Magneto and belts

[rotorwrench]

There is a caveat to using magnetos. They don't generally have any way to change the spark advance. Aircraft use them but they pretty much run at a fixed RPM for the most part. They have to have a starting aid on at least one mag that retards the spark or they will kick back. Most folks that run them are using them for racing. Fuel mileage suffers if there is no load control to retard the spark. I'm not saying don't use one but there may be regrets later on if you do.

[Ronnieroadster]

Originally Posted by rotorwrench

There is a caveat to using magnetos. They don't generally have any way to change the spark advance. Aircraft use them but they pretty much run at a fixed RPM for the most part. They have to have a starting aid on at least one mag that retards the spark or they will kick back. Most folks that run them are using them for racing. Fuel mileage suffers if there is no load control to retard the spark. I'm not saying don't use one but there may be regrets later on if you do.

Rotorwrench this type of magneto made by Scintilla - Vertex which Hank is using has a centrifugal advance system in the lower bowl of the housing. So they this type of mag will work for fine for a non racing application. Many of us Hotrod types have always used the Vertex mags on the street for many thousands of miles.
Another point of interest fuel milage is rarely a concern in application's like this.

Ronnieroadster

[solidaxle]

Originally Posted by 3W Hank

Like this, a extra tension wheel move away the belt from mag.

I'm jumping in here without reading all the posts. Bored and Stroked is correct, running v-belts backwards on the idler at this extreme angle will be too tough on the belts.

[rotorwrench]

There is not really any way to put load control on a mag unless the whole mag rotates or at least the magnet rotates along with the points. Centrifugal impulse couplings are not for anything other than starting aids. They retard the spark until the engine starts and then the centrifugal weights cut the starting aid out of the system. Mags have to maintain proper internal timing to keep E-gap at the point opening or they won't run. You move the points plate and the internal timing is off.

The old Motorcycles that had load control moved the whole mag to change the advance for load control. The old S2R Lucas mag on my 58 Indian Enfield just has a little impulse coupling for starting and then runs full advance all the time. Aircraft mags work the same way. They will run OK but their is no load control. It's just full advance all the time.

Perhaps they have a model that moves the magnets along with the points but most of the old Vertex mags are the Locked type. The Lucas K2R Cycle mag was set up for adjustable advance but it was manual and worked by having the coil built into the rotor with fixed magnets. That way they could move the magnets and the breaker points a little bit. P-Mags are starting to show up on aircraft now days and they are electronically controlled mags much like an electronic ignition. They have a programmable advance curve but they are basically a little alternator with an electronic ignition. They are not a true magneto that runs off the building magnetic field in the coil which inducts as the breaker points open at E-gap when the magnetic field reverses due to rotation of the magnet.

[Ronnieroadster]

Originally Posted by rotorwrench

There is not really any way to put load control on a mag unless the whole mag rotates or at least the magnet rotates along with the points. Centrifugal impulse couplings are not for anything other than starting aids. They retard the spark until the engine starts and then the centrifugal weights cut the starting aid out of the system. Mags have to maintain proper internal timing to keep E-gap at the point opening or they won't run. You move the points plate and the internal timing is off.

The old Motorcycles that had load control moved the whole mag to change the advance for load control. The old S2R Lucas mag on my 58 Indian Enfield just has a little impulse coupling for starting and then runs full advance all the time. Aircraft mags work the same way. They will run OK but their is no load control. It's just full advance all the time.

Perhaps they have a model that moves the magnets along with the points but most of the old Vertex mags are the Locked type. The Lucas K2R Cycle mag was set up for adjustable advance but it was manual and worked by having the coil built into the rotor with fixed magnets. That way they could move the magnets and the breaker points a little bit. P-Mags are starting to show up on aircraft now days and they are electronically controlled mags much like an electronic ignition. They have a programmable advance curve but they are basically a little alternator with an electronic ignition. They are not a true magneto that runs off the building magnetic field in the coil which inducts as the breaker points open at E-gap when the magnetic field reverses due to rotation of the magnet.

It must be a miracle on how the Vertex mags actually have an advance system. But they do. Oh and you can get them locked as well meaning no advance.

Ronnieroadster

[rotorwrench]

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I know how they work but even with 10 degree advance it still has no load control. A street engine would function much more efficiently with load control is my main concern. A Chevy distributor with automatic advance can be taylored to a flathead for a lot less time, money, and energy. They work just fine.

[Bored&Stroked]

I have a few vintage Scintilla magnetos - they were the company long before Vertex. Every one of them has advance plates in the bottom.

The advance mechanism is 100% mechanical - it only understands RPM. With that said, in 100% race applications, the advance plates are frequently setup to lock the mag down - so what you set the initial advance too is the final advance.

