What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

impulse magneto gasket replacement

Wunderon

Well Known Member
Hi,

I had to retard the left Slick impulse magneto timing after about 150 hrs, as it had advanced to 27 degrees. I must have damaged the gasket as it now has a drop of oil after running for 5 minutes. It appears that if I set the engine to 25 degrees, making sure the impulse mechanism is not 'cocked', that I can simply ease the mag out enough to replace the gasket without removing the harness nor adjusting the internal mag timing. This assumes I don't move the mag gear while I do this. Then I would re-time the mag before torqueing it down.

My question is, is there something in the 'impulse' spacer housing that will fall out?

Thanks,

Dave
RV-8 IO-360-M1B Left Slick 4373, Rt Pmag
 
I think I have the same issue with my lane. I have O-320 and Slick mags. Since it was re-times at annual I have a leak. It is a small one but it is a leak. I just ordered 4 new gaskets from ACS. I do not look forward to removing the mag that is leaking and replacing the gasket but I cant find any other place it could be leaking so it is going to have to happen.

Good luck with yours. When I get to mine I will let you know how it goes.
 
Picture attached

Hi,

I had to retard the left Slick impulse magneto timing after about 150 hrs, as it had advanced to 27 degrees. I must have damaged the gasket as it now has a drop of oil after running for 5 minutes. It appears that if I set the engine to 25 degrees, making sure the impulse mechanism is not 'cocked', that I can simply ease the mag out enough to replace the gasket without removing the harness nor adjusting the internal mag timing. This assumes I don't move the mag gear while I do this. Then I would re-time the mag before torqueing it down.

My question is, is there something in the 'impulse' spacer housing that will fall out?

Thanks,

Dave
RV-8 IO-360-M1B Left Slick 4373, Rt Pmag

https://www.google.com/search?q=pic...bile&ie=UTF-8#imgrc=fg1-VUZc5_qg_M&lnspr=W10=
 
Mag

DON'T take short cuts. There will very likely be pieces of gasket material stuck to the mag, the accessory case and the spacer. Remove the mag completely and clean everything. Then start over on mag timing.
 
DON'T take short cuts. There will very likely be pieces of gasket material stuck to the mag, the accessory case and the spacer. Remove the mag completely and clean everything. Then start over on mag timing.

I think that is what happened. I was not comfortable doing the timing myself so I got a mechanic to do it at my annual and he did not remove the mag - just loosened it turned it a bit. In researching my leak and possibilities of where it was coming from I am pretty sure the gasket got screwed up at that time. I will have a different guy show me how to do it correctly. It is the stuff you dont know that gets you.
 
Hi,

I had to retard the left Slick impulse magneto timing after about 150 hrs, as it had advanced to 27 degrees. I must have damaged the gasket as it now has a drop of oil after running for 5 minutes. It appears that if I set the engine to 25 degrees, making sure the impulse mechanism is not 'cocked', that I can simply ease the mag out enough to replace the gasket without removing the harness nor adjusting the internal mag timing. This assumes I don't move the mag gear while I do this. Then I would re-time the mag before torqueing it down.

My question is, is there something in the 'impulse' spacer housing that will fall out?

Thanks,

Dave
RV-8 IO-360-M1B Left Slick 4373, Rt Pmag


No, on the 4 Cylinder mags, the impulse coupling has the gear attached. I would set the engine to #1 25 degrees BTDC, unscrew the mag harness (super easy with only 3 screws) then remove the mag. Clean all surfaces accessory housing, both sides of the impulse spacer, and the mag itself, new dry gasket between the engine and spacer, only grade one side of the mag gasket. Reinstall the mag using the “pin” to ensure the mag is at it’s correct position, then remove the pin and re time. There’s no need to do the “internal timing” as that involves opening up the mag and setting the points. Any mechanic can help you reinstall the mag within minutes.. very easy job. It’s so easy, I would do both sides just to have fresh gaskets all around. I only lube one side of the mag gasket so it doesn’t squeeze out. If this one tore from moving the mags, it probably means they were all put on dry and could stand to get changed anyway.
 
Back
Top