Speeditwin Spark Plug Choices

[gearhead4]

Another question for my 1929 Model U Speeditwin project. The engine came with Champion R7’s in it which do work but I am wondering whether I should replace them with something newer to be more reliable or should I just run them as is? My Evinrude Specifications book calls for the 28-29 Speeditwin to have Champion Name 0 spark plugs. Before I took the engine down it did fire right up with a shot of fuel mix in the cylinders so I know they will work. I’ve taken them apart and sonic cleaned everything (almost every part of the engine that would fit in the cleaner, pistons came out very nice aiding with carbon breaking off) so they are ready to go back on once complete.

I’m also missing one of the screw on nuts that the wire clips to. I believe there’s a few people online that sell them but I’ll have to check the size before doing that.

I hope to have this engine reassembled and running within the next couple weeks after new bearings for the lower unit show up, finish the powerhead and piston replacement and lastly have all the new carb castings thanks to Art Dekalb, machined to fit! Then it’s off to YouTube for some videos with it.

Any help is greatly appreciated, thanks!

[RICHARD A. WHITE]

I have similar problems, I am going to run Champion D9’s in most everything that takes the 18mm plug.
That covers 11 of my motors…. I find this would be easier than trying to keep 14 different plugs.. out of those 14 motors, no 2 motors have the same plug in them.

Motors I will run them in:
1938, 1939 Neptune Mastertwins,
1929 Evinrude Fastwin,
1926 Johnson P-30
Lockwood 72T
1933 Evinrude Fisherman
1932 Evinrude Lightwin
1925 Elto Ruddertwin
1926 Johnson A-25
1932 johnson OA-60
1933 Johnson OA-65

Only 7 have not run yet…

LOL Better get my butt back to work 🙂

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[gearhead4]

I did think of the D9’s as I believe I have those in my 1939 Speeditwin which runs well but wanted to run it by other members and see what they said. And yes I couldn’t agree more with you, I too have far too many in the pipeline half finished or just in pieces, time to start working on getting them all back together. Think I have two that all I have to do is assemble but other things show up and distract you even when your laid off like I am but job hunting takes a ton of time.

Thanks for the input! I’m probably going to go the D9 route anyways but it’s worth checking before.

[mini-motors]

I’d like to point out that spark plugs are "heat range" sensitive, and using the proper heat range plug is important. If you run a plug too cold, it won’t burn the mix completely, and a plug too hot could burn a hole in a piston(extreme case scenario). Using a conversion chart, the old Champion #0 equates to a new Champion W10 plug.

[RICHARD A. WHITE]

Well, I agree, so here is some info to chew on.

First chart shows Champion W10 as being on the cold side of the heat range:

http://www.fordbarn.com/forum/showthread.php?t=6458

And here is the heat range chart for the D9, it is on the second page: also on the cold side of the heat range:

http://www.federalmogulmp.com/en-US/Tec … 0Chart.pdf

Also maybe I am wrong, been there many times before, but the D9 is an 18mm plug and the W10 is 7/8-18.

I did not take the time but they are not the same???? Are they?

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[mini-motors]

I do not know for sure. All I did was to Google "champion 0 com spark plug", and a conversion chart on the Antique Small Engine Collectors Club came up. That led me to looking at the W10, which was corroborated by the Champion site. I did not look closely at the specs for each.

My concern stems from working a motorcycle parts counter, and having to explain, almost on a daily basis, why it’s important to use the correct heat range plug, and that deviating from this won’t cure a jetting issue. There are so many idiot bikers out there who change over to a "hot lick" aftermarket exhaust and free flowing air filter, not re-jet, and wonder why the bike runs rich or lean.

I was used to repeating myself, as I am a parent. But I don’t work there anymore, and am much happier.

[mini-motors]

It seems that the #0 is 7/8s as well, according to this discussion;

http://www.smokstak.com/forum/showthread.php?t=100770

[RICHARD A. WHITE]

So it seems the 29 Speeditwin is 7/8 and mine are almost all 18mm… then there you have it 🙂
See my previous statement 🙂

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[mini-motors]

I’d be mildly curious what the R7 is, 7/8ths, or 18mm.

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