I ordered a Brison 3.2 today and one of the options was for the ignition replaceing the manual throttle spark advance with a "automatic " system. I am just a causual flier at the time. Is there an avvantage to the optional system. The other option was a Bisson muffler. This engine is going in a Sig Morrisey Bravo. Any comments??

Thanks Gene

No real advantage...Costs more..

Well I dunno if I would say no advantages. I would agree that it will be performance wise just like mechanical advance. I had the mechanical advance on my Brisson 2.4 and changed to synchrospark. The reason was the mechanical likage kept binding no matter what I tried to free it up. So the electronic advance system will eliminate this potential. I suppose that it is possible for it to open up it's own problems but after a couple of years of use mine is still flawless and a good investment.

Vince L

What did they want extra for the Synchro Spark? I'm not sure I would agree with the no real advantage comment either. It gets rid of all that linkage that over time will develope slack. I put a Synchro Spark unit in my G62, and it has been one of the best things I have shed bucks for. I don't ever have to worry about the ignition timing. I wish my Fox 2.4 had it instead of the linkage, but then I only paid $400 for the Fox.

Vince

The standard ignition is 89.95 for which you are credited. Syncro Spark is 102.00 about a 12 buck difference.

Gene

A difference of only 12 bucks is a steal..C&H charges $130.95 for the single cylinder ingition with Syncro Spark...Brison probably pays C&H $102..for the system...

Not all mechanical advance systems are created equal..
My system, made for the last 15 years, uses a ball bearing ring mounted behind the hub on the crank,directly connected to the carb..The carb is turned so that the shaft is parallel to the cylinder. The servo connects to the same shaft, NO bell cranks, NO play, NO binding..Every other system except Byron Originals copied the old A&M setup....A $2.00 ball bearing is cheaper than a $40.00 Syncro spark module, and will outlast the rest of the engine....RC....

$12 differance, that is a "no-brainer", I would go for it in a New York second.

Vince

Well, There is one more thing to think about. With mechanical linkage you have much more control over your timing and can tweak the timing to fit your particular engine and application. For the backyard mechanic the mechanical system could lead to better performance, or maybe just one more thing to play with.

The Syncro Spark part of the ignition is a small circuit board, about 1 inch square..It is wired in series with the ignition circuit..It can be set up for full advance at either 4 or 6 thousand rpm, and either 20 or 28 degrees total advance..The timing is set by placing the Hall sensor at the correct spot relative to top dead center, usually 28 degrees..The first flip of the prop retards the ignition to 0 or 8 degrees, depending on the setup of the Syncro spark module..Advance is automatic after that..The advance happens when the crankshaft starts turning faster, like the tail wagging the dog--more rpm, more advance..It happpens is milliseconds, so there is usually no perceptible delay..If the low speed needle is set too rich, however, the advance happens slower and there will be a slight delay in the transition while the crank speeds up..
With mechanical advance the throttle controls the advance curve, linear from idle to wide open...
The price difference of $12.00 is way less what the Syncro Spark board costs...Currently $39.95 from C&H.......

Say Rcignition:
Could you explain a little more on the retard mechanism of the CH ignition? Since the engine is static timed at 28 degrees advance, I assume there must be some rpm below which the timing circuit allows full advance (for timing purposes). Also, there must be some rpm above which the circuit knows that you are flipping the prop and need the timing fully retarded. Is that how it works? Do you know what rpm the change occurs? If this is how it works, a very slow flip might bite you with a kickback because of full advance....true?

The first time the magnet passes the hall sensor the circuit retards the spark..The Syncro can be programmed to advance either 20 or 28 degrees, and full advance can occur at either 4000 or 6000 rpm...The timing is set at 28 BTDC static either way...Full retard is either 28 degrees, to 0, or 20 degrees, to 8 BTDC..Most of the engines are set up for the full advance at 4000..Below that the timing is retarded by the circuit..It's almost linear...R C ...

Good information RCIGN.

Vince

Say RCignition:
I'm still confused. If the ignition retards the first time the magnet passes the sensor, how can you get full advance to static time the engine at 28 BTDC? When you're setting up the timing, wouldn't it also spark in the retarded position?

