1948 Iron 4G Coil Ignition

Anything about Ariels
john.whiting
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1413
Joined: Sun May 22, 2011 2:10 pm
Location: Brisbane QLD
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby john.whiting » Fri Sep 13, 2019 11:37 am

I was talking to someone had a 6 cyl head reco d,and decided to fit all new ignition electrics.......bulk trouble ,like a carby problem,but he was able to borrow a working carby off another motor ,which made no difference...........after much mucking about,he discovered his new coil was too high voltage.....like 40,000v Vs the correct 20,000v for the old dizzy......the excess volts flashed over all the time and carbon tracked the cap....replaced the coil with one meant for a 70s Holden ,and the cap,and now all is well.

nevhunter
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3700
Joined: Tue May 10, 2011 9:42 am
Location: Victoria.. Australia.
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby nevhunter » Sat Sep 14, 2019 4:15 am

Maybe had suppression leads and "R" plugs too, to make that happen. Nev

chris.matthews
Posts: 34
Joined: Wed Oct 16, 2013 6:29 am
Location: Tokyo, Japan
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby chris.matthews » Sat Sep 14, 2019 11:50 am

Hello Everyone
Not much to report on the 4G- but I have a unique excuse.
We had a monster sized typhoon in the early hours of Monday 7th.
No damage to my house or workshop - but a big tree was uprooted in the garden - it fell across the garden, so that took some tidying.
Power lines were down 350,000 without power, its slowly coming back - as of tonight 14th there are about 100,000 still off. Knock on effect is most businesses are not fully functional, very few petrol stations open, no phones and no internet - we had water many didn't.
My neighbor says he now knows what 3rd world is like. Good news is we were back to normal on Thursday evening.

So no progress at all on the 4G.
But there has been some thinking (always dangerous)
A while back it ran ok, my problems started when I looked into dynamo and charging circuit.
Pulling the dynamo lost the distributor timing.
I can set and check the contact breaker timing (Dave Lindsey indicator - LED on when points just opening).
BUT how do I check the Distributor Timing, to be sure the spark is at 8mm BTDC ?

Best regards,
Chris in 3rd World Tokyo

User avatar
chris.shearwood
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 430
Joined: Mon Feb 28, 2011 5:28 pm
Location: Sutton, Quebec, Canada
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby chris.shearwood » Sat Sep 14, 2019 1:09 pm

chris.matthews wrote:BUT how do I check the Distributor Timing, to be sure the spark is at 8mm BTDC ?


Can`t you put a couple of centre-punch marks on the end of the front crankshaft, one for TDC and one for fully advanced? This can be done by putting a stick or wire down the plug hole. Remove the rocker box lid to make sure you are on the right stroke. Once you have the crankshaft at TDC on the power stroke you can remove the distributor cap and see if the rotor is pointing to where the #1 spark plug cable would be. If that is correct then the motor should start and then fine timing with a stroboscopic light should be done.
1946 4G, 1950 NG and 1951 VH

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1784
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby paul.jameson » Sat Sep 14, 2019 8:23 pm

The distributor drive is a potential source of problems on the 4G (and 4F 1936 and 1939). The fibre gear on the magneto shaft which drives the dynamo and distributor will shear its teeth off without warning which loses the drive to the distributor and stops the engine. To check for stripped teeth, take off the distributor cap, hold the rotor arm gently in your fingers and turn the engine over. If the teeth are ok, your fingers will not be strong enough to prevent the rotor arm turning.

If the rotor arm does slip when turning the engine over, do make sure that you have the distributor drive engaged correctly in the gear on the dynamo end. You shouldn't be able to push the dynamo fully home unless it is engaged properly, but who knows what wear there may be?

Assuming the drive is ok, set the engine to 5/16" before TDC on the firing stroke on No 1 cylinder (front right). The rotor arm should point to that plug lead position in the distributor cap. Because of the length of the contact on the end of the rotor arm, distributor timing is not too critical but it has to be able to cope with the variation in timing as you advance and retard the ignition. So, if set badly, you might get a spark when fully advanced but not when retarded, or vice versa.

