|
|
Post by jeff on Apr 20, 2023 16:31:04 GMT
Hi all.
Fitted the Hardi fuel pump, but today on a run, noticed on very minor engine cut out lasting less than a second. Very irritating.
So, I've reverted to old service parts, capacitor, rotor arm etc which were known to be good before the mystery cut out. I'm not yet certain of the cause but it's process of elimination.
I am considering fitting an electronic module such as powerspark to the distributor, and silicone leads.
Has anyone got experience of such toys? I'd be very
interested in your views.
Jeff
|
|
|
|
Post by Penguin45 on Apr 20, 2023 17:39:12 GMT
  You'll set them all off again with this one... including me! You couldn't give me one of the little red Hall Effect electronic units. I got through three, one of which was a rather expensive PerTronix. I suspect that the heat gets them. Both my 'Crabs still run points, which operate 1970s electronic boxes. Apart from checking the points gap from time to time, I never have to touch them, which suits me just fine. It also gives me the option of hooking the condenser back up again and going back to traditional ignition if things go wrong. A modern version of this system is manufactured by Gammtronix and works very well. If you really want to go electronic, do it properly and spend the money! 123, Lumenition, Magnetronic, Mallory all make high quality reliable fully electronic systems. Beyond the "standard" source of mis-fires, also add in the ignition switch. There have been a couple of instances on here over the years where random misses were cured by a new ignition switch. Chris.
|
|
|
|
Post by jeff on Apr 20, 2023 18:12:38 GMT
Now I've got some homework to do.
I did replace the ignition switch a couple of years ago but that doesn't mean it's all good.
I've tried to induce the fault but without success. I'm sure I'll crack it and when I do, I'll be thinking "why didn't I find that sooner" grrrr
|
|
|
|
Post by andrewa on Apr 20, 2023 20:18:25 GMT
I’ve used accuspark kits on both my old boat which ran a Ford Crossflow and the Model A which has as a similar engine and never had a problem with either.
On the 1800 I used a 123 programmable dizzy which was brilliant which is expensive but enabled me to get the best out of a modified engine.
On the Bristol I’ve gone for Mallory electronic dizzy and it’s perfect!
I’d probably go with accuspark if I were you…..
Good luck with whatever you decide .
Cheers Andrew
|
|
|
|
Post by dave1800 on Apr 21, 2023 0:13:36 GMT
Hi Jeff
Chris is right this will get us going. It's even woken me up! Before fitting electronic ignition my advice is to find the source of the problem before adding a new uncertainty to the equation and more headaches!
The ignition switch is a possibility especially if you have a lot of weight on the fob. You may be able to discount it my monitoring the voltage while wiggling the key. A good test would be to check the voltage drop across the switch, it should be no more than 0.5v preferably closer to 0.2v under load.
There are a lot of factors to consider with electronic ignition. When I used a crab as a daily driver to get to work I opted for a system that retained the contact breakers and they fed an external black box. This meant there were no electronics inside the distributor getting cooked and in the event of failure it was a 30 second job to change back. You really don't want to break down on a fast dual carriageway or motorway nowadays.
If you can get a good quality capacitor and points and the distributor bearings are in good condition they should serve you well.
As you are probably aware there are many good reports on Accuspark, Powerspark and Pertronix etc but also many reports of failures.
All of these systems (apart from CDI) have one thing in common. They use a type of power transistor usually now an IGBT to switch the current to the coil on and off. They have an inbuilt protection to save the IGBT against excessive inductive voltages but if an ignition lead becomes open circuit or high resistance then this protection starts to fail as does the unit, the damage is cumulative. Ideally the total resistance from the carbon brush in the distributor cap (which can also fail) to the plug should be around 5K ohms. The other main source of failure is thermal stress. Whether some of the cheaper systems cut corners by using non automotive spec high temperature components that can cost several times the standard versions is unclear.
I believe many of the reported failures are probably down to poor maintenance of the leads and distributor cap, but unfortunately electronic parts can fail without warning at any time.
