What's this bar for in the COP boot?

[RichardH]

I have some COP's with this small bar in the boot 'spring', looks like graphite (maybe not). I was wondering what it's for?

Some of my COP's have them some don't.

Thanks in advance.

 

[RichardH]

Finally got the pic to post...

 

[Hamfisted]

That would be my guess. Are you the original owner ? Are the coils with these in them originals ? I would guess they were installed by somebody to cut down on radio interference?

 

[Trainmaster]

I would say a resistor to reduce radio interference also.

 

[RichardH]

That's interesting. I would have thought it had to do with conduction from coil to plug.

Ham, I am not the original owner, and replaced 6 of 8 coils.

Here is another shot with 'bar' in situ.

 

[Plati]

center core?

https://www.denso-am.eu/products/automotive-aftermarket/ignition/ignition-coils/how-they-work/

 

[RichardH]

center core?

https://www.denso-am.eu/products/automotive-aftermarket/ignition/ignition-coils/how-they-work/

It's in the spring though, in the boot.

Reason for the question, wondering if I should add the 'bar' to the coils that do not have. The expy is running just fine though. Maybe if it's not broken don't fix it...

 

[CountrySplatt]

Good question...and one I will be asking soon, I think. I need to give mine a tune-up, since it throws "Cyl x is rich" failures in the OBD. I am going to be replacing the COPs as part of the tune-up. My guess is that the bar is there to avoid kinks in the wire and to force it up out of the way, but I haven't been into the COPs on mine yet. I had something similar in my old MR2 in the plug wires.

 

[CountrySplatt]

...and not to hijack the thread, but where did you get your COPs? I am seeing them online for roughly Direct-replacement and performance ones at $100 for the set, but I am also seeing OEMs for $40. I understand that OEM is similar to running to the local Auto Zone or O'Reilley's, but figured I would see what you went with.

 

[VoxVeritatis]

I have some COP's with this small bar in the boot 'spring', looks like graphite (maybe not). I was wondering what it's for?

Some of my COP's have them some don't.

Thanks in advance.

View attachment 35550

It's not graphite, it's ferrite. Researched several years ago when changing my factory COPs out the first time. One (and only one) of my factory COPs had the ferrite slug in the spring. It was in pieces. None of the new replacement COPs came with the ferrite slug.

IIRC, the intent was/is to mitigate RFI (radio frequency interference). I carefully removed the pieces when changing the COP. There may be a barely noticeable difference on the AM radio band running without the ferrite slug, particularly with increased sensitivity to driving/parking under or near obstructions and areas with overhead power lines, etc. I.e., areas already prone to interference with or without the ferrite. If so, it was marginal.

I notice little to no difference when driving in open areas with a strong (unobstructed) signal, and none on the FM frequencies.

 

[RichardH]

...and not to hijack the thread, but where did you get your COPs? I am seeing them online for roughly Direct-replacement and performance ones at $100 for the set, but I am also seeing OEMs for $40. I understand that OEM is similar to running to the local Auto Zone or O'Reilley's, but figured I would see what you went with.

No worries... I bought off of Amazon. Took a chance on an inexpensive set and they are working just fine. YMMV. I'm Amazon Prime, but $30 for set of 8. I keep a few spares (and tools) in the expy in case I need to do a swap on the road. Lifetime warranty.

For S&G's I called Autozone. They sell their brand, Duralast for $59.99 for one, or set of 8 for $219.99. I don't even want to know what a dealer quotes....

Link to Amazon set for $30 of course:

https://www.amazon.com/gp/product/B014CCKIT4/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

 

[RichardH]

It's not graphite, it's ferrite. Researched several years ago when changing my factory COPs out the first time. One (and only one) of my factory COPs had the ferrite slug in the spring. It was in pieces. None of the new replacement COPs came with the ferrite slug.

IIRC, the intent was/is to mitigate RFI (radio frequency interference). I carefully removed the pieces when changing the COP. There may be a barely noticeable difference on the AM radio band running without the ferrite slug, particularly with increased sensitivity to driving/parking under or near obstructions and areas with overhead power lines, etc. I.e., areas already prone to interference with or without the ferrite. If so, it was marginal.

I notice little to no difference when driving in open areas with a strong (unobstructed) signal, and none on the FM frequencies.

Thanks. And interesting. Never would have guessed. Noticed it wasn't graphite (would not leave a mark on paper or the wall in my house lol). So it only effects AM? Never tune into AM so I guess I'm A-OK.

Thanks again for the feedback.

 

[texasscot]

...and not to hijack the thread, but where did you get your COPs? I am seeing them online for roughly Direct-replacement and performance ones at $100 for the set, but I am also seeing OEMs for $40. I understand that OEM is similar to running to the local Auto Zone or O'Reilley's, but figured I would see what you went with.

I bought "ENA Pack of 8 Curved boot Ignition Coil compatible with Ford Lincoln Mercry..." from Amazon for $29.99 on prime. Put them all in 3 months ago when i changed out my intake manifold (Dorman, also Amazon) and it all works great.

 

[VoxVeritatis]

Thanks. And interesting. Never would have guessed. Noticed it wasn't graphite (would not leave a mark on paper or the wall in my house lol). So it only effects AM? Never tune into AM so I guess I'm A-OK.

Thanks again for the feedback.

No problem.