Ignition Timing

[kevinw]

Mike - after starting this long thread, I've now got mine running at 10 degrees advance at 750 rpm idle speed. This was eventually set with the vacuum advance removed and plugged (admittedly, plugged with just my finger over the end). I had a problem last year with my points getting corroded and generally covered in all sorts of muck after just a few miles. Car would either not start or not run properly until the points were cleaned and then would repeat the cycle every 40 miles or co. Eventually, having changed everything else in the ignition circuit, it turned out to be the coil.

My car is a 1972 build pre-facelift 2000 auto with now 55000 miles on the clock which is verifiably genuine. This runs on ordinary unleaded with a bottle of Millers VSP added with every 40 litres of fuel. Well, to be honest, it's a bottle with every tankful of petrol, but a refill is usually between 40 and 50 litres, so close enough. Millers VSP came out well in the FBHVC tests and as well as a lead replacement, it is also a 2 octane boost, so you end up with unleaded being about the same octane rating as the old four-star that these things were designed to run on.

Also, for the fun of it, I checked the timng on my TR6 (PI) this morning - which is again at 10 degrees btdc. This is fully converted for unleaded, but only ever gets fed on super unleaded (Shell Optimax when possible).

Kevin

[mikeyb]

I wonder if my coil is the problem too then, as my arm and cap were quite furry, I had put it down to moisture.

I was getting 6v at the coil.

[kevinw]

Does it have a ballasted ignition system? If it does, then 6v is about right. Coils seem to have two modes of failure - either one of the windings fails and goes open circuit which is obvious because it just doesn't work, or else, the resistance changes and so the characteristics of the circuit get changed and you get other werd things happenning - liek the points getting caked in gunge.

If this thread now follows the usual format, a few of the other electronics engineers around here will join in and we'll have a long chat all about tuned circuits and so forth until one of the administrators tells us we are supposed to be discussing engine things and not electronics!

Kevin

[mikeyb]

Could be its a ballast resist then, I really should have a proper look one of these days, but you know how it is, if it ain't broke don't fix it

Its got an aftermarket lumenition ignition on it (bladed thingy in the dizzy with the hall effect doo dad) so not points to faff with

[CAR]

Could be its a ballast resist then, I really should have a proper look one of these days, but you know how it is, if it ain't broke don't fix it

Its got an aftermarket lumenition ignition on it (bladed thingy in the dizzy with the hall effect doo dad) so not points to faff with

How do you find the lumenition then Mikey? Do yopu carry the bits with you to convert back if the need arises?
I only ask, cos I have all the parts in the garage ready to try, but there are always a lot of guys on here who don't do electronic ignition.

Cheers Colin.

[mikeyb]

I have yet to find a problem with it, it has never failed to start.

I don't have any bits to convert back, it came with the car, as far as I can tell its been on the car about 10 years.

It looks like a pretty simple system to fit, I would give it a go

[Mike Stevens]

If this thread now follows the usual format, a few of the other electronics engineers around here will join in and we'll have a long chat all about tuned circuits and so forth until one of the administrators tells us we are supposed to be discussing engine things and not electronics!

Kevin

I won't rise to the bait!

It is true, there is a 'ringing' effect which the capacitor is supposed to damp.

However, in spite of being a licensed Radio Amateur for (nearly) 40 years, I have no intention of getting embroiled with discussions on resonant circuits!

Cheers,
Mike.