David
|
|
|
|
Post by jeff on Apr 21, 2023 10:01:04 GMT
Sorry guys, I didn't mean to get anyone going or stirring amongst old wounds. It's now worse than when I started this. Yesterday, I put the gold sports coil back on,and a capacitor which I "Thought" was a good old used one. I didn't take account of age deterioration with the capacitor. Its box reads 2001. Also a rather old rotor arm. And now it ticks over worse than ever. I really must learn to chuck this old and probably substandard junk in the bin. One thing I did notice which may be significant. There is a very noticeable arc burn on the top of the brass leg of the rotor arm, both the one installed, and the old one i put in yesterday. It is right where the dizzy cap carbon brush sits. The brush seems OK and is free under light spring tension. I cleaned it up but it reappeared straight away on second inspection. So, possibly something ain't right in there. I would have thought a good contact should be made giving no arcing. Hmmmmm?  ? I took the dizzy out and inspected it. No lateral or end play evident. Points seemed OK, so I just cleaned and regapped them. So now I'm going to put on again, the old known good lucas coil and put it all back to how it was when the miss first started. Back to the drawing board. I think I'll ask Tony Wood to send me a new capacitor, points and rotor arm, maybe a new dizzy cap. I know he will only supply decent stuff. In answer to David's point. I think on reflection, I'm clutching at straws in considering electronic ignition, hoping it will make the problem go away, at a price. I have great faith in the good old Lucas points and coil system and have driven starship miles on them without hindrance. Only once, back in 1978 did I experience a rubbish, new capacitor. (Not Lucas). I did all the right things, during my Landcrab service an within about 10 days the car started playing up, backfiring and running rough. It never crossed my mind that a new component could be faulty. I even took the cylinder head off and found nothing wrong. Only after a much older and wiser head (my dad) suggested putting the old capacitor back in and "give it a try". Problem solved. Grrrrrr. So, on balance I think I'll stick with points for now. The ignition switch is worth a look. I only replaced it a couple of years ago with a "so called" Lucas one. It was only £12 with 2 keys. So, from the bay of evil, it might not be the genuine article.Hmmmmm??? The only weight on it is the car keys and a small leather fob. The wiggle test is fine. Oh well, upwards and onwards for now. Jeff |
|
|
|
Post by dave1800 on Apr 21, 2023 10:49:16 GMT
A few years ago I was helping a friend with a MGB to sort out a poor running issue and we found that the carbon brush in a new distributor cap had a very high resistance across it. Normally this is just few ohm at most. It looked fine, weird and another new cap sorted the problem. If by chance you have the same sort of carbon (or whatever it was) brush then it may well arc. Easy check.
We enjoy the sparring about electronic ignitions on the forum. I think if anything works for Chris without blowing up it can be recommended. One day we may divulge what Nick and I have been up to in this area, but that's for another day!
David
|
|
|
|
Post by jeff on Apr 21, 2023 13:10:48 GMT
Dave,
I have a spare cap..but I will check the resistance across the carbon brush.
Also had the ignition switch out and checked all the connections amongst the Spaghetti. Nothing found other than a lose-ish lucar on the switch but nowt obvious.
Oh well lunch done, back into the fray.
J.
|
|
|
|
Post by Penguin45 on Apr 21, 2023 13:29:47 GMT
DISTRIBUTOR DOCTOR supplies first class ignition components to original Lucas specifications. You can also find "competition" condensers which mount externally to the distributor. Expensive, but virtually indestructible. I have arrived at a position now where if it's "Lucas" in a green box I just won't buy it. You haven't opened old wounds, BTW. It's more a combination of hobby horses, pet hates and good and bad experiences. I'm quite sure that David has had his head in his hands with some of my ignition antics over the years. I do have history.... Chris.
|
|
|
|
Post by andrewa on Apr 21, 2023 14:07:43 GMT
Second that….for all my electronic preferences I still carry the old dizzy just in case on long runs!
|
|
|
|
Post by jeff on Apr 21, 2023 15:58:54 GMT
Well that nice to know Chris, dare I lift my head slightly just for a fleeting moment and peer out into the daylight?
I beat the old Gal hard today.
Even swapped the cotton lead in the dizzy. The carbon cap brush tested fine. I tested all the copper HT leads which showed just a bit of resistance, but the same in each so i guess thats how they should be. They're faily new, old stock Swedish made from Tony Woods.
I found a capacitor from a service donkeys years ago. Put in an old rotor arm with no signs of arcing, and a known good but ancient lucas coil, with 69, stamped on the bottom. Then took her for a fairly harsh run up hills, down hills, tight bends etc. Not a hiccup heard or felt.
Maybe now it just needs a tweek in the points and timing, and maybe a reset in the mixture. There is a tiny waver in the exhaust note when just warm on tick over and maybe a few rpm waver on the tacho but nothing noticeable. Probably me being anal. The tacho has occasional bouncing fits its never been very stable, a bit like it's owner 😀
Here's hoping....
Jeff
|
|
|
|
Post by dave1800 on Apr 21, 2023 23:38:00 GMT
That's good news, it just shows how much the quality of parts nowadays has deteriorated although as Chris notes he Distributor Doctor's stuff seems to have a good reputation. I don't suppose there is any correlation with the tacho having a fit and the misfire?
David
|
|
|
|
Post by jeff on Apr 22, 2023 9:07:22 GMT
Dave,
That tacho thought has crossed my mind too. TBH, it's never been very stable and has always been rather bouncy, long before any misfires were noticed.it came from an MG B.
BUT....it is wired directly to the coil so in the event of an intermittent component failing allowing current to earth or breaking down, it could ⁸theoretically Rob the points of current and cause a misfire.
I haven't noticed the tacho as the mis is unexpected and very brief.
If it misses again after I've replaced points and capacitor and Rotor arm with new, I will disconnect it and see what happens.
Jeff
|
|
?