Spark Plugs & Leads

Spark Plugs & Leads

Author
Discussion

lesR

Original Poster:

58 posts

86 months

Friday 21st April 2023
quotequote all
Hi,

I'm having trouble with the HC reading on my 450SE.

Starting from basics, I want to change the plugs and leads first. I'm using NGK B7ECS at the moment but wanted to check if there is any updated plug that's recommended.

I also want to fit new leads, so does anyone have recommendations for a make/set number etc that can replace the ones I have fitted. These seem to have a thin core with I'm guessing, carbon impregnated in it.

The car is mainly used for enjoyable sunny days so is not really pushed hard.

Les

phillpot

17,306 posts

192 months

Friday 21st April 2023
quotequote all


Bosch HT leads, sensible price and good quality smile

https://www.ebay.co.uk/itm/183997394731?epid=24877...

lesR

Original Poster:

58 posts

86 months

Friday 21st April 2023
quotequote all
Thanks for the details, I'll check them out now

Les

Belle427

9,959 posts

242 months

Friday 21st April 2023
quotequote all
NGK BPR6ES was always a recommended plug in the Chimaera section.
Some chose to use the iridium equivalent too.
https://www.pistonheads.com/gassing/topic.asp?h=0&...

lesR

Original Poster:

58 posts

86 months

Saturday 22nd April 2023
quotequote all
I didn't think about looking at a grade change. A hotter plug may also help the HC reading. Thanks for that, now I need to brush up on plugs. I havant done that since my motorcycle days.

The car is only used on sunny leisurely drives so may not need grade 7 as fitted from new.

I checked 4 of the 8 plugs yesterday, 3 of the 4 were reading 0 ohms. The 4th showed about 300 ohms, not much difference, but a difference.

The plugs are non resistor plugs so need resistor leads, an I right or wrong? confused

mrzigazaga

18,591 posts

174 months

Saturday 22nd April 2023
quotequote all
Hi
I used the iridium BPR6EIX in my 350i and so have a few owners of larger V8's, never had problems for 5 years...good for winter and summer..leads are mid range (£30) RV8 efi make sure you get an extra long king lead...30" should do it...smile

Lesliehedley

250 posts

269 months

Sunday 23rd April 2023
quotequote all
NGK B7ECS are the recommended plug for the 450SE. I had these in my 400SE and they were constantly getting fouled or the engine would flood. Then I changed to NGK BPR6ES and I've had no trouble since. I think the B7ECS is the wrong plug unless you drive the car hard all the time to stop the plugs fouling.

lesR

Original Poster:

58 posts

86 months

Monday 24th April 2023
quotequote all
Thanks for all your help.

I now have all the details, so I will order the bits today. smile

Les

lesR

Original Poster:

58 posts

86 months

Saturday 29th April 2023
quotequote all
Just fitted new plugs, leads, rotor arm and distributor cap. Luckily it fired up first turn.

The plugs may be where the problem lies as at least three of the plugs showed higher resistance readings than the others. One was in the 2k range. The distributor caps aluminium posts also had some corrosion.

Not sure if this trick is known, but number 8 plug is a pain to fit as the clutch master cylinder gets in the way. After pondering on it for a while, I cut a short length of small bore PVC fuel line (similar to brake bleed hose) and pushed it over the end of the plug. It makes a great plug insertion tool and also stops the plug dropping to the floor and damaging the electrode. A 3/8 inch plug socket will also fit over it if required. The grip it gave on the plug was enough to allow it to be fully wound in ready for the final tightening. I used it on all the plugs and it worked like a dream.

Next question it about getting the HT leads to fully push home on the plugs. Is it best to get a special tool, if there is one, or just push as hard as I can?

Les

LLantrisant

1,002 posts

168 months

Saturday 29th April 2023
quotequote all
common rule:

maximum 1 component in the ignition system should have a resistance. (and this is only for noise-depression)
as all modern HTLeads are restistance-types, the plug MUST be without.

so fitting modern leads AND R-type plugs is already the first mistake you can do.

Speaking for Chimaera´s there was another mistake possible:
the orignal plug-extenders where R-Type....so with the HT-Leads used on those cars AND R-Type plugs you had 3 resistances in the ignition-circuit: Leads, Extenders and Plugs...totally wrong!!!
Chim Plugs were therefore never R-Type!!

lesR

Original Poster:

58 posts

86 months

Saturday 29th April 2023
quotequote all
Hi LLantrisant

Thanks for your comment, and I will try and remember it for further reference, but if you check my opening post it shows that the plugs removed were the same as fitted originally so do not have resistors. The leads are also the original set fitted by TVR when the car was new. The 450SE as far as I know never has extenders fitted, well not to my car anyway. smile

Les

TwinKam

3,201 posts

104 months

Saturday 29th April 2023
quotequote all
I use a tool like this on every plug I fit, don't know how/why I ever managed without it, esp on modern DOHC engines, and Hondas where half the plugs face the bulkhead!


lesR

Original Poster:

58 posts

86 months

Saturday 29th April 2023
quotequote all
That looks like a professional version of my lash-up smile

Do they have a name, as I scoured Amazon yesterday and nothing like that showed up. The photo looks like it has a taper, if so is that to fit smaller plugs?

Les

TwinKam

3,201 posts

104 months

Saturday 29th April 2023
quotequote all
I won't do Amazon. Plenty of sellers on ebay though. Or just google 'spark plug installation tool' for more retailers.
Sure, any bit of pipe will work, but these are silicone so really flexible, curve-memory free(!), and yes the smaller end is for the later smaller plug types.

lesR

Original Poster:

58 posts

86 months

Sunday 30th April 2023
quotequote all
Thanks TwinKam,

Found one, and just ordered it this morning.