. Keep foot off for a good half minute, then away you go.

 

<SNIP>

Watch out for plugs, I have had a very nasty experience with some brand new NGK plugs for my Sierra fitted them, then 4 months later would hardly fire in the mornings, hell of a job to start, did not consider it would be the plugs changed everthing else to no avail until I spoke to a friend who is in to mowers and he said they have loads of trouble with NGK, so I put the old original plugs back in and had no other problems, no more maintenance for my cars............................

<SNIP>

 

Now I do have electronic ignition, but this is the starting procedure advocated for pigs in NI, which obviously had the original ignition.

 

I recently saw a rotor arm them was recently supplied. It was the cleanest, shiniest & nicest rotor arm I had ever seen. But measuring the leakage from the end to chassis there was a leakage due to a resistance of 100megohms. Now a tatty secondhand one on a stall nearby had double the resistance IE half the leakage. Now why was that?

 

 

<SNIP>

Beware of cheap copy rotor arms using cheap plastic ( bakerlite ) for the body of the rotor arm, the quality of the material can make a massive difference to the resistance of the tip to base reading also some are more prone to being effected by damp, this is also true for the distributor caps as well try meggering between the plug lead connections !!!!!!

 

<SNIP>

 

 

I tested my two spares I had with me, they were better still but still leaked. I tested the one on my vehicle & that was nearly infinitely IE a near "perfect" resistance.

 

Now this leakage can be measured from the ht electrode of the arm to the distributor shaft, but it virtually the same as the leakage to the overspeed earthing collar. So the rotor arms can be tested not necessarily in situ but just by themselves. Removing the earthing pin where it contacts the shaft makes virtually no difference to the electrode to shaft leakage.

 

My theory is that moisture is the problem. I doubt that the lovely NOS condenser has been stored in a heated & moisture controlled environment. But the old one on the stall had been baking in the sun.

 

I found another rotor arm in my workshop which is a bit damp. Similar reading to the NOS one. Put it in the sun after an hour the resistance had doubled. After another 2 hours it had doubled again.

 

Whether this leakage in not recently used rotor arms is significant, I do not know. But it certainly won't help. Off hand the figures I quoted are comparative, I can't quite recall the calibration of the megger, figures may be 10 or 100 times greater. These readings could not be detected on 250/500v meggers. It was only using a 1000v megger that this showed up.

 

Anyone had similar suspicions or experiences of damp rotor arms?

 

 

[Tony B]

Hey Mick, tell her that it will you spend less time playing with your toys and more helping her :angel: Just try to keep a straight face when you do it :evil: