Itinerant Air-Cooled

Just pulled them after ~ 9000+ miles. Guess I didn't tighten 1 & 3 down tight enough...not much effort getting them loose. All in all they look pretty uniform. I'll see if I can get some better shots. Plugs are NGK B5ES gap at .028. Jetting is in my sig.

That is pretty good indeed, looks like you're right where the engine likes it!

Will only allow 1 pic per post??? Here goes cylinder #1 Just got my LM-2 in the mail today, first chance I get I'll post up the results. But I feel I'm pretty darn close. The pics are actually appear slightly darker around the rim than in person. At the base of the ceramic where it meets the steel I can faintly see some discoloration ever so slightly (not white like midway up the plug towards the nose).

Cylinder #2

Cylinder #3

Cylinder #4

From my armchair I'd say you are a tad rich but within "Normal". Interesting to see what you get with a LM2.

What range should I shoot for. I'm thinking 13:1- 13:5...for a bus? If you had to guess Bley what do you think the LM-2 will say? Your saying a tad rich...so I'll start by saying it's somewhere between 12.8 - 13:0. Can't wait for the LM-2 reading.

One other thing...I to am running with an S&S 4-1 header. I have a section between the collector and quiet pack muffler that is roughly 5 - 6 inches long. Where should I weld the bung in? I looked from underneath but I don't think I have the room due to the other exhaust pipes. Also you have any suggestions as to where I should run the wires for the LM-2 (given there length).

You have any pictures with the bung installed?

That sounds like a good spot for it. The official reading of VW/Porsche for the 914 was 13.7 to 1 at a cruise 2000-2500rpm in 4th gear with a light load. Meaning tooling down the road in 4th giving it the gas without any coasting up a slight grade.

Tris also quoted 13.1 - 13.5 way back when as the very healthy range for VW's, mainly to keep the head temps lower.

All of those plugs look fine. =)

72Hardtop wrote:What range should I shoot for. I'm thinking 13:1- 13:5...for a bus?
If you had to guess Bley what do you think the LM-2 will say? Your saying a tad rich...so I'll start by saying it's somewhere between 12.8 - 13:0. Can't wait for the LM-2 reading.

This is a difficult question. You will find numbers all over the map. We can only compare at specific points that we all share, like:
Full Throttle At Torque Peak
Full Throttle At Horsepower Peak
Off Throttle At Above RPMs.

Do not be surprised to see the mixture leaning out as you move from the torque to horsepower peak, this is normal. Your best power comes in at 12 to 12.5. You want to have the correct fuel mixture when the engine is working the hardest, then see if you can lean it at low load/low rpm.

Do you have a CHT gauge?
Colin

Agreed that 12.5 at Full throttle at hp peak about 4000 rpms is a important marker! Cruising down the freeway at 65-70 at half throttle is also important but can be all over the place

I've found that in a bus ones foot is generally in it more than say a bug, 914 or Ghia. Not often one is going down the highway at 65mph+ with 1/2 or less throttle in a bus. On the flip side here is another picture of the above #3 opened up...no that's not a shadow at the base of the plug. What do you guys feel/think?

As I said, checking the Cruise "Part load" setting is important as we drive a lot at 2500-3500 rpms with half throttle with a load not coasting. This is where you should be at the 13.7 setting. Find a long slight uphill slope of the freeway and do your check there for this setting or a city street where it is a long slight uphill grade. I use a section of Beacon Ave and then jump on the freeway at Columbian Way going south up the long hill. You will see "off throttle" the AFR will lean out to 16 or higher to 1 which is fine as there is no load. Its that when you are placing a constant load on the engine the AFR must be right. Try it.

Thanks Bley...I know the spot your talking about. I get this LM-2 hooked up we should get together. I'm over in Renton Highlands. I'm going to the exhaust shop on Wednesday and have them weld the bung in for me.

No CHT gauge for me...not much of one for excitement. I believe if built properly and not skimping on quality one should end up with an engine that should garner at least 120,000 miles before rebuild time. At least that's how it's worked out for me the last 25+ years.