Antique

My Feedback: (4)

[
My mechanical advance was and still is the best method for spark control...
There is a hub mounted on the tapered end of the crank..The hub has an extension on the back side that has a ball bearing pressed on to it..The ball bearing has an aluminum ring with a sensor expxied into it, pressed on the the O D of the bearing...There is a DuBro ball mounted on the periphery of the aluminum sensor ring with a link to the rotated carb shaft that advances the spark when the throttle is opened...Simple, cheap, and linear...
This requires the carb to be rotated so that the throttle shaft is parallel to the cylinder to make connection to the throttle a straight line...Also easy...
The carb insulator is made from 3/8 G10 epoxy board...Simple, cheap, and insulates the carb from heat...
Only problem with this setup is the user..If the throttle is opened too far for starting the engine kicks back...It's impossible if the throttle is set just above idle, 2 degrees BTDC won't hurt anyone. the piston is already past TDC when the engine fires...
It weighs only a few ounces, the weight of a thin ball bearing...But since the G62 is an overweight underpowered boat anchor most flyers took the advice of some so called expert on a forum there were not enough G 62s sold to make it worthwhile...None of my good customers ever complained about the mechanical advance...It was used on all manner of conversions for many years, but when Bill got the syncro spark circuit from Ed Vollmer he had an exclusive on EI for a few years, then it became easier to just put a syncro on the engines...Easier to just connect a circuit board in series with the ignition and forget the extra machining required....

My conversions started in 1987

Props4ever

Here are pics of my engine, it sure looks as mechanical advance but i'm not expert of these engines so ur advise will be taken.

jedijody

My Feedback: (1)

That's a mechanical advance set up. Good stuff, if Adrian will make you up a fixed timing unit thats what I would use if it were mine.

Tired Old Man

My Feedback: (1)

And if not, you have great access and it's an easy modification to get to an auto advance arrangement. Just drill a vertical hole in the white ring that will tap to 6-32 or 8-32 for a set screw, determine 28* btdc, and lock it down. Remove the coupling linkage, plug in the ignition, and go fly.

Props4ever

Jody,

How is fixed timing unit differ from what i have on me?....

How differ one works from other, pls explain a bit...

Props4ever

Can u pls illiterate how to do this by using my pictures, also if you can make arrows on each part with there names, it will be easy for me to know what part is what ie: coupling linkage, plus how to lock it down etc etc...

Thanks in advance.

Tired Old Man

My Feedback: (1)

Working it.

Yellow arrow is hall sensor in current location.
Red arrow is the timing ring.
Blue arrow is the coupling linkage.

jedijody

My Feedback: (1)

There are two different types of EI modules, one has a fixed sensor position and the module automatically advances and retards ignition timing based on engine RPM. The module computes engine RPMfromthe dwell duration (time)that the sensor "sees" the magnet in the hub during each revolution of the crankshaft.Timing isadvanced in increments at multiple points along the RPM band between about 2000 and 4000 RPM. The more points or steps a module has in it's timing curve the better and smoother the throttle response will be. There areno moving parts, this is the most common version and most modern, not necessarily the best.

Yours, a fixed timing ignition module does no computing, it just throws a spark every time the magnet passes the sensor. The sensor is linked to the throttle linkage and is moved to advance the timing as the throttle is advanced, timing is retarded as the throttle is retarded. Because it's coupled mechanically in this way, the ignition advance is perfectly linear AND it's tune-able if you know what you're doing and have certain needs/desires.

Warbirdguy

I have to agree with Tired Old Man on the auto sensor arrangement. It was a gimmic. It appears on the outside to clean up the engine and therefore, gives the illusion of being better. Let me explain my point. I am in the marine repair industry. Have been since the late sixties. When outboards left the old points and cond. ignition, they went into various kinds or electronic. They finally settled in on basically the same igniton as the CH mechanical timing. Various ways of sensing when to spark, but the same. They All still use the same method of advancing the timing. A mechanical arm advances the timmer base ( the ring under the flywheel that holds the pickup sensor/sensors). If those guys, and I mean all makes, thougth it was a good idea for all those years, then Im pretty sure its about the best thing out there. Now, I think some of the PWC's use an auto advance and they seem to have prolems all the time. I wont even work on them anymore.

