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-   -   how to keep coils alive for 30k+ (https://www.rx8club.com/series-i-tech-garage-22/how-keep-coils-alive-30k-196476/)

MrVei 05-02-2010 04:55 PM

how to keep coils alive for 30k+
 
after replacing my coils 3x in one yr, i found how to keep it form happening, the coils are of the c.o.p style, witch on a 4cyc car the coils are "up side down" from how they are in the rx8. the resion the coils over heat and die is they are mounted up side down. the fix:
remove all four coils, put a 6mmx1.25 nut on the post of the plate and spin it all the way down on each post. re-install all coils and enjoy. the spacing gives the coil breathing room needed. mine have been in for over a yr with 30k now on them and still getting 19mpg in town.

laythor 05-02-2010 04:58 PM

you had to replace your coils 3 times in one year? yeah, that's a sign something else is going on.. or you're getting really crappy replacement coils

wrenchrob 05-02-2010 05:14 PM

??????????????????????????

expo1 05-02-2010 05:54 PM

1 Attachment(s)

Originally Posted by wrenchrob (Post 3543196)
??????????????????????????

I think this is what the OP is talking about doing. In the attached photo I have the bracket the OEM coils mount to. Going right to left this is how they are configured.

Normal mounting

Small nut on the mounting post

Coil mounted on a post with a nut on it.

The theory is the small gap under the raised coil will keep it cool and make it last longer. I myself do not have an opinion on this yet.

endowdly 05-02-2010 06:57 PM

I've never heard of this being a problem before. Interesting...

bse50 05-02-2010 07:38 PM

A better explanation would help.
Sorry for posting drunk though.

spinning triangles 05-03-2010 06:07 PM

The coils are not C.O.P which stands for "Coil on Plug". They do not sit right on top of the plug like most modern ignition systems use. There is a spark plug wire that connects them, which is what C.O.P. eliminates. Anyways, this is an interesting thought that has crossed my mind a few times, but I just upgraded to yukon coils so I never tried the idea. My stocks ones have 33K and resistace is showing that they are slowly dying. Good luck with the experiment

Rote8 05-03-2010 06:25 PM

Try a smaller spark plug gap too.

maskedferret 05-03-2010 07:16 PM

Eh... wouldn't the bracket be more effective as a heatsink? Maybe use a thermal paste/compound to join the base of the coils to the bracket?

Stingray 05-03-2010 07:52 PM

What are you guys using as replacement? OEM or aftermarket?

spinning triangles 05-03-2010 08:11 PM

Stingray, what are you referring to? For coils I went with the yukon setup, as for spark plugs I use stock NGK's. There was no way in hell I want to replace coils all the time, especially when they're $140-180 a set. Plugs are bad enough at $70-80.

Mazurfer 05-03-2010 08:13 PM


Originally Posted by maskedferret (Post 3544784)
Eh... wouldn't the bracket be more effective as a heatsink? Maybe use a thermal paste/compound to join the base of the coils to the bracket?

This is what I think, and he may have very well just defeated that. :scratchhe

However..........Our engine is soooo damn hot running that a lot of heat is transferred into that bracket, so it could be better if the coils are off it????

endowdly 05-03-2010 08:19 PM

^Air doesn't defuse thermal heat as well broad bracket with cooling fins...

I'm kind of well versed with heat sinks. Although the heat is eventually transferred to the air, and the more surface area on a heat sink present (contacting air) the better it performs, direct contact to a heat sink (like the bracket) should draw the heat off the coils more rapidly than this air gap. So this method has me a little confused.

spinning triangles 05-03-2010 08:24 PM

So then what would you guys think of having the coils upside down, but using thermal paste or whatever to apply a heatsink to the bottom of each coil, sort of like the yukon coils are?

Mazurfer 05-03-2010 08:26 PM

^...............I think mo betta!

spinning triangles 05-03-2010 08:34 PM

Well someone needs to rig this up and test it then. Start with a new set, ohm them out, apply heat sinks, drive 30K miles, ohm them out again and report findings. If it works I still wouldn't switch back to oem, but this would make a sweet DIY for everyone using oem coils

Mazurfer 05-03-2010 08:35 PM


Originally Posted by endowdly (Post 3544847)
^Air doesn't defuse thermal heat as well broad bracket with cooling fins...

I'm kind of well versed with heat sinks. Although the heat is eventually transferred to the air, and the more surface area on a heat sink present (contacting air) the better it performs, direct contact to a heat sink (like the bracket) should draw the heat off the coils more rapidly than this air gap. So this method has me a little confused.

Totally agree here.
Being in the Semiconductor Industry, I've learned a thing or two about heat sinking at all levels of current or heat over the years. :mchase:

But again, our plate might be transferring a lot of heat from the engine to the bracket????? This should be tested out with a thermal scanner to see which is hotter.......coils on the bracket, coils on the bracket with heat sink paste, or coils off the bracket.

Mazurfer 05-03-2010 08:37 PM

^.............I don't use OEM either!

endowdly 05-03-2010 08:39 PM

^+1

maskedferret 05-03-2010 08:41 PM

The moment my revA coils give me grief, I am hitting BHR up.

endowdly 05-03-2010 08:50 PM

^Great product by the way...

(Got em)

spinning triangles 05-03-2010 09:08 PM

To be honest I would just say f*ck screwing around with mounting the coils differently and adding heatsinks and stuff. Just save up the dough and get the BHR kit or custom make something along those lines. Those coils will out-perform oem anyday.

Stingray 05-03-2010 09:12 PM

Stupid question, does anyone use auto part store coils? Like O'Reilly or Autozone? Lifetime Warranty when they go out.

spinning triangles 05-03-2010 09:16 PM

Not sure if they supply a coil for the 8. Don't know of any 3rd party companies that build them. I'm probably wrong though. Wouldn't trust them if they do exist.

imop45 05-03-2010 09:22 PM

autozone probably wouldn't apply it to rx8 coils.. Excluded from warrantee or something.

but just an opinion


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