Spark plug review

[bran100]

I've been reading a bit on how to analyze plugs and wanted to get opinions from people smarter than me. I rebuilt my motor about 1,500 miles ago, and while it's running good, I find the power lacking, particularly as I bored it over, added 4mm dome pistons, and Mark's 274fi cam among many other things. I'm still waiting on Mark's computronix ignition to come back in stock, and while I'm waiting I'll likely upgrade the stock exhaust. I added the adjustable cam gears, and set them according to true TDC, but haven't experimented with adjusting the cams yet. I'll probably wait until I get the ignition and exhaust dialed in before I experiment with that.

Anyway, what are your thoughts on these plugs? In the first photo, #1 is on the right, and #4 is on the left. For the second two photos, it's the opposite - #1 to the left, #4 on the right. I think they look pretty decent, but if I had to pick on anything, maybe a little rich? If so, I'm not sure how to tune an FI to lean it out a little.

[seabeelt]

Not really sure about FI plug colors, but if you look at a Haynes manual, I'd say if anything they were ok or worst case on the lean side with normal being a light brown color.

[So Cal Mark]

I wouldn't lean it out if you're looking for more power

[narfire]

Not sure about your plugs, but if you can find someone to degree in the cams properly do so. The power difference when they are dialed in properly is really noticeable. When the engine is in the car, I pulled the rad to make it easier to see the wheel and made the fellow who did mine happier.
I have more or less the same set up and have really enjoyed using the Fiat as my DD the past month or so.
Chris

[TStark]

White is best, grey is bad..
Can't really tell much more from tip color.

One needs to do an extended wot run then use a plug scope or cut away the plug threads to measure the width of the soot ring on the base of the insulator. 2.3 to 3 mm is the target

I've jetted boats and Int loadstars, where you find out quickly if one does it wrong.

[bradartigue]

They look great for a Bosch injected car with non stock cams. Most cam jobs on L-Jetronic burn terribly rich and the owners go back to stock or mild cams. Cam adjustment is essential if you are using anything but the stock camshafts; the lack of power you are feeling is due to them being set to a pretty tame baseline. The power will be in the adjustments.

Do not mess with the L-Jetronic system itself; it is a waste of your time (and potentially money as components fail). Don't let someone tell you to try to fool the spring, it only creates top-end problems (right around the time your cams "come on" the L-Jetronic will "lame out").