Jump to content
Click here if you are having website access problems ×

Spark plugs !


Paul van

Recommended Posts

NGK plugs normally have pre-set gaps.  My R400D NGKBR7EFS were pre-set to 0.65 (25 thou) but I increased them to 0.9mm (37 thou) on advice from the Two Steves. 

Your NGKB9EFS is a colder plug, but I don't know what the optimum gap would be for a 620. However, I would advise against going as far as 1.3mm, simply because that's likely to overly stress the coils.   IIRC, Ford have reduced their recommended 1.3mm (at least on FoMoCo TRAP6-13 plugs) to avoid this problem.

No doubt CC would advise.

JV

Link to comment
Share on other sites

The higher the cylinder pressure the smaller the gap otherwise you will 'blow it out',

I run 25 thou for a high compression Duratec (12.6:1)

1.3mm is for stock engines with significantly lower pressures, '9' is a very cold plug though bearing in mind stock is 6, 260-290BHP Duratec run 7's and there's been some comment regarding the accuracy of the map on this model too.

Link to comment
Share on other sites

1.3mm is for stock engines...

Neil, do you know whether Ford's apparent advice re coil stress actually exists?  I seem to recall coming across it on a car forum (not this one) within the last 2-3 years.

Out of interest, having run for a year or two on NGKBR7EFS plugs, I've now reverted to the standard TRAP6-13, but with a reduced gap of 1.0mm.  I did this following a spell of slight misfiring after a period of gentle running (such as through a town).  I put this down to the NGK-7 being a tad cold for normal road use (I no longer track the car).  Certainly, the car runs impeccably now.

JV 

Link to comment
Share on other sites

  • Area Representative

JV #2 - surprised to read that you used NGKBR7EFS but now have reverted to NGKTR6AP -13 which I have used in my R400 (220bhp) since new in 2013. The plug gap is the standard 1.3mm/52 thou & have had no problems.

It seems that plug applications & gaps are a lottery?! 

Link to comment
Share on other sites

On my R400D I binned the original TR6AP-13 plugs gapped to 1.3mn after a coil failure at about 10,000km and high rev misfires on the track. Currently using BR7EFS with 0.9mm gap, standard gap seems to make the car harder to start and larger gap gives misfires at times.

I've tried gaps from 0.7mm to 1.3mm on a variety of Autolite, Champion and NGK plugs, BR7EFS seems to be the optimum on the R400D if it is used on the track, with the main compromise being low rev misfires in cold weather after starting the car due to a slight amount of fouling until the plug is hot.

 

Link to comment
Share on other sites

Re #6:  Geoff, I'm a bit confused.  Do you mean you've always used the TR6AP-13 as supplied?  I only changed on advice from Steve Greenald.

Re #7:  James: Interesting. It was a COP failure a few years ago that persuaded me that 1.3mm may well be too wide -- backed up by Ford advice that I can no longer find!

Comparing BR7EFS and TR6AP-13, the former has a much shorter, "shrouded" insulator.  I'm wondering if that induces misfires?

Sparkplugs-NGKBR7EFSvsFord(NGK)TR6AP-13.jpg.15588431b462cf02388aa5f8766f545f.jpg Sparkplugs-NGKBR7EFSvsFord(NGK)TR6AP-13_2.jpg.e18f05265b44121cb78027cc8af43488.jpg

JV

Link to comment
Share on other sites

Re #5:

... but I run a coil pack with wasted spark as opposed to coil per plug.

Out of interest, what year is your car?  (I'm guessing pre-2006/7?).

My 2008 car (with COP) has a redundant platform at the rear of the engine.  Is this where the coil pack would have been mounted?

JV

Link to comment
Share on other sites

  • Area Representative

JV - Yes have run with TR6AP-13 out of the box (2013) & changed faithfully every two years (iaw Caterham service schedule) irrespective of condition or mileage. Gapped to 1.3mm/52 thou. 

Engine is coil on plug ignition. Have never experienced any starting or running problems in the seven years that I have owned the car. Even after a long run of 100 + miles there are no poor ignition indications even when giving it the beans.

If there is advice out there that this could be the incorrect plug/gap combination then we need to nail this for all R400/420 2.0L Duratec owners whether coil on plug ignition or not.

 

Link to comment
Share on other sites

Thanks, Geoff.  Presumably you have the flexi coil loom fitted?  I suffered a lot of problems (notably at Llandow) with a fractured COP wire on cyl #1 (ditto the brown TPS wire).  Solved in the end by fitting the race looms.  I suspect that those problems may have led to COP failure on cyl #1.  That happened while touring in France -- happily, I had a spare with me.

JV

Link to comment
Share on other sites

  • Area Representative

JK - Yes I have the flexi loom & the updated TPS loom.

To all who have so far contributed to this thread:

It appears that there could be some variation in not only plug type but gap depending on the YOM, state of tune of the 2.0L Duratec & if it is coil on plug or not..

If this is the case then all these differences could be logged on the club web site under 'Guides/Maintenance' to assist members in making an informed decision on the direction that they may wish to proceed.

So - from the silence my late 2012 R400 2.0L Duratec (220 bhp), coil on plug, using NGKTR6AP-13 gapped to 1.3mm/52 thou is correct.

If there are sufficient variations then PM me & I could collate to uplift to the mentioned page?

Link to comment
Share on other sites

... I could collate to uplift to the mentioned page?

Well played, Geoff!

This is how I see it:

Like you, my 2008 R400D had the TR6AP-13 (FoMoCo in my case) from new, and CC didn't alter that during the RB upgrade.  So, I think your set-up would be pretty much the standard for 210/220bhp COP Duratecs.  Higher power outputs (like 7WotW's, albeit with coil pack) would seem to benefit from a colder NGK-7 plug.  My dalliance with NGKBR7EFS resulted from Steve G's advice, but I suspect he was considering Duratecs that were tracked (as mine was at the time).  As noted above, I went back to TR6AP-13 (to address a misfire), but with a reduced gap in order (I thought) to reduce COP voltage stress.  Independent  evidence from Ford or elsewhere would help here.

Are "standard" Duratecs with coil packs different?  I don't know. No doubt 7WotW could advise.

JV

Link to comment
Share on other sites

Mines not a standard engine *biggrin*

However the coil pack is a stock Ford item the one which mounts on the water housing on the rear of the head.

If your concerned about low speed fouling you could use BR7EV - with precious metal electrodes these burn off deposits better than conventional tips. NGK did alter some numbers so it might now carry an EIX suffix.

We used them on pokey Xflow's albeit with an '8' grade.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...