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fivelugshortaxle
Samba Member
Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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 Posted: Mon Sep 02, 2013 7:40 pm Post subject: |
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| Jake Raby wrote: |
People who favor conventional tuning and engine design simply cannot wrap their head around twin plug engines, their combinations and optimum tuning. When they try, they often fail. Instead of altering the combo they generally just say "it doesn't work" and then slam the technology.
It took us over a decade to come up with the optimum combinations. These are dramatically different than their single plug counterparts. I start at 11.25:1 CR with any twin plug engine.
In 2014 all of my engines will be twin plugged as standard offerings.
I
love my 993 twin plug, vario-ram, daily driver! |
I'm going to want a 2176 type 1 build with twin plugs from you by 2014. A true daily driver .....pushing at least 190 hp. Think you can deliver? Without absolutely killing my bank account?
_________________
Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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Jake Raby
Samba Member
Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Mon Sep 02, 2013 7:47 pm Post subject: |
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| fivelugshortaxle wrote: |
| Jake Raby wrote: |
People who favor conventional tuning and engine design simply cannot wrap their head around twin plug engines, their combinations and optimum tuning. When they try, they often fail. Instead of altering the combo they generally just say "it doesn't work" and then slam the technology.
It took us over a decade to come up with the optimum combinations. These are dramatically different than their single plug counterparts. I start at 11.25:1 CR with any twin plug engine.
In 2014 all of my engines will be twin plugged as standard offerings.
I
love my 993 twin plug, vario-ram, daily driver! |
I'm going to want a 2176 type 1 build with twin plugs from you by 2014. A true daily driver .....pushing at least 190 hp. Think you can deliver? Without absolutely killing my bank account? |
I haven't based my engines from the T1 foundation for several years now. All we build are Type 4 based engines.
I only have one Type 1 engine on my property.
_________________
Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell" |
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Juanito84
Samba Member
Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Wed Sep 04, 2013 8:21 pm Post subject: |
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| gears wrote: |
No need to "clear out fins" .. just carefully machine through them.
Required tooling:
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For those of us who aren't machinists could we buy these tools reasonably somewhere and try this at home, maybe doing a few test runs on some old heads? Or do you think a local machinist would be fine and willing to do it? Or is it so precise that only someone experienced in cutting dual ignition plugs should attempt it?
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If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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gears
Samba Member
Joined: October 28, 2002
Posts: 4391
Location: Tamarack, Bend, Kailua
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| Posted: Thu Sep 05, 2013 8:40 am Post subject: |
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All it takes is a Bridgeport & Balls ..
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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Juanito84
Samba Member
Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Thu Sep 05, 2013 9:47 am Post subject: |
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| gears wrote: |
| All it takes is a Bridgeport & Balls .. |
Bridgeport as in a milling machine? So I guess this isn't the kind of job to try on my drill press.
_________________
If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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Jimmy111
Samba Member
Joined: October 05, 2006
Posts: 2643
Location: Wyoming
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| Posted: Thu Sep 05, 2013 9:55 am Post subject: |
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| gears wrote: |
| All it takes is a Bridgeport & Balls .. |
Takes more than that. You need a jig to hold it in place very ridgidly or the fins just snap off. |
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Juanito84
Samba Member
Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Thu Sep 05, 2013 6:03 pm Post subject: |
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| Jimmy111 wrote: |
| gears wrote: |
| All it takes is a Bridgeport & Balls .. |
Takes more than that. You need a jig to hold it in place very ridgidly or the fins just snap off. |
Would a homemade wood jig work along with a drill press?
_________________
If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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Jake Raby
Samba Member
Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Thu Sep 05, 2013 6:54 pm Post subject: |
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Approach angle is everything. You have to consider pushrod tube clearance, exhaust primary location (else you'll melt plug wires) and how strong the chamber is where you'll break through the casting.
_________________
Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell" |
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Juanito84
Samba Member
Joined: March 17, 2012
Posts: 2436
Location: Colorado Mountains
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| Posted: Thu Sep 05, 2013 8:40 pm Post subject: |
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| Jake Raby wrote: |
| Approach angle is everything. You have to consider pushrod tube clearance, exhaust primary location (else you'll melt plug wires) and how strong the chamber is where you'll break through the casting. |
Good points. It also seems to me that each combustion chamber would have a different aproach angle due to differnt positions of the push rod tubes. Right?
