Adjustable ignition timing

Is it compatible with other ignition changes??
I just installed the Jaguar CDI it changes the ignition as well but both ignition settings are a little off on my engine. Would changing the degree on a magnet affect it too much?

2door said:

It is my belief that the factory's idea of quality control has something to do with the variance we see in the performance of engines. Whoever cuts the crankshaft key ways or the ones in the rotor are just getting in the ball park, so to speak, and not concentrating on maximum power output. That's the problem.
Tom

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I'd prefer to use the term "tuned for maximum fuel effiency". - as a properly set up engine, makes the most efficient use of the fuel, where as a lesser standard of tuning, wastes a proportion of the potential energy of the fuel.

(making up the values)

Thus a properly tuned engine will drive the said vehicle 100Km for every liter of fuel consumed, where as a poorly tuned engine may only get 60 or 70Km per liter.

It's not a case of more power, it's a case of a more efficient conversion of the fuel into force.

I'd love to get ahold of this adjustable magnet as well, not only would it increase power but the design seems to make maintenance much easier (I'm assuming this design eliminates the need for the half-moon key?).

I can countersink my magnet myself but the issue is the tapered lock. But yes, I have noticed a boost in power from switching magnets. The one I'm using has the key closer to the top of the magnet (maybe 5 degrees), the one that came with the motor the key is closer to the magnet notches (looks to be about 10 degrees, eyeballing it of course).

There is a way to do this OK.

I used to own an OLD 1936 Harley and the main engine shaft has a sproket on it that was always slipping and shearing the keys.

The solution....

Define the absolute location of the NEW keyway to the correct position for the engine timing - using a metal scriber and marking out dye / water proof marker etc..

You can hand cut a keyway into the insert or the magnet block, with either a fine saw, and a fine file, or using a metal cutting chisel, or a proper keyway broach.

If the fit of the magnet / and insert, is a reasonably accurate one, hand lap the taper onto the shaft with a grinding compound...

TEST the fit and the timing of the assembled shaft, insert and magnet....

WASH all the parts thoroughly in petrol. Clean thoroughly and dry.

Then rewash all the parts in acetone. Clean thoroughly and dry.

Then spray the parts with the anerobic shaft / bearing locking PRIMING compound (Loctite etc).

Then apply the correct shaft locking / bearing retaining compound - probably a low to mild strength one.

Then assemble and tighten up to the correct torque.

Bingo...

Inserts and keyways, are actually fairly easy to make.

And if your a little bit out, or it's a bit sloppy, you can always pack a little something into the keyway to get a few degrees of rotation one way or the other....

Mew905 , got a freind that bought two when manic was still in bizz. The tapered lock is nothing more than a tapered Ferrell for plumbing, Like 5/16" in diameter . Like you'd put on a water line for an ice maker .

Huffydavidson said:

Mew905 , got a freind that bought two when manic was still in bizz. The tapered lock is nothing more than a tapered Ferrell for plumbing, Like 5/16" in diameter . Like you'd put on a water line for an ice maker .

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thanks, sadly I dont have much experience in the handyman area so that is helpful, I should be able to find it at any plumbing shop then?

Yes, their more common in nylon, so you'll have to look a little harder for a brass one will work. The ones Jim the former owner of manic mechanic used to drill the magnet out a little bit and put his steel sleeve in it. You can try this theory out by milling of one millimeter of the woodruff key to advance it or you could flip around retarded I had bad results.Loss of power and it seem to run hotter. But good luck anyway.

Creative Engineering said:

From the factory these engines are, typically, set-up with the timing 2-5 degrees advanced...which is about 15 degrees retarded from ideal.

Interestingly enough the Chinese do understand that 20 degrees advanced is a good starting point...The crankshaft key slot is cut at 20 degrees from T.D.C...Unfortunately the magnet guy ran his broach through at, (you guessed it), approximately 20 degrees...which completely nullifies the 20 degrees of advance that the crank maker built in.
Jim

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I have not pulled off the magneto armature ??? - but I had a thought, and this one is a good one.

A simple solution -

Make an OFF-SET Key.

How to - this is a little bit fiddly - going by the HUGE shaft and all...

Someone will have to fill in the dimensional omissions on this for me.

OK the KEY is a simple cheap and mechanically bad way to align two mating parts on a shaft - with repeatable accuracy.

It's BAD because it's a stress raiser - which causes shafts to break, and so it's only used on LOW power low stress, transmissions - i.e. engine shaft to magneto.

