How to install spark plug ?
 

Wayne's book said the set the gap of the plug before installing it.

I'm putting in new plugs. Do I need to do anything prior to installing it? How do I find out what gap I need to set it to? And how to do that?

Thanks...

Here's a good link
http://www.ehow.com/ehow/ehowDetails.jsp?index=1105&id=110

The gap should be in a service manual, the owner's manual, or possibly even on a sticker somewhere near the engine. Someone from the board may even post it for you. What sort of plugs are you going to use, certain plugs require a little more care than others when gapping (like Bosche platinum) because instead of a large metal center electrode they have a thin wire in the center of a porcelain insulator and the platinum wire can easily be damaged.

I am using the factory recommended Bosch W3DPO so sounds like I have the fragile plugs then :(

You know, I think the copper plugs will still work better in your car than the platinum ones. In water cooled cars, in a fairly narrow but high temperature range, platinum has nice self-cleaning properties. But in our cars, copper actually works better. YMMV.

Gapping tools are cheap cheap cheap, on the counter of your favorite auto parts store. If you install plugs without one, just look carefully at all six. They are gapped at the factory, so really you're just looking to see if one has been damaged, or is different from the others. If they all look the same, install them.

And finally, the torque spec for spark plugs is about 18 lb/ft. That's the force it takes to crush the crush-washer at the base of the plug. When you feel that washer get crushed, you're done. Do not overtighten. The factory toolkit spark plug tool works best.

Thank you guys... will run out to get the tool tonight.

Superman,

I have heard the same suggestion as well - platinum is good for water cooled cars but not air cooled. But my limited research didn't return any useful alternative so I thought I'll bite the bullet this time & go with the expensive ones again.

Are you running with copper plugs but at the same temp range as factory recommended?

are you planning to use anti-sieze?????????

no - per Wayne's book & factory recommendation

Yes, I run copper plugs, but mine is not a 930. Your mileage may vary. Anti-sieze or no, just don't overtorque, or undertorque, spark plugs. The heads they screw into are aluminum. The proper torque spec is achieved just when the crush washer is finished crushing.

I think the expensive Bosch platinum plugs for the Turbo's are a different (better) animal than the $2 platinums use on 911's.
-Chris

Sometimes I have to use two "crushies' to get the plugs indexed just right. :)

Does the "book" cover indexing??

Don't forget to get the "boot" down onto the #6 plug ( rigth side, front). Its a pain, but if you don't water etc gets down in there and can corrode the connector.

"Sometimes I have to use two "crushies' to get the plugs indexed just right. "

Using two spark plug gaskets may inhibit heat transfer from the plug to the cylinder head and thus change the heat range.

Don't the indexing kits include thicker spacers to position the plug electrodes?

Sherwood

Also, when gapping them, DO NOT do so by leaving the feeler gauge in and tapping it to the right height. You will damage the electrode.

:eek: I used to do it that way. Have not done the 911 yet. What is the proper procedure??

There is bending/gap check tool available from Bosch.

Good God. It's time to change my plugs. I opened the hood and it looks like a nightmare to get at the plugs. I see why you guys pull the A/C...I could use the extra room right now. Any other tips on getting to these things?

I know that it is possible to do all the plugs without moving the AC (did it several times). The pipe on the left side is a no-brainer.
Biggest tip: get the factory tool!!! It works great and you won't drop a plug or extension.
Second biggest tip: go easy on putting in the new plugs because a cross-threaded plug is a nightmare. If you feel resistance, pull out the plug and start over.

I never heard of that!!! Indexing washer vs. squishy - a material heat transfer difference?? Is that just your personal theory or do you have some test data to back that up??

Guys have been using extra squishies for years if washers aren't available!!!

No test data, just something I read.

Do you have any data showing there is no difference other than some folks have been doing this for years?

I also used the term, "may inhibit heat transfer..." so as not to appear to be an expert in this matter.

In fact, the power increase from indexing spark plugs may be negligible in most engines and very minor in others. There I go, using that "may" word again.

