Spark Plugs

[Mark Larmour]

Over the years we have used a special "racing" spark plug in our Sprint race cars. We were fortunate enough to have had a large supply of these items that have now been exhausted.<br>
<br>
I have been using a performance road spark plug, but recently been having problems in cold starting with the plugs failing to fire when cold and once they have been "over fuelled" that fail to clear and are then basically stuffed.<br>
<br>
I am interested to know what sort of spark plugs people are using in their race motors, Brand and spec, and if they are happy with their performance.<br>
<br>
Thanks<br>
<br>
Mark

<p><!--EZCODE LINK START--><a href="http://www.sprintparts.triumphowners.com">SPRINTPARTS</a><!--EZCODE LINK END--></p><i></i>

[gmsclassics]

Mark<br>
<br>
I've been using the same NGK BP7EFS plugs for about 2 years (20 race meetings) with no problems whatsoever. This is the second set that have been in this engine - I only changed them when I last did some work on the head, not because they failed. Always starts well and run up to 7000rpm.<br>
Having said that, I doubt that my engine is in quite the state of tune of yours.<br>
<br>
Geoff

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[MaddMart]

I've been using NGK BP7EFS in my track car (170 bhp, 8-10 trackdays) & have had no problems. I've also been using these for many years in my road Sprints with no problems.

<p>Martin<br>
<br>
<!--EZCODE LINK START--><a href="http://www.dolomitesprint.com/" target="top">www.dolomitesprint.com</a><!--EZCODE LINK END--></p><i></i>

[Stephen Grellet]

I have used Champion S52R retracted earth plugs for a number of years which are a very cold plug. I had no problems starting or running with these. However Champion recommend a retracted earth plug as a last resort(only when you are limited by piston clearance) I have now gone to Champion S57 and S59YC's. These are extended tip. As yet I havent raced the engine on these as I have just rebuilt it and am trying to get time to run it in. These are available from ERC in California Fax no 001 510 278 3571. Last price paid USD 3.27 each (very reasonable)<br>
<br>
Regds Stephen

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[Dolly racer 33]

Hi, I use the same as all the others. NGK BPR 7EFS. I tried a Bosch equivalent but they were no good. This is using 8,500 rev/min & CR of 11.3:1. (Going up next year).

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[ALG1K]

nippon denso IK31<br>
Best plug in the world <!--EZCODE EMOTICON START ;) --><img src=http://www.ezboard.com/intl/aenglish/im ... s/wink.gif ALT=";)"><!--EZCODE EMOTICON END--> <br>
I can rev to 9500 rpm <br>
and they can cope with an engine making 693 hp<br>
<!--EZCODE IMAGE START--><img src="http://img.photobucket.com/albums/0903/ ... <!--EZCODE IMAGE END-->

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