Andrew Smith Posted May 31, 2019 Report Share Posted May 31, 2019 I understand the generally preferred plug for TR5/6s is the NGK BP6ES, but note the BP5ES is specifically for use in lead free head - VUX's head is gas-flowed and unleaded. Anyone using the BP5ES and notice any benefits over the BP6ES? Cheers, Andrew Quote Link to post Share on other sites
barkerwilliams Posted May 31, 2019 Report Share Posted May 31, 2019 Andrew, I used BP6ES and noticed the two plugs 5 & 6 were running blacker than 1-4. I checked the mixture and butterfly opening to no avail then I fitted 5 & 6 with BP5ES (hotter) now I get a better colour match over all plugs. Probably due to reduced air flow down to the end of the original inlet plenum. So my answer is both! Alan Quote Link to post Share on other sites
Andrew Smith Posted May 31, 2019 Author Report Share Posted May 31, 2019 Thanks Alan, a useful observation. Cheers, Andrew Quote Link to post Share on other sites
GT6M Posted May 31, 2019 Report Share Posted May 31, 2019 5s will be ok for anything but race use used em for yonks, as said, better colour than colder plugs in normal drive Alan says Probably due to reduced air flow down to the end of the original inlet plenum. ..this is why ye all need a small KnN type filter at end oft log as a RR session yonks ago showed, rear cyl was not same trace on screen as other plugs try the 3 or 4 pronged type quite a few say they run better, me own seems to after I got right grade meb,e something t,doo wid spark coming out of end,not being hidden by electrode!! Quote Link to post Share on other sites
Steves_TR6 Posted May 31, 2019 Report Share Posted May 31, 2019 I’m trying the tripple electrode Bosch w7dtc this year after quite a bit of research. i do have spares in stock Andrew if you’d like a set :-) steve Quote Link to post Share on other sites
Kevo_6 Posted May 31, 2019 Report Share Posted May 31, 2019 (edited) I bought a couple of bp5es to go in numbers 5&6 but still not got round to doing it, also nearly bought a set of the Bosch ones Steve has mentioned but my concern was gapping them correctly as I think they come as 40th but I may be wrong with that. Let us all know how you get on with them Steve. Edited May 31, 2019 by Kevo_6 Quote Link to post Share on other sites
Mike C Posted May 31, 2019 Report Share Posted May 31, 2019 Over the years I've tried both BP5ES and BP6ES plugs but had problems with fouling and hard starting after a few hundred miles . After a fair bit of research I switched to NGK BUR 6ET triple electrode plugs and the fouling and starting problems have gone away. Quote Link to post Share on other sites
Tom Fremont Posted May 31, 2019 Report Share Posted May 31, 2019 Those are both hot plugs, and the BP6ES works well in the U.S. market applications, grey colour on my stock TR250 engine long ago. When I tried them with my CP spec engine with Weber DCOEs they ran white. So I've been using BP7ES since the 1900s. These get changed out at 30K miles whether they need it or not. Apart from LUCAS P.I. equipped TR5/6 fast road engines I'm told the 7s are the favourites. From what I've seen on this forum the P.I. cars do better with hotter plugs. The above issue about #s 5&6 is a recurring theme too. Some have fattened the plenum to 4" in an effort to correct this. Cheers, Tom Quote Link to post Share on other sites
DRD Posted May 31, 2019 Report Share Posted May 31, 2019 24 minutes ago, Tom Fremont said: Those are both hot plugs, and the BP6ES works well in the U.S. market applications, grey colour on my stock TR250 engine long ago. When I tried them with my CP spec engine with Weber DCOEs they ran white. So I've been using BP7ES since the 1900s. These get changed out at 30K miles whether they need it or not. Apart from LUCAS P.I. equipped TR5/6 fast road engines I'm told the 7s are the favourites. From what I've seen on this forum the P.I. cars do better with hotter plugs. The above issue about #s 5&6 is a recurring theme too. Some have fattened the plenum to 4" in an effort to correct this. Cheers, Tom Hi Tom, what compression ratio are you running on the Weber engined car. Is it a Stage 2 type head? Cheers Daz Quote Link to post Share on other sites
Tom Fremont Posted May 31, 2019 Report Share Posted May 31, 2019 (edited) 49 minutes ago, DRD said: Hi Tom, what compression ratio are you running on the Weber engined car. Is it a Stage 2 type head? Cheers Daz Hi Daz, I'm not versed on " Stage XYZ " heads, but one of my BP7ES equipped engines with CP cam has 9.5:1 c/r and the other has 10.7:1 with high lift ( 0.504" ) / 282 degree duration cam. Heads are both Racetorations produce ( caveat emptor! ). The [ dated ] information I have is that the 7s correlated to Champion N9Y and the 6s correlated to Champion N12Y, specified for TR5/6 P.I. and TR250/6 carb respectively, by TRIUMPH. So my experience amounts to " going by the book ". Cheers, Tom Edited May 31, 2019 by Tom Fremont Quote Link to post Share on other sites
DRD Posted May 31, 2019 Report Share Posted May 31, 2019 Tom - a Stage 2 head is basically gas flowed and ported with slightly larger valves. Mine is approx a CR of 9.75. Daz Quote Link to post Share on other sites
AndyR100 Posted May 31, 2019 Report Share Posted May 31, 2019 My memory may be fooling me, but I think BP5es would equate to an N12Y, a BP6es (being a bit colder) would probably be an N9Y. your BP7’s would be cooler still, so an N7 in Champion ...... Andy Quote Link to post Share on other sites
Tom Fremont Posted May 31, 2019 Report Share Posted May 31, 2019 I ran stock '250s from 1976 to 2004 using Champion N12Y, Autolite 55 and by 1990 NGK BP6ES, all giving the same colour. I used Bosch once or twice but don't remember the model; I would have cited N12Y Champion as a cross reference. The proper correlation between NGK and Champion is the question, and at the end of the day the colour ought to govern the choice. Tom Quote Link to post Share on other sites
Andrew Smith Posted June 1, 2019 Author Report Share Posted June 1, 2019 Thanks for the feedback folks, very useful. Steve - thanks for the offer, although I'll wait until you've tried them and see what you think. Cheers, Andrew Quote Link to post Share on other sites
AarhusTr6 Posted June 1, 2019 Report Share Posted June 1, 2019 Hi If you use the function to fit your car on the NGK web site mine comes up with NGK 6637 BPR6EIX IX Iridium Plug (which I have and are a bit sooty). I there a guide to what all the numbers etc mean? I am easily confused ;-) Rich Quote Link to post Share on other sites
AndyR100 Posted June 1, 2019 Report Share Posted June 1, 2019 6 hours ago, AarhusTr6 said: I there a guide to what all the numbers etc mean? I am easily confused ;-) I have used this one for a while, there are probably others, hope it helps ..... Andy Quote Link to post Share on other sites
JochemsTR Posted June 2, 2019 Report Share Posted June 2, 2019 not wanting to ruin the NGK debate...but is no one using Bosch? I am driving 4-point WR78X. Someone once noted such 4-point plugs are a better fit for an engine such as ours... Jochem Quote Link to post Share on other sites
AarhusTr6 Posted June 2, 2019 Report Share Posted June 2, 2019 Looks good Andy, all I need do now is understand whats best for my engine :-) Rich Quote Link to post Share on other sites
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