Sherwood

Too many "opinions" and "theory" on this board. Most it it hyping non existent or theoretical problems with no practical experience or data to support it
I have never seen a problem or difference from using two type of washers. Unless your plugs are beveled!!! LOL!!!

If you have seen a problem - state it and when and how and document it.

Otherwise be clear that this is just your opinion and you have no facts to back it up.

Plug Indexing
 

Years ago I was at a tech session hosted by a shop that maintains a lot of Porche race cars. Someone asked the owner of the shop about spark plug indexing. He said words to the effect "If you stand on a ladder so you are closer to the Sun you are probably warmer but it would you notice the difference?"
-Chris

" If you have seen a problem - state it and when and how and document it."

Tsuter,
Do we now have to footnote and reference sources when we give an opinion? Must I have at-the-ready various books by Smith, Ricardo, VanValkenberg, etc. whenever I open my mouth here?

Accept or reject opinions on this forum for what they are and who they're from. If you think something sounds like BS, you can say so. It's the internet after all. That's your/anybody's prerogative. BTW, shouldn't you also produce evidence and sources you so firmly suggest? You might find collaborating evidence of your position on the Edelbrock or Car Craft websites. I think even the two guys on the "Two Guys Garage" show found more power from this technique once upon a time.

Another BTW. When I say I read about it somewhere. I meant from a reputable (I think) source or sources; not necessarily from what Hot Rod Magazine says or from a glossy 4-color brochure. While some or even many folks might choose to invest in an assortment of spark plug washers, I'll probably pass on the add'l dyno time it takes to rotate the spark plugs searching for those last few ponies.

JMHO,
Sherwood

OK... then I reject this opinion as unfounded and baseless.

heat transfer ignition problems - a squishy washer vs an indexing washer. Jeeeez!!!

Newbs actually read some of this rubbish and as a result they park their cars in their garage and clean the heat exchangers. :eek:

Dang, you mean that I did all that cleaning for nothing?!

How often do you guys change your plugs? 101 Projects says every 10,000 miles...but they are in the business of selling parts so I cant take their word on it... I had heard previously, every 25,000-30 anyone know?

I pull mine with every oil change. If everything looks OK, replace after 10-20k depending on your faith in the plug. Copper plugs are cheap so 10k is decent.

Please bear with me here. I recently bought a lawn mower with a Honda GXV 160 engine. If I'm not mistaken, it has an aluminum head, as does the Porsche air cooled engine. My greatest fear in changing plugs in my POrsche is that I overtorque, stripping the threads in the head, aluminum being softer metal than the steel of the spark plug. The following quote from the lawn mower
engine manual: "When installing a new spark plug, tighten 1/2 turn after the spark plug seats to compress the washer. When reinstalling the original spark plug, tighten 1/8-1/4 turn after the spark plug seats to compress the washer."
My question: Considering that it's damned tough to get a torque wrench in there when changing plugs on a 911 engine, do you guys think this "rule of thumb" would work well on a 911 engine?
Wayne? Pro wrenches? Anybody? Thoughts please...
:confused:

Tip for starting plugs.
Use a piece of rubber fuel line that will fit over the end (tip) of the plug.
The fuel line allows for enough flex so you don't cross thread the plugs.
The plugs should thread in finger tight until the washer makes contact with the head.
A 3 inch extension is too short and a 6 inch extension is too long so you will need a 1 inch extension and stack together. That seems to work.
These are Craftsman sizes.

1] I use the 1/2 turn as more as a baseline.. I developed a "feel" for the washer crushing, which is easy to do. Once the new plug bottoms out it's a consistant turning "feel" for the crushing. I think that maintaining the turn helps the "feel". A reg. hand size 3/8in rachet gives more control than a full size 1/2in rachet

2] reusing a washer is not as precise.. so it's a kinda snug enough "feel" without being over tight. and reusing a washer means the job is only good enough, not a very good..

all above is IMO

Paul -- Yes, I think that's fine. (BUt haven't you been tightening those plugs since 1972?) Also, ask Gamroth -- do they torque the plugs all the time?

