Ballast coil ID?...

[Jules TR6]

TR6 PI, with ballast.

As you may have read in another thread I started, the poor engine response/misfire/ignition seems to have been cured by taking out the new resin-filled Viper coil, and putting the old Lucas coil back - which is possibly original to the engine from 1969, so 54 years old!

I'm now really curious as to what exactly this old coil is, number etc, and what would be it's exact new equivalent, i.e Lucas again (if they are still good), and oil filled etc.

I can just make out maybe an H then 1.3 - 1.5, under that, Resist...

Lucas ballast coils now (DLB102) say they are 1.5 ohms and for 1.6 ohms ballast resistors (no mention of a 1.3 - 1.5 range).

https://simonbbc.com/Genuine-Lucas-DLB102-Ballast-Ignition-Coil-SILVER

- that is from a business that sells in electronic ignition, and says it is for points (so I assume they don't recommend it for electronic ignition?).

I did find reference to an out of stock Lucas '6 volt coil for 12 volt ballast ignition, use with 1.3 to 1.5 OHM ballast resistor.' - which has the ohm range correct though say 6 volt on it.

What would be the best new coil that is as close as possible the old one I have, i.e not a newfangled upgrade, just like for like that won't upset anything, with push-on spade connectors.

 

Edited October 8, 2023 by Jules TR6

[RobH]

It's probably best to steer clear of modern Lucas stuff - the name was sold to a different company and seems to have a bit of a reputation for unreliability now.  

The exact Ohms range isn't critical so don't get hung up on it.  Oil or resin filled doesn't make much difference either.  If the coil is properly designed, the filling won't make any difference to performance  - it is only there to transmit heat from the winding to the case. 

 Bosch, Remax and  Pertronix  coils are good, or those sold by the electronic ignition makers to match their systems   ( If your ignition is Powerspark then that Viper coil should be returned to them as faulty. It ought to work with their own kit). 

 

Have a read of the document for download here, the last page has some data on different coils :

 

Edited October 5, 2023 by RobH

[Mike C]

+1 "It's probably best to steer clear of modern Lucas stuff".

[Jules TR6]

Ok I thought I'll look at a Flamethrower 1.5 ohm (supposedly 40,000 Volt), I quote :

'We find these uprated coils to be the most reliable on the market at present.
This coil is not suitable for cars still fitted with the original points & condenser.'

So this could not be used with points & condenser (- either the points/condenser gets damaged or the coil?

What coil could be used with either electronic ignition module or points? - in case I want to swap between them.

Can I use my v.old 1.5 ohm Lucas coil with electronic ignition - or is that a no no? (the old coil obviously works with points, and seems to work with electronic ignition - but I don't want to damage the coil with prolonged use on electronic ignition if not compatible!).

A Bosch Red or new Lucas 1.5 ohm would work fine with either ignition system (and I should avoid coils sold by electronic ignition companies?)

I notice there's the 1.5 ohm -

Lucas DLB102 (£20)

and

Lucas DLB110 Sport (£25).

I understand the 1.5 ohm equation with the ballast system, but don't understand why some 1.5 coils are supposedly not suitable. How to make the correct choice, would the gold Lucas Sport be better (or worse) than the standard Lucas - with both EI and points?

Edited October 6, 2023 by Jules TR6

[Steve-B]

Just a thought, why not give Distributor Doctor a call and chat it through? I’ve learned a lot here, and a bunch more from him.

[RobH]

5 hours ago, Jules TR6 said:

Ok I thought I'll look at a Flamethrower 1.5 ohm (supposedly 40,000 Volt),

The Dizzy Doctor supplies flamethrower coils so he must find them to be OK. 

5 hours ago, Jules TR6 said:

This coil is not suitable for cars still fitted with the original points & condenser.'

 

Where did you see that?  I've no idea why they say that for the standard-resistance coils  (1.5 or 3 Ohms).  Electrically there is absolutely no reason why that should be so .   I use a 3 Ohm Flamethrower (40511) with a points system and it works just fine.   See the note below re constant dwell systems.

5 hours ago, Jules TR6 said:

I don't want to damage the coil with prolonged use on electronic ignition if not compatible!).

