Andy Jones Spark Plug Colours & Comp Ratio

[Steve Horrocks]

Reet guys/gals,

Was checking out Andy Jones' compression on his tubby the other day & on taking the spark plugs out noticed all 4 where very 'white', now obviously this means that it is over heating in the cylinders, generally caused by running lean or the timing being out.



Only thing to cause questions, is the fact that it's currently been set up at RC Developments & also been down to Thor for a power run, & nothing has been mentioned about fueling/timing issues so i'm now wondering if anyone here has any other suggestions???

Oh, by the way, what should stock compression be?
With warm engine & throttle fully open, we 'only' got:

165, 168, 165, 165

all very similar, but i'd have expected slightly more, although we didn't try adding any oil to cylinders.

cheers

[^Trickster^]

170 across the board are classed as good condition. your readings are fine.

Have you checked the timing on the car? How old are the plugs?

Graeme

[Steve Horrocks]

i've not checked timing yet, as my strobe is a bit pooh!

but i'd have expected RC to have it sorted whilst mapping the power fc he has??
he should be posting some graphs soon

[Andy Jones]

Cheers Mr Horrocks, Here's the graphs:

[AM TUNING]

my plugs have allways come out just like that, mine has been mapped and all was perfect


dont worry

[Andy Jones]

Hi Graeme,

The plugs have been in 18 months as the previous owner changed these on it's last service before i bought her. The car was in for a service a month before the recent re-map and they said the plugs were fine so i'm presuming they've deteriorated due to the recent re-map?

IIRC RC asked what plugs i had in (before re-map last year) as they recomended using Iridium if you start increasing boost levels, I said these were already fitted (as my garage had informed me) Turns out they're the stock NGK BKR6EP's, So these will be getting replaced ASAP.

Just wondering what plugs everyone else are using/recomend before i start handing out the £

[pizza boy]

Iridiums are just a gimmick. All they do is foul quicker (dont like short journeys) and have no better performance than Platniums. The best plugs to go for all round for moderatley tuned 3sgte are NGK Plats BKR7EP.

[Bender Unit]

Slot in some colder plugs first I suggest NGK BCR8ES.

[Andy Jones]

Cheers for the info guys, i'll avoid the iridiums then cause mine does do a lot of short journeys

Is gtschris about or does anyone know if the colder type plugs he sells are either the BKR7EP or BCR8ES you both mention?

[BenF]

Cheers for the info guys, i'll avoid the iridiums then cause mine does do a lot of short journeys

Is gtschris about or does anyone know if the colder type plugs he sells are either the BKR7EP or BCR8ES you both mention?

Andy, don't stress about white plugs - on modern engines where the ECU tunes the fuel delivery white plugs are normal.

Certainly mine are grey/white and they're fine.

For colder plugs, just ring up NGK UK and ask for your local distributor of their plugs. I'm using the BKR7E copper plugs for 280-300bhp without problems. I wouldn't use the -ES plugs are they're resistorless - having the resistor in the end actually means that more energy is transferred to the spark plugs - its all to do with electronic tranmission line impedance matching stuff

[GT Rich]

Iridiums are just a gimmick. All they do is foul quicker (dont like short journeys) and have no better performance than Platniums. The best plugs to go for all round for moderatley tuned 3sgte are NGK Plats BKR7EP.

I disagree, iridiums are better as they cope with the heat better under higher boost levels/heat levels.

Steve mukka how we doin?? if you did the compression when the engine was cold you prob would of found the compression to be a little bit higher but those levels seem fine dude. Call ya later dude

Rich

[pizza boy]

Sorry I meant in regards to the benifit of placing them into "moderately" tuned engines. Only if your running a 400bhp+ beast/race car are they any benifit.
But if your running a 250bhp mr2 its not worth the £70+ squid. Platinums are fine..like NGK BKR7EP-8.

[GT Rich]

Sorry I meant in regards to the benifit of placing them into "moderately" tuned engines. Only if your running a 400bhp+ beast/race car are they any benifit.
But if your running a 250bhp mr2 its not worth the £70+ squid. Platinums are fine..like NGK BKR7EP-8.

