Spark plug gap

[blown motor]

This is number six out of my 340. It's a Bosch W8DC. What should the gap be?

[cuda hunter]

I believe .035 is what a 340 is supposed to be gapped at?
Stock build anyway.

[cuda hunter]

I like the autolite 65's . 
That plug looks like it's getting too hot or is too lean.  But I"m no expert. 

[kawahonda]

I think it shows too much timing?

[JS29]

 

[blown motor]

I think it shows too much timing?

Timing at idle in Park is 10 and at 3000 rpm is 34.

[Chryco Psycho]

What ign system / coil , I usually gap @ .040 if you have an upgraded coil at all
Looks like it could have a few more ponies with a richer mix

[blown motor]

Rev-N-ator wih a Blaster 2 coil.

[kawahonda]

That plug looks perfect except for the electrode. I'm curious as someone who wants to learn more about tuning by the plug what is the fix there...

FBO has an EXCLELANT page on this. But of course, experience paired with info is the best way.
http://www.4secondsflat.com/Spark_plug_reading.html

Original Poster, shoot FBO an email with your plug. Curious as to what he thinks. Not trying to yell "fire" here, but I'd be curious to learn as much as possible about spark plugs as I'm starting to tune.  He seems to know his $hit when it comes to reading plugs.

I showed this photo to a mechanic of mine (Ford guy) and he said:

"No color change on the strap. Too hot of plug. Other than that, looks good."

Go 1 step colder on your plug. Your Bosche plug is 1 step too hot. I'd go one step cooler is that's all I'd do IMO.

[Maddawg]

I believe .035 is what a 340 is supposed to be gapped at?
Stock build anyway.

Correct .035" for stock motor.  For 1970 at least, from my reproduced manual.

[blown motor]

That plug looks perfect except for the electrode. I'm curious as someone who wants to learn more about tuning by the plug what is the fix there...

FBO has an EXCLELANT page on this. But of course, experience paired with info is the best way.
http://www.4secondsflat.com/Spark_plug_reading.html

Original Poster, shoot FBO an email with your plug. Curious as to what he thinks. Not trying to yell "fire" here, but I'd be curious to learn as much as possible about spark plugs as I'm starting to tune.  He seems to know his $hit when it comes to reading plugs.

I showed this photo to a mechanic of mine (Ford guy) and he said:

"No color change on the strap. Too hot of plug. Other than that, looks good."

Go 1 step colder on your plug. Your Bosche plug is 1 step too hot. I'd go one step cooler is that's all I'd do IMO.

Interesting reading. Thanks for posting.

[71383bee]

That plug looks perfect except for the electrode. I'm curious as someone who wants to learn more about tuning by the plug what is the fix there...

FBO has an EXCLELANT page on this. But of course, experience paired with info is the best way.
http://www.4secondsflat.com/Spark_plug_reading.html

Original Poster, shoot FBO an email with your plug. Curious as to what he thinks. Not trying to yell "fire" here, but I'd be curious to learn as much as possible about spark plugs as I'm starting to tune.  He seems to know his $hit when it comes to reading plugs.

I showed this photo to a mechanic of mine (Ford guy) and he said:

"No color change on the strap. Too hot of plug. Other than that, looks good."

Go 1 step colder on your plug. Your Bosche plug is 1 step too hot. I'd go one step cooler is that's all I'd do IMO.

Interesting reading. Thanks for posting.

I agree with kowahonda. Also used a lot of dons advice and agree that there should be a distinct color change near the bend on the strap which is an indicator of timing.   From what your describing it sounds like total is good but initial is low. Only way to fix that is to change the amount of mechanical advance in the dizzy.

The colder plug idea sounds like a good start though.


Sent from my iPhone using Tapatalk

[kawahonda]

I think you can also tell by the threads also to that the plug is too hot. There are actually NO threaded portions that are black! There should be a few layers of black.

@Chryco Psycho is right too, that it probably could stand to go richer too along with solving heat range. Chrycho, it looks like his "idle/cruise" is fine but the WOT jetting could be one step more?

[blown motor]

Well it all doesn't matter at the moment because I can't get it to start. Went out this morning to get it going for a run this afternoon. This is the first start up of the year. It cranked over some and fired up. Ran for about 5 seconds and stalled. Now it just wont fire up, turns over great but won't even sputter.

[kawahonda]

carb type? choke on verified with aircleaner off?