Ignition ballast voltage drop question

[dcmarsh]

Great tip on accessing the tach, Hawksfield. That would have made the speedo cable replacement easier had I known it a few weeks back!

[dcmarsh]

2cams70 - attached is the coil I installed. Amazon feedback had users who answered the question about points vs no points with “works great with my standard points ignition”. I measured resistance and it fit what someone earlier posted as ok if I recall. I paired it with a 1.5 ohm ballast resistor. Run voltage at the coil is 5.8 with factory wiring, and 8 using BillWill’s temporary bypass method. Problem?

[2cams70]

A coil with around 1.5 ohm primary resistance is the correct type for an ignition system with a ballast resistor if that's the type you ordered and indeed received. I'd suggest though that you actually measure the primary resistance just to ensure that what you think you ordered is what you actually received.

Craven is correct if you have 12V going in and a 1.5 ohm ballast resistance and a 1.5 ohm coil resistance you'd expect a 6V drop across across each so 6V measured at the coil is not an unreasonable result. Hawksfield's measurement results confirm this also.

Just to be sure though I'd suggest that rather than taking further voltage measurements you take a measurement of the resistance between the "run" output on the ignition switch side to the coil input. This will give you a measurement of the ballast resistance which will hopefully be in a normal range.

This path of thinking we have all been taking maybe completely wrong however if the cause prompting your initial investigation is "hard starting". There's many things that can cause hard starting of course. So maybe we should all go right back to the origin of your question at the beginning and take it again from there!!

[Slowtus]

This path of thinking we have all been taking maybe completely wrong however if the cause prompting your initial investigation is "hard starting". There's many things that can cause hard starting of course. So maybe we should all go right back to the origin of your question at the beginning and take it again from there!!

I alluded to that in my usual cryptic fashion...but was confronted by Ohms law with a bit of Kirchoff thrown in, a hint of Joules (with Farady and Lenz waiting in the wings and Biot-Savart also hoping), even though - almost all were irrelevant.

The OP can either solve the hard start problem and go from there or can solve the measurement problem and then return to the hard start issue but cozying up to Herr Ohms isn't going to help here.

I am going to post my my possible solution for the fourth time...on second thoughts, why bother.

[2cams70]

I alluded to that in my usual cryptic fashion...but was confronted by Ohms law with a bit of Kirchoff thrown in, a hint of Joules (with Farady and Lenz waiting in the wings and Biot-Savart also hoping), even though - almost all were irrelevant.

The OP can either solve the hard start problem and go from there or can solve the measurement problem and then return to the hard start issue but cozying up to Herr Ohms isn't going to help here.

I am going to post my my possible solution for the fourth time...on second thoughts, why bother.

I've got to say yet again that the Lotus Elan.net forum disappoints me on many occasions. Seem to be quite a few self righteous nasty people on here that can't ever learn anything new, admit that they make mistakes or aren't always the font of all knowledge. It's becoming a forum more about politics than substance. Plus there's all the people that raise issues and never close off topics after everyone has taken the time to offer suggestions. I'm going to stop contributing further to this topic now and I'm really seriously considering leaving Elan.net altogether and leave you all to continue polishing your paintwork, worrying about the market value of your cars and otherwise squabbling amongst yourselves.

Not to mention the weirdos that seem to exist here also - J.J DIKE being a prime example with his 12 Lotus cam covers who is determined not to do a weld repair and needs a project to divert himself from his cellar of 500 Argentinean red wines. Well at least it's good for entertainment value is all I can say!

[dcmarsh]

Ok, latest update!

After all the great helpful suggestions and knowledge, the car now starts! My apologies for not posting results of every test suggested but believe me, they have all been very helpful and educational. I’m now getting the correct voltage to the coil on both starting and running conditions, and that seems to have fixed the problem. Here is the list of what I did, based on all the input.
- new 1.5 ohm coil
- new 1.5 ohm ballast resistor
- new ignition switch
- checked voltage at all the locations suggested, and checked resistance across connections to trace down where there were problems. Multiple found.
- wire brush all relevant connections and treat with Brexit. Ok not the real name, so will look at the bottle that one of you suggested I purchase and update. It is indeed great stuff. Goes great with French fries. Grin.
- wire brush and redo trunk and engine compartment ground braids and cables.
- remove, disassemble and clean distributor
- remove the anti theft switch and solder the wires together, leaving out the one to the horn
- add a new 12 gauge wire from the fuse box to the ballast resistor. (I’ll remove that when I have the dash pulled and redone, by an expert)

Not only does the engine start fairly easily, but the starter (new) cranks a lot faster.

Now it’s on to why the carb is spurting gas out of one of the holes. Going to send those to British Superior in New York for a professional rebuild.

I can’t thank all of you enough for taking the time and patience to help me with this issue and educate me along the way. I see that this thread is getting a lot of views so hopefully all your knowledge is helping others as well.

I’m planning to be at Lotus Owners Gathering in Salt Lake City in September so maybe I’ll run into some of you there!

Thanks again

Dave

[Slowtus]

I alluded to that in my usual cryptic fashion...but was confronted by Ohms law with a bit of Kirchoff thrown in, a hint of Joules (with Farady and Lenz waiting in the wings and Biot-Savart also hoping), even though - almost all were irrelevant.

The OP can either solve the hard start problem and go from there or can solve the measurement problem and then return to the hard start issue but cozying up to Herr Ohms isn't going to help here.

I am going to post my my possible solution for the fourth time...on second thoughts, why bother.

I've got to say yet again that the Lotus Elan.net forum disappoints me on many occasions. Seem to be quite a few self righteous nasty people on here that can't ever learn anything new, admit that they make mistakes or aren't always the font of all knowledge. It's becoming a forum more about politics than substance. Plus there's all the people that raise issues and never close off topics after everyone has taken the time to offer suggestions. I'm going to stop contributing further to this topic now and I'm really seriously considering leaving Elan.net altogether and leave you all to continue polishing your paintwork, worrying about the market value of your cars and otherwise squabbling amongst yourselves.

Not to mention the weirdos that seem to exist here also - J.J DIKE being a prime example with his 12 Lotus cam covers who is determined not to do a weld repair and needs a project to divert himself from his cellar of 500 Argentinean red wines. Well at least it's good for entertainment value is all I can say!

Curious as to why you quoted my post to vent your spleen?

I offered the OP solid advice, more than once, based on decades of both knowledge and experience and you somehow see that as 'political' and then wander off to reference red wines...I can possibly see a connection here with red wines and your post but that is pure conjecture = and I have no objection to you "leaving Elan.net altogether"

Or staying.

[dcmarsh]

Just. Quick followup as to hard starting, which is why I was going down the electrical route. I turned it over to the British Car expert here (JD’s British Cars) and after much debugging, it turned out to be fixed by adding a choke to the rear carb, and fashioning a cable connector from an AH 3000. He also removed the ballast and went the standard 3 ohm coil, and moved the mounting location for the coil to be safely out from under the carbs. Car starts cold or hot fine now

[HCA]

I did not appreciate that this was an old thread until well into the dialogue.

I was not here in 2017, but on reading your opening post of the supply being 14V dropping to 11V, and then going on to say that all readings were static without cranking - my question would have been, and is now, how have you found a 12V battery that produces a static 14V? Please share!

[dcmarsh]

Ah, I should have mentioned it was on a battery maintainer.

[HCA]

OK! Understood! And there was pretty well 90% of your issue! Maintainers only put out 800mA to 1A, so the poor thing must have been in agony when it saw itself connected to a coil asking for 4 - 6A

It is all academic now and glad you have it all sorted. Happy driving!