Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: BDA on Tuesday,March 13, 2018, 04:27:49 PM
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I've been running 7 heat range NGK plugs and the engine seemed to run pretty well. Not perfect but it idled pretty smoothly at 1000 rpm, accelerated pretty well, (though it occasionally stumbled a little from a stop but not much), and ran smoothly up to 6000.
Then I let it idle for about 15 - 20 minutes while I talked to my neighbor. I finished talking and drove into the garage. The next morning, I went to take it out and it was soon pretty obvious that I had some fouled plugs so I drove for quite a while at elevated rpm (4000 - 5000). This used to clear it out when I used to run colder plugs but it didn't clear up this time. I took a look at the plugs and the front two were the ones that fouled so it's pretty clear to me that I have some work to do on that carb, but in the meantime I'm looking at buying warmer plugs. (Or should I try to clean them?) I found some 6 heat range plugs but the hex is 5/8 rather than 13/16. Is there any reason why I shouldn't use the smaller hex plugs (Seems like it shouldn't matter but just making sure).
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I recently installed ngk iridium plugs bpr7eix. They fouled very quickly. I now use champion n7y plugs and don’ have a problem with fouling. They are a lot cheaper as well.
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One man's plug is another man's poison.
There are a lot of counterfeit NGK spark plugs out there. Make sure you buy from a reputable supplier.
Fuel formulations vary from location to location so different issues can arise. Tune your carbs with a air/fuel gauge matched to a wide-band O2 sensor. The odd fuels we run these days do not colour plugs the same way as they used to. Then use the heat range recommended and go up or down no more than one heat range if needed.
Got a wild cam? Run it hard? Then you will have to run colder plugs and watch you don't idle it too long. Ask any Lamborghini Miura owner, they know the drill.
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Never let your engine idle too long! I use NGK BP6ES plugs in my Weber carb twin Cam Engines. I used to use Bosch RO 102, but they are only good for constant high rpm use. They foul way too quickly for street use.
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Thanks guys! Ordered warmer plugs, will play with the carbs when I get them and watch the idling.
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I find NGK 7s just a bit too hard, both in Elan and Europa TC.
6s are just right. Road use only, mind you.
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Thanks, Roger. I have 6s on their way.
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Ngk bp6es are the plugs to use in my opinion for normal use and for tune up to 150 bhp. For hard use I’d go hotter or more specialised.
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Hard use = more full throttle = more heat = a colder plug.
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Running 2 stroke motorbikes was the learning curve to me in my younger days on plugs.
Running around town and they’d foul up. A good thrash and they’d misfire. Always had sets of different heat ranges from 6 to 9... and nothing other than ngk
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jb - Yeah, I don't track or even autocross my car. As I said, I had been running 8s with minor issues. I had a panic stop and the plugs got fuel fouled. The moderator at sidedraft central suggested going one or two ranges warmer. I ran 7s with no known issues till I had the problem I mentioned above. When I get my 6s, I'll look at the carbs and will surely end up leaning out the front carb and might enrich the rear - the 3 & 4 plug were nice and clean with a hint of brown color on the insulator.
buzzer - I can imagine a 2 cycle bike would make plug selection a challenge.
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I have to agree 7's have always been problematic, since I changed to NGK BP6ES in both the Elan and Europa I've had no more problems
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Oy, this is all news to me. I thought sparkplugs were sparkplugs. Guess I have some reading to do.
Question: I am going to be installing electronic ignition with a Pertronix "Flamethrower" coil. Would a high power coil affect my choice in sparkplugs?
What about the type of fuel used wrt sparkplug choices? (A pilot friend offered to hook me up with some avgas, but I imagine I'll be stuck with pump-premium at some point.)
Sounds like the consensus is NGK 6, barring extenuating circumstances. Every day a new lesson.
Tom
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I’ve got electronic ignition in my cars. Don’t use av gas. Your better off tuning for high octane pump gas (93 if available). Unless your racing only (auto cross does not count as racing) no sense in using av gas. (I’m sure I’ll get rained on for this comment. Fair warning I’m an ex-track guy with lots of experience with fuel mixtures and blown engines).
“AvGas is short for Aviation Gasoline. AvGas is of interest to motoring enthusiasts because of its availability, octane rating and low price compared to commercial race fuels. AvGas might seem an obvious choice but closer study raises some doubt.
AvGas LL100 stands for "Low Lead 100 Octane". TEL (Tetra-ethyl-lead) is added to raise the octane. When used in a motor vehicle this fuel will leave a lot of lead deposits in the motor. 100LL has a high lead content (0.5 grams per litre), even higher than leaded race fuels. The deposits left when TEL(lead) is burned are corrosive and damaging to valves, valve guides, valve seats and cylinder heads. Lead deposits will also block oxygen(lambda) sensors and catalytic converters and foul spark plugs even after only a short use. Also, 100LL has a chemical package added to make it perform at high altitude, and that isn't the best thing for motor vehicle performance here on the ground.
