Side gapped spark plugs

Information and discussion of EFI hardware and specifications
Post Reply
L67PSI
Posts: 177
Joined: Mon Dec 12, 2016 11:27 am
cars: L67 VT Calais

Side gapped spark plugs

Post by L67PSI »

Hi all,

I saw the idea online of side gapped spark plugs and thought I'd give it a go on my VT supercharged L67. Today I removed the plugs to fit new ones, anyway here is a pic of one that I removed. It's approx 6 months old and gapped to 1.1mm on a 45 degree angle from the center electrode to ground strap. I noticed that the center electrode has slowly started to wear on the edge. With these installed it ran smooth and no issues under boost.

Has anyone else tried this? Also any comments on the plugs condition?
Side_gapped_NGK.jpg
Side_gapped_NGK.jpg (92.46 KiB) Viewed 6388 times
User avatar
The1
Posts: 4694
Joined: Mon Jan 04, 2010 10:23 am

Re: Side gapped spark plugs

Post by The1 »

Youl find the plug centre and strap will wear quickly, performance won't be any better only worse as you've reduced the surface area where spark can arc from. Obviously your coils are upto the task if you've not seen any more knock introduced, from testing I've done the only better design that creates more consistent spark is the v groove, which adds slightly more surface area again
User avatar
delcowizzid
Posts: 5493
Joined: Sat Feb 28, 2009 8:38 pm
Location: Wellington NZ
Contact:

Re: Side gapped spark plugs

Post by delcowizzid »

Yeah one would expect side gapped to be going bad in a shorter amount of time with only a third of the centre electrode surface used and a third of the ground electrode surface used to produce spark probably clever marketing by manufacturer really lol
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem
User avatar
festy
Posts: 1039
Joined: Sat Apr 30, 2011 6:27 pm
cars: Alfa Romeos
Location: Narellan, NSW

Re: Side gapped spark plugs

Post by festy »

My alfas and bike all use OEM 'side gapped' plugs, although I usually run single ground plugs in the alfas because the OEMs are about $30 each :oops:

Advantages are that you don't have to index the plugs on hot motors, better plug life and less sensitive to voltage (more forgiving on gap).
You'd lose most of the advantages with a single ground side gapped plug though.

These two plugs have plenty of miles on them, but wear looks minimal and even.
side.jpg
side.jpg (155.3 KiB) Viewed 6282 times
GL.jpg
GL.jpg (101.97 KiB) Viewed 6282 times
NGK-R.jpg
NGK-R.jpg (75.42 KiB) Viewed 6282 times
User avatar
vlad01
Posts: 7780
Joined: Mon Oct 08, 2012 6:41 pm
cars: VP I S
VP I executive
VP II executive
VP II executive #2
VR II executive
Location: Kyneton, Vic

Re: Side gapped spark plugs

Post by vlad01 »

I've used those multi electrode bosch ones before. They were shite
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
User avatar
delcowizzid
Posts: 5493
Joined: Sat Feb 28, 2009 8:38 pm
Location: Wellington NZ
Contact:

Re: Side gapped spark plugs

Post by delcowizzid »

Nothing beats a standard copper plug lol
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem
User avatar
vlad01
Posts: 7780
Joined: Mon Oct 08, 2012 6:41 pm
cars: VP I S
VP I executive
VP II executive
VP II executive #2
VR II executive
Location: Kyneton, Vic

Re: Side gapped spark plugs

Post by vlad01 »

genuine Nippon denso GM plugs ftw!
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
User avatar
festy
Posts: 1039
Joined: Sat Apr 30, 2011 6:27 pm
cars: Alfa Romeos
Location: Narellan, NSW

Re: Side gapped spark plugs

Post by festy »

delcowizzid wrote:Nothing beats a standard copper plug lol
Big valves and high lift cams beat them pretty badly in some hemispheric combustion chambers :comp:
p1.jpg
p1.jpg (88 KiB) Viewed 6265 times
p2.jpg
p2.jpg (50.55 KiB) Viewed 6265 times
Obviously no one style of plug works best in all engines.
User avatar
vlad01
Posts: 7780
Joined: Mon Oct 08, 2012 6:41 pm
cars: VP I S
VP I executive
VP II executive
VP II executive #2
VR II executive
Location: Kyneton, Vic

Re: Side gapped spark plugs

Post by vlad01 »

Thats the builders fault, not the plug.

I don't see how its possible for the valves to do that, looks like the pistons was contacting the plug.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
User avatar
festy
Posts: 1039
Joined: Sat Apr 30, 2011 6:27 pm
cars: Alfa Romeos
Location: Narellan, NSW

Re: Side gapped spark plugs

Post by festy »

No, that's using the wrong length plugs on a well built head.
Trust me, it's a thing.
Post Reply