F/M "RV" Magneto Questions

[Lisa Johnson]

I have a 1935 FM 2 hp Z engine. After a lot of research I have determined that it has a "RV" Magneto on it. This mag throws a nice spark and my engine is an easy starter. But I would like more info on this mag. Point settings, service requirements and maybe where I could get a repair manual for it. The sources I have found offer 2 and 4 cylinder versions of the mag but I would like info on my great working single mag. I would even like to find a good picture of this mag if anyone can help........

Love this forum and thanks for your help......

Lisa

[ErikG]

Lisa,
The RV-1 does throw a hot spark. The J magneto takes a little more speed to get the same spark! I also am familiar with the R magneto, this one seemed to be the hottest.
I put new points in a RV-1 last year and I think I gapped them between .012" and .015". I don't have a picture on hand but could get one. I don't know of any service the magnetos need until they quit working. A new condenser if it's bad or recharging of the magnets, but if it's working I'd leave it alone.

Erik Grund

[Lisa Johnson]

Hi Erik.....

Thanks for the information. With all my research lately I have discovered I have a "RV" mag on my engine. But I can't get any information on this mag such as Service, Adjustments or repairs......... Also I'm still looking for a picture of this "RV" style so I can confirm this is exactly what I have..........

Any further information I can get will be appreciated.

[ErikG]

I can take a picture but it will be a couple of days before I can get to the engine.



Erik

[KidDynamo]

Originally Posted by Lisa Johnson

Hi Erik.....

Thanks for the information. With all my research lately I have discovered I have a "RV" mag on my engine. But I can't get any information on this mag such as Service, Adjustments or repairs......... Also I'm still looking for a picture of this "RV" style so I can confirm this is exactly what I have..........

Any further information I can get will be appreciated.

I have an RV-1 in my lap right now. (I guess I better not give it a spin ! LOL !)

It pretty hard to mistake an RV-1: It has a round flat cover opposite end from the drive shaft end that is held on by 3 screws and this plate has raised lettering on it that says: FAIRBANKS MORSE in an arc acrosss the top half and MAGNETO in an arc on the borttom half; and in the middle, there is raised lettering saying TYPE RV followed by a small raised boss that has a 1 stamped on it.

Furthermore, the top almost half of the magneto is a magneto cap of a plastic material that has a sparkplug wire connection opening that protrudes from the top-center of the cap. The cap on "mine" is held on with 4 fillister head screws.

I do not know of another magneto that resembles an RV-1 a whole lot.

Sorry I cannot provide a photo at this time but I can say that the two RV-1 magnetos that I have throw large sparks, although 1/2" might be the slightest exaggeration. My other one is missing the cap and will jump an internal spark from the coil high tension lead to the mag housing if I try to increase the gap to 1/2"

Besides, this really isn't the best thing to do to your coil on a regular basis.

I have an "R" that performs this well, too. A real flamethrower. A "J" mag really should go to this level too.

[Lisa Johnson]

Dear Kid..........


Thanks so much for the detailed description. You have described my mag to a tee....... Who needs a picture now. And yes after I serviced mine and still had it in the vise it threw a spark with just the snap of my fingers that traveled out the top of the cap and down the side to the cap screw. Very impressive. When I saw that I knew I was ready to go and reinstalled the mag and the engine fired right up. What I'm looking for now I guess is some printed literature on overhaul and repair. Point adjustment specs would be helpful too. But now I know I have a RV-1 mag.......

I so appreciate the help.....
Thanks.... Lisa

[Ray Cardoza]

Here is a picture of a type j mag with impulse setup on a wisconsin abn she shoots a HOT blue spark found out the hard way
http://albums.photo.epson.com/j/Albu...444&a=32111733

[David M. Lyon]

I think the "RV-1" mag is the hottest that Fairbanks Morse ever made ...If you roll the armature over and the points break, it's GONNA FIRE!...Who needs an impulse with a mag that hot?...I guess the first time I discovered this is when I had one off the engine. Then, like an idiot, rolled the gear over with my fingers in the wrong place.... I learned REAL QUICK how hot they were ...I think 1/2 inch in the open air is about right...And a 1/4 inch under compression...I don't run 'em with a gap like that 'cause I suspect it would be rough on the coil windings. But they are capable of it.

David M.
ILTFME

[jeff jamerson]

so ... kid dynamo? since you seem to have an extra rv-1... want to donate one to my cause? i wil even come pick it up.
sorry .. i had to ask jeff