Spark plug reading

[Alpha_Maverick]

I figured I'd start another thread, for this subject. I've been "breaking in" my engine for several thousand miles, now, and I decided it was time to get the tune just right, and I'm looking for advice on what my plugs are telling me.

I am running a 1600SP with stock everything from '69 (it was a 1500 from the factory, though), including a solex 30 PICT-2. The stock cam is retarded 5°, so that it is actually installed straight up. I had all stock jets in it, (125 main) and vacuum only distributor, timed at 0° base, with ~34° full advance. I am willing to adjust the timing, but I don't want to mess with the curve.

Here are the best pics I could get of my plugs, 1-4, 4 pics each. The plugs are NGK B5HS

They looked cold and lean to me, so I replaced the plugs with BP6HS, and increased the main jet to 127.5. Am I headed in the right direction? Should I do anything with timing?

Thanks in advance!
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[udidwht]

Not bad. The heat range looks good. How many miles on the motor?
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1972 Westy Hardtop/Type-4 2056cc
96mm Biral AA P/C's~7.8:1CR
Headflow Masters New AMC 42x36mm heads w/Porsche swivel adjusters
71mm Stroke
73 Web Cam w/Web solids
Dual 40mm IDF Webers - LM-2 - 47.5 idles/125 mains/190 air corr./F11 tubes/28mm Vents - Float height 10.45mm/Drop 32mm
Bosch SVDA w/Pertronix module (7.5 initial 28 total @ 3400rpm)
Bosch W8CC plugs
Pertronix Flamethrower 40K coil
S&S 4-1 w/Walker QP 17862
3 rib 002 Trans
185R14 Hankook tires

[Alpha_Maverick]

The engine (and those plugs) has ~5200 miles on it.

Was I right to go one jet richer, and one step colder, with projected nose, on the plugs? Any ideas on the timing?
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[jfats808]

Idles on old plugs look like they are too small. After changing to warmer plugs post a.new picture. Start with a .028 gap and static 7 or 8 idle timing.
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2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125

[[email protected]]

make changes slowly, one at a time.

I think the plugs are one heat range too hot. I also think the engine is still a touch rich.
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[udidwht]

The fuel banding on the electrode strap is midway which is ideal for heat range. As John stated make any change/s 1 at a time.
_________________
1972 Westy Hardtop/Type-4 2056cc
96mm Biral AA P/C's~7.8:1CR
Headflow Masters New AMC 42x36mm heads w/Porsche swivel adjusters
71mm Stroke
73 Web Cam w/Web solids
Dual 40mm IDF Webers - LM-2 - 47.5 idles/125 mains/190 air corr./F11 tubes/28mm Vents - Float height 10.45mm/Drop 32mm
Bosch SVDA w/Pertronix module (7.5 initial 28 total @ 3400rpm)
Bosch W8CC plugs
Pertronix Flamethrower 40K coil
S&S 4-1 w/Walker QP 17862
3 rib 002 Trans
185R14 Hankook tires

[modok]

Looks OK IMO. Probably a bit rich under some conditions(maybe with the choke on?) but overall about right. Considering what the engine is I'd have expected worse

[Quokka42]

That is a pretty hot plug for an air cooled engine - try BP6S
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There has only ever been one man who was perfect, and they nailed Him to a cross.

[mark tucker]

I have a stupid question. 5200 miles..and you are just tuning it??? why?? or do you just like killing parts?? the engine shoukld be broken in in the first hour after 1~ 2 ol changes have been done.and should be tuned in that time or very soon after.

[hooker]

[modok]

You can't tune it after it's broke in? why not? you work for CARB?

Quite the opposite. engines always run different when new, and fresh they like to be rich and use more timing as a general rule.

No reason to quit tuning either. I've tried different manifolds and 8 sets of carbs and different velocity stacks and 30 different headers. That could be 200+ different combinations of them
If I checked the plugs every time I'd have worn out the threads

looking at it again, IMO you should run a step cooler in #1 and #3

[Alpha_Maverick]

I clearly am not organizing my posts in an understandable manner.

The reason I'm only now getting to the tuning is what modok said, and the fact that all the parts are stock specs, with a stock tune.

That being said, as stated in my opening post, I have switched to BP6HS, and 127.5 main jet. I'm gonna run that for a bit, and check again after a few hundred miles, unless the consensus is that I was already too rich.

Also, keep in mind that #3 is, indeed, ~3° retarded, so that might account for the slightly different coloring on that one.

[modok]

You did a fine job but it's still a siamese-port engine with a simple carb on a very long manifold.
cylinders #1 and #3 will always be a bit leaner/hotter looking due to it's nature of course. If those don't look too lean and #2/4 don't look too rich then you must be in the happy middle ground.

[Alpha_Maverick]

Ah. gotcha. I'll do a WOT chop test, and if I have soot, I'll go back to the 125 main. I'm a little nervous pulling fuel from stock, since lean=hot (up to stoich, then invert)

Does that sound logical?
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[Alpha_Maverick]

I've put about 500 miles on these plugs. Many of those were done at or near WOT, ~4000rpm (80mph)

Haven't done the WOT chop test, yet, but I had a few minutes to spare, today, so I pulled #3 and #4. Keep in mind that this is a 127.5 main, BP6HS plugs.

#3 looked almost identical to #4, except it had a pure white ceramic. No browning at all.

Here's #4:

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