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MG Midget and Sprite Technical - ignition systems .. worth upgrading to multispark?

Out in my car again today bedding brakes in etc and just enjoying driving, but started to have what i think are ignition troubles.

i've just got normal points,, but when the engine gets to around 4000 rpm i get the odd stutter and the tachometer needle gives a 'blip'.
i'll replace the points and condensor tomorrow and hope that fixes it.i've never replaced these despite stripping and rebuilding the engine... i've got an new coil and ballast resistor already fitted..

This got me looking at ignition alternatives though, from just keeping the points, to putting in a points replacement 'pertronix' type system right the way through to an MSD CD system with revlimiter, and even megaspark system with crank sensor and EDIS...

All very interesting stuff to learn about.. what do you guys all run... and is there any advantage in real world daily driving for the high end systems ?
Andy Phillips (frankenfrog)

Make sure you put the LT connector on the points on the right way around Andy. After 10 years off the road I found the PO had put mine on the wrong way around and I copied it. (The PO is my brother in law - he must have serviced the car and then left it for the 7 years before I started work on it). Took 3 days to work through to it. The points ground if its not the right way around. BTW clearly shown in a pic in the Drivers Handbook which is how I worked mine out in the end.
Dave Squire (1500)

How much play is the the distributor shaft. It may need to be serviced (I'm not familiar with the Datsun distributor types). With the 25D lucas units the bushing gets worn and you end up with a fair amount of slop that can effect the dwell.
Trevor Jessie

the Westlake head design on the A series engine has exceptional burn characteristics, so the difference between a well sorted stock ignition and an aftermarket, electronic ignition is small

However, a worn out ignition system will rob the engine of power.

As Dave and Trevor pointed out, make sure your bushings are not worn, that the leads and points and condenser are all in top notch shape, and the adjustment is done carefully, it should run as well as it is going to.

There are electronic ignitions that allow you to modify the advance curve, which is valuable if you've got a heavily modified engine, and there are simple, "pointless" ignition modules that can fit under the cap which can get you away from having to replace the points and condenser every 5k miles or so, but your biggest benefit will come from making sure about the basics first.


Norm
Norm Kerr

Andy...

What ever direction you go, Do NOT use a timing gun, do it by ear, and use the static ignition timing set up while refusing to use dynamic and if it dosnt work, by all means, please avoid telling us as long as possiable that you avoided
Using the timing gun....and please throw in all kinds of red hairings to throw us off the path .

god forbid someone would make this easy...

Hahahaha

Prop

Prop and the Blackhole Midget

Thanks guys, i will be replacing points/condensor today once the shop opens...
i have checked the play in the distributor, there is some there, with the rotor arm off you can wiggle the top of the shaft by about a quarter of a millimeter..
is that a lot ?

Now ignition systems have my attention ive been looking at the many options and found this :
http://www.maplin.co.uk/ignition-amplifier-kit-3162#overview

the website says :
********

Easy to fit, only four wires
Significantly reduces contact breaker wear
Original connections can be easily restored at any time
Improved coil performance
Applications:
For any petrol vehicle
Suitable for engines of 2 to 8 cylinders

One type of electronic ignition that can be fitted is an ‘up-grade’, producing what is commonly called ‘transistor assisted ignition’. This type still makes use of the ‘conventional’ mechanical timing switch (the contact breaker points). Fixing this electronic ignition system will lead to improved starting and smoother running, particularly at very high and very low rpm.
**********

seems like a good idea, and very cheap too.....



Andy Phillips (frankenfrog)

Thanks Prop,
I'll try and follow your advice... but how do you set a .45-.55 gap in the points by ear ?

i think its good advice to avoid using guns in the engine bay even if they are subject to almost no control in America....

;-)
Andy Phillips (frankenfrog)

Andy...

timing GUNS dont set timing....people do

The answer to a bad guy with a timing gun, is a good guy with a better timing gun...hahaha

To gap the points... just eye ball it....if you want to be dead on, use a match book cover ....feeler gauges, are so over rated. ...hahaha

On a serious note...I think a 1/4 of a mm is well with in spec...mine had about 1/2 inch of play and it ran (somewhat okay) before the breaker plate fell apart and I had to get a new dissy

Prop
Prop and the Blackhole Midget

Andy,

I used the Maplin kit for many years in my Sprite and it worked well and never had a problem with it. Points life is greatly extended as well and after the usual bedding in of the points needed virtually no maintenance. The kit is still in the car but the car is off the road awaiting attention.
David Billington

Andy,

Slight correction, the kit Maplin sell is actually made by Velleman so can be bought from many vendors. I can't remember who I got mine from but as a Velleman kit it doesn't really matter but the price of their kits can vary surprisingly between sellers but at £10 from Maplin I would say that's a good price but I doubt free shipping applies to Thailand.
David Billington

David, thats encouraging...i think i'll give the Maplin kit a go,(see if i can get one locally first) .

did you put it in a box or other method to protect it from the elements ?

i'll get the car running on the std set up first.

