Iridium Sparkplugs in a 0520

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lbdb1a
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Re: Iridium Sparkplugs in a 0520

Post by lbdb1a » Sun Jun 24, 2012 9:26 pm

The 14mm BCH 9602 is also listed as Bosch # HR 8 LII33U ,on the plug box, which is heat range 8 like the 18mm Autolite 386 (ie:18mm Bosch M8ACO per the cross reference chart).

A lot of folks and engine builders use the 386's which are resistor plugs and solid core plug wires. It takes about 10,000 volts to fire a resistor spark plug and our mags are producing about 30,000 volts

The RH 12 is a little colder plug than the 386 (which is medium hot) so maybe it is fouling because it is a medium/cold heat range plug..?

The 386 crosses to a Champion RD16.

Anyway

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CRACKERSTYLE
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Re: Iridium Sparkplugs in a 0520

Post by CRACKERSTYLE » Sun Jun 24, 2012 9:38 pm

Why get the adapters?

Why not just run an autolite 386 like the rest of the world.......
John 3:16

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lbdb1a
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Re: Iridium Sparkplugs in a 0520

Post by lbdb1a » Sun Jun 24, 2012 10:04 pm

Cracker,
I have the GITSU cylinders with long reach plug holes. I know you can use short plugs but this exposes several cylinder threads to the hot combustion gases plus the 386 plug tip is recessed into the cyl. head. I had to clean the cyl.threads very carefully to remove the carbon build up after only 40 hrs of using the 386's.

With the extended tip 14mm plug the tip protrudes out into the combustion chamber for better flame propagation . A boroscope inspection gives you a better idea of this.

I wanted to go with the long reach plugs so the inserts let you use 14mm long reach plugs. Hard to find 18mm long reach plugs without going to aircraft plugs.

I think i may get a little better fuel economy and perf. etc but it will take time to know. Also the fine wire tip plug takes less energy from the mag. to fire due to the very small 6mm (0.236 " dia center electrode).

Anyway i am going to give it a try....

Larry Brister

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Re: Iridium Sparkplugs in a 0520

Post by TIGO541 » Mon Jun 25, 2012 7:51 am

8 heat range is probably why they are fouling. Thats probly too cold. Usually ur motor should need a 5or6 heat range to keep the oil burned off but depends on the motor. Tip-when you remove the plug the coloration change on the ground strap should be right at the 90 degree bend. Any further toward the electrode is too cold and closer toward the weld is too hot. Hope this helps. Google (reading spark plugs) there is some very helpful info for just what to look for. Good luck. I want to eventually try some iridium plugs myself. I will be staying tuned
13-6x7-6 Hamant Ultra-lite,Custom TIG Stainless rigging,1.7 Rotator,Supercharged 480,Electronic Ignition,80 inch 3BLD R,B&S trailer

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CRACKERSTYLE
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Re: Iridium Sparkplugs in a 0520

Post by CRACKERSTYLE » Mon Jun 25, 2012 10:16 pm

I hear ya on the longer reach plugs- I figured they had a long reach 18mm plug.
I use the 386 autolite but would prefer a longer reach plug and a tad colder than the 386........
John 3:16

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lbdb1a
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Re: Iridium Sparkplugs in a 0520

Post by lbdb1a » Mon Jun 25, 2012 11:00 pm

TIGO541,
The NGK 5 crosses to the Bosch 8 heat range

http://www.ngk.com/glossaryImages/721.jpg

Thanks for the plug reading tip...

Larry Brister

TIGO541
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Re: Iridium Sparkplugs in a 0520

Post by TIGO541 » Tue Jun 26, 2012 7:34 am

I see. An 8 may be too hot then just watch your ground strap. You might have to go to a 6or7. These iridium plugs may burn differently. Hard to say. Crackerstyle if you get the adapters to 14mm you have many choices in the 3/4 reach plugs. Thats what i have.
13-6x7-6 Hamant Ultra-lite,Custom TIG Stainless rigging,1.7 Rotator,Supercharged 480,Electronic Ignition,80 inch 3BLD R,B&S trailer

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lbdb1a
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Re: Iridium Sparkplugs in a 0520

Post by lbdb1a » Tue Jun 26, 2012 12:02 pm

TIGO541,

Okay i will do that.

I made a short run on the trailer up to 2800 rpm and checked the top plugs. Although the test is preliminary due to the short run and not up to full temp. etc , the strap color is changing just to the ground side near the radius. This indicates the plug maybe a little hot but i will take the boat out for a test run next week to get a more accurate reading.

Thank You for the tips...

Larry Brister

0520 Gitsu Cylinders and a 72" 3-Blade NGH
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hmgm123
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Re: Iridium Sparkplugs in a 0520

Post by hmgm123 » Tue Jun 26, 2012 5:21 pm

lbdb1a wrote:TIGO541,

Okay i will do that.

I made a short run on the trailer up to 2800 rpm and checked the top plugs. Although the test is preliminary due to the short run and not up to full temp. etc , the strap color is changing just to the ground side near the radius. This indicates the plug maybe a little hot but i will take the boat out for a test run next week to get a more accurate reading.

Thank You for the tips...

Larry Brister

0520 Gitsu Cylinders and a 72" 3-Blade NGH
Ground strap indicates timing, the threads color indicate heat.

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lbdb1a
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Re: Iridium Sparkplugs in a 0520

Post by lbdb1a » Wed Jun 27, 2012 12:43 am

Take a look at this video and comment.....just overlook the Elevator Music.... :lol: ...be better with a little Willie Nelson or ...Hank Williams Jr.l

http://www.youtube.com/watch?v=fiMM2S0aADM


Larry Brister

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