Spark plugs….

[Jonny TR6]

Having read up a lot on plugs I went for triple electrodes. Just been out for a blast and there was a lot of spluttering, hesitation etc.

I pulled the plugs and they were filthy - probably only 200 miles or so on them.

Please can someone give me a definitive plug that will work well with PI with electronic ignition and save my head spinning round even further with all the opinions.

Many thanks !

[Nigel Triumph]

If you want multi electrode, go for Bosch WR78 or NGK BUR6ET. Both have worked perfectly over thousands of miles in my CP series TR6 and my GT6.

Nigel

[Jonny TR6]

Got the BUR6ETs in at the moment. The timing was a bit out and I suspect they’ve been the victim of too much fuel and not enough air,  as the underslung throttle linkage needed some fiddling with to get it to tickover at 800rpm (had been 1200ish).

What’s the best way to resurrect the existing or should I just go with different plugs. I’ve read that the ETs don’t like too much fuel.
 

[andyb633]

i used to have problems with the BUR6ET plugs , they just never ran right so i tried the Bosch WR78 s and have never looked back . i am running lumenition magnetronic ignition .

[RobH]

12 minutes ago, Jonny TR6 said:

I’ve read that the ETs don’t like too much fuel.
 

If they have been fuel-soaked they are probably dead. Modern plugs have unglazed ceramic which gets contaminated and cannot be cleaned successfully once wetted, as the old ones could. (Cars with modern engine management do not over-fuel so the plugs are designed for that regime now).

You could try a hotter grade - 5 rather than 6 for NGKs. 

[Jonny TR6]

Useful knowledge Rob - BP5ES then ?

[Waldi]

If your plugs fouled after limited milage, I suspect the issue is elsewhere, ignition or more likely fuel related.

Waldi

[Mike C]

I've used BUR6ET's for years and found them excellent. If the plugs fouled after 200  miles I'm pretty sure you have a fuelling problem, and I'd start by making sure the fuel enrichment lever is not sticking and correctly adjusted.

Edited February 19, 2023 by Mike C

[Jonny TR6]

10 hours ago, Mike C said:

I've used BUR6ET's for years and found them excellent. If the plugs fouled after 200  miles I'm pretty sure you have a fuelling problem, and I'd start by making sure the fuel enrichment lever is not sticking and correctly adjusted.

I did have an issue in that the air bleed screw into the inlet manifold was screwed all the way in. This probably caused the plugs to foul initially.

BP5ESs on the way from Green Spark Plug Co - £14 delivered, so a cheap method of checking.

[astontr6]

On 2/19/2023 at 3:40 PM, RobH said:

If they have been fuel-soaked they are probably dead. Modern plugs have unglazed ceramic which gets contaminated and cannot be cleaned successfully once wetted, as the old ones could. (Cars with modern engine management do not over-fuel so the plugs are designed for that regime now).

You could try a hotter grade - 5 rather than 6 for NGKs. 

+1 I have always used grade 5 after having trouble with grade 6. Cylinders 5 & 6 have never given me trouble after switching to grade 5? Are you sure that your M/U does not need re-calibrating as it must be over fueling?

Bruce.

[alec]

Only buy spark plugs from a proven safe supplier many fakes on the market

[Steves_TR6]

1 hour ago, alec said:

Only buy spark plugs from a proven safe supplier many fakes on the market

Too right!

i spent ages trying to get an old honda motorcycle to run properly after a rebuild, turns out the ‘ngk’ plugs were useless fakes!

on the tr6 i use the Bosch multi electrode plugs and they have been in for years with no attention or trouble.

steve

[alec]

Yes I found out the hard way buying what I thought was a bargain on ebay

[Jonny TR6]

Bought the 5s from the Green Spark Plug co via their eBay site, as fully aware of fakes !

Will pop them in at the weekend, with my 9yr old helping and learning a bit of spannering and the basics of how an engine works.

Will also check the MU although it passes the vacuum suck test and was rebuilt 2,000 miles ago.

[Jonny TR6]

New plugs in and the car runs much much better. Pulls strongly and no coughing or hesitation and idles nicely.

The old plugs are in the bin.

[BlueTR3A-5EKT]

1 hour ago, Jonny TR6 said:

New plugs in and the car runs much much better. Pulls strongly and no coughing or hesitation and idles nicely.

The old plugs are in the bin.

We used to call old plugs ‘fishing weights’

[Paul Hig]

Been advised by an old hand (over 40 years with TRs) that NGK BPR6ES are best for a CP TR6. Anybody else use these?

[astontr6]

On 2/19/2023 at 3:40 PM, RobH said:

If they have been fuel-soaked they are probably dead. Modern plugs have unglazed ceramic which gets contaminated and cannot be cleaned successfully once wetted, as the old ones could. (Cars with modern engine management do not over-fuel so the plugs are designed for that regime now).

You could try a hotter grade - 5 rather than 6 for NGKs. 

I have used the hotter grade 5 for years it stopped 5 & 6 from becoming sooted up and did not affect 1 to 4 cylinders.

Bruce.

[Mk2 Chopper]

23 hours ago, astontr6 said:

I have used the hotter grade 5 for years it stopped 5 & 6 from becoming sooted up and did not affect 1 to 4 cylinders.

Bruce.

I use two 5's in 5 & 6 and 6's in 1 to 4, seems to be a good combination for my set up. 

Gareth

[KiwiTR6]

On 4/14/2023 at 3:37 AM, astontr6 said:

I have used the hotter grade 5 for years it stopped 5 & 6 from becoming sooted up and did not affect 1 to 4 cylinders.

Bruce.

After I disconnected the rocker cover vent from the intake manifold and fitted it with a small filter I found that cylinders 5 and 6 no longer sooted up.  This was based on a comment I has read on this forum suggesting that with the standard arrangement oil mist is drawn into the two rear cylinders causing this problem.  I'm convinced that the advice was indeed correct.

As a teen my dad was the local Triumph dealer in our town and from time to time he would ask me to take our PI sedan for a good thrash to clear the plugs from its mostly around town running.  Of course I never turned him down, and in hindsight it was probably this very same issue at play.

[Tom Fremont]

I've been using NGK BP7ES since the last century, over 140K miles on my '250s, one CP spec and the other with much more c/r and cam without issues. They get changed out every 30K miles whether they need it or not. These are gapped to 0.030" vs. the 0.025" as per factory.

Distributor has excellent points ( STANDARD brand ), yellow wire condenser, red rotor and copper( or brass ) contact cap with solid copper plug wires. Coil is LUCAS Sport type.

This is a cooler plug than any of those listed above...but then I don't have the LUCAS P.I. but Weber DCOEs instead. So this reference may be of little use or interest here!

[Tim D.]

3 minutes ago, Tom Fremont said:

I've been using NGK BP7ES since the last century, over 140K miles on my '250s, one CP spec and the other with much more c/r and cam without issues. They get changed out every 30K miles whether they need it or not. These are gapped to 0.030" vs. the 0.025" as per factory.

Distributor has excellent points ( STANDARD brand ), yellow wire condenser, red rotor and copper( or brass ) contact cap with solid copper plug wires. Coil is LUCAS Sport type.

This is a cooler plug than any of those listed above...but then I don't have the LUCAS P.I. but Weber DCOEs instead. So this reference may be of little use or interest here!

Suspect you do need slightly hotter plugs with lucas PI as they do tend to be set quite rich at idle to cover the lack of acceleration enrichment.