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JimG

Tr4 Spark Plug And Indexing Poll For Full Race Spec Motor

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Gentlemen

 

I was curious as to what spark plugs everybody runs and favorite gaps.

 

I’m playing around with index washers now and opinions seem to vary on that subject.

 

It’s been said that it’s best to index the plugs facing the exhaust valve, between the valves and toward the

 

intake valve. Lots of opinions on that subject.

 

Any comments ?

 

 

 

Thanks,

 

jim g

post-995-0-40620400-1310838121_thumb.jpg

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As you've said, opinions vary.

 

That's because chambers vary, engines vary, quench zones vary and most of the people doing the talking are selling magazines. Myself, I don't think it matters enough to fret over and it would take a well tuned dyno to note a difference. I'd much rather spend my time finding the optimum timing marks for my engine on modern fuels.

 

But that's just me....whistling.gif

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Ok, my 2 cents worth.

 

I have found (by accident initially) that the small 4 cyl Triumphs and 6 cyl Triumphs seem to like the triple electrode style plug. These aren't particularly intended as a performance plg - it's a long life thing. However, you get what is, in effect, a side electrode plug with the spark open to the chamber and not shrouded behind the electrode.

 

I got some abuse for suggesting this on the TR forum, but then I also got a couple of PMs from people who actually tried them and found it made a positive difference. Certainly easier than indexing plugs!

 

I always used to use the Bosch plug listed for the Mk2/Mk3 VW Golf GTI 8v although these are now NLA. NGK also do them - got some in the PI and they seem to work ok.

 

Cheers

 

Nick

 

Edit: And that's a nasty case of detonation you have there - hope the plug was the only casualty!

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Ok, my 2 cents worth.

 

I have found (by accident initially) that the small 4 cyl Triumphs and 6 cyl Triumphs seem to like the triple electrode style plug. These aren't particularly intended as a performance plg - it's a long life thing. However, you get what is, in effect, a side electrode plug with the spark open to the chamber and not shrouded behind the electrode.

 

I got some abuse for suggesting this on the TR forum, but then I also got a couple of PMs from people who actually tried them and found it made a positive difference. Certainly easier than indexing plugs!

 

I always used to use the Bosch plug listed for the Mk2/Mk3 VW Golf GTI 8v although these are now NLA. NGK also do them - got some in the PI and they seem to work ok.

 

Cheers

 

Nick

 

Edit: And that's a nasty case of detonation you have there - hope the plug was the only casualty!

 

 

Nick,

That wasn't my plug, I just came across the picture while researching plug reading.

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Ok, my 2 cents worth.

 

I have found (by accident initially) that the small 4 cyl Triumphs and 6 cyl Triumphs seem to like the triple electrode style plug. These aren't particularly intended as a performance plg - it's a long life thing. However, you get what is, in effect, a side electrode plug with the spark open to the chamber and not shrouded behind the electrode.

 

I got some abuse for suggesting this on the TR forum, but then I also got a couple of PMs from people who actually tried them and found it made a positive difference. Certainly easier than indexing plugs!

 

I always used to use the Bosch plug listed for the Mk2/Mk3 VW Golf GTI 8v although these are now NLA. NGK also do them - got some in the PI and they seem to work ok.

 

Cheers

 

Nick

 

Edit: And that's a nasty case of detonation you have there - hope the plug was the only casualty!

 

 

 

Nick— have you got a part number?

 

Makes a lot of sense— a modern plug probably works best with our modern ignition?

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Just use the right grade of NGK plug.

 

Have listed them before.

 

Indexing plugs?? it's for nuts!

Any good engine, makes a fat lot of difference what oil you use, what plugs you use, what fuel you use, just gives good power.

Nothing complicated, just put together right.

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