Hi there

I am curious about others experience with plug and coil combinations used with the Pulsar dizzy.
I notice that the GT40R (without a resistor) is recommended but I have been running a different combo for 10+ years (from before the Pulsar dizzy mod post was on this site I think).
Lomin, I notice that you say that my combo will not have a strong spark:

My combo: (On 1275 SC12 supercharged)
Bosch MEC717 Transformer coil
Primary 0.45 Ohms
Secondary 6.6K
NGK BPR5ES 0.8mm gap. (smaller gap to avoid foul on rich tune - BPR6ES - 1.1mm was fouling at idle)

The GT40R Coil specs
Primary 1.2 Ohms
Secondary 8-10K

I was always under the impression that the low primary resistance meant stronger spark hence the MEC 717 and have been using resistor spark plugs just due to them being listed for the pulsar (i think that was why - it was 10 years back when I set it up)

I guess I just want to know if it is worth my while to change over to a GT40R and BP5ES plugs.
which will cost a grand total of about $80.

Car is running fine as is but every bit of HP helps.

Cheers
Rick

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Years ago I built a 1387 stroker motor for a friend with a Pulsar dizzy and original ex Pulsar 1.5 ohm Hitachi coil. Plug leads Bosch inductive core 1.8 K ohm.
Spark would jump well over 1" from a plug lead.
Pretty good for a standard system.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hi
No real help here, except to ask questions. I thought a ballasted coil only received say 9 volts instead of 12- so my first question is what wiring do you have?

I have run a pulsar dizzy , but i think i ran it with a gt 40 - at about the 1.5or 1.8 ohms (not the lower ohm figure of the GT40R. The spark plugs i used were NOT R type, just plain old BP6ES - the mini has no sound system to interfere with hence no need in my instance for BPR6ES. It throws a good spark.

The dizzy has also had the cam movement reduced - i cant remember figures , maybe 10 degrees at dizzy? ( 10 degree static + 10 degree dizzy X 2 = 30 all in?

Hi FNQ

Running the 12v transformer coil wired direct, so no resistor.
Also wired through MSD boost retard module, but that shouldn't make any difference.

The GT40R recommendation is also to run at 12v, so without resistor.

I think from memory that the GT40 (non R) has a large primary resistance of like 3.5 ohm so low energy.

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Hi drmini

Yeah, I am running the same bosch plug leads but possibly a little longer than I need.
Was noted by Lomin that I could improve some spark there also by reducing lead length.
So, if the stock hitachi coil is 1.5ohm then I guess the GT40R at 1.2ohm is a close match.
The higher current draw of the transformer coil at 0.45ohm hasn't hurt the dizzy module though.

cheers
Rick

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Hi Rick, I will put my two bobs worth of MY opinion again, and i think you are trying to work out the best combination without spending lots, which is great.
The technology that yourself and probably 95% of mini owners are using was designed for leaded fuel, low outputs, cooler running motors, and an era of increasing pollution requirements, it was not the optimum then, and is even worse now with ULP. and useless with E85
I think you can only gain incremental amounts, but they will still be gains. You cannot afford to waste spark output ,as no matter how you slightly vary your system the output is low
Today I talked to one of the best cam grinders about a cam fitted to a supercharged car I am trying to sort out using our dissy. As he said, we have moved on a lot since we designed that cam with now different exhaust duration etc, etc, and this has drawn us into the quagmire of cylinder pressures, high compression, and a small sprintex spinning too fast that creates hotter mixtures.(This car has blown lots of head gaskets ) A bit of a nightmare for advance curve.to avoid detonation but still give good smooth power , especially when maximum revs used is 5000rpm
Anyway to move back to your post, the line, WE have moved on also applies to ignition systems that are NOW specifically designed for ULP, alcohol (ethanol) fuels etc
I do not think you can get the best out of a mini engine with the old technology, but for a lot of people it will do the job
I am only trying to help you get the best out of what you have
I do not compare my systems with others ( except for reliability) as most times its not comparing apples with apples
As another aside, this supercharged car has a bosch points dissy fitted and one of the problems is many bosch rotor buttons have a resistor between the centre and the tip. If you cannot see all the brass on the top on any rotor you may be wasting a lot of spark. You can solder in a joiner if you have to.

cheers Lindsay Siebler

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1967 EX works rally mini restoration virtually complete OBL45F
1965 Mk1 Cooper S
1970 Colt 1100F SS
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

Hi Lindsay

Thanks for that. You are correct in that I am trying to get the best bank for buck on a budget and I appreciate and respect your information. I understand that with more funds there are better options out there, but I must admit that I quite enjoy trying the get the most performance that I can, on the least amount of money. It is important to always keep in mind that with this budget setup, I am always going to struggle to get much more than 100hp atw which ever way I put it. But that is fine and the fun is in the problem solving.

My Cammed HSV is where the genuine performance is for me but that is yet another project. Cam technology for the LS2 holden engine has also come a long way in the last 5-10 years (Less duration and more lift in particular)

I guess that best case scenario would be for a slightly stronger spark, which could be slightly less prone to fouling at idle, and could lead to me using a colder plug. This in turn could lend itself to some more ignition advance. Ultimately, as per most of this build, trial and error gives the answers but also becomes expensive at times. (especially when you have several projects on the go as you know).

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

If this stuff really tickles your fancy go and study transformer theory .Was first year trade stuff in electronics trades.Injectors in efi are driven by pulse width modulation . Yep and old school cars are super cool

Rick

Thanks for taking the time to respond to all the posters.

Again , just throwing thoughts out there.
Lindsay (and others) supply good quality low resistance HT leads - test your current ones- i think Dr mini says if they test above 5 bin them.
Secondly is there any manipulation in the boost retard module - ie increase base timing but tweak the MSD to take out more timing off the top?
Thirdly, in a similar way - de cam the dizzy - instead of a mechanical 12 dizzy degrees, reduce it to 9 - and adjust ( advance) timing to compensate.
I am picturing that the mini will run a little better at low revs if it is more advanced at that point.

No worries.

Ok, I will test the leads and see.
Yes, the MSD module has an adjustable knob on the dash board 1 to 4 deg retard per pound of boost.
Running a fair bit of static timing at the moment. Just adjusted it this morning, 20deg advance at idle .
Getting a calculated 32 all in at 9psi. (No way to tell for sure as need to be in boost to see). I run as much timing as I can already without audible detonation.
The dizzy has the 12.5 deg mech advance plate but no real point in reprofiling as the msd module restricts this.
I have thought about running less static advance and removing 2 of the springs to get the dizzy to advance quicker and to make starting a bit easier but seems ok as is. (Bosch starter does struggle a bit when hot)

My other mini 1275 (non boosted 45 weber) runs a pulsar dizzy with 15.5 deg plate but I have reduced it to 11 by welding the slots and I have also removed one set of the double springs on that one. (Project not finished though)

The main issue that I am trying to work out is, do the transformer type coils throw a weaker spark than the canister type.

Just fitted 1.5 forged rockers this morning and quite a noticeable difference. More that I was expecting so I am stoked!


cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw