humptybump
Well Known Member
I've read most of the threads, blog posts, and Savvy articles on aviation spark plugs so my experience confuses me and I could benefit from some experts.
History:
My carbureted O320 runs great but is a bear to start - we're talking that battery draining, often flooding kind of bear.
It actually seems to have gotten worse over the past 3 years and the last 250 hours.
In thinking it all through, I didn't have much trouble when I bought the plane and then I remembered we replaced plugs about three years ago. We pulled the "well used" dual-finewire plugs and install Unison massive electrode plugs.
The confusion:
Today, I pulled the bottom plugs. I measure their resistance. They were all In the 1.2k-1.4K OHM range. I pulled out the mothballed dual-finewire plugs and measured them. They were all in the 4K-5.5K OHM range.
I installed the old dual-finewire plugs into the bottom of the engine. The test run was eye opening.
The engine started almost immediately. Once warmed, the MAG test showed a 60RPM drop on the dual-finewires and 100rpm on the nearly new massive electrodes.
I thought the resistence on the dual-finewires is too high (or right up there) and yet the Bedix MAGs seem to much prefer them.
Is it the resistance? Are dual-finewire plug that much better? Weak MAGs? A total fluke?
History:
My carbureted O320 runs great but is a bear to start - we're talking that battery draining, often flooding kind of bear.
It actually seems to have gotten worse over the past 3 years and the last 250 hours.
In thinking it all through, I didn't have much trouble when I bought the plane and then I remembered we replaced plugs about three years ago. We pulled the "well used" dual-finewire plugs and install Unison massive electrode plugs.
The confusion:
Today, I pulled the bottom plugs. I measure their resistance. They were all In the 1.2k-1.4K OHM range. I pulled out the mothballed dual-finewire plugs and measured them. They were all in the 4K-5.5K OHM range.
I installed the old dual-finewire plugs into the bottom of the engine. The test run was eye opening.
The engine started almost immediately. Once warmed, the MAG test showed a 60RPM drop on the dual-finewires and 100rpm on the nearly new massive electrodes.
I thought the resistence on the dual-finewires is too high (or right up there) and yet the Bedix MAGs seem to much prefer them.
Is it the resistance? Are dual-finewire plug that much better? Weak MAGs? A total fluke?
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