Jump to content

Recommended Posts

Just a quick question before I buy them.

Having got a bit disillusioned with NGK  plugs (they don't seem to last too long), I thought I'd try Champion. Moss currently list L87YCC as the Champion plug, but they appear to be out of stock across all suppliers, including Moss. My question, is L87YC, which is listed by some suppliers as an alternative, a suitable replacement. My TR3 as a standard engine not enhanced in anyway.

Rob

Link to post
Share on other sites

I'm intrigued by the comments about NGK. Are these genuine plugs( fakes seem very common)? I haven't had problems, but reading on here many do seem to be changing their allegiance.

Iain

 

 

Edited by iain
Link to post
Share on other sites

Iain People are too tempted to buy cheap off of Ebay . NGK are fine if you get genuine ones, as an Alternative why not get Nippon Denso, I ran them for years in my previous Volvo and they would do intergalactic mileage without any bother.

Stuart.

Link to post
Share on other sites

I have been using NGK BP7HS with 32 thou gap ever since the car went back on the road in 1993.

Never had a problem with plugs, but I purchase solely through the man who re-built the car - down on the Somerset levels.

Ian Cornish

Link to post
Share on other sites

Rob, L87YC are a suitable and often used alternative to the Champion 101/11s. Genuine NGK should be fine and perhaps one of the best OEM options. 

You may want to investigate your problem further... the polarity of the HT lead. The spark should be negative with respect to the engine block irrespective of the battery polarity.

A minefield of a subject but if a positive-earth car has been converted to negative earth then the coil should have been changed to ensure the plug leads are negative. (swapping CB/SW contacts round fixes it but introduces other problems). There is a simple test using a graphite pencil that will help you confirm what you have. The link below is to an excellent article on the subject. Potentially a reduction of 25% 'ish spark intensity and depletion of the electrode if it is wrong. 

Plug leads are critical and another technical minefield, I got some expensive ones from RTR and never looked back!

Regards, Mike

https://mgaguru.com/mgtech/ignition/ig104.htm

 

Link to post
Share on other sites

There are reports of problems of short life even with genuine new spark plugs. The story goes like this:

At some point the process of glazing the centre porcelain insulator was altered. This makes no difference for modern cars with computer-controlled fuelling which never allows the engine to flood.

Older cars with carburettor systems are less well controlled though and may flood during starting, particularly if the car hasn't been used for some time.  If these 'new' plugs get wet the insulator becomes contaminated in some way and the process may be progressive, shortening the life of the plug. 

The plugs cannot be recovered to normal operation even when fully dried out or using the usual cleaning methods.

https://www.gsparkplug.com/shop/fouling-shortingout-problem-modern-plugs-champion-vs-ngk/

Link to post
Share on other sites

Thats been a thing for years, hence use old plugs for first fire up of a rebuilt engine or carbs or injection system until youve got it all tuned correctly then fit the new plugs. Once theyve been used for a bit they will be fine.

Stuart.

Link to post
Share on other sites

Interesting part about not sand blasting the plugs to clean them.  I have been doing that for many years, & have not had a problem ?

Bob.

Link to post
Share on other sites

You may want to investigate your problem further... the polarity of the HT lead. The spark should be negative with respect to the engine block irrespective of the battery polarity.

A minefield of a subject but if a positive-earth car has been converted to negative earth then the coil should have been changed to ensure the plug leads are negative. (swapping CB/SW contacts round fixes it but introduces other problems). There is a simple test using a graphite pencil that will help you confirm what you have. The link below is to an excellent article on the subject. Potentially a reduction of 25% 'ish spark intensity and depletion of the electrode if it is wrong. 

Mike

Thanks for your post re the above. I have read the article and it's very interesting. However, my car is still positive earth and additionally I have a CSI fully electronic distributor fitted along with a Lucas DB105 sports coil. The two leads from the CSI, blue and black, must be fitted correctly or the CSI will be destroyed  (manufacturers words). The blue lead goes to ignition and the black lead to the coil - terminal. A separate lead goes from the coil + terminal to earth. The CSI distributor is set up by the manufacturer for positive or negative earth and you state which one you want before purchase. I understand the point on polarity but given my set-up I don't think this is my problem.

The Green Spark Plug company has been mentioned a couple of times and when you use their spark plug finder e.g. Triumph TR3 1957, up comes about three options one of which is Champion L82C not L87YCC or L87YC! Interestingly, the original 'Service Instruction Manual' specifies Champion L10S for normal running and L11S for high speed motoring. If you use the GSP finder and type in L10S, it will come up, but state 'out of stock'. However, if you click on alternatives, again about three choices, one of which is L82C not L87YC or L87YCC . So why do suppliers i.e Moss etc specify Champion L87YCC or NGK BP6HS? Is it that the recommended plugs are very close together in terms of performance i.e. hot/cold etc.

