The Stovebolt Site Forums The Shop Area Engine Shop magneto

I have a 261. does any one know wherei can get a magneto for it or if one even exists

You might be able to hook a magneto to it but the hard part is rigging up the hand crank.

Any particular reason, or just trying to be different? Most of the modern electronic ignition systems will outperform a mag, and unless you're working in an environment where there's no battery power, what's the point?
Jerry

There was one on ebay about a month or so ago...

I am just an old school kind of kid who thinks they are cool. I am building a late 50's early 60' hot rod. with all period perfect stuff on it. My next pertchase is a 12 port head.

Yeah,

One of my "period perfect" '50s "souped-up" trucks might be a candidate for another novelty. Why/when were magnetos used in the old school in the '50s/'60s? Batteries were pretty cheap back then and there was a convenient place to put them.

TSP C

Mags were mostly used on drag racers, and it was VERY difficult to get one spinning fast enough to generate a reliable spark. Once it's running, the spark gets hotter as the speed increases, but it was not unusual to see a mag-equipped car pushed the full length of the local drag strip before it wouild fire. On farm tractors, airplanes, etc, an "impulse coupling" was used to snap the mag around with a spring for starting. That also retards the ignition timing, so the engine doesn't kick backwards when using a hand crank or hand-turning a propeller. Most aircraft mags have no provision for advancing the timing according to speed or load.

Magnetos are very useful, on a Briggs & Stratton lawn mower engine, a chain saw, or something else that starts without a battery. On a vehicle, they're just a PITA!
Jerry

There are mags out there,what fits a GMC inline will also fit a 216-261.The mags for the later Chevy inline 6's will also work with a little bit of hand work.The problem is parts,expensive,as it getting them rewound and magnetised if necessary.You can run fixed advance on the street if you get the engine spinning on the starter,then flip on the ignition, but a kickback can break the starter drive.
I run magnetos on my old kick start British bikes,they fire up on one kick if the mag is in good shape.You will have to set the plugs close at maybe .020,or use gold racing plugs like on my bikes.
You might be better off with an old school Mallory distributer,actually the stock single points dist with a recurved advance works quite nicely up to 5000 rpm.

not to be disagreeable, but, there's nothing wrong with a magneto. I've run them on my ih tractor, my motorcycles, and my flathead ford, and early olds powered 32 ford. with no problems, driven across country and never tought twice about it, there very reliable. the mag you are going to find for a 235 chev, is a vertex. made for racing, all types of racing, (check the wayne site, he has them for sale new, don't buy the taylor vertex copy with the electronics inside, they look the same but are junk, they don't work)I just purchased one for a 235, i'm building for a 31 chev coupe i'm working on, 1st of all, nothing looks like a mag sticking out the side of a chev 6, 2nd, I can relate with what he's trying to do, you can't build a old hot rod using new parts, I've spent the last 28 years trying to recreate the old rods, by using old parts, fabricating everything, besides ordering stuff out of a magazine or catalog is the easy way out.and anybody can do it, heck you can order a hole car in parts and have it delivered to your house, all you have to do is assemble it. it dosen't interest me. In the old days you had to fabricate all the parts, except the speed equipment for the mill. an early 50's hot rod dosen't look right with a msd ignition in it, just my opinion, anybody have a edmunds 2-2 intake for 235 for sale?

I ran a mag on my 39 but there is no curve I didn't like the idle too much just didn't match what I was doing the GMC has a mild cam and not much compression

Mags are fine Expensive but fine......

Pushin' half the track.....BS

Listen up I took the mag off the GMC and put it on the 39 BMW
BMW had a real cam in it.... it would idle at 500 rpm start on the starter and run 6000+

If you wanna play get a Vertex and go see Hunt Magnietos
A rebuild will cost you a couple hundred
Vertex use an impalse spark and have a plate that dictates the curve

Hot Rod...You speak as if you have never had your hands on a mag! If you don't think a mag puts out a real spark at no RPM just pick up a Vertex and turn it by hand holding the end of any or all plug wires but do it over a bench please Cause when you drop it you don't wanna break the cap!!!They cost a ton

Tony they don't break starters unless they have the wrong advance plate

GMCKUSTOM

I'm build the engine your talking about....but please know the 12port is also a myth in some ways....but it really looks GOOD

I'm sorry this isn't flaming and I don't mean any offence but some of you are wrong
I have had my hands on all of this and run it! I'm not guessing

The old school drive is an SW and you get a mechanical tach drive with it

If you look at the photos of the 39 here I think you can see it

The dist or mag used with this is a blade like a VW

The drives are rare but out there

I don't think Vertex or whatever they call themselfs today make a six

Do a Google for Hunt Magnitos they are just the best...nice guys that know their stuff

Mags have their place, just not on the street. I've set up and used lots of them on farm tractors and aircraft engines, and I'm no stranger to the Vertex race mags. They're just not worth the effort when as good, or better spark can be had from an off-the-shelf system that can be purchased in any parts store. The General Motors DIS system delivers up to 100,000 volts to the spark plugs, and computes ignition timing every 1/10 second. There's not a magneto made by anyone that can do that.
Jerry

do a search for wayne, you the 12 port guys, there's a pix of a vertex they have avail. I wouldn't run anything but that, It has adv curve in it, proffit knows what he's talking about. can you post pix on this board? by the way forget the 12 port, unless you have mega $$$$ 3200.00 there making them new,

The problem with running the Mag on the street in my GMC wasn't the mag....it was the fact that the rods and pistons are just too darn heavy

The BMW is a little hemi.....loved lottsa advance.....if you didn't start the fire early it would never get over the piston lump

The old Sentilla/Vertex and clones are about two amps newer mags will make many times that.....A friend of mine went to twist a new mag and ended up on the ground foamin' at the mouth. If he'd had a pacemaker he be dead!

Street or racing? I guess it's all in what you call street.
I've build street motors for guys that used warm up plugs and half way to work switch to cold ones.That was their STREET engine

Anyone that wants to put a 12 port GMC on the street may be talking different kindda streets

My is just gonna be a mild 400hp in a Sam Barris chopped 40 Ford coupe.Most people wouldn't wanna drive the car with any engine cause you can't see outta the 3 inch rear windows

$3200 for the head is only the begining....buy the Bosch fuel injection.......

The whole project is a lot cheaper that my SCOT Blown Ardun for the duce

I've been watchin this thread--because I figured at some point we were gonna hear the other side. :p Proffit, I wud like to hear ur criticism of the 12 port. MYTH?

JOE HUNT MAGNETOS

proffit, where did the ardun come from, I used to run with a friend from n.j. that ran an ardun in 32 roadster w/ scot. I think he sold the motor to a guy in tx. If my memory is right. I have a 32 cabriolet with a blown flatty. ran for years with a scot, now has a 453 gmc that I used to run on a 34 I had. I ran a vertex in that motor with the scot, but took it out and run a front dist becauce of clearance problems. I haven't been around awhile (personal reasons) but still have the car. and will be getting it out again.

32 Ardun is all new.......
Ardun.com
The SCOT is an original Old one
I think the only old parts are the block and SCOT but I'd have to think about that

Buzzin...
There are lottsa tested ways to make a GMC run pretty hard
I can tell you the myth starts with 'Bolt it on and make more power than GOD'

Both these Ardun and 12 port take a motor that is built around them and some testing

BUT BOTH SET-UPS LOOK TOOOOOOOO COOOOOL!

Got an old Mallory dual point. Looks like a magneto. 1950's vintage.