Bit of a nightmare with it yesterday, took all day and not yet finished...
first i was given the wrong set of points and only realised after an hour or so of trying to get rotor arm and the timing cam to line up with dizzy cap when at -7 TDC.Then going back to the shop to replace it to be told they only have that type , then having to find another shop.
Then ...after all that i put the dizzy cap back on to find that it has a big crack where you attach the cable from the coil....
Andy Phillips (frankenfrog)

New dizzy cap fitted, points gap checked with feeler gauges, started first time and bang on 7 degs advance when using my timing gun (note for archive: its a datsun engine..).
Need to get a dwell meter, or some way to measure the advance up to around 40 degs to set the full advance.
but very happy with myself, its the first time ive had to do this...

ordered the Maplin kit so i dont have to do it again !!

went for a test drive, everything seems ok, double checked with the timing gun again and its still at 7 degs...
however, i noticed that my coil gets very hot , so hot you cant really touch it.
its a normal coil with a ballast resistor... should it be getting this hot ? ive never noticed before with other cars..... my under bonnet temp is quite hot though....
Andy Phillips (frankenfrog)

Andy,

I did put it in a sealed box with the heatsink on top of the lid.
David Billington

Accuspark. £30 and fit and forget. Prop, you do need a timing gun and more importantly, know how to use it! The idle timing mark is rock steady with electronic ignition, compared to the erratic timing that you see with points.
Robin Cohen

Robin,

Accuspark may be good as a points substitute, not used it myself, but as such stability will depend on the condition of the distributor and its bearings.
David Billington

Hi Robin,
Yes, i did notice it 'hunted around' a bit when under the gun... maybe 2-3 degrees of wander.. but i read on the datsun website that the engines have about 4 degrees of tolerance from new in the timing...i assumed it was that that i was seeing.

i'll have a look at the accuspark and see if they have one for my Hitachi dizzy.

i think prop was being sarcastic about not using the gun...i think me and him seem to be on the same wavelength (on this occasion anyway)... which worries me greatly...
Andy Phillips (frankenfrog)

>>i think me and him seem to be on the same wavelength<<

you poooor devil !
Nigel Atkins

Drove to work today in my frogeye.
76km(47m) at around 110km/h(68mph) with the engine buzzing at around 4000 rpm.
It didnt miss a beat.

Andy Phillips (frankenfrog)

Hey robin...

I was just having a bit of fun based on some of the past visitors that didnt belive in timming guns....sorry to have misled

Andy...

What about a timming tape that fits to the crankshaft pully with a pointer

Thats what I have and I use a advancing timing gun to zero it in...I think peter may sells a kit

I think you would be well ahead of the game if you know the degree at 800 rpm, 2000 rpm and 4500 rpm

THATS NOT GOOD !!!

If the coil is that hot, something is wrong...id feel up your wiring loom also... if its hot, then that is really not good... id disconnect the battry when not around and keep a "ABC" fire extinguisher close by

But im very serious... I think something is not hooked up correctly... if I was forced to guess to avoid sleeping with arie... id say its a grounding issue

Prop


Prop and the Blackhole Midget

Hi Prop,

yes i found a timing card on the datsun website, i just need to print it out to scale and attach to the front of the block. for my engine 36 degrees at 4200 rpm is recommended....

my wiring loom is completely brand new and designed and made myself (i do have experiance designing control panels for industrial applications) and the cables are all at least 1mm sq. also i have a battery cut out switch which i always use in addition to the key.
And i carry a fire extinguisher.

i did have a long look through the archives and it seems that a hot coil is quite a common ocurrance.
My under bonnet temp must get to about 50 degrees, as its already 36 degrees ambient outside....
also, yesterday i bought a new set of plugs, only 100 baht each (about 3 usd) and the coil didnt seem too hot.
i'll keep my eye on it...

as for a grounding issue, you may actually be onto something there, my dizzy has an unused male spade on the side of it, it wasnt attached to anything when i got the car and it seemed to run ok.
two days ago i sent a picture to the datsun engine forum (which is as lively and helpful as this one) and was told its an 'optional' grounding point.. so it wouldnt hurt to ground it and see what happens...
Andy Phillips (frankenfrog)

As the cars at work, ive just double checked and the wire from the coil to the dizzy is a 2mm sq one, which is quite thick.... other cables from ignition switch to coil are 1.5mm sq.


Coil is wired to a relay which gives 12v to the coil while the starter motor is engaged, then switches back to route through the ballast resistor for normal running which in theory should give the coil 9 volts on the primary....

Maybe just giving the coil 12v all the time would reduce the temperature as it wouldn't have to work so hard ?
However, i understood that the purpose of the ballast resistor was actually to reduce load on the coil so maybe my 'figurin's' all screwed up.....
Andy Phillips (frankenfrog)

Andy,

Keep the ballast resistor as if you remove it and give the coil 12V during normal running it'll run hotter. As you've got a fixed dwell angle with points or the likes of the Velleman kit applying 12V during normal running will result in more current flowing through and so more heat.
David Billington

This thread was discussed between 04/05/2013 and 08/05/2013

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