On a related issue, which is the best way to clean a plug? I use a bronze wire brush to clean the around the electrode. Should they be cleaned at all? can the efficiency of the plug be damaged by wire brushing it - is this my issue?

Rob

 

Link to post
Share on other sites
On 5/28/2020 at 12:14 PM, RobTR3 said:

 

Mike

Thanks for your post re the above. I have read the article and it's very interesting. However, my car is still positive earth and additionally I have a CSI fully electronic distributor fitted along with a Lucas DB105 sports coil. 

Rob

 

Grasping at straws here, but could the Sports coil be the cause of your problem. As I understand it these are to provide a bigger spark for tuned engines with high compression. A bigger spark will cause more eroding of the spark plug electrodes. I was advised to use a standard coil when I bought the electronic distributor and coil for my car.

Ralph

Link to post
Share on other sites

Ralph

Conflicting advice it seems. The manufacturer advised on the type of coil with two suggestions - the Lucas DB105 and a Bosch. The reason they gave was that the CSI required a high output coil to run efficiently.

Rob

Link to post
Share on other sites

Further to the post from Ralph and my reply, just a thought, would a hotter plug suit better? I note the post from Ian who has been using BP7HS, which I assume is a hotter plug. Also, I use a high octane petrol - Esso Supreme with a Castrol petrol additive which increases the octane level. Does this combination affect spark plug performance?

Rob

Link to post
Share on other sites
On 5/30/2020 at 8:02 AM, Ralph Whitaker said:

Grasping at straws here, but could the Sports coil be the cause of your problem. As I understand it these are to provide a bigger spark for tuned engines with high compression. A bigger spark will cause more eroding of the spark plug electrodes. I was advised to use a standard coil when I bought the electronic distributor and coil for my car.

Ralph

Now I think about it, Powersparks do 2 types of electronic units and one does need a "sports" type coil with a resistance of less than 1.5 ohms, the ordinary module uses a standard coil with greater than 1.5 ohms.

By the way, exactly why do the plugs fail, is it burnt out electrodes or do they just short out through the insulators and start misfiring. I have the latter problem on my A35 Van (with tuned MG engine) if I leave the choke on too long it wets a plug and no amount of cleaning/ drying out will get it working again, and I have had this with NGK and Champion. I prefer to buy Champion plugs where possible( now made in France), as there are known to be a lot of fake NGK plugs about.

Edited by Ralph Whitaker
Additional thoughts
Link to post
Share on other sites

Ralph

I often check the plugs to check the colour re mixture level and I clean them each time with a bronze cleaning brush. The last time I took the car out it was fine until I got home and when idling before I put it in the garage it started missing and running rough, never had that before. Once it cooled off I examined the plugs - all were blackish with No 1 worse. I cleaned them up and fired the engine and it ran smoothly, I haven't taken it out since. It seems as if the plugs, after successive cleaning and me fine tuning mixtures, give up the ghost and are not as robust as when first installed. As you say, no amount of cleaning is sufficient to restore them 100%. It's not as if they are old, only bought them a few months ago. I'll try Champion plugs shortly, L82C, and leave well alone for a while in terms of checking them over and see how I get on with them. 

Link to post
Share on other sites

I wonder about that bronze cleaning brush.  Bronze is pretty soft and it is possible it is leaving particles behind on the un-glazed insulator nose. If that builds up each time you clean them, it might account for the rapid failures? 

 

Link to post
Share on other sites

'I wonder about that bronze cleaning brush.  Bronze is pretty soft and it is possible it is leaving particles behind on the un-glazed insulator nose. If that builds up each time you clean them, it might account for the rapid failures?'

 

You could well be right Rob, I half suspect I am cleaning them too much, hence I'm leaving their replacements well alone as far as possible.

Rob 

Link to post
Share on other sites

If my car is running ok I don’t touch the plugs all year.

Link to post
Share on other sites

You might enjoy this......NGK poster on my barn wall for about 35 years. (Courtesy of Father in Law who ran a light machinery repair business from here for a few years.)
 

C4B2D526-56DE-4EC2-B708-F30645CA071E.jpeg

Edited by iain
Link to post
Share on other sites
9 hours ago, Hamish said:

If my car is running ok I don’t touch the plugs all year.

+1  mine go untouched from one year to next.    

Then........

What's wrong with sand blasting them.?

Did a roaring trade as an apprentice when I worked in the grit blast  and process dept.  Tanner a plug including vapour trichloroethalene  degreasing and masking plus regapped to 0.025"  Give them to me at shift start and all were done by lunchtime.  

Peter W

Edited by BlueTR3A-5EKT
Link to post
Share on other sites
  • 3 months later...

What octane do people normally run?  I have been running Petro Canada 94 until I found out that it has ethanol in it.  :angry: Another stupid assumption on my part.  Just switched to Shell 91.  hopefully it will get rid of the occasional backfire.  Timing is fine and the plugs are clean.

 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.