Mag Question

[160STol]

HI, I was checking out the mag timing on a C 85 in a EXP the other nite. It has impulse on both mags. They are Eiseman LA 4 s . Anyways, we had the plugs out of it to to look at them and while there decided to do a compression check. It was good. Anyways we turned the engine over with the plugs out and noticed the right impluse didn't always catch. (which would explain why sometimes on cranking it would kickback maybe 1 time out of 10 ? ) We seen the impluses would click very close together maybe 1 or 2 degrees before TDC. So we decided to put a buzz box on the mags. Now we see the Left mag ( after tripping the impluse and backing up) the points open at approx 29 degrees BTDC . But the right mag seems more like 45 degrees for the light to go out on the buzz box. It seems when one light goes out, the other comes on.??

We pulled the mag and looked at it, the point setting was in tolerance , timing marks on the gears are right , everything looks ok, ( we had a old O/H manual on the mags) While there , we seen no reason for the impluse to miss catching, since the ears work on gravity, and they weren't hanging up ( per manual )
I should also state before we started this inspection, the engine ran fine, and mag check was less than 50 RPM. We haven't run it since we pulled the R Mag off.
So now we checked the timing with another buzz box and get the same results. How can the impulses trip together but not agree with the 28 -30 degree BTDC ? With the top and bottom plugs lying on the cylinder , you can see they are firing together . Thanks Sam

 

[S2D]

My only guess from the info you give,--
If the mags internal timing and points are set correctly
ie the gears are matched to the proper mesh and the points to the proper opening degree, would be impulses with different lag angles.

 

[Steve Pierce]

impulses with different lag angles

My guess also.