You can configure the advance plates to achieve the correct amount of total advance as well as when it comes in. On flathead Ford engines, I like to have about 8 degrees of mechanical advance in the mag (16 crankshaft degrees) and then about 8 degrees of initial advance. This gives me the total of 24 degrees of advance - which is usually about the right amount (give or take 2 degrees). I like to have all the advance in by about 2000 RPM.

The original Harman-Collins magnetos had no advance mechanism - the total advance is 100% configured via the rotation of the whole unit.

[rotorwrench]

I found a good diagram and can see the way the drive fits into the the advance mechanism which in turn is driving the magnet shaft and breaker cam. It showed a clothes pin spring set up to push the advance weights back to starting position. It was a simple design but effective. It is likely as reliable as the performance distributors made by Mallory and other centrifugal advance set ups. They need need a little lubrication now and then. They can have spring wear over time just like any other.

As was mentioned previously, the advance function is a product of RPM. There is no way to affect load control. This is the way most aftermarket performance distributors are set up as well. Few have vacuum advance.

If a mag is locked then a person would have to turn the engine over a revolution or more before turning on the mag switch. It could kick back too easy if started with the mag switch on prior to starter function. At least the centrifugal advance would allow for retard at starts.

I don't know how much power the mag robs from the engine but they do take more torque to spin than a points distributor. Two of those bad boys is going to take that much more.

[Bored&Stroked]

Yeah, when running a locked-out mag (all advance in), I will pump some fuel into the motor, leave the mag switch OFF, hit the starter and let it spin a couple times - then turn the mag on. This is the best way to be "kind" to the starter! LOL

[3W Hank]

I has as I said bought parts to the BA block with AB parts ( camcover and cam and the magneto shaft ) and try get it to fit the pre 39 generator and to use the 32 fan.
Mix is not easy solve.
At this stage I cant change cam as to much time/money in it.
Anyway I find and bought BA car pumps so my idea is to go 1 belt with a tension puller, but that need me to get all groves out to free belt hit the camcover.
This was not something they did do in the old days but I will try.
As my front cross is cutted I has space for RT pumps and that will solve issue, but I dont like the pumps and then the generator and fan need be replaced, sounds not a big issue but I invested time and money get those parts plus I like the look ( idea on heads/intake/carbs/aircleaners/generator is from Hetfields roadster )

Why did I leave the 3-bolt camcover.
Well I never found a angle adapter or a magneto and then I ’thought’ the 8AB desl on belt was the solution even if I really did not like to use the AB parts, but once find the magnet, then I got a cam cover and then the cam I wanted to use ( the 425 Potvin )
But mix it with old style generator and the 32 fan get it harder.

Best idea here is use all 8AB parts in front of course.
Now I will bought a radiator ( has work on it for 6 month ) and see how it fit.
By the way, not easy find a decent V8 radiator so collect parts take time.
…then one see the next isdue :- )

[3W Hank]

Hetfields set-up but not a Vertex..

[petehoovie]

Originally Posted by 3W Hank

Hetfields set-up but not a Vertex..

[3W Hank]

I’ll just talked to Skip Heney and he could make me the early pumps and has the pulley out 1/4” or 3/8” out.

[rotorwrench]

I can't tell for sure but the Photo in posts 51/52 looks like a crab type cap. That would be a 1942 type set up or a modified rabbit ear distributor. With centrifugal advance and a vacuum brake they work OK and have some load control. Maybe not as hot as the Scintilla/Vertex mag though. The Harmon Collins dual coil set up was one of the hot items back in the day

[3W Hank]

Yes that engine has not a Vertex but it shows my idea of set up.

[3W Hank]

I got my 32 fan today from LA and if 6K its shore is a intresting ride…:- ))

[petehoovie]

Originally Posted by 3W Hank

I got my 32 fan today from LA and if 6K its shore is a intresting ride…:- ))

[Ronnieroadster]

The photo may be deceiving since it looks like the fan is going to end up in the middle of the radiator!
Ronnieroadster

[3W Hank]

Yes it shore look odd, maybe its not a 32 but if fit on generator.
My Lincoln transmission is soon done then I will be look on a radiator ( again ) so then its wait on my restored waterpumps from Skip in Florida and I has new Drake motor mounts ( as the Speedway was joke ) and mounts brace is from and 60 HP 37 engine that will be into frame.
-Then I will see if fan hit the radiator.
Fan is in a really nice condition, no pittings and tube inside is like new… but rivets is old and that long fan and ’maybe’ 6K…
I never used mech fans on my cars before ( race, only electric but in this case a Big No.

[3W Hank]

Here is what seller said on a 32 fan in a 32 frame ;

I’ve run that intake set up many times on 32’s
I’ve added a pic of my recent project…….
32’s have lots of forward space!
Full length is always best.
Hope this helps