AvGas is blended for large-bore, long-stroke, low RPM engines which run at high altitude. While AvGas' higher octane is useful, smaller-bore, shorter-stroke, high RPM engines will perform better on racing fuel or high quality octane boosters. AvGas has lower volatility so when used in proportions higher than about 40%, part-throttle drivability and cold starts may be compromised. AvGas has a lower specific gravity so it will require a change in air-fuel ratio calibration for the engine to perform at its best. LL100 is blended with a high percentage of aromatics causing reduced throttle response which is not an issue with an aircraft engine but certainly an issue in a high-performance automotive engine. These high levels of aromatics will also damage rubber components in automotive fuel systems such as fuel lines, fuel pump seals and injector washers.”
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The temperature range of the plug is a rating of how quickly it conducts heat from the plug to the water jacket. If the electrodes get too hot - or rather if the heat isn't conducted quickly enough, the hot electrode can ignite the fuel-air mixture causing pre-ignition. As JB said, if you run hard - high rpms - you'd want a cooler plug because there is less time to dissipate the heat. On the other hand, the plug has to retain a certain amount of heat to burn away oil or excess fuel so if you don't run your motor hard and your plugs are too cool, you'll get fouling like I did. All this is with the engine in otherwise good tune.
It seems that if you're using NGK, you'd probably want the 6 heat range like the rest of us. The ignition system shouldn't matter. BTW - I have a Petronix setup in my car, too. They're great!
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Like I said, every day is a lesson. Certified's observations about avgas just saved me my valves and about $2/gallon of fuel. I will revisit this discussion when I do my Himalayan Europa/Lycoming conversion (kidding!). Thanks BDA for the solid advice.
Surf
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Everyday is a lesson for me too! There are a lot really sharp people here. I appreciate them all!
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Yup, +1 on not using aviation fuels. They are not formulated for auto engines at all. Besides, lead is nasty stuff. It’s good it’s not in wide use anymore. Much as we rag about today’s fuels, deservedly so in some cases, it sure burns a lot cleaner than the “good” stuff we had in the 60s.
Unless you are seriously racing, just tune to whatever no/low-ethanol, high-octane fuel you can moderately easily access. I run over 10:1 compression on pump fuel.
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Thanks for the lesson on av gas, Mr Certified. A very interesting commentary, indeed.
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Rejuvenating this thread because I had a recent experience that might help folks.
Having the single aim to save money, I bought some NGK plugs from a seller on ebay (quickdog-autopart at a very good price). Sometime later, I remembered that counterfeit plugs were a potential problem so I bought another set from a local Advance Auto Parts store figuring that whether or not the ebay plugs were conterfeit, I'd at least have one good set of plugs and if they were counterfeit, then I should be able to get some sort of refund.
I looked at several sites and videos explaining all the ways to tell if an NGK plug is counterfeit. No doubt some are valid such as poor printing quality on the insulator but many probably were not such as printing on the box. The ebay plugs had some possible evidence of being counterfeit and quickdog-autopart is based in China where most of the counterfeit plugs come from (whoda thunk!). but I didn't feel certain enough to accuse someone of selling fakes so I called NGK tech support (in the US: 877-473-6767; I expect there is a similar number for other countries). The NGK lady asked me the lot number stamped on the hex of the plug and my lot numbers were good. "Is the lot number determinative?" I asked. "Yes", she said. I asked her about some of my other concerns, for example:
The picture of the spark plug on the box has a blue cast to it where other NGK boxes were more true to color.
The box says they are made in Japan but the plugs had a stamping that it was made in the US with Japanese parts.
The ground electrode had an angle to it where some said it was supposed to be a curved piece.
She said none of that mattered. For example the boxes were printed in Japan and the plugs were made in the US.
So I dodged a bullet. The ebay seller had sold me genuine NGK plugs at a VERY good price. Would I buy from him again? I don't know. He was certainly honest with me so I have no reason to believe that he wouldn't be honest in the future. On the other hand, I might figure the extra price I paid at Advance Auto would be worth not having to worry about them at all.
If you got your plugs at Amazon or ebay (counterfeits are commonly bought from them) and you have any concerns, I strongly advise you to call NGK at the number I gave above. The websites and videos that try to explain how to tell a fake are well meaning but they are not a substitute for finding out directly from NGK.
Be careful! A counterfeit plug can cause a lot of very expensive damage to your engine - especially if your drive your baby hard.
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Wow, I didn't know people made counterfeit sparkplugs :o
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I was surprised when I found out too. I would have expected that the cost of manufacturing fake plugs that looked like real plugs would not be enough less to make sense to a crook but I was apparently wrong.
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I run Bosch W5DP plugs in my Renault crossflow. They work very well in situations where you want a cold plug for high speed and are having fouling problems when bumbling along. I used to use them in high-hp Healey engines as well.
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I gradually migrated to NGK 6 heat range. That's pretty warm compared to the Bosch 5s you're running (according to the heat range cross reference chart I have - see attachment), but it is what most of the Elan folks seem to use. They seem to work pretty well but as warm as they are, they still seem to foul. Maybe the Bosch is a bit more flexible in the heat range department then the NGK. It might be worth a shot.
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The W5DP plugs are special platinum plugs designed for the early Porsche Turbo. They are not cheap, usually $35 a plug.
Since you know your NGK plug is good for high speed work, why not try an iridium version? I have used them successfully in hopped-up 2 stroke engines.
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If I’m tight enough to buy plugs on eBay, I think I’ll pass on the $35 plugs!
Yep, the NGKs I’m using are iridium. My BDA takes the same plugs as the TC. In case anybody’s interested I’m using BKR6EIX.