To alter the distributor timing, pull off the rotor arm and undo the screw in the centre of the distributor drive. You can then lever the drive upwards to free its taper with a suitable screwdriver. Rotate the drive to the correct position, making sure you have taken up all the backlash by turning anti-clockwise, and retighten the screw. There is a line on the distributor baseplate to help you to get this right.

My apologies for not posting the coil conversion article yet. I need to bring in my other printer from the shed as it is the only one with a working scanner and then ideally I need to find the originals for Square Forum which are somewhere in the archives. The book itself is not well printed so a scan of the book may not be ideal. But if necessary I will do it. Please check the distributor timing first!

Paul
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

chris.matthews
Posts: 34
Joined: Wed Oct 16, 2013 6:29 am
Location: Tokyo, Japan
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby chris.matthews » Sun Sep 22, 2019 12:32 am

Hello Everyone, welcome to more frustration.
Back in May 4G was running well (with electronic AVR). Dynamo not connected so misfire developed with low voltage.
I then got into the Dynamo; Re-magnetized/Flashed and Motored on the bench.
Refitted to bike, it started and I checked voltages. Seemed OK.
BUT in this process I shorted an output from the dynamo (F and/or D) and the bike stopped.
Looking back this is when all problems started.
So I decided to do back to something like the May configuration (when it was running).
Charged Battery; Disconnected Dynamo (F & D); Checked Point Gap (OK); Checked points timing (OK); Checked Distributor timing (OK).
The feeling was that if it ran then the problems must be coming from AVR or Dynamo.
Petrol on - full choke, no throttle, turn over on KS two or three kicks.
Hard wired direct from Battery to Coil.
Lusty kick and it fired.
Another kick and it fired and ran on all four...……….joy & happiness.
Tickover speed OK and Oil Pressure OK.
Never touched the Bi-Starter, slightly lumpy running (I was scared to touch the Bi-Starter) and I wanted a few more revs so I applied the lightest touch on the throttle and it stopped.
It was running about 30 seconds.

BUT, it would not restart.
Battery Volts OK; Checked coil LV (2.3ohms and HV 9,600 ohms, my other two coils have similar reading). I think this is OK.
Spark at plugs, fuel at float chamber.
15 kicks with hardwiring - not a glimmer. Reconnected the permanent wiring - spark at #1, but would not fire at all.

Retreated to watch World Cup Rugby.

My thinking is-
AVR ? Back in May, did I cook it ?
Capacitor - I have two, they are about 60 mm long and 12mm diameter. The only new ones I have are much smaller - the type that fit next to the points on lesser makes (Norton. BSA etc).

Once I get it running, I will make a new points cam based on circle and two flats as Forum Suggested.

Bright ideas are most welcome.

Regards Chris.

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1784
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby paul.jameson » Sun Sep 22, 2019 9:34 pm

Hello Chris,
I am trying to work with what you have done. Let us assume that the shorting of F and D on the dynamo led to a high voltage from the dynamo (which it would) but this high voltage would only wreck electronic components. Unless sustained for several minutes, I would not expect damage to the coil, or to the condenser(s). You say that you have two, and that they are physically larger than the usual type. There is potential for failure here, but it does seem unlikely unless the condensers are totally unsuited to the job. But changing them for a standard condenser is neither expensive nor difficult.

Going back to what happened today, my first thought is that I always start an Ariel with the throttle slightly open. Yours ran for 30 seconds, sounded lumpy and stopped when you touched the throttle. In 30 seconds of running of a bi-starter Square, I would expect to have gone to bi-starter completely off. I can't remember ever needing to use even half bi-starter to move off on the bike, unless it was start, into gear, move off then shut the bi-starter, all in rather less than 30 seconds and then in very cold conditions. The Solex carb is a cunning device and I expect that opening the throttle richens the mixture as a first step above tickover. So if the bike was running lumpily, opening the throttle without shutting the bi-starter might simply have over richened the mixture to the point where the engine stopped. Attempts to re-start with the bi-starter in full choke position would give an over rich mixture and so it wouldn't go.