IF the magneto must be advanced by 12* - this will either be an easy or nearly / good enough solution.

I wish I had the dimensions... anda stripped magneto and key and it's shaft in front of me.

OK a key in terms of radians or degrees, occupies SOME space - and the magneto is held on by the lock of the taper.

One can forgo the use of the key, IF the shaft and the magneto are lapped to a dead accurate fit, washed with fuel, wiped with rags, washed with acetone, wiped with rag, primed with a chemical primer for the compound i.e. Loctite, and then wiped over with Loctite and promptly done up, keeping the magneto and the crank shaft IN the premarked and scribed alignment - probably by setting the piston at TDC and aligning the magnetio - with it's tiny center punched dimple (from you) with a tiny center punched dimple on a thick part of the engine casing.

But use a LOW strenght shaft / bearing locking compound.... and use a LOW heat to soften the bond, to remove the magneto.... and a mechanical puller...

This is ONE way.


The other way, which I cannot tell you the exact advance or the range of advance, because I do not have the dimensions or an accurate scaled picture in front of me to work from.

But off the top of my head, this will work...

Get 3 sets of keys - grind or file all three of them into half thickness, the hardest bit of this is holding them while you do it...

Get one key and grind the top of it off (the flat part), so it sits flush to slightly under the profile of the shaft, and then get the second key, and grind the bottom of it off, so it sits flush inside the magneto..

Now by using the third "half thickness" key - you can assemble the magneto to the shaft by using a half width half height key as a packet in the shaft, and a half width half height key as a packer in the magneto, and a half width and full height key in the remaining half keyways.

Again - hand lap the magneto onto the shaft and IF the advance is pretty right, use a thorough cleansing with clean rag, fuel, a wipe over, then a wipe with acetone, and then another wipe over, and then the primer and a low strength shaft locking compound...

(The magnetism may be an issue here - probably use an adhesive to hold the keys in the slots prior to assemmbly

Now since 12* advance is not a HUGE amount... in terms of offsetting the rotation of the magneto to the shaft, without the dimensions in front of me, I am making an estimated assumption.

It would be appreciated if SOMEONE could provide the measurements and draw up a simple diagram.

Half a key thickness advance MAY be spot on... I think it is, but it may be not enough or doubtfully a bit too much....

Best to check.

I actually use Libre Office DRAW for all of my engineering drawings...

It's very good.

So this is two more of several options to select from.

IF I had a gear puller though and I could do do up the magneto tightly into the shaft, I'd be selecting the keyless option, and aligning the magneto by TDC and punch marks, and then using the loctite option to cement the parts together on the tapered lock, between the lapped together parts.

The best results I found was using the Jag to actually advance the roots are retard the timing . not the lectric see to the CDI .

Huffydavidson said:

The best results I found was using the Jag to actually advance the roots are retard the timing . not the lectric see to the CDI .

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What!?!?
hommina hommina hommina

Huffydavidson said:

The best results I found was using the Jag to actually advance the roots are retard the timing . not the lectric see to the CDI .

Click to expand...

after reading this post... I remembered the jag CDI can adjust the entire curve up or down (derp). So I just went outside, re-studied the design of the CDI and changed the jumpers. I now run 2A (~21* BTDC @ 1kRPM) and 1B (mine has 4, 2 for each). It does run a bit quicker now for acceleration but the top speed jumped a solid 3mph. I'll GPS test to confirm but it kept up with traffic much better uphill this time. I really gotta take a link off my chain though, the tensioner is as tight as it will go and the chain has a lot of slack... like... lots (probably 1.5", dangerous I know. In a straight line I'm not too worried though).

I did cut my rear mount down 0.5" for a better fit, thats what caused the insane slack but it gave me much more room to work.

cannonball2 said:

Lapping the magnet rotor to the crank will also work. Properly lapped and tightened it will stay where you put it with out a key. If you have ever seen an old 2stroke outboard, the first third of throttle advance is just timing, the carb begins to open after that. Timing is crucial on a 2 stroke.

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Whats lapping. Ive tried looking up the term. But no luck on magneto lapping.

Dear Jim,
Sounds like exactly what i need,
Where do I buy it?
I'm trying to make a China Girl run backwards so I can use a 3 speed or such transmission. I have the jugs spun so the exhaust is right and the transmission is right., I just need to adjust the timing.
Thank you very much.
Karl

Checkout this home brew programable ignition system. It's TCI not CDI so external power source required.