Coil Packs

Author
Discussion

Graham

Original Poster:

16,368 posts

286 months

Sunday 12th March 2006
quotequote all
Do they need th be earthed?

Im looking to use 2 * range rover coil packs. No these have 3 inputs, power and 2 drivers for the 2 paired outputs. the coils normally mount to a metal base that bolted to the engine, so obviously earthed. As Im mounting these to the grp iner wings, do i need to earth the bases? the bolt holes are metal lined rather than plastic so the bolts wold earth them out on a steel car?

ta G

GreenV8S

30,263 posts

286 months

Sunday 12th March 2006
quotequote all
I had a similar dilemma. In theory the coil pack should just contain a pair of double-ended coils, with no earth required on the HT side. Practice seems to back up this theory because mine ran fine with no separate earth. You could confirm that yours is the same by measuring the resistance between the earth and the other terminals. If it's electrically isolated (as mine was) then there's no point earthing it.

steve_D

13,770 posts

260 months

Sunday 12th March 2006
quotequote all
You may want to re-think your mounting.
Coils get pretty hot when running and the metal sleeved bolt holes may be that way to disipate heat into the mounting plate.

Steve

stevieturbo

17,310 posts

249 months

Sunday 12th March 2006
quotequote all
Coils generally do not need earthed, although I have seen some that do for some strange reason.
I would imagine they work fine even if not earthed though.

Graham

Original Poster:

16,368 posts

286 months

Sunday 12th March 2006
quotequote all
steve_D said:
You may want to re-think your mounting.
Coils get pretty hot when running and the metal sleeved bolt holes may be that way to disipate heat into the mounting plate.

Steve


They will actually be bolted to two big alloy plates, so they should act as a heat sink. The plates aint earthed though..


Cheers

All

Avocet

800 posts

257 months

Sunday 12th March 2006
quotequote all
The metal liners are to stop the plastic breaking when you tighten the bolts - they're not for electrical purposes.

Graham

Original Poster:

16,368 posts

286 months

Monday 13th March 2006
quotequote all
Ok then another stupid question...

working through my spare loom, i can make up two separate coil feeds ( power plus signal) using



coil 1 ( afm leads = power from main relay & 2 afm signal wires)

coil 2 ( purge canister= power from fp relay & 1 signal)
+
(ignition sense = signal 2)

that works niclely allowing me to stick the coil packs on either side of the engine bay ala ajp race setup, and as I dont have an afm,purge canister or use the ignition sense it would seem to work well)

My question ( finally) is do you see any prolem with powering the 2 packs through different relays? they are switched slightly differntly but both will be active when the engine is cranked or running?

Cheers

G

GreenV8S

30,263 posts

286 months

Monday 13th March 2006
quotequote all
They both need 12v, I don't see it matters where it comes from.

Graham

Original Poster:

16,368 posts

286 months

Monday 13th March 2006
quotequote all
I couldnt think of a reason it would be a problem but thought I'd ask in case i was missing somthing fundamental

G

wedg1e

26,817 posts

267 months

Monday 13th March 2006
quotequote all
One possible reason for earthing the coil cans is RF suppression... but I don't imagine that will be a huge worry