Can I suggest going back to the set up where the bike started today and seeing if it will start again. If it does, quickly go to half bi-starter and open the throttle a bit at the same time, or open the throttle slightly before you go to half bi-starter. Assuming it continues to run, keep the throttle open whilst you shut the bi-starter completely.

If it won't start, try to clean the plugs using a wire brush. If they appear to be clean anyway, still give them a brush but pencil the points of the plug. To do this, take an HB pencil and apply the end of it as if you were drawing a line around the plug points, along one side, across the tip, then along the other side. Why this works I still cannot fathom, but I have known it start engines which were otherwise completely impossible to start. It is a trick I learned on Platelayer's trolleys powered by JAP V-twin engines but I have used it successfully on a 2-stroke scooter which stopped outside our house, much to the astonishment of its teenage owner.

Let us know how you get on with this. If you don't even get the bike to fire, it is time to look wider.
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

john.whiting
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1413
Joined: Sun May 22, 2011 2:10 pm
Location: Brisbane QLD
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby john.whiting » Sun Sep 22, 2019 11:27 pm

As a general interest question here....but how does the advance/retard work on the new point setup.....is there more of the donor point setup behind the plate shown?........and second,question for experts.....can a new cap,and rotor be bought for the early Lucas magdyno distributor?...........Years ago ,this part was broken on my S4,and was irreplacable in those days.

chris.matthews
Posts: 34
Joined: Wed Oct 16, 2013 6:29 am
Location: Tokyo, Japan
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby chris.matthews » Mon Sep 23, 2019 3:36 am

QE2 Solex IMG_0637.JPG

4G distributor rotors IMG_0631.JPG


Good morning,
I have spent most of the morning with digital frustration - its worse than 4G frustration.
I tried to put 2 photos in the text.
First one is the bane of my life - The BiStarter.
I always have to use it, even on very hot days - the Solex Name was missing so I used a Canadian Penny...Yes it should be King George but I didn't have one so I used one of QE2 - I hope she doesn't mind.
Saturday I had the 30 sec start but couldn't replicate it afterwards - nor on Sunday.
Second one is 2 rotors. The new one on the right came from Draganfly - I have never managed to run with it - the old one was pressed back into service. In the course of the rebuild DraganFly came up with a new distributor cap - correct type with rear exit. The new cap and used rotor have done about 150 miles.
I couldn't manage a photo of the advance / retard its just like a Lucas magneto. Lever moves the cable which then moves the backplate.

Its a holiday today - I'm undecided to struggle with the 4G or maybe the '38 MSS - also not an easy starter but much simpler with BTH magneto.

Best regards
Chris.

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1784
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby paul.jameson » Mon Sep 23, 2019 8:41 pm

So Chris, you "always have to use the bi-starter". Do you mean starting from cold, or do you also have to use it when starting from warm? If it is neede when starting from warm, you must be running very lean. Please clarify so that we can move onwards.

Look at the edge of your old rotor arm to see where the evidence of the spark going to the distributor is. This is a black mark usually surrounded by a few minute spheres of brass where the spark has eroded the contact. You may find it is close to the end of the brass contact furthest from the central strip. As the Draganfly replacement rotor arm has a shorter "leg" round to the right, it may not be close enough to the distributor cap contacts to pass the spark. If so, you need to retime the rotor arm.

I may not be able to reply to you for several days in the near future as I am running off and leaving the wife at home whilst I play with steam engines. But given the information requested above, I will reply. Sooner or later we will beat this.

Paul
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.


Return to “Ariel Talk”

Who is online

Users browsing this forum: No registered users and 13 guests