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> Twin plug update, Can i do it.
904svo
post Mar 22 2010, 06:10 PM
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While trying to make the jigs to drill my heads for twin plugs I ran into a
major problem. Where is the plug going to be located on the bottom of the head.
I made up this jig to located where the plug will be located.

Angle jig
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Test jig installed
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Installed
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Bottom view
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r_towle
post Mar 22 2010, 06:17 PM
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There are pics here or on STF or Jakes site.

Jake has done this and he ended up in the same place, for the same reason.

Rich
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Katmanken
post Mar 23 2010, 12:53 PM
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Nice idea for a jig.

It's quick and dirty and shows what is going on.
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Jake Raby
post Mar 23 2010, 01:07 PM
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The next problem you are going to have is how to get enough material in that location for the plug to seat.
You are about to see why this costs so much.

And you'll still have to choose the plug carefully, make a socket to remove and install it and find the perfect spark plug wire for the lower set of plugs.. Have fun
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RJMII
post Mar 23 2010, 04:55 PM
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QUOTE(Jake Raby @ Mar 23 2010, 01:07 PM) *

The next problem you are going to have is how to get enough material in that location for the plug to seat.
You are about to see why this costs so much.

And you'll still have to choose the plug carefully, make a socket to remove and install it and find the perfect spark plug wire for the lower set of plugs.. Have fun



That sounds like experience talking.
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Katmanken
post Mar 23 2010, 07:10 PM
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It's a little daunting trying to drill two angled holes in each head when each hole is at a different angle to each of the x axis, the y axis and the z axis, and not parallel or perpendicular to anything on the head.
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904svo
post Mar 23 2010, 09:18 PM
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QUOTE(kwales @ Mar 23 2010, 05:10 PM) *

It's a little daunting trying to drill two angled holes in each head when each hole is at a different angle to each of the x axis, the y axis and the z axis, and not parallel or perpendicular to anything on the head.


Thats why I'm making jigs up to locate the holes, and yes it hard to drill the
hole but my mill can handle it after I modify it. After I'm done I can modify
a good set of heads.
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RJMII
post Mar 23 2010, 09:21 PM
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QUOTE(904svo @ Mar 23 2010, 09:18 PM) *

QUOTE(kwales @ Mar 23 2010, 05:10 PM) *

It's a little daunting trying to drill two angled holes in each head when each hole is at a different angle to each of the x axis, the y axis and the z axis, and not parallel or perpendicular to anything on the head.


Thats why I'm making jigs up to locate the holes, and yes it hard to drill the
hole but my mill can handle it after I modify it. After I'm done I can modify
a good set of heads.



I hope you're able to figure it out, that's a pretty cool project. not anything i'd use (v6 car here) but it's sure cool to watch your progress.
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904svo
post Mar 23 2010, 09:22 PM
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This is the engine I'm going to try them on. My version of a type 547 engine
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The fan does cool the engine.
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URY914
post Mar 24 2010, 06:31 AM
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What are you hoping to gain from all this?
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904svo
post Mar 24 2010, 07:20 AM
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QUOTE(URY914 @ Mar 24 2010, 04:31 AM) *

What are you hoping to gain from all this?


So I can say "I did it."
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ME733
post Mar 24 2010, 09:03 AM
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.I think that , based on some old 4-cam carrera information., a twin plug engine -a type 4-engine, could see a 5-to 15 percent increase in H.P....the more radical the engine the higher H.P. potential.-to a 15% increase....MM
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URY914
post Mar 24 2010, 11:48 AM
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What are you doing for a dizzy?
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904svo
post Mar 24 2010, 11:54 AM
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QUOTE(URY914 @ Mar 24 2010, 09:48 AM) *

What are you doing for a dizzy?


I'm using Megasquirt rotary option ( design for Mazda 2 rotor engine) to fire
the fire the plugs in wasted mode. Circuit has been tested and works on my
simulator
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HAM Inc
post Mar 24 2010, 12:01 PM
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The heads will require lots of welding to accomodate the second set of plugs. Having done this to several pairs I can tell you from experience that it is a lot of work. Like Jake said there is a reason that it is expensive.
Good luck Larry!
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URY914
post Mar 24 2010, 12:04 PM
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QUOTE(904svo @ Mar 24 2010, 06:20 AM) *

QUOTE(URY914 @ Mar 24 2010, 04:31 AM) *

What are you hoping to gain from all this?


So I can say "I did it."



Good enough (IMG:style_emoticons/default/biggrin.gif)
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Todd Enlund
post Mar 24 2010, 12:11 PM
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Curious... why a bus head? Are you planning a lot of other machine work as well?
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904svo
post Mar 24 2010, 02:58 PM
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QUOTE(Todd Enlund @ Mar 24 2010, 10:11 AM) *

Curious... why a bus head? Are you planning a lot of other machine work as well?


Just a set of heads I had laying around, if they work out thats OK for a test.
Better to trash bus heads than a good set of 2.0 ltr heads.
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tat2dphreak
post Mar 24 2010, 03:15 PM
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isn't that angle going to be REAL close to the Exhaust?
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Dave_Darling
post Mar 24 2010, 03:28 PM
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QUOTE(ME733 @ Mar 24 2010, 08:03 AM) *

.I think that , based on some old 4-cam carrera information., a twin plug engine -a type 4-engine, could see a 5-to 15 percent increase in H.P....the more radical the engine the higher H.P. potential.-to a 15% increase....MM


In the 911 engines, going dual-plug generally lets you run about one full point more of compression on the same grade of fuel without detonation. A fair bit of the extra power comes from the extra compression, from what I can tell.

The 914 chambers are very different from the 911 ones; not sure how much (if any?) more compression you can run in them.

--DD
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