Lotus Elan

NGKBP6ES & BP7ES Plug Test

PostPost by: William2 » Mon Aug 22, 2016 11:25 am

On my rebuilt stock SE engine with Delortto carbs I started using NGK BP7ES plugs. After a long drive I checked the plug colour and found the centre electrode to be correct and the outer metal rim of the plug to be slightly sooty. I then did the same run using BP6ES plugs. This time the centre electrode was similar (grey/brown) but the outer rim was completely clean with no soot. Is it therefore better to stick with these plugs?
The engine idles and picks up with no hesitation so I assume the jetting, etc is fine.
William2
Fourth Gear
Fourth Gear
 
Posts: 943
Joined: 20 Jan 2013
Location: West Sussex

PostPost by: rgh0 » Mon Aug 22, 2016 11:59 am

BP6ES I have found best like you for a normal road twincam engine in normal mixed city / country road driving. BP7ES only really needed in a road car if doing lots of continuous high speed full throttle driving in places like German autobahns or the equivalent

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7513
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: ecamiel » Mon Aug 22, 2016 12:51 pm

what plugs are folks using for hot (160 HP) street motors on the street and for track events? Currently using BP6ES

Eric
64 S1 Hart
User avatar
ecamiel
Second Gear
Second Gear
 
Posts: 219
Joined: 02 Oct 2003
Location: Ct. USA

PostPost by: Paul Chapman » Mon Aug 22, 2016 1:46 pm

Hello William

I am also now using BP6ES plugs in my tired Twin Cam and it runs a lot better than when I used BP7ES's.
Paul
Paul Chapman
Second Gear
Second Gear
 
Posts: 117
Joined: 19 May 2009
Location: North Lincolnshire G.B.

PostPost by: terryp » Mon Aug 22, 2016 3:26 pm

My two old +2s both on Dellortos were definitely happier on BP6ES but the funny thing my current Elan with Strombergs prefers BP7ES, the BP6ES I had originally fitted becoming slightly over burnt.
I think it must be a case of fit and see.

Terry
terryp
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1666
Joined: 29 Nov 2007

PostPost by: HampshireMush » Tue Aug 23, 2016 7:19 am

My S4 SE with Strombergs, which has had some engine mods done by Oselli by a previous owner, came with BP5ES but kept fouling so after reviewing this forum I changed to 6's. Still was getting problems occasionally so had a regular routing of cleaning them. I met another owner at Brooklands one day and he suggested going back to 7's which is what is in the handbook.

I have been using 7's for several months now and they have been by a long way the best - no regular cleaning and engine has run fine hot and cold.



John
John

1969 Elan S4 SE
HampshireMush
Second Gear
Second Gear
 
Posts: 60
Joined: 22 Jun 2014
Location: Camberley, Surrey

PostPost by: Galwaylotus » Tue Aug 23, 2016 8:07 am

HampshireMush wrote:My S4 SE with Strombergs, which has had some engine mods done by Oselli by a previous owner, came with BP5ES but kept fouling so after reviewing this forum I changed to 6's. Still was getting problems occasionally so had a regular routing of cleaning them. I met another owner at Brooklands one day and he suggested going back to 7's which is what is in the handbook.

I have been using 7's for several months now and they have been by a long way the best - no regular cleaning and engine has run fine hot and cold.



John

There must have been something else at work there as BP5ES is a hotter plug than BP6 or BP7. If fouling was caused by too cold a plug then going to 6 or 7 would have made it worse. See NGK's explanation: http://www.ngk.com.au/spark-plugs/technical-information/heat-range-explanation
Mechanical Engineer, happily retired!

'67 S3 SE FHC

See Facebook page: W J Barry Photography

Put your money where your mouse is, click on "Support LotusElan.net" below.
User avatar
Galwaylotus
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1357
Joined: 01 May 2006
Location: Galway, Ireland

PostPost by: RogerFrench » Tue Aug 23, 2016 1:21 pm

I wonder if there's some confusion between different makes. NGK heat range numbers run the opposite way from Champion, for example.
Champion N7Y is equivalent to NGK BP7ES (roughly), but a NGK 5 burns hotter, a Champion 5 burns colder.

Also, Stromberg engines run a bit hotter than Weber or Dellorto, explaining Terry's findings.
1967 Elan S3
1972 Europa Twin Cam
2005 Elise
User avatar
RogerFrench
Fourth Gear
Fourth Gear
 
Posts: 619
Joined: 01 Dec 2009
Location: Richmond, TX

Total Online:

Users browsing this forum: mickmade, Pfreen and 11 guests