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E30325i
09-05-2004, 09:16 AM
My girlfriends father used to race 325's professionally, and he said by indexing plugs he got 10hp and 13lbft gains over just throwing in plugs any which way. Has anyone ever done this/knows how to do this?

swartz
09-05-2004, 12:24 PM
indexing???? gapping? diff heat range im confused?

nitro325is
09-05-2004, 05:38 PM
I think he means by installing the plug in a manner which the prong does not interfere with the combustion. This is why platinum 4 suck.I used to do it on my mustang idled better but doubt it got that much power even on a displacemetn of 5 liters.

Neo187H
09-06-2004, 03:03 AM
that would be a pain in the ass to do. no way you coud see gains of that much tho.

bimmerjim®
09-06-2004, 01:59 PM
you could see a few hp gain. iv seen a few big bloks make 5-10 more hp by doing that, but they have 4x the displacement as us.. :wink:

jason, indexing is where you mark the plug so you can see where the electrope points, then you put small shims under the spark plug where the washer goes to make it so when the plug is tight, the electrode is positioned so its pointing twards the center of the combustion chamber. it works well on non himispherical motors.

swartz
09-06-2004, 05:26 PM
never heard of it before....thanks jim for settin me straight

straight6
09-06-2004, 05:28 PM
Sounds interesting but don't our engines have a hemispherical combustion chamber anyway?

swartz
09-06-2004, 06:08 PM
na, cuz the spark plug comes in from the side? isnt a hemi when the spark plugs is in the top middle of the cly?

bimmerjim®
09-07-2004, 09:47 AM
your exzactly right jason. :D

JSF252
09-07-2004, 11:06 AM
Just to be technical, a "Hemi" or Hemispherical combustion chamber is a Hemi-sphere, or half of a sphere. I dont think you HAVE to put the spark plugs in the center, but that's the way it's typically done.

just my $.02
Josh

straight6
09-07-2004, 06:26 PM
I was thinking what Josh was but if you people say it needs a plug in the top then that's good enough info for me. :lol:

Teaguer
09-07-2004, 07:50 PM
jason, indexing is where you mark the plug so you can see where the electrope points, then you put small shims under the spark plug where the washer goes to make it so when the plug is tight, the electrode is positioned so its pointing twards the center of the combustion chamber. it works well on non himispherical motors.

Yeah , what he said . :withstupid:


Just to be technical, a "Hemi" or Hemispherical combustion chamber is a Hemi-sphere, or half of a sphere. I dont think you HAVE to put the spark plugs in the center, but that's the way it's typically done.

Exactly . :smt023

Giga Shadow
09-07-2004, 08:45 PM
So you mark the plug with like a market or somthing to know where to gap is pointing and put those little gaskets (shims) in to adjust the position of the gap?
Sound good.

Sombody should do this just to see. :lol:
I vote E30325i should do it since he brought it up.

E30325i
09-08-2004, 08:32 AM
I'll tackle it this weekend as tomorrow the cars getting a few adjutments and a new oil pan gasket and motor mounts (both snapped). I'll post details when I'm done. Granted I won't have accurate numbers as I don't have access to a dyno, but I'll butt dyno it as best i can. :lol:

Teaguer
09-08-2004, 09:25 AM
There is no doubt that it works and you should see gains .
Although the previously mentioned numbers of 10hp and 13tq seem a bit optimistic on our M20 engines .

bimmerjim®
09-08-2004, 11:48 AM
Just to be technical, a "Hemi" or Hemispherical combustion chamber is a Hemi-sphere, or half of a sphere. I dont think you HAVE to put the spark plugs in the center, but that's the way it's typically done.

just my $.02
Josh

actualy thats incorect, a hemispherical head has nothing to be shaped like a sphere, it only has to have the plug directly in the center, and vavles at opposinge angles. the combustion chamber itself can me rounded or v shaped.

http://abbysenior.com/mechanics/images/valve.10.jpg

screaming_bmwe30
09-08-2004, 12:27 PM
jimmy is right. It can be either cone shaped,hemispherically shaped, etc. as long as it has a REvolved shaped.

Chris
09-08-2004, 01:02 PM
FYI, that pic doesn't work.

bimmerjim®
09-08-2004, 03:32 PM
:smt102 works for me?

Teaguer
09-08-2004, 03:42 PM
Works for me too .

