Replacing ign coils

[Davedavies]

I am about to replace the coils and plugs - can't wait for the fun to start !!

Can someone advise what is the best / recommended silicon grease to use.
I don't want to repeat this job more than I have to

Thanks
Dave

 

[Richard_Hamilton]

Where do you plan using silicone grease? You might want to consider using Copaslip or a similar high temperature grease on the coil pack and heat shield screws, which might make it easier next time.

 

[Davedavies]

Many people recommmend coating the coil shaft with silicon grease to keep moisture out.
I was planning on giving the outer surface of the coil a coating.

I've seen moisture on Bentleys dispite being sealed at the top - leading to coil failure and in some cases flames

 

[Richard_Hamilton]

Oh, I see. It gets pretty warm down there, so try and find a high temperature version. (But that's why you asked................sorry)

 

[Richard_Hamilton]

I hadn't realised silicone grease is good up to 200 degrees C!!

You might want to check these out:

http://uk.rs-online.com/web/0283404.html

http://uk.rs-online.com/web/0494124.html

 

[Davedavies]

Hi Richard,

Many thanks, I have just ordered a tube.
Got your reply from 911UK as well.

Many thanks once again.

Dave.

 

[Davedavies]

Just thought I'd post an update.

Replaced 6 coils and 6 plugs today.
Found 4 coils with cracks in - hope you can see cracks in the pic attached

Appears to run a little smoother now []
Got silicon grease form RS as Richard advised - with a coating of grease, it made the coils harder to fit as air couldn't get out as fast.

Glad it's done, but don't want to have to do that too many times.

 

[Mike IRL]

Hi Dave,
I'm about to do a similar job.

Do you mind me asking where you sourced the parts ?

Did you notice much of a difference after job was done?

In general is it recommended to replace all 6?

 

[watlina]

PC Prices

3.4 M96.01/02 997.602.107.00 ignition coil £40.23 inc VAT
3.6 M96.03 997.602.104.00 ignition coil £40.23 inc VAT

3.4 M96.01/02 999.170.207.91 spark plug 14FGR 6KQU £12.86 inc VAT
3.6 M96.03 999.170.223.90 spark plug FGR 5KQE0 £10.30 inc VAT

or from euro carparts (all BOSCH parts)

3.6 coils for £23.75 inc VAT
3.6 plugs for £3.64 inc VAT

3.4 parts appear to be the same price

 

[Mike IRL]

Wow, that's a huge difference in price!

Certainly would make it a no brainer to change the lot.

 

[Davedavies]

Hi Mike,

As Andy says,

I bought coils from Euro car parts - £23.75 each
I also got plugs from Opie oils. I went for Denso Iridium Power plugs (IK20) at £37.91 for set of 6 - (they are supposed to be good for 80K miles)

I put a light coating of silicon grease on the shafts of the coils and on the outside of the electrical connector part of the coil.
There are a few posts on 911uk forum suggesting a coating of silicon helps to prevent moisture ingress.

I found on other vehicles using these coils that although 99% sealled, it is possible for moisture to enter through a small vent hole and as the engine cools, it draws moist air into the plug hole allowing moisture to build up.

The car seems a little smoother and sounds more regular when the throttle is blipped.
It previously sounded like a slight misfire.

It's a fun job, but I found worth the effort and worth doing yourself if you want to save £££s.

hope this helps

Dave.