You can slowly turn the crank without retarding the spark..I don't know what the rpm needs to be to retard it..If you turn the crank slowly back and forth it will spark several times..I used to time the engines with a non syncro igntion first, but found out that slow turning will not trigger the retard function..RC.....
Myself, Silent Spark, and C&H buy the syncro board from the same place.We all use different igniton circuits .Don't know what the other systems (Pro Spark and early Air Hobbies) use..The 3W and DA sensors will not trigger other systems....Reichmuth, now sold by D&B, is also different....

I have the brison 3.2 and I know Gary Allison the owner, He feels that he gets more horsepower from the standard Ign that he supplies over the sync. spark. He can run less inital timing to help the engine start, more total timing for better top end and the advance comes in slower making for better throttle response. In my own experiance I have found that small changes really help performance with differant props and altitudes. If you do run sync. spark I would like to hear your findings.

Why would an engine timed at 28 BTDC with syncro be any different from and engine timed at 28 BTDC with mechanical ??
Either one can be set for 28 degrees total, so initial advance, for starting, can be exactly the same also...

Not to change the subject but the other option offered "Bisson muffler over Abell exhaust diverter" is a good one. The Bisson is quite a bit quieter.

Wiz

Bisson mufflers are not known for durability. I would choose either J&A or Supersonic Exhaust if you want a Pitts muffler.

I have a Bisson Pitts on one of my 3.2's & yes it is quiet but it is also more restrictive....a loss of about 200 rpm. vs. the deverter.

Of course, any effective muffler is going to take a little bite out of the power as opposed to running an open header. In my opinion, the Abell isn't much more than an open header. If you need those last couple of ponies and noise is no issue by all means run the Abell.

As for Bisson durability, I've owned several (4-5) without any problems at all. In fact, I've never heard anyone say anything negative about Bisson before today. What kind of durability issue are we talking about, cracks? I've heard complaints about J&A mufflers cracking. I've owned a J&A before and it held up well too. I wonder what the circumstances are around these failures.

Wiz

What if:
You choose to use a mechanical advance-
BUT- supposeyou always jamb the throttle from low to full -as fast as possible. (not a great idea -but I see it all the time)
Doesn't the advance go to full even tho the engine is at say 2000 rpm?
As I recall - this really created a low/midrange shake.
On some engines - (heavy engine heavy/solid model -no problem).this would not be desireable.

Yes..Never found it to be a problem..How long can the engine be in transition ??A few seconds at the most ?? How much shake can there be ??

agreed- but the condition is there-for the nit pickers

...Of course, there won't be too many occasions where a throttle slam is desirable over smooth motion of the throttle stick. On to my question>>

I bought a Brison 3.2 almost 2 years ago, and finally got it in the air yesterday. Hadn't ever run it before that. Hadn't run any gas airplane engine before that. However, the previous owner had run it for a few gallons. It ran perfectly, especially considering the time it spent static on the bench. BTW, it was kept in AC-air, oiled, and turned over every few weeks. Anyway, got it going, let it warm, ran it up - all without a problem. Didn't touch the screws. The only worry I had was whether the mixture was too lean. Pinching the fuel line doesn't seem to have an effect on the walbro carb, and I didn't see any visible exhaust. I'm used to seeing some oil smoke from pre-mix motors and didn't see any here. What do you think? Was I running lean? Didn't check with a tach because it had been jostled on and my new batts were dead.

The other concern I had was it's ability to prime itself. I have about 8" of fuel line and it didn't draw fuel down the line by itself. I pulled the line and tipped the plane to prime the line, then put it back on the carb. Choked with ign off, I didn't see any visible fuel movement in the line when I flipped it. It took about 12 flips on choke to get a pop, then another 10 to get it started. Could this be a result of sitting along time as well? Suggestions?

Thanks

Gas engines usually don't smoke unless there is way too much oil in the fuel..
If a Walbro carb won't draw fuel the usual problem is stiff diaphragms or an air leak under the carb that keeps the crankcase pulse from reaching the pump side of the carb..
A diaphragm kit is only about $5.00 from a chainsaw dealer or sometimes a rental yard that rents out saws and weedeaters..The 3.2 engines usually use a Walbro WT76 carb..