FE-FC Holden Discussion Forum

From time to time we get requests on this for infomation on cross flow heads etc. I know of a person who comes from a stock car racing back ground who has got a grey motor magneto. I have never heard of these before. Does anyone know much about these. Are they very rare?
The block assures me that its bolt on horsepower. Out of curiousity what would something like this be worth?

Rod

Rod,  funny you mention crossflow heads as  the magneto was certainly used on these.
I can't see how you could describe it as bolt on horsepower since all it does is provide the spark.  Sure the spark is stronger through the magneto and may make the burn go a little harder, but I can't see what else it can do.
Maybe someone can enlighten further.
All vintage cars used magnetos until the distributor was introduced in the 40's I think.

Ken

Ken's right.

The magneto would provide a higher voltage and more consistant spark - with a distributor and coil setup (Kettering Ignition) the field in the coil tends to dissapate very quickly after the points open. I've seen this on an oscilloscope and the difference is quite marked. The magneto generated spark would allow the spark plug gap to be opened - all this would combine to produce more complete burning of the fuel mix in the cylinder. Maybe a small increase in power but without other mods to assist breathing (exhaust and head work) and fuel quantity (Carburattion) then the you would most likely just get better fuel economy ;) and a good feeling cause you had a magneto and your mate didn't ;D

For 'interesting' reading check this out http://www.autospeed.com.au/A_0772/P_1/article.html


Hope this helps.

Cheers,

Craig.

 ;)HI ROD, KEN, CRAIG
  MAGNETOS WERE AVAILABLE FOR HOLDEN INDUSTRIAL ENGINES.
  MADE BY 'SCINTILLA'  PART NUMBER 7414491
  HOLDEN INDUSTRIAL ENGINE PARTS CATALOGUE NUMBER        
  M35030  HOPE THIS HELPS
  REGARDS ACE 8)

Good one ACE.

Here's a picture of a SCINTILLA Magneto http://home3.inet.tele.dk/forda/G28Tmain/magneto.jpg. I haven't seen a Grey Motor unit but I would expect it looks similar?

Craig

Craig

I take your point about the effectiveness of the magneto. I am not in a position to question you. But my racing mate begs to differ on how subtantial HP would be. He asked me to ask "What percentage of fuel is burnt with a dizzy sit up ?" Therefore if there is a stronger spark a greater percentage of fuel must be burnt hence higher HP (how much ???).

He races a 202 and runs a magneto to increase it HP output. So does his competitors. So if it wasn't going to give substantial output why pay the huge expense that a mag is worth. However, on the other hand I am sure he has made some other mods that you hinted on which may make the mag more effecient.

Anyway thanks for the discussion it has enlightened considerably. Any ideas on what they would be worth.

Rod

Hi Guys
The good thing about a magneto is they require no power supply. With a coil and dizzy setup, the spark quality is down when trying to start the motor ,  because the voltage is down a bit cos of huge current drain of the starter motor. This can make starting a hi compression, well fueled engine hard, the maggy over comes this problem. The magneto also provides a better spark which ignites more fuel and provides a bit more HP.
When racing , running a magneto also means you don't have to run a generator or alternator. A gennie sucks about 4 hP just to run it, so getting rid of it adds a bit more output to the motor. the battery is just used for the starter and brake lite etc.
Hope this helps a bit

Cheers
Tony

I need a magneto, anybody got one for a grey?

Tony

Thanks for the reply. It making more sense now. He had his 202 out and was showing me. He said to hold the end of one of the leads while turning the magneto (I'm not that stupid). He indicated that it would put out up to 60000 volts.
You are looking for a grey magneto? The guy I spoke about would be willing to sell (I think) but he is unsure how much its worth. He paid over $1000 for one thats goes in his 202.

Rod

Hi Rod
Yeah, even at a really slow cranking speed they still put out a massive spark. Smart boy for not holding the lead!

I'd like a maggy for the current project, it would fit in with the theme of things and a good spark would be handy. It would have to a cheapie though, funds are really tight at the moment.
I was told by a guy who racers crossflow greys that a grey maggi would cost about a 1000 bucks second hand and about 700 bucks to rebuild it. That scared me off a bit, well, a lot!. Thats a lot of cash for a sparker.
The one that guy is selling, is it a straight drive or angled drive as used on the crossflow greys ?
Cheers
Tony

To correct the problem IHADAV8 talks about (low spark output at cranking) you could run a wire from the battery +ve through the start position of the ignition switch to the coil +ve. At cranking, maximum battery volts (a good battery will output a cranking voltage of at least 9.6 Volts, anything else and you should get rid of it) will be available to the coil. In the run position the coil power should be supplied through a ballast resisitor to reduce the current supplied to the coil. As IHADAV8 indicated spark voltage requirement when running is less than when starting, especially when cold, when the fuel charge is harder to ignite. This is why you apply choke, pump the accelerator 3 times and hope ;), the richer charge is easier to ignite in a cold engine. When running, the ambient cylinder temperature assists in the combustion process allowing a leaner fuel mix and a lower spark. I have a red motor in the Poo Mobile and have modified the wiring in this manner.

On a stock FE/FC there is only one wire, mainly due to the fact that the things are so low compression it doesn't take a whole lot of current to turn them over. If you increase the compression on your grey (or red) you should always look to doing the mod above, or at least getting a battery with a higher CCA (cold cranking amps) output.

Later Holdens used a ballast resisitor so it is important that you use the correct 'resistor' coil. What commonly happens is people replace the standard coil with a resistive type one (or vice a versa) but don't replace/reconfigure the wiring. If you look on the underneath of the coil (bosch GT40 or similar) you will see the 'resistor' marking.

You can get 60KV from a good coil based ignition but as I pointed out in an earlier post it's the ability of the coil (or magneto) to 'carry' the spark that gives the magneto the advantage (besides the removal of the alternator). In theory terms a distributorless ignition such as that used from VN onwards, and now by our Ford friends, has the ability to easily supply 80KV, with the added advantage that when firing on one cylinder the companion cylinder also fires on its exhaust stroke. This is not only good for extra power and lowering emissions, but also for keeping cylinders clean because of the complete burning of the fuel charge. Have a look at the recommended spark plug gap settings for a late model Commondore compared to an FE!

I spent about 15 years repairing automotive diagnostic equipment and was heavily involved when the VN's first arrived in Sydney in late 1988, so I have seen plenty of this stuff. If you own or have owned a VN you will know what happens because of this ability to supply heaps of volts - carbon tracking into those metal covers over the plug leads, blown coil packs (the spark actually breaks down the insulation inside the coil). Have a look at the 'evolution' of the Holden coil pack. Guarranteed field tested reliability ;D

All said and done I would still have the magneto cause it's cool  ;), but for a mainly street car your 1000 bucks is probably best spent improving something else in your engine, a good quality coil, plugs, leads, battery - or better still used for VB supplies for a trip to Bathurst.  ;D

Your mate with the racing 202 is a different matter......