that's the Hazet 2505-2

Steve,

I rarely tested sparkplug indexing because most 911 engines that I felt it might make a difference were race engines with recessed electrode. What engine-plug combinations have you tried.

A set of indexing solid soft copper gaskets costs less than $10 for a V8. They are good for three angles and with swapping plugs and some wet-sand you can get any position exactly.

Now I know this isn’t exactly compatible but for the past several years we have carefully indexed the plug on our shifter karts with measurable results. It may not be much on a 911 but if you are looking for that last …. Does anyone have input?

Best,
Grady

Ron's right...I should have opened my tool roll and looked at a number before typing. :rolleyes: Grady? Thanks for the tips...valuable info seems to come most often from guys who did it for a living...

As of this posting, 946 views and 46 postings. Wow! :eek:

Q: How many forum members does it take to install a spark plug? (With apologies to rattlsnak)

A:

1 to choose the plug.

1 to post that the plug has been selected.

14 to share similar experiences of selecting plugs and how the plugs could have been selected differently.

7 to caution about the dangers of selecting plug.

27 to point out spelling/grammar errors in posts about selecting plugs.

53 to flame the spell checkers.

6 to argue over whether it's "plug" or "ignitor"

Another 6 to condemn those 6 as anal-retentive.

2 industry professionals to inform the group that the proper term is "engine detontation initiator."

15 know-it-alls who claim they were in the industry, and that "plug" is perfectly correct.

156 to email the participants' ISPs complaining that they are in violation of their "acceptable use policy."

109 to post that this forum is not about plugs and to please take this discussion to a plug forum.

111 to defend the posting to this forum saying that we all use plugs and therefore the posts are relevant to this forum.

306 to debate which plug is superior, where to buy the best plug, what brand of plug works best for this technique and what brands are faulty.

27 to post URLs where one can see examples of different plugs.

14 to post that the URLs were posted incorrectly and then post the corrected URLs.

27 to post about links they found from the URLs that are relevant to this group which makes plugs relevant to this group.

33 to link all posts to date, quote them in their entirety including all headers and signatures, and add "Me too."

12 to post to the group that they will no longer post because they cannot handle the plug controversy.

19 to quote the "Me too's" to say "Me three."

4 to say "didn't we go through this a year ago?"

143 to say "do a search on 'plug' before posting questions about plug."

16 to say, "I sent you a private message about plug."

1 new forum member to respond to the original post 6 weeks from now to start it all over again.





:D :D :rolleyes:

http://www.pelicanparts.com/support/smileys/wat6.gif

Harry,

Yes, I agree.

Put 911 on rotisserie.
Insert sparkplug in head at proper angle.
Rotate 911 until plug gasket contacts head.
Carefully rotate 911 12.5 degrees to crush washer.
Reposition 911 on rotisserie for next sparkplug.
Post results.

Best,
Grady

so i thought it was a naive / innocent question that I raised... :(

But Grady, my engine is on a stand, so will definitely use the rotisserie method :) I'm sure it will come out evenly roasted, uh i mean, crushed (the washer that is).

Patrick,

No, it was not a naive / innocent question at all. You can see this from all the posts and good advice from Pelicans, my lame attempt at humor excepted.

Spark plugs on a 911 are a big deal. A first-timer can screw it up big time cross threading a plug and other. Even “pros” are not immune if they don’t know when to stop.

Tomorrow, I’ll go find some specific tools and offer more.

Best,
Grady

Hi Grady:

We tried several Champion and Bosch race plugs in our 3.0 & 3.5 litre RSR's as well as the 3.2 litre 935. I also did some dyno tests with 2.8, 3.2 and 3.5 litre race motors using "normal" plugs such as W2DC, W3DC and the like,...

The resolution of our engine dyno is 2 HP and I never measured any changes no matter which way the ground electrode was facing. I did see some changes when using single electrode plugs vs triple electrode plugs,....:)

Just my opinion, but I think opening the plug gaps pays FAR more dividends than fooling around with plug indexing washers in 911 engines.

I'd fully acknowledge that indexing makes a difference in wedge-shaped combustion chambers and it might also make a difference in 2-stroke engines depending on placement of transfer & booster ports.

My curiosity now extends to the Top Fuel crowd using twin-plug hemi engines,..... :)

One more thing, results must be posted with pictures of all positions on rotisserie with at least 3 different angles of each position.

Right-on as usual, Steve.
I found that out on several 2-stroke m/c roadracers.

Steve,

I wouldn’t have pursued the subject if there hadn’t been such a difference on our little 80 cc cylinder (Honda CR-80 2-stroke). We have four of those engines and in three years of racing went through more than 70 pistons. The NorCal kart guys know lots more than I ever will but it opened my eyes to indexing.

I agree; a fat spark makes up for a world of sins. The price you pay is shorter life on some ignition components and the necessity for a powerful CDI.

Perhaps we are looking at the wrong application. Could indexing make a difference with a high compression CIS engine with extended tip plugs? What about a nice 11:1 MFI 911S twin plug on the street?

Let’s keep talking this issue.

Best,
Grady

Grady, I just posted the indexing thing because I wanted to see the theoreticians with garage queens take a break from cleaning their heat exchangers and polishing their Fuchs and think they know something about performance tuning get going.... and get going they did. ! :)

Even heat transfer experts jumping in! LOL. Its like Thermo101 again!!

"I got another guy on another thread saying that if one of your six spark plug washers is a different type of metal from the other five it will adversely affect the hot cold properties of that plug and adversely affect ignition/detonation!!! I just think he's been riding a desk and thinking waaaayy too long!!!'
suitably referenced. I hope.

