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Spark plug adapters- If you?re in need of read below.

Rbb469

Active Member
I just purchased spark plug adapters from Protek performance, Inc out of California. Extremely prompt courteous service and fast shipping. Machined in house. A package of 8 for $133.00 shipped to my house. Give these guys a try. www.FlyEFII.com 951.317.3473
 
Reducers

I?ve been using Brillman reducers for at least 15 years and have installed then on at least 12 planes. So yes they?re good. I?ve never told them what I was using them on, but if they ever ask, it would be for my Allis Chalmers tractor.
 
To be frank, I ordered a set of Brillman adapters and sent them back. I'm sure they will work, but they were not as good as adapters from EFII and SDS.
 
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Not to reason...

I just purchased spark plug adapters from Protek performance, Inc out of California. Extremely prompt courteous service and fast shipping. Machined in house. A package of 8 for $133.00 shipped to my house. Give these guys a try. www.FlyEFII.com 951.317.3473

Glad U like them but...
I never liked adapters, so I use Denso L14U or Autolite 386 plugs. 25 years on they still work great on my Electroair/ P-Mag's and thread right in.
V/R
Smokey
 
Autolite 386

Smokey,
Hold on a sec..You mean this Autolite 386 18mm plug will work for our Lycomings?..I have a carbed 0-320..160 hp mods..???
I just looked it up and these things are 1.99 at AutoZone!!.. I realize a harness change would be in order..but it the heat range comparable?..are you running them in an lycoming? Im pretty interested in this!!
Don
 
I just swapped out my Denso plugs for 386's on my Lightspeed system. At annual (just bought the plane) I found one of the Denso-s about 2/3s of the way backed out of its adapter. Decided the 386s were too easy a solution.
 
I'm currently trying Champion stock # 526, RD15Y on my RV-8 Parallel valve O-360, 8.5:1 . It's an 18mm resistor plug like the Autolite 386, but also has a projected tip. I'm hoping it's slightly cooler, but I only have a few hours on them, trying both high power, and very low power flight. I won't know much until something happens :eek: or it's oil change time and I pull the plugs for a look.
3.99 ea thru Summitracing.com
I also have successfully used Autolite 386 on my Thorp T-18. They stay clean and do not show heat stress on my O-290 with 7:1 compression.
 
Why does e-mag recommend adaptors?

Hello all,

Why do the P-mag folks recommend using adaptors in lieu of using 18mm plugs?

A couple years ago I had a conversation with them at Sun-n-fun, and they reccomended against 18mm plugs.

For me, it's all about safety, not cost or complexity of maintenance, etc...

Thanks,
Sean.
 
The 386 would appear to equate to about a 6 heat range plug in NGK which would be way too hot for a Lycoming where we normally fit an 8 heat range (2 steps colder).

Might work, but doesn't seem prudent given that plug heat range can have an impact on pre-ignition and detonation margins.
 
Dan is correct and we've seen one EFI/ EI vendor supply the wrong plugs and adapters for the 390/580 engines. If in doubt, check what you have installed.


Incorrect!



Here is the difference in short and long reach components.
 
The 386 would appear to equate to about a 6 heat range plug in NGK which would be way too hot for a Lycoming where we normally fit an 8 heat range (2 steps colder).

Might work, but doesn't seem prudent given that plug heat range can have an impact on pre-ignition and detonation margins.

I had a hard time figuring out the heat chart for the 386. Is there an 18mm equivalent to the Denso plug supplied by SDS? I've been having problems with the inserts on my IO-540.
 
The 386 would appear to equate to about a 6 heat range plug in NGK which would be way too hot for a Lycoming where we normally fit an 8 heat range (2 steps colder).

Might work, but doesn't seem prudent given that plug heat range can have an impact on pre-ignition and detonation margins.

Hi Ross,

Since I just installed some 386s, & obviously don't want to hurt my engine, can you expand on that a bit? According to Champion's info on their aviation plugs, they have a heat range from 25 (cold) to 50 (hot). The recommended plugs for my IO-360-B1B (parallel valve, 8.5-1 compression) being 37, 38, and 40, or just on the hot side of midrange. The Autolite chart I was able to find shows the 386 as being 1 'step' above the center of a 6 step heat range for their plugs.

Our dilemma is, how to relate the two ranges. I can tell you that an REM37 aviation plug has a *very* long insulator, and a very extended tip, compared to an aviation REM38. I have *not* examined how deep into the barrel each insulator goes; I just read your post. The REM 38 and the Autolite 386 both have nearly flush tips. As soon as possible, I'll check insulator depth into the barrel on both plugs.
edit: should have mentioned that the 37's I have are REM37BY (dual electrode, extended tip).