- Randy

There was an article about plugs in Pano a couple of months ago. The guy got a few hp by indexing. Checked on a dyno and I believe it was about 5 hp. This was in a 944 and he said Bosche silver plugs gave a small bump also.

The 3 inch extension too short and 6 inch too long. Snap on has a 4 inch extension which seems to be just right. Of course the factory tool is still the best. Snap on, and I believe S&K have a disk shaped palm ratchet which works pretty good in the confined space for the #1 plug. I always seem to turn the back of my hand black and blue getting that one out and back in. That pointy little bracket near the plug well just beats me up!

Hi:

FWIW,..I've never seen any gains on the dyno by indexing plugs on the 911: single or double ignition. We use either Bosch Copper or Silver plugs....opening the gaps (.040) makes more HP and improves idle & drivability only IF you have a suitable ignition to support those.


Paul- Randy:

Nobody here uses a torque wrench on plugs; its all done by "feel. My suggestion for anybody who is not comfortable doing that yet would be aquire a junk 911 head and practice tightening plugs until one learns what it feels like to crush a new plug washer. You would also feel what a used plug washer feels like. Both feel very different and its an aquired skill.

Its really not difficult to learn. :)

The thing about performance tuning is you have ask yourself... "Would you do 20 things that each incrementally provides 1/2 of one percent improvemment?" None of which is "easily" discernable on a dyno - even just changes in operating temp affect the dyno record from one run to the next 60 seconds apart.

So heres' my advice:

If you're the tuner for appearance - keep cleaning those heat exchangers and polish those Fuchs!!

If you're the tuner for perfomance - don't do these small things either... that way I'll keep beating you on Saturday!! :)

Anybody sand down gaskets where they protrude slightly into the manifolds??? Intakes and exhaust??
Don't do that either OK!!!

The Snap-on is $18.00
What does the factory part cost?
Thanks!!

Cold engine. Screw the plug by hand until it seats. When the crush washer is crushing, you are just right at about exactly 18 lb/ft, so it would be okay to stop any time. When the crush washer finishes crushing the torque needed to turn the plug will rise sharply. DO NOT turn the plug any more. It's as simple as that.

I saw a factory plug wrench go on ebay not long ago for over 35$...that's where I stopped bidding. Craftsman 13/16 plug wrench and a 4" extension from snap-on is a less expensive combination.

the Hazet 2505-2 is a flex length plug socket..

Another option, tho a bit $pendy...it's middle setting matches the factory wrench, a 3/8" drive ratchet plugs right in...

http://www.samstagsales.com/images/hz2505-2.jpg

Yes, the plug should spin in with only easy finger pressure. If otherwise find the problem, usually it is dirty threads. The thread chasers are also appropriate for just cleaning. Make sure it is perfectly clean. When using a thread chaser, hook your vacuum up to the exhaust outlet in the “blow” mode. Make sure it isn’t blowing dirt and position the engine where only the exhaust valve is open on that cylinder. This tends to keep junk out of the cylinder.

There is the issue of the small terminal on the threaded end of the plug. All(?) 911 plug connectors need that terminal to be in place. Some plugs don’t come with a split lock washer. All plugs should have that terminal tightened significantly. I can’t tell you how many times I have seen that terminal off and the connector just rattling on the plug.

Another related issue with sparkplug change is cleanliness. If there is muck around the plug, it will be dragged onto the threads and into the cylinder. The muck can make it difficult or impossible to spin in the plug by hand and can deposit damaging stuff in the cylinder. Additionally it can fowl the plug sufficiently so it won’t fire.

I use aerosol “brake clean,” high pressure air, a 25c wash, and more air to clean around the plugs. I only change one plug at a time so I don’t force dirt into an adjacent open hole. A light and inspection mirror is worthwhile to insure nothing is around the plug.


Best,
Grady