The problem isn't the ignition killing the coil, but rather the coil killing the electronic ignition. 

5 hours ago, Jules TR6 said:

What coil could be used with either electronic ignition module or points

Any coil with the right resistance. 

5 hours ago, Jules TR6 said:

A Bosch Red or new Lucas 1.5 ohm would work fine with either ignition system (and I should avoid coils sold by electronic ignition companies?)

Bosch is fine as should be a coil matched to a makers own ignition. system. 

See my earlier opinion about modern Lucas coils.

5 hours ago, Jules TR6 said:

I understand the 1.5 ohm equation with the ballast system, but don't understand why some 1.5 coils are supposedly not suitable.

Neither do I for the run-of-the-mill standard resistance coils. I think it is just marketing hype from companies who want to sell their ignition systems - there is no electrical reason that I know of.  

However some electronic ignitions have clever tweaks such as constant dwell and there are coils with very low resistance which are designed specifically to work with those systems. They are definitely not suitable for use with points. 

[Jules TR6]

13 hours ago, RobH said:

The Dizzy Doctor supplies flamethrower coils so he must find them to be OK. 

Where did you see that?  I've no idea why they say that for the standard-resistance coils  (1.5 or 3 Ohms).  Electrically there is absolutely no reason why that should be so .   I use a 3 Ohm Flamethrower (40511) with a points system and it works just fine.   See the note below re constant dwell systems.

The problem isn't the ignition killing the coil, but rather the coil killing the electronic ignition. 

Any coil with the right resistance. 

Bosch is fine as should be a coil matched to a makers own ignition. system. 

See my earlier opinion about modern Lucas coils.

Neither do I for the run-of-the-mill standard resistance coils. I think it is just marketing hype from companies who want to sell their ignition systems - there is no electrical reason that I know of.  

However some electronic ignitions have clever tweaks such as constant dwell and there are coils with very low resistance which are designed specifically to work with those systems. They are definitely not suitable for use with points. 

The Dizzy Doc recommends I bypass the ballast and go for a 3 ohm coil, mainly to keep it simple.

Looking at the PowerSpark page of the EI I have :

https://simonbbc.com/Powerspark-Electronic-Ignition-Kit-for-Lucas-22D6--25D6-Distributor-K1--R4

...the requirements there say : To be used with a coil resistance above 1.5 ohms only.

I'm wondering if all these recommendations to swap to a 3 ohm system is because that's what these 'drop-in' EI modules need

...and therefore I should swap back to points ASAP if I want to keep the ballast - and stay with points. I'm sure the car seems more lively/responsive on points.

So while it does seem like I can use the Flamethrower 1.5 ohm (for points), it might not be a good idea for a normal 'drop-in' EI module. The couple of people locally who have installed a 'drop-in' EI module, don't have a ballast setup, so for them there's no murky water. For me, if I wish to keep the ballast I'm still unsure if that's possible with EI, ...as going back to the Powerspark requirements : To be used with a coil resistance above 1.5 ohms only ....why's that?

 

Edited October 7, 2023 by Jules TR6

[RobH]

17 minutes ago, Jules TR6 said:

To be used with a coil resistance above 1.5 ohms only ....why's that?

Because a lower resistance draws a higher current.  That overheats the ignition module.  

It would be marginal on a ballasted system during cranking because although the ballast is shorted out so the module sees only 1.5 Ohms , the voltage is reduced also but that depends on the health of the battery so the current is a bit indeterminate and might exceed the capability of the ignition unit.

When running, the ballast resistance adds to the coil resistance so  it is the equivalent to a 3 Ohm coil and will work fine with the module.  (Many 3 Ohm coils are actually 1.5 Ohm ones with an added resistor inside the case which increases the total. )

Edited October 7, 2023 by RobH

[Jules TR6]

16 minutes ago, RobH said:

Because a lower resistance draws a higher current.  That overheats the ignition module.  

It would be marginal on a ballasted system during cranking because although the ballast is shorted out so the module sees only 1.5 Ohms , the voltage is reduced also but that depends on the health of the battery so the current is a bit indeterminate and might exceed the capability of the ignition unit.

