Autolite Spark Plugs

[swamper]

Bought the Autolite Spark Plugs for my dual plug 2004. After searching the forum here I bought the primary 3923 and secondary 4164 plugs. During the search for these Autolite numbers there wasn't any confirmation about the recommended gap size. What are you guys gaping the Autolites at?

[AZBMWRIDER]

There's a thread on plug gaps a bit down on this page .

[swamper]

Doesn't cover the autolite plugs.

[kirby]

OK take this for what its worth to you personally.

Sparkplug companys go to great length these days to ship new plugs gaped at the optimum performance for the plug as tested by the plug company. The plug is protected by the cardboard tubes and if they are damaged it could mean that the gap could be damaged as well.

I run NGK and Bosh specified by BMW and in 300K miles on oil heads (not to mention other motos I have never changed the gap from the gap that it came out of the box with. (I do check that it has not been damaged.

That's all I have and will not debate the subject...do what you think you must.

Spark plugs ain't what they used to be.

BTW if you run a non specified plug your on your own anyway.

[swamper]

I understand what your saying however I'd like to check. Autolite plugs don't come with the protective tube covering the end.

[kirby]

If not damaged I would run what ever they are, compare them and see if they are all the same or very close..that will most likely be what autolite considers correct or go to their(autolite's web site) and see what they recommend.

I'm not trying to burn you here but I think your over thinking this matter. Why autolite anyway...cost? I usually change my plugs once a year or about every 18K miles or so and they come out looking like they could run another 18. I have a truck that has the original plugs with 150K.

Modern ign system will fire about anything as long as there is a gap.

All I have, good luck.

[swamper]

Napa had the Autolites in stock. Bike has never had the plugs changed from new, 24,000 miles. Just thought it might be a good idea to change them.

[kirby]

Yes quite right!

Actually if the engine is running properly as in not missing and fuel mileage is still where it should be (normal) starts OK, then why change them. If cost is a factor. The proper plugs are just a internet visit away.

??

[Tundra Dweller]

Considering multiple vehicle applications for a given spark plug the gap should be set to the vehicle specifications...IMHO.
Consider all the different factors of ignition systems, cylinder head configurations, compression ratios etc.
I set the Autolites for my 2002 R per the manual to .031”. Out of the box they were gapped much farther than that.

[kirby]

They will still work fine at a higher gap. Having said that if you buy the plugs specified by BMW they will have the correct gap from the factory.
.031 is for the proper NGK or Bosh.
Having never seen the autolite we are talking about I'd bet the gap form the factory will be opt. for that plug, from lawn mowers to Autos.

Like I have stated, I have never changed the gap out of the box in 100s of thousands of miles unless it was obviously damaged. That's why it a good idea to use what the manufacturer specifies. This is very important in terms of heat range (especially air cooled high compression engines, Much more than gap. Gap is unlikely to burn a piston or destroy the plug.

Forgive me but this is getting like an oil thread, plug gap is not rocket science these days of precise manufacturing techniques they come from the factory very close to opt. for that plug #.

In the old days you HAD to check gap.

My .02c

[swamper]

I'm an old guy.

I'm looking forward to a 8,000 mile trip this summer on the R1150R, so preventive maintenance is my basic thought changing the plugs. Towerworker seems to have a good track record using Autolite plugs and they are available at most auto-parts stores.

[kirby]

I'm with you!
On a 5,000 mile one now.

Ask him what he gaps. The heat range must not be out of line as he hasn't burnt anything. But remember this is a guy (Mr. Towerman) that uses antifreeze in his moto!

Hope you have a great trip.

:-)

[swamper]

So here what I found out while trying to install the new Autolite plugs.
The Autolite for the Primary switches out without problem. The secondary plug, Autolite 4164 is 11/16 which is larger than the tool kit socket. A normal spark plug 11/16" socket will not go down into the area around where the spark plug goes. So the secondary Autolite 4164 is a no go. I'm going to find the standard NGK BKR7EKC and Bosch YR6LDE and return the Autolites. Should have listened to Kirby

[kirby]

Probably a wise choice.
The engine designers usually pick two different brands( plug company(s)) to make a plug for BMW in this case in the heat range requested/desired by BMW.
The plug company then produces the plug, testes it and THEY (plug co) specify the gap for optimum performance. Then BMW conducts their on tests and consults w/plug co.
When autolite produces a plug they will send it to you at the optimum gap. If you change it from that, your on your own, but that doesn't mean its a show stopper, it just means that your running a plug at some gap other than the tested optimum.
I probably couldn't not tell the difference so does it matter? probably not. Single electrode plugs tend to have a higher gap than twin electrode.

I personally from experience prefer to stick with the manufacturer's spec. I sometime wonder if the different plugs effect the life of the stick coils. I have always used the NGK or Bosch specified by BMW and have never had a stick coil fail. Only had them miss fire at near red line one time.(1) didn't fail, ran fine except full load max rpm.

Over 250K miles so far.
'04 R1150R
.



I get mine online. https://www.euromotoelectrics.com/

[swamper]

Thanks Kirby, I've placed an order at euromotoelectrics for both the NGK and Bosch plugs. My old plugs were showing a lot of miles.

[kirby]

They have always been a good source for me, glad to hear it! When you get them you can put the wire feeler in there and I'd bet they will be real close or spot on. the BMW manual allows .04 tolerance. Ha!

cheers.

[towerworker]

I heard my name mentioned. I still run the 3923P (platinum) but like some have found the 4164 plug wrench will not fit in the plug tunnel. But the plug gap I've run is .032 +/- Runs good with no issues. I'm using the BMW recommended secondary plugs.

The Autolite plugs were discovered to help with the surging issues found in the earlier single spark models. Not sure who was the first to discover this. I ran them in my '03 and it did help. The twin spark model came out in '04. Supposedly one of the twin spark benefits was to help with surging. I've never experienced any surging with mine. Currently have just under 90K.

[swamper]

Thanks for the info TW. I did put the Autolite primary plug in our 2002 and it does get rid of the surging for awhile, about 8,000 miles if I recall right. We started on that bike changing the Autolite plugs (3923) every other oil change, works out good. Hadn't thought about trying the Platinum ones.

[Hyja1]

l also run spec NGKs. I have a pair of autolites but never installed them. I remember early on when everyone was complaining about surging, so I picked up the autolites. But then I never had any surging issues so I’ve been staying with stock plugs. The only issue I have is cold starts but I keep up the revs until she’s warm and I’m good.