Notices

What size spark plug gap???

Thread Tools
 
Search this Thread
 
Old 06 February 2010, 10:28 PM
  #1  
gra2730
Scooby Regular
Thread Starter
iTrader: (1)
 
gra2730's Avatar
 
Join Date: Jun 2009
Location: Somerset
Posts: 355
Likes: 0
Received 0 Likes on 0 Posts
Default What size spark plug gap???

I am looking at buying some spark plug's, they come with a 0.8mm gap, is this correct for a 1999 uk turbo, lightly modified with a decat, induction kit & dump valve. Searching the forum gap's used see to range from 0.6-0.8mm.

Cheer's.
Old 06 February 2010, 10:39 PM
  #2  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

If you still run the OEM boost, then gap to 0.7mm... if running 0.2bar/3psi above that, then 0.65mm... if 0.4bar+/6psi+ above std, then gap to 0.6mm.

It's the extra boost pressure that could literally blow the spark out if the gap is too 'wide' (i.e. spark has a greater distance, therefore time, to travel from one electrode other - thus increasing its chances of getting blown out by the hurricane-like charge of air!...)

Last edited by joz8968; 06 February 2010 at 10:48 PM.
Old 07 February 2010, 03:16 PM
  #3  
gra2730
Scooby Regular
Thread Starter
iTrader: (1)
 
gra2730's Avatar
 
Join Date: Jun 2009
Location: Somerset
Posts: 355
Likes: 0
Received 0 Likes on 0 Posts
Default

Thank's for the info, is it ok to re-gap iridium plug's with feeler gauge's?
Old 07 February 2010, 03:26 PM
  #4  
99greenwagon
Scooby Regular
iTrader: (39)
 
99greenwagon's Avatar
 
Join Date: Oct 2008
Posts: 6,870
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by gra2730
Thank's for the info, is it ok to re-gap iridium plug's with feeler gauge's?
yes fine,and 0.7 will do nicely
Old 07 February 2010, 03:31 PM
  #5  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

Using a feeler gauge is the only 'proper' way of doing it. I don't think the fact they're iridium means you can't, can it? Are they soft or something and therefore will break easily

Anyway, best plugs for your car are:

NGK PFR6B (if standard/std boost/mild mods like air filter/exhaust)
NGK PFR7B (if upped boost/decat/remap or more...)

When you gap, the correct gap is when you feel an ever so slight drag or resistance against the feeler gauge. If it's 'stiff', and reluctant to pull/push, then it's too tight and you need to open the electrode out a miniscule amount...
Old 07 February 2010, 03:39 PM
  #6  
gra2730
Scooby Regular
Thread Starter
iTrader: (1)
 
gra2730's Avatar
 
Join Date: Jun 2009
Location: Somerset
Posts: 355
Likes: 0
Received 0 Likes on 0 Posts
Default

I am looking at a set of ngk PFR6B that I can pick up cheap, these are gapped to 0.8 as standard, I am running a full decat/stainless, k&n induction kit & forge dump valve so guess I should be gapping to 0.7? Or should I pay the extra & get the NGK PFR7B?

Desicion's desicion's!!!
Old 07 February 2010, 04:01 PM
  #7  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

Get the 7Bs and gap to 0.7mm...

Trending Topics

Old 07 February 2010, 04:03 PM
  #8  
gra2730
Scooby Regular
Thread Starter
iTrader: (1)
 
gra2730's Avatar
 
Join Date: Jun 2009
Location: Somerset
Posts: 355
Likes: 0
Received 0 Likes on 0 Posts
Default

Cheer's chap, will have to stump up a few more readies then!!!
Old 07 February 2010, 04:20 PM
  #9  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

Originally Posted by gra2730
Cheer's chap, will have to stump up a few more readies then!!!
That's the beauty of the 7s over the 6s - they're all but the same price! Check on eBay - should be able to get 4 brand new boxed jobbies for a tad over £30 delivered.......
Old 07 February 2010, 09:36 PM
  #10  
gra2730
Scooby Regular
Thread Starter
iTrader: (1)
 
gra2730's Avatar
 
Join Date: Jun 2009
Location: Somerset
Posts: 355
Likes: 0
Received 0 Likes on 0 Posts
Default

I looked these up PFR78 4853, are these the right one's or are they just for the sti/wrx, seem's to be a bit of confusion when asked?

Sorry about all the question's!!!
Old 07 February 2010, 09:45 PM
  #11  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

You sure that's an 8 and not a B after the 7?

If it's not a B then they're not the ones we're discussing. Defo PFR7B...
Old 09 February 2010, 06:29 PM
  #12  
gra2730
Scooby Regular
Thread Starter
iTrader: (1)
 
gra2730's Avatar
 
Join Date: Jun 2009
Location: Somerset
Posts: 355
Likes: 0
Received 0 Likes on 0 Posts
Default

Yes they are a b, having a funny 5 minute's, think it was your avatar putting me off!!!
Old 09 April 2010, 08:38 PM
  #13  
nickparry62
Scooby Newbie
 
nickparry62's Avatar
 
Join Date: Apr 2010
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default

I have a wrx 53 plate. just bought new plugs pfr6b 's . someone told me that the plugs can be changed from underneath. is that nonsense, as there is a vid on You tube of some one taking off the wiper washer bottle and the air filter box, then changing from above!
Could someone advise me please!! Also, what is the gap size, it is a standard 2.0 wrx turbo