Chris
09-08-2004, 03:45 PM
:smt102 works for me?
Works for me too .

:evil:

Giga Shadow
09-08-2004, 03:53 PM
Btw.
Where can I get some "shims"? I'm
going to do this... :lol:

Chris
09-08-2004, 04:03 PM
Btw.
Where can I get some "shims"? I'm
going to do this... :lol:

What's with the big font lately? :lol:

Giga Shadow
09-08-2004, 04:14 PM
I don't know.. Makes me look bigger I guess, or somthing..? :? :lol:
My screen is set to 1280 x 1024 so the bigger letter is more soothing but probably anoying to people with say... 1024 x 768.

Chris
09-08-2004, 04:22 PM
I don't know.. Makes me look bigger I guess, or somthing..? :? :lol:
My screen is set to 1280 x 1024 so the bigger letter is more soothing but probably anoying to people with say... 1024 x 768.

If you don't have it already, then get mozilla.

You can make font bigger with "Ctrl" & "+" or smaller with Ctrl" & "-".

bimmerjim®
09-08-2004, 04:31 PM
Btw.
Where can I get some "shims"? I'm
going to do this... :lol:

we sell them at my work. you can order online. yes, our spark plugs are 14mm.

link \/

http://www.speedwaymotors.com/xq/asp/strBase_List./hilt./source./base_no.54571900/str_base_no.44745001%2C54526150%2C54562160%2C54571 900%2C54573225%2C5471000%2C54731689%2C5476200%2C54 76400%2C5476600%2C5478203%2C5478225%2C59022340%2C5 9022390%2C6101754%2C6501648%2C6982524%2C69870050%2 C69870051%2C69870054%2C/header_title.Keyword+Search/page_name.search%2Fkeyword%5Fresults%2Easp/search_type.spark/search_option.Exact/deptsearch./deptSearch_id./dept_id./dept_id_p./dept_name./dept_name_p./ShowImages.yes/sq.20/cont.1/intPgNo.2/redirect./qx/product.htm

Giga Shadow
09-08-2004, 04:50 PM
THANKS JIM!!!!!!!!

I'LL TRY TO FIND SOME ALITTLE MORE LOCAL NOW THAT I KNOW EXACTLY WHAT THEY ARE.

bimmerjim®
09-08-2004, 04:55 PM
ANYTIME IVAN

swartz
09-08-2004, 05:18 PM
see i was right to begin with

bimmerjim®
09-08-2004, 05:40 PM
here ya go jason

http://www.chocolatechips.biz/images/mm-chocolate-chip-lg.jpg

:wink:

swartz
09-08-2004, 05:48 PM
http://images.snapfish.com/33%3B78%3A9523232%7Ffp63%3Dot%3E232%3C%3D5%3B3%3D9 73%3DXROQDF%3E23235%3C8%3B%3B9566ot1lsi

THANK YOU

Chris
09-08-2004, 05:58 PM
http://images.snapfish.com/33%3B78%3A9523232%7Ffp63%3Dot%3E232%3C%3D5%3B3%3D9 73%3DXROQDF%3E23235%3C8%3B%3B9566ot1lsi

THANK YOU

:spitwater:

You've got a strange bite... :shock: :lol:

bimmerjim®
09-08-2004, 06:07 PM
i dont want to know the next pic hes gonna post :shock:

Neo187H
09-08-2004, 07:44 PM
the whole point of the Hemi engine is so that when the piston comes up it "swirls" the gas and air better, creating more even and faster combustion. the technical term for it is actually "squishing" believe it or not, tho i am prob wrong bout that part.

bimmerjim®
09-08-2004, 08:10 PM
im not trying to contradict you, your right about the swirling, i just wanna add a few things... primaraly it makes for better air fuel mixture. the swerling happens while the cylnder is being filled. on the intake stroke and further swerling occurs on the compression stroke because of the momentum of the air..... it would be much better to explain with a drawing.....to compare a 2 valve per cylnder hemi engine - basicaly think of it like filling a bucket with a garden hose. fill it from the side, at an angle, the water follows the round contour of the bucket. its kindof like that. kindof.