_________________
If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine? |
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gears
Samba Member
Joined: October 28, 2002
Posts: 4391
Location: Tamarack, Bend, Kailua
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| Posted: Fri Sep 06, 2013 6:51 am Post subject: |
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Jig must be absolutely rigid. From a performance standpoint, you want both plugs pointed toward exhaust .. so angle selection on one of the plugs is critical.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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bj
Samba Member
Joined: April 09, 2003
Posts: 111
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| Posted: Sat Sep 07, 2013 7:59 pm Post subject: |
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Gears,
Does the napz dist fire the plugs at the same time or is the a few degrees between them?
And yes, Bob from Pele Bug still has the original distributor  ... Even though he has since closed shop.
BJ |
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gears
Samba Member
Joined: October 28, 2002
Posts: 4391
Location: Tamarack, Bend, Kailua
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| Posted: Sat Sep 07, 2013 8:59 pm Post subject: |
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| bj wrote: |
Gears,
Does the napz dist fire the plugs at the same time or is the a few degrees between them? |
Not sure what a "napz" distributor is, but after experimenting with advancing the bottom plug 2-4 degrees with my distributor, I settled on simultaneous spark.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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bj
Samba Member
Joined: April 09, 2003
Posts: 111
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| Posted: Sat Sep 07, 2013 9:47 pm Post subject: |
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Gears,
The distributor is from the twin plugged Nissan motor (z24).
Thanks.
BJ |
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ALB
Samba Member
Joined: August 05, 2008
Posts: 3483
Location: beautiful suburban Wet Coast of Canada
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| Posted: Sat Sep 07, 2013 9:50 pm Post subject: |
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Doesn't that distributor spin the other way? What happens to the advance when it spins backwards?
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On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!! |
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gears
Samba Member
Joined: October 28, 2002
Posts: 4391
Location: Tamarack, Bend, Kailua
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| Posted: Sun Sep 08, 2013 5:44 am Post subject: |
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Oh .. of course. The distributor we're borrowing the cap & rotor from. I remember there being two styles .. I just chose one style and stayed with it. We had to wait a couple years for Nissan to begin using Zytel plastic, so the rotor wouldn't disintegrate at 6,000 engine rpm.
I'm pretty sure the Nissan also used simultaneous spark .. (but I never worked on one)
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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58 Plastic Tub
Samba Member
Joined: September 03, 2007
Posts: 418
Location: Nowhere, USA
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| Posted: Sun Sep 08, 2013 3:19 pm Post subject: |
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Paul-
Is this work you are doing for other people, or just for your own cars? I'd be interested in seeing your distributor set-up, etc. I'm assuming you are adapting the Nissan cap/rotor to a better-known distributor, if you aren't using crank-fire.
Twin plugging just makes sense, especially as the bore increases. I think something >10:1 is completely possible with this setup (Jake said as much earlier in the thread.
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Stan Galat
"Everybody is entitled to their own opinions, but not their own facts." |
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gears
Samba Member
Joined: October 28, 2002
Posts: 4391
Location: Tamarack, Bend, Kailua
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| Posted: Sun Sep 08, 2013 5:48 pm Post subject: |
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I did a fair number of heads and distributors for mainland guys during the mid-90s when I had a Bridgeport & lathe on Maui. While I still have all my tooling, I haven't had a mill or lathe in over a decade.
Early distributors were merely an adapter plate shrunk fit onto any centrifugal advance distributor. I later had castings made, which after machining resembled "billet".
I seriously doubt that any of my customers went as far as Jake with his high compression combos, but I don't know .. they were all so far away. Gary Peloquin had pretty good results.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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58 Plastic Tub
Samba Member
Joined: September 03, 2007
Posts: 418
Location: Nowhere, USA
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| Posted: Sun Sep 08, 2013 6:08 pm Post subject: |
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With that in mind, is anybody currently doing this correctly (with the bottom plugs aimed at the exhaust, and so everything clears the P/R tubes)?
... and probably equally important, is anybody building dual plug distributors or adapters?
_________________
Stan Galat
"Everybody is entitled to their own opinions, but not their own facts." |
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58 Plastic Tub
Samba Member
Joined: September 03, 2007
Posts: 418
Location: Nowhere, USA
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| Posted: Sun Sep 08, 2013 6:08 pm Post subject: |
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With that in mind, is anybody currently doing this correctly (with the bottom plugs aimed at the exhaust, and so everything clears the P/R tubes)?
... and probably equally important, is anybody building dual plug distributors or adapters?
_________________
Stan Galat
"Everybody is entitled to their own opinions, but not their own facts." |
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gears
Samba Member
Joined: October 28, 2002
Posts: 4391
Location: Tamarack, Bend, Kailua
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| Posted: Sun Sep 08, 2013 8:47 pm Post subject: |
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I found the ideal placement possible only when using 10mm lower plugs. We usually changed the upper plugs to 12mm at the same time.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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