No problem dude, just thought i would see what your views were on them

all the best matey

Rich

[Andy Jones]

Andy, don't stress about white plugs - on modern engines where the ECU tunes the fuel delivery white plugs are normal.

Certainly mine are grey/white and they're fine.

Thanks Ben, Will go and have a chat with the guys at RC in the new year regarding the timing to clear things up (I remember them saying they had to retard the timing slighty due to det.) hopefully not running lean as Pete at Thor said they'd mapped it a bit richer than he usually does and Niel Johnson said the same thing when i posted one of the graphs on the old IMOC *Wipes tear from eye

ALL THE BEST FOR 2005 EVERYBODY AND IF YOUR OUT TONIGHT DON'T STAY TOO SOBER

[Bender Unit]

I wouldn't use the -ES plugs are they're resistorless - having the resistor in the end actually means that more energy is transferred to the spark plugs - its all to do with electronic tranmission line impedance matching stuff

Hello Ben,

The ES plugs I suggested have resistors the secret is in the name

bc "R" 8es ---- R ='s Resistor

However I would like to point out that resistor plugs actually result in less spark. The difference are minimal these days bewteen resistor and non resistor plugs but for the strongest spark you want no resistor. Resistorless plugs are usually race plugs and carry a big price.

Regards

James

[Dale_V]

Have a look on http://spark-plugs.co.uk , once you've decided which you want

[BenF]

Dang, good point. I've dug out the info I have on NGK Plugs from a post to the old US Email list (Hmm, I need to buy a set of BKR7E's)

FWIW, I gave a set of 7ES's to a friend with a Rev1 and his engine really didn't like them.

Part #6097 : BKR7E Stock #: 6097 - £1.43 / £1.68 (not in stock)
Part#4930 : BKR6E - 1.53 ea inc £12ish all in (stock heat range, with resistor)

Looking back through the archives, others have used: (resistorless)
Part #5030: BCP7ES Stock #: 5030 - £ 1.16 /
Part #: BCP6ES Stock #: 4930 - £ 1.01

The first digit in the NGK part number indicates the heat rating. Lower numbers are hotter, higher numbers are colder. Without trying to describe the whole NGK part number system, the above part numbers break down as follows, from first letter/digit to last:
B - 14mm thread diameter
C - 5/8" hex size construction
K - 5/8" hex size construction, projected tip (ISO)
P - Projected insulator type
R - Resistor type (heat range 2 through 11)
E - 19mm (3/4" )thread reach
P - Premium platinum VX - High-performance platinum
Y - V-grooved center electrode (14mm only) 2.5mm insulator
A - Special Design - -11 - 1.1mm gap - -8 - 0.8mm gap For plugs with a flat seat and gasket (all of the above, I believe), NGK recommends torquing 14mm plugs to 18.0-25.3 lb-ft in cast iron heads and 18.0-21.6 lb-ft in aluminum heads. If you don't have a torque wrench they say to give it between 1/2 and 2/3 of a turn after finger tightness.

[Ian Geary]

Sorry to cut in on this thread, but I'd just like to clarrify something GT Rich posted:

if you did the compression when the engine was cold you prob would of found the compression to be a little bit higher but those levels seem fine

I would have thought a cold engine would result in lower than normal compression results: the engine would not yet have built up oil pressure, the pistons & rings etc wouldn't have yet expanded within the bores, which would allow compression to escape out of the cylinder??

I'm only asking because I want to confirm or rule out knackered rings on my 1994 GTS causing the masses of oil smoke I'm experiencing. 3 cylinders are returning 120-ish psi when freezing cold. Unfortunately I can't get the car started to warm up the engine though

Cylinder 4 isn't returning any psi at all although I could feel pressure coming from the plug hole with my palm over it.

I was hoping that with a warm engine, these compression readings would be pushed higer, and nearer the 165 psi target?

cheers,

Ian