honda has taken this one step further with the vtec-e by opening one intake valve less than the other intake valve to promote the swerling, and it also very slightly cracks oppen one of the exhaust vavle on the opposite corner of the intake valve that is open the most side durring part of the intake stroke to cause a low pressure area in the cylnder, witch helps to pull more fresh air and fuel into the cylnder and clean out the combusted material.

thats all for increaced efficency and economy.


the main reason hemi's make more power:

engines make the most power when they are on the verge of detonation..... that is fact.

a hemispherical head combusts in a symetrical wavefront. meaning when the plug sparks, ignition occurs, and the flame front travles directly down on the center of the pistion and then moves out across the pistion in a symetrical fassion. this makes hemi motors less suseptable to detonation. thus, hemispherical engines can run leaner and not detonate.

flat head motors and wedge motors have a flamefront that indirectly acts uppon the cylnder. so there are more hot spots. that makes it more likely to cause detonation.

straight6
09-08-2004, 10:44 PM
Great explanation Jim. That really clarifies things.

Chris
09-08-2004, 11:16 PM
Great explanation Jim. That really clarifies things.

Indeed, nice work.

You're successful at creating an image of what your describing in my head.

swartz
09-08-2004, 11:39 PM
jim what pic was i going to post next WTF??

bimmerjim®
09-09-2004, 11:04 AM
jim what pic was i going to post next WTF??

poopie

swartz
09-09-2004, 06:31 PM
jim what pic was i going to post next WTF??

poopie

damm....ur crasy

what kinda person do u think i am.... :roll:

bimmerjim®
09-09-2004, 07:03 PM
jim what pic was i going to post next WTF??

poopie

damm....ur crasy

what kinda person do u think i am.... :roll:
somone that would post a pic of poopie. :wink:

swartz
09-09-2004, 07:15 PM
ya ur right

http://i1.ebayimg.com/03/i/02/51/1a/40_1.JPG

E30325i
09-16-2004, 06:31 AM
WoW....

Anywho, I just got my car back from Motorworks west. NO MORE OIL LEAK!!!!!!!!!!

So I think tomorrow or later today I'm going to tackle the indexing of my plugs.

I'll keep everyone updated.


p.s. this thread went to hell in a hand basket lol :smt098

bimmerjim®
09-16-2004, 09:14 AM
hey, let us know whay kind of numbers the butt dyno put out. :D

dwonda
10-06-2004, 04:49 AM
i'm still inclear of this indexing thing, should the electrode be on the bottom side or the top side when it is almost horizontal and going into the hole.

E30325i
10-06-2004, 08:12 AM
the gap should face the intake side....

bimmerjim®
10-06-2004, 09:36 AM
iv always been told the gap should point away from the intake valve... well wait.. thats on FI cars. NA cars yeah the gap should face the valve.

JSF252
10-06-2004, 11:18 AM
iv always been told the gap should point away from the intake valve... well wait.. thats on FI cars. NA cars yeah the gap should face the valve.

If your putting the shims between the plug and the head, your making the depth of the electrode change from cylinder to cylinder (yes, I know its nominal). Does this play a factor?

Josh F.

bimmerjim®
10-06-2004, 12:39 PM
slightly, if the plug is shimed to much, it wont have as many threads to grab onto.. but thats nothing performance related, it might make it a little more suseptable to striping.... if the plug is shimed so that the plug is resessed in the head, then the plug wont get to as much of the air fuel mixture right at the spark point as it would by being right in the combustion chamber. so, i would imagine poor performance would be a result..

THe Sly
10-06-2004, 01:15 PM
Guys what about a MSd unit for a more powerful spark to burn all of the gas????

JSF252
10-06-2004, 01:52 PM
Guys what about a MSd unit for a more powerful spark to burn all of the gas????

I think the MSD's MAIN selling point is it's multiple sparks. Yes, the spark is more powerful, due to a more powerful coil, but MSD sends a couple of sparks to fully ignite the fuel. It gets more technical than that, as Jim will probably state, but that's all I'm going to elaborate on at the moment.
Josh F.

THe Sly
10-06-2004, 07:23 PM
Don't forget that the MSD will give you multiple sparks at lower rpm and then it gives you a more powerful spark at higher rpm.

E30325i
10-06-2004, 11:21 PM
wow i really need to stop working so much. I posted the top of this page at work thismorning and i jsut gothome....

i'd say indexing for the $ is a lot more effective than msd. sure you lose an afternoon, but its cheaper