The Number One Club for owners of Triumph's range of small saloons from the 1960s and 1970s.
https://forum.triumphdolomite.co.uk/
According to the sticker under the bonnet N12Y, but currently running NGK BP5ES as there seems to be a shortage of N12Y at the moment.Magenta Auto Sprint wrote: ↑Tue Jul 04, 2023 10:22 am Are N12Y the correct plug? I thought they should be N9yc
Correct !! N12Y are for a dolly 1850 and have a different 19mm reach, the correct plug is N9YC for a 1300 dollyMagenta Auto Sprint wrote: ↑Tue Jul 04, 2023 10:22 am Are N12Y the correct plug? I thought they should be N9yc
, is it the correct sticker ? the correct NGK for a 1500/1300 are BPR6ESIn the supplement section at the rear of the Haynes Toledo and Dolomite 1300 manual it says " Later models inc Dolomite Champion N12Y" Also says N12Y in the back of the original 1300/1500 Handbook.mahony wrote: ↑Tue Jul 04, 2023 1:56 pmCorrect !! N12Y are for a dolly 1850 and have a different 19mm reach, the correct plug is N9YC for a 1300 dollyMagenta Auto Sprint wrote: ↑Tue Jul 04, 2023 10:22 am Are N12Y the correct plug? I thought they should be N9yc
The above is correct for Champion plugs, however NGK are the opposite confusingly, the lower the number the higher the heat range, or to be more precise, the hotter the plugs run. Example, my TR3 kept fouling the plugs, usually at the most inconvenient times, a change from BP6HS to BP5HS cured it completely, as the hotter running plug burned the deposits off.marshman wrote: ↑Wed Jul 05, 2023 10:17 am The number on the spark plug code refers to the heat range - the bigger the number the higher the heat range. The ideal heat range depends on the state of tune of the engine. Years ago when I had a Standard 8 with a 948cc (SC) engine fitted with twin carbs etc. I ended up using N3 plugs in place of the "standard" N9Y's (I tried N5's first) as I had skimmed the head and upped the compression ratio and had issues with pre ignition as the plugs were running too hot.
Is it possible the change from "9" to "12" on the Dolomites was in response to tweaks to the engines for emissions purposes?
I bought 4 N12Y from Abingdon Parts for Triumph earlier this week, so they have stock...Ralph wrote: ↑Tue Jul 04, 2023 1:11 pmAccording to the sticker under the bonnet N12Y, but currently running NGK BP5ES as there seems to be a shortage of N12Y at the moment.Magenta Auto Sprint wrote: ↑Tue Jul 04, 2023 10:22 am Are N12Y the correct plug? I thought they should be N9yc
Ralph
Yes, I should have mentioned it was Champion I was referring to. As with most things every manufacturer has their own numbering system, sometimes I think they do things the opposite of other manufacturers just to confuse usRalph wrote: ↑Wed Jul 05, 2023 1:51 pmThe above is correct for Champion plugs, however NGK are the opposite confusingly, the lower the number the higher the heat range, or to be more precise, the hotter the plugs run. Example, my TR3 kept fouling the plugs, usually at the most inconvenient times, a change from BP6HS to BP5HS cured it completely, as the hotter running plug burned the deposits off.marshman wrote: ↑Wed Jul 05, 2023 10:17 am The number on the spark plug code refers to the heat range - the bigger the number the higher the heat range. The ideal heat range depends on the state of tune of the engine. Years ago when I had a Standard 8 with a 948cc (SC) engine fitted with twin carbs etc. I ended up using N3 plugs in place of the "standard" N9Y's (I tried N5's first) as I had skimmed the head and upped the compression ratio and had issues with pre ignition as the plugs were running too hot.
Is it possible the change from "9" to "12" on the Dolomites was in response to tweaks to the engines for emissions purposes?
I am sure it was probably due to chasing emissions that incurred the change of plug.
Ralph
See chart at https://www.ngk.com.au/technical_info/heat-range/
OK, I fitted the ABF needle to the dolly, with no other adjustments or modifications, and on a short 5 mile test run it seems transformed. It no longer feels like it is holding back when setting off from standstill, and revs quicker and more cleanly. Pulling away in 2nd is now easily done where I wouldn`t have risked it before, and where it used to run out of steam at 55mph, it now romps to over 60 easily. Also, although early to tell yet, it seems to have lost the occasional missfire, or hiccup it had when cruising.Ralph wrote: ↑Fri Jun 30, 2023 7:45 amSingle carb, plugs are white, no exhaust smoke, using Esso super (no ethanol where I am), engine is sweet having only done 15,00 from new.yorkshire_spam wrote: ↑Thu Jun 29, 2023 2:38 pm What colour are the plugs after a good run?
Single or twin carb?
Any signs of general engine health? (Exhaust smoke?) Ever had/done a compression test?
What fuel are you running on?
I have been doing a bit of research on Burlens website, and between 1976 and 1980 there were 3 different carburettor needles , all spring needles. All get progressively weaker when you compare their profiles on a needle chart.
All the carbs for the Dolly were "waxstat" jet types, that weaken the mixture even more as they heat up.
1976-77 used ABF needles
1977-78 used ADM needles which were much leaner on the first half but actually slightly richer towards full throttle.
1978-80 used ADQ needles which were pretty much the same as ADM at low throttle openings, but weaker at the top end.
Given that my plugs are N12Y which are running white, it is fairly clear to me that the set up on my 1979 car is running extremely weak and the ADQ needles should be the ones in my car. As a quick experiment therefore I have ordered an ABF needle from Burlens which is an easy swap and will see if that makes a difference. I know it will increase fuel consumption, but it might restore some Va Va Voom.
Ralph
None of the brakes are binding guaranteed, but thanks for the suggestion.DoloWIGHTY wrote: ↑Sat Aug 12, 2023 10:54 am Before looking under the bonnet I'd be checking that none of the brakes are binding.