Charlie
 
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I had a hard time figuring out the heat chart for the 386. Is there an 18mm equivalent to the Denso plug supplied by SDS? I've been having problems with the inserts on my IO-540.

I could never find an 18mm plug with the correct heat range which is why we (and other EI manufacturers I assume) go the adapter route. They may exist but I didn't find any.

If you're using our adapters, see the April 26/19 SB. In a nutshell:
1. Thread the spark plug into the adapter
2. Torque the assembly into the cylinder head using the PLUG hex to 19 ft./lbs.
3. Torque the ADAPTER further to 25 ft./lbs. Use only a thin stripe of anti-seize compound on the plug and adapter. Do not coat the threads.
 
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After poking around on the Brillman web site I fount that they list a dozen 18mm spark plugs, Autolite, Champion and AC Delco. The short reach #C87 AC Delco is listed as ?Medium? heat range. No idea what that translates to for our needs. Any thoughts?
 
Hi Ross,

Since I just installed some 386s, & obviously don't want to hurt my engine, can you expand on that a bit? According to Champion's info on their aviation plugs, they have a heat range from 25 (cold) to 50 (hot). The recommended plugs for my IO-360-B1B (parallel valve, 8.5-1 compression) being 37, 38, and 40, or just on the hot side of midrange. The Autolite chart I was able to find shows the 386 as being 1 'step' above the center of a 6 step heat range for their plugs.

Our dilemma is, how to relate the two ranges. I can tell you that an REM37 aviation plug has a *very* long insulator, and a very extended tip, compared to an aviation REM38. I have *not* examined how deep into the barrel each insulator goes; I just read your post. The REM 38 and the Autolite 386 both have nearly flush tips. As soon as possible, I'll check insulator depth into the barrel on both plugs.

Charlie

The Autolite plugs may not have a strictly comparable heat range according to some sources, rather it describes heat range within a family of plug types.

Other sources say they are 6 heat range in NGK terms. Given the usual applications for these plugs, typically low output liquid cooled engines, it's seems doubtful that they are an 8 in NGK terms.

They may work fine, I'm just putting out a caution here. Just because they screw into the hole, doesn't mean they are a good choice for Lycoming engines.

Generally speaking colder plugs are fitted on air cooled engines and engines with continuous high load or higher specific outputs.
 
Here is a link describing spark plug heat range:
https://www.briskusa.com/spark_plug_cross_reference_heat_range_chart
The graphic description of plug construction and the effects of temperature are very good.
You can see the use of 'hot' plugs reduces the safe margin against thermal runaway. This would be a test with the cylinder head temp at the limit, full load and poor fuel octane. This would be a factory certification type test, which an owner/operator would be challenged to duplicate.
Thanks Ross, you always make us think.
 
Here is a Champion spark plug numbering system chart:
https://www.sparkplugs.com/Data/uploads/Charts/Champion_Numbering_System.jpg
The Champion D series 18mm x 1/2" thread reach plugs that I have found run from cold D6 (Stock #506) to hot D23 (stock #523)
The RD15Y (stock #526) is the only 18mm 1/2" reach resistor plug with extended tip that I have found, and the heat range is equivalent or cooler than an Autolite 386, hopefully.
I also have cooler Champion D9 non resistor, non extended tip plugs to try with my MSD 8.5mm suppressor core wires to see if the radio is effected ...and I'm trying to find spark plug cover shields that fit.
I have a modified Bendix mag plate with suppressor wire and plug boots, and I have P-mags with suppressor wire & boots for auto plugs....but I experiment rather cautiously, this takes time.
 
Bummer! Now it doesn't work for me either.
They must have recently changed access?
If you copy that link into a search engine, and select images, you can still see these charts in reduced size....for now.
 
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Source For Spark Plug Adapters

Spent some time with a local RV-7 builder, and he told me he purchased spark plug adapters from the following source:
https://www.ebay.com/sch/i.html?_nk...pters 18mm Down to 14mm Brass&ssPageName=GSTL

The company that makes them is gsparkplug.com Here is the link:
https://www.gsparkplug.com/1x-spark-plug-thread-adaptors-18mm-down-to-14mm-brass-m14-m18.html

Held them in my hand and they are very good quality and essentially identical to the ones from US sources.
 
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