Tsuter,
I found your above statement while cruising another thread. I think you were referring to something I might have said on this thread. However, I failed to find where I claimed all this and it wasn't mentioned anywhere else.

For the most part (with some noted exceptions), I find your other posts measured and thoughtful. So what is your problem? Do you suffer from sporadic attacks of hyperbole?

Sherwood

BTW, Steve -- about how much hp (or torque?) increase can one expect from opening up the gaps to 040? And is a twin plugged (distributor) MSD set up an adequate ignition? As I recall from your web site, it would be....

Thx.

Hiya Grady:


You are right about the 2-stroke business,...they do improve by careful plug indexing and further, become a tad more resistant to plug fouling,..:)

Many years ago, I raced off-road motorcycles professionally (Husqvarna) with some Factory support and we did extensive modifications on those things. Given the cylinder swirl imposed by placement of the main & transfer ports, aiming the open plug gap and flame kernel resulted in measureably more HP and cleaner running.

I have not plug indexed any CIS engines with those swirl-inducing piston domes, but that might yield some modest improvements with extended reach plugs. Hemi chambers are SOOO lazy, tho...:) Perhaps someone here who is building a hot-rod CIS motor will mark their plugs and heads and go to the dyno.

Based on what I've done thus far, I do not think that an MFI'ed, high-compression, twin-plugged "S" motor will benefit from this.

Fun stuff, though,.......

Randy:

Depending on compression ratio and camshaft profile, you'd see around 6-10 HP with wider plug gaps and much improved idle. Mid and upper end HP & torque in better plus its a boost to drivability.

Any MSD (with its matching coils), twin-plugged or otherwise, will handle plug gaps up to .080 with ease,.... :) Its MORE than adequate.

My 5 cents:

Only reason that Porsche stopped using anti-sieze is the fact that it's techs kept smearing too much of it so it shorted/fourled the plugs.

I always change plugs on hot engine, use a little click of anti-sieze and torque it by hand to "no too much" -value.

Plug indexing can in theory give you a horspower or two but is generally not worth it. I never bothered to pre-gap the plugs. Always run NGK B8EGV and those platinum puppies (20$ a piece!! :( ) always worked right anyway.

tsuter,

<b>Bosch, NGK, and Champion publications have said for decades to NEVER use two washers on a spark plug ... and that doing so would impede heat transfer characteristics!!! Do you suppose their engineers did more than pontificate to come to that conclusion?</b>

Hi Steve

Do you recommend opening up plug gaps on a stock motor (say and early 2.0-2.4 MFI)? I know that many people do when running the MSD box but haven't heard of people doing this with a stock setup.

TIA

MSD instruction manual says..

"The gap of the plugs can be opened in .005 increments, then tested until the best performance is obtained"

So what are indexing washers??? Or are you just recommending to torque that plug on down until you get the right angle.... squishy be dammed?? That's OK too but you better be careful. You get maybe 20-40 degrees or so. :)

Oh ... and I know why Bosch, NGK, and Champion recommend never to use two.... do you??

Bosch also would never say its ok to use a diode with an N75 valve either!!! You say... what's a diode!!!

That's what performance tuning is all about. and it isn't OEM! :)

Well, just finished putting in new plugs. Not that bad. The Porsche tool helped greatly. The car runs great now.

I think mine is cross threaded!
 

My car may be why this topic has drawn so much interest. I went to change my plugs Thursday for the first time since I bought it and found plug # 6?? to not want to come out easily. I have done about 3 revolutions and it still is feeling pretty tight. I think the previous owners mechanic crosstreaded it in. I have left it 3 revolutions loose (or not so loose) and hooked up the spark plug wire. It is running fine. I was afraid to keep turning it until I'm at a shop in case I can't get the new one back in. Anyone else had this occur on a 911? Any words of wisdom?

Yes. It happens once in a while. Maybe a case of the steel spark plug and the aluminum threads in intimate contact due to electrolysis. Go to the anti-seize thread and see what they say.

Good move not going any further until you can get prof. help. Hope it's not too serious.

Sherwood

Seems like as a good a time as any to revive the topic of plug indexing! The best explanation I've seen of plug indexing is on the Automedia web page:

Indexing Spark Plugs.

"Generally speaking, the idea of indexing is to position the spark plug so that its gap is facing the center of the cylinder, angled slightly toward the exhaust valve—the most common arrangement. (Some engines work better with other gap locations.) This is important because, as the piston approaches TDC, the air/fuel charge is being compressed. The charge or "mixture" is being forced toward the area of the spark plug—and normally, the exhaust valve. The true speed of this force inside the combustion chamber is extremely fast. Some experts speculate that it surpasses supersonic speeds.

The shape of the combustion chamber, the shape of the piston dome, the type of ignition system, and a myriad of other variables influence the "location" of the spark plug in the cylinder head. Because of this, the spark generated from the plug should be in a "position" to create the best possible flame front. Looking at a typical side-gap spark plug, you'll note that the electrode can actually block the flame process. On the other hand, if the electrode gap faces the on-rushing air/fuel charge, it stands a much better chance of igniting a flame front ...

Real-world power gains vary. Some engines or combinations respond differently than others. In fact, all engines will pick up power, but some gains will be more dramatic than others.

In the end, it can't hurt to index the spark plugs. This can contribute to superior engine efficiency and improved economy."

P.S. +1 Old member to revive the thread! http://www.pelicanparts.com/support/smileys/wat6.gif

well put, David!

Best,

DSHEPP806