Now, Tired Old Man, you say you have dealt with thousands of CH and CH type ignitions, well, so have I And, I have had several CH ignition equipted engines, Walker 4.2, Walker 2.4, Brison 4.2 and a Brison 3.2 All had mechanical advance. The first Walker 4.2 I had did what I explained before about the magnet coming loose because it was pointing outward and the glue let loose and flung the magnet out into the timing ring which rung off all the wires from the sensor and wraped them around the engine This was on the second flight of a new engine. I sent it back and they send me a new engine with the magnet and timing ring changed to like I explained in an earlier post. No more problems. I have changed 2 hall effect sensors on the other engines over the years.

Now, one more note. Mercury Marine had an issue with one of their designs on a "trigger" the sensor that picked up the firing pulse. The circuitry that controlled it was prone to fail and when it did, it would let the timing run away on top end and detonate #3 piston. Melt the top right off the piston. That is my main concern with auto timing. Do they have a redundant system built in to keep this from happening? I dont know. I would think so, but when its automatic, how do you know what the module is thinking

I prefer to use mechanical myself. I thought of changing over, but as long as it works, I think Ill just keep it as it is until Im forced to change.

Thats my manifesto for today LOL

WBG

captinjohn

I want to get a fixed point CD and make my next ignition advance with carb linkage...seems like the best way to go....Period! Capt,n

Tired Old Man

My Feedback: (1)

WBG,

My intent was not to say that CH was not a good unit. Far from it because I have been a proponent for CH Ignitions, the best RC ignition on the planet, for many years. I was once involved in a process that proved that. More on that subject I cannot say.

CH ignitions last longer than any other, and have a far reduced in frequency of failure than any other. Unfortunately nothing electronic lasts forever, and even the best ignition coils have a finite life span. Older design coils have a shorter life cycle than newer. The later CH units can easily last well over a thousand hours of use with minimal care. Only the installation needs to be correct with the avoidance of impacting the ground for that to happen. The people that have maintained 5 volts or less to their CH ignitions would have a tremendous unit. Those using 6 volts or more would have a tremendous unit with a somewhat shorter lifespan. You just can't get better that a real CH ignition.

However, as mentioned earlier, nothing lasts forever and even CH has suggested replacing the old brown box units before they fail. Clearly the one in this thread has experienced some abuse, which does indeed impact the life of the electrical components. TKG made that recommendation in this thread. TKG is Terry Grant, one of the two people that were CH while they remianed in business. The second is Bill Carpenter. I was advised by one of the two a long time ago what the anticipated lifespan of the brown box units were and this one is well outside of that time frame. I have two of the old brown box units in permanent retirement at my shop.

I'm all for saving money, especially where conditions make sense for that to happen. But I have problems in trying to skimp in areas that could end up costing far more than the cost of even the most expensive component. As already noted, the cost to repair the unit of interest in this thread is close to the cost of a new unit, rendering comparative $$ savings virtually nil. That a new ignition, made to the exact specifications of the CH design, instead of a Chinese shortcut copy, can be obtained at nearly the same price as a repair provides a decision process one that is quite easy to make.

A warbird is heavily dependant on keeping the engine running because of weight, wing area, and wing loading. The old Nosen kits came in pretty heavy and typically need to be flown with a relatively high power loading all the time. You want to keep the engine running and minimize the number of potential failure points. If it was mine I would install a new CH with much newer/modern electronics and anticipate many more years of reliable use. But that is, of course, a matter of personal choice.

Props4ever

Juss an quick update:

I'm trying to find sometime to talk to Adrian about this issue, after that i will make my final decision. Keep u all posted.


Sam

Props4ever

Jodi,

Just talked to Adrian about sending in my ign unit for repairs, he was at Reno races when a P-51D crashed into VIP stands!...

[youtube]http://www.youtube.com/watch?v=hzvro_u73xM[/youtube]

jedijody

My Feedback: (1)

Yes, I heard and saw the videos earlier today. Sad day, prayers and condolences to all involved at the Reno races today.