Lotus Elan

New plugs - amazing

PostPost by: john.p.clegg » Tue May 07, 2013 8:48 am

Time spent on the Lotus is a pleasure,and it certainly doesn't harm the plugs....

John :wink:
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PostPost by: richardcox_lotus » Tue May 07, 2013 11:14 am

I seem to clean my plugs quite often, as I always appear to be stuck in traffic these days...................

Must be time to move !!

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PostPost by: rgh0 » Tue May 07, 2013 11:18 am

I spent many years cleaning old plugs and at one stage had one of those mini plug sand blaster. Even then I ended up replacing the plugs half the time as they still performed poorly.

These days on my race engines I put in a new set of plugs about every 4 or 5 race meetings and don't have a problem. Beyond that time even if I inspect, clean and reset the gaps, I will start to have a high rpm misfire that is instantaneously fixed with new plugs. The exotic iridium / platinum racing plugs last longer but not the 10 times longer needed to justify the 10 times higher price as it is the insulation failing not the electrodes

On the road engines replacement time are less predictable but I tend to change them out after about 3 years. If I get the plugs badly wetted due to heavy fuel in the tank or carbs due to evaporation I find it difficult to get them back to running well after they are dry and cleaned, and again a set of new plugs at $20 fixes the problem. I have tried the exotic new long life plugs but these suffer from fouling damage as much as the standard $5 plugs and dont appear to last any longer despite their 5 times higher price in my road cars at least

A lot of road engines have tuning problems or oil fouling problems that mine don't have much of so I would expect a shorter life than the 3 years I get in a lot of road Elans given many run excessively rich and have excessive oil consumption down the inlet valve guides.

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PostPost by: PBrown60 » Tue May 07, 2013 9:30 pm

I have a very old pneumatic spark plug cleaner from my grandfather's auto shop, the thing is a beast but still works.
I found several inexpensive new ones using a google search
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PostPost by: ElanSeries2 » Wed May 08, 2013 12:23 pm

I used to work in an engine development team, and one of the guys was an ignition specialist, a real beardie expert on plugs, HT leads, coils, etc. I remember when I was very green, I asked about cleaning plugs... He was adamant that both electrodes needed to be clean, parallel and unscratched. The quality of the spark drops off quite quickly when these are not in place. He insisted that "cleaning" plugs using wire brushes or abrasives leaves scratches.

In addition, there are at least two different kinds of deposits/areas of deposits on plugs: 1) carbon deposits (which may be burned off during harder driving) and 2) chemical deposits, which can glaze the core nose. Once this has happened, you may get discharge across the nose rather than the gap to the electrode. You can't clean the glaze off the nose.

I did sit and watch him testing occasionally, but I can't pretend to understand or remember it all. But I was sufficiently convinced not to try cleaning plugs again.

However, I should say that I have a Champion technical briefing on spark plugs, where they state that the centre electrode can be "filed square" and the gap reset to "extend service life" - not clear whether they were recommending this as a service measure, or a short-term fix.
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PostPost by: alaric » Wed May 08, 2013 1:41 pm

Thanks Roger I'll check that. Back in the UK today so can get some parts easily.

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