When running, the ballast resistance adds to the coil resistance so  it is the equivalent to a 3 Ohm coil and will work fine with the module.  (Many 3 Ohm coils are actually 1.5 Ohm ones with an added resistor inside the case which increases the total. )

ok I get it, ...so 'To be used with a coil resistance above 1.5 ohms' is only applicable if there's no ballast.

I could check the cranking voltage at coil I suppose, though not sure what that would tell me in terms of good or bad.

Anyway you've put my mind to rest, I was about to rush and and get the points back in! I guess if the EI keeps working, all is fine, if it fails in the short term, I should go back to points.

I'm giving the fuel pump a full 20 seconds to build pressure, before starting, this does help the engine fire up with least cranking. If I give the pump 10 seconds, the engine then needs 10 seconds of cranking! - so I've leant to be patient and wait the full 20 seconds.

Planning an hour drive tomorrow, with a pub lunch half way - and will say cheers to you Rob.

[Jules TR6]

Not sure which of my recent threads to reply to... anyway here to wrap it up... as the main issue did seem to be the new coil or maybe a bad connection to it (and this thread is focused on the coil).

Driving on the local English country roads today went very well indeed. First time I've had a 1hr drive (i.e everything under the bonnet hot and working hard) in my ownership of the car that there was no misfire.

Two issues did arise...

1. Performance was good, though when driving in a very spirited manner we did smell a burning rubber smell.

Thought it might be the fan belt slipping, checked it when back, seemed even fractionally tighter when warm than when I tensioned it cold, so not that. Probably the clutch. Tricky not to slip it a bit, when trying to be smooth, but I guess when 'giving it some' best to be be super sure the clutch in 100% in before giving it full acceleration again. I say performance was 'good', as I still think it was smoother, 'warmer' and more responsive on points, rather than the EI drop in module now fitted.

2. Rear end clunk, usually two or three clunks when moving off, or after braking hard on the move. I presumed this might be the rear drum brakes, shoes reseating and coming out a bit, but reading more on this forum it seems the most likely cause is the rear diff mount rods/rubber bonding. Not sure where they are, but if it is them, if seems some kind of up-rating of their strength might be in order. I don't think it'll cause any major damage though? - just a curious eye-brow raising clonk clonk when moving off.

Anyway great to be on the road again, zero misfire, and I did raise a glass to you Rob and this forum.

Actually there was a third issue, my driver side door clank clank clanking while driving, something loose, might be the window - though doesn't change if the window is up or down. Maybe part of the joy of a 'roadster'.

Edited October 8, 2023 by Jules TR6

[DRD]

Clonking is usually either cracks in the diff mountings or worn drive shafts.

[Jules TR6]

11 minutes ago, DRD said:

Clonking is usually either cracks in the diff mountings or worn drive shafts.

...embrace the clonk or stop driving and get it looked at - what's the worst than could happen living with the clonk?

I see we both have a yellow TR ...and actually I have AWD BMW X1 twin turbo - which has it's points in terms of road-handling / cornering grip, but I prefer the TR !!

Edited October 8, 2023 by Jules TR6

[DRD]

If its worn drive shafts then you can live with it for a while, but cracks in the diff mounts will only get worse and result in more damage. The diff will need dropping and the mounting points on the chassis repaired and reinforced.

[Jules TR6]

18 hours ago, DRD said:

If its worn drive shafts then you can live with it for a while, but cracks in the diff mounts will only get worse and result in more damage. The diff will need dropping and the mounting points on the chassis repaired and reinforced.

I was reading about possible causes of a 'rear end clunk clunk', when I came across a story of a women who took her car into a garage to investigate a clunk from the rear of the car.

Turned out to be her bowling ball.

So thought I'd apply Occam's razor (a new method to me, which has just solved a v.bad misfire). What had I just been doing? - and what was the simplest explanation for this clunk?

I'd just bought a spare-wheel fixing plate, drop-down hook and wing nut (the hook fixed to the base of the boot was already there). If was getting annoying hearing the spare wheel jumping up and down over bumps, so I had to fix it down. In doing this I'd moved the jack. Currently I think that was the cause of the clunk clunk when accelerating from having braked. Can't be 100% sure, but now that everything it truly solid in the boot recess, at least I've ruled out the jack potentially moving around if I do hear a clunk again!