Many Thanks

Nick
Old 01 January 2012, 01:09 PM
  #14  
Baz82
Scooby Regular
 
Baz82's Avatar
 
Join Date: Apr 2010
Location: Dublin,Ireland
Posts: 641
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by nickparry62
I have a wrx 53 plate. just bought new plugs pfr6b 's . someone told me that the plugs can be changed from underneath. is that nonsense, as there is a vid on You tube of some one taking off the wiper washer bottle and the air filter box, then changing from above!
Could someone advise me please!! Also, what is the gap size, it is a standard 2.0 wrx turbo

Many Thanks

Nick

Yeah change them from above
Old 01 January 2012, 06:45 PM
  #15  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

lol at the time elapsed 'twixt Q and A!
Old 01 January 2012, 07:48 PM
  #16  
carlosWRX
Scooby Regular
 
carlosWRX's Avatar
 
Join Date: Jan 2010
Posts: 95
Likes: 0
Received 0 Likes on 0 Posts
Default

Still a useful thread though - i changed my plugs this afternoon on a 55 plate WRX.
The Subaru manual says NGK6G (not 6B) so i used those gapped to 0.7mm.

Took me 2 hours - i took off the battery and washer bottle on passenger side, then air filter box on the driver side.

A great set of instructions (with pics) is here:
http://www.subaru-impreza.org/forum/...s-classic.html

The Youtube vid is here:
http://www.youtube.com/watch?v=DgwA2BdLJwA

Carl
Old 11 January 2012, 04:32 PM
  #17  
ray555
Scooby Regular
 
ray555's Avatar
 
Join Date: Dec 2009
Posts: 30
Likes: 0
Received 0 Likes on 0 Posts
Default

What is the spark plug gap on a 1.8 impreza cheers
Old 11 January 2012, 10:37 PM
  #18  
99jdee
Scooby Regular
 
99jdee's Avatar
 
Join Date: May 2011
Location: United Kingdom, Bedfordshire
Posts: 460
Likes: 0
Received 0 Likes on 0 Posts
Default

4 inches... lol joke
Old 12 January 2012, 04:58 AM
  #19  
ray555
Scooby Regular
 
ray555's Avatar
 
Join Date: Dec 2009
Posts: 30
Likes: 0
Received 0 Likes on 0 Posts
Default

Hahaha very funny if you don't no the answer don't dick about it might only be a 1.8 but its still a scooby and needs the plugs changing so if anybody can help with out Being a dick please do
Old 12 January 2012, 02:58 PM
  #20  
99jdee
Scooby Regular
 
99jdee's Avatar
 
Join Date: May 2011
Location: United Kingdom, Bedfordshire
Posts: 460
Likes: 0
Received 0 Likes on 0 Posts
Default

It was a joke, I'll say what I want mate.. can anyone please help Mr. Serious here?
Old 12 January 2012, 03:01 PM
  #21  
99jdee
Scooby Regular
 
99jdee's Avatar
 
Join Date: May 2011
Location: United Kingdom, Bedfordshire
Posts: 460
Likes: 0
Received 0 Likes on 0 Posts
Default

Why don't you try and Google OEM impreza plugs look up the info or just type impreza 1.8 plug gap??? Lol I bet I could find you the answer in seconds but am on a mobile atm so can't...
Old 12 January 2012, 03:24 PM
  #22  
ray555
Scooby Regular
 
ray555's Avatar
 
Join Date: Dec 2009
Posts: 30
Likes: 0
Received 0 Likes on 0 Posts
Default

Iv tried google and it says 0.044 but that's on American sites iv got a full set of feeler gauges and it hasn't got a 0.044
Old 12 January 2012, 04:02 PM
  #23  
Gambit
Scooby Regular
iTrader: (6)
 
Gambit's Avatar
 
Join Date: May 2003
Location: Belfast
Posts: 3,294
Received 236 Likes on 176 Posts
Default

Originally Posted by ray555
Iv tried google and it says 0.044 but that's on American sites iv got a full set of feeler gauges and it hasn't got a 0.044
thats imperial measurements, im assuming you have a metric set, so just convert it
Old 12 January 2012, 06:36 PM
  #24  
joz8968
Scooby Regular
iTrader: (13)
 
joz8968's Avatar
 
Join Date: Aug 2006
Location: Leicester
Posts: 23,761
Likes: 0
Received 8 Likes on 6 Posts
Default

As Gambit says, it's imperial i.e. "thou" (thousandths of an inch).

For the metric equivalent:-

0.044" (or 4 thou) = 1.12mm.


Wow, that's large lol

Last edited by joz8968; 12 January 2012 at 06:38 PM.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
FuZzBoM
Wheels, Tyres & Brakes
16
04 October 2015 09:49 PM
thunder8
General Technical
0
01 October 2015 09:13 PM
IAN WR1
ScoobyNet General
8
28 September 2015 08:14 PM
Sub-Subaru
General Technical
1
28 September 2015 12:47 PM
shorty87
Other Marques
0
25 September 2015 08:52 PM



Quick Reply: What size spark plug gap???



All times are GMT +1. The time now is 11:11 AM.