1996 Ford F150 4.9L (300ci) I6 5MT 4x4

[Christ]

Originally Posted by vskid3

Offroaders use dual transfer cases or "doublers" to further reduce gearing. They usually take the low range section of a transfer case and attach it to the existing transfer case. You could do the same, but reverse the add on. The only problem is you wouldn't be able to shift it on the fly.

I know about this, I've done it to get as low as 60:1 gear ratios for crawlers.

My thing is that I need something that I can shift on the fly, and it needs to have two very specific gear ratios.

I actually have also considered using an old automatic transmission w/o the torque converter as a sealed unit. (They don't need the fluid cooled if it's not going through a torque converter or being shifted up/down constantly.)

The problem is that there's only one 2-speed solution that I know of, and I don't think it has a gear that's close to 1:1

[Christ]

All the plugs from the engine


This was #1... they're all this bad, the electrodes are worn at nearly 45* angles, and the ceramic insulator is burned on the opposite side of the angled wear on every plug.

What would cause that, other than age?

[Frank Lee]

They look fairly normal to me, just really aged and worn.

However, there's that one, maybe two, where the ground electrode extends so far past the center electrode... or is that just the angle of the pic? Strange.

[Christ]

I changed the gap on the #1 plug, it was initially a little under 100 thou.

There are a couple that the ground straps were slightly offset from center, due to careless gapping, best I can figure.

Clearly, those plugs are very old. I can only wonder how old, as it honestly appears they'd almost never been changed in 160k. Never seen 'em get that bad, personally.

I'm going to keep checking my new ones periodically to make sure nothing's going on w/ the engine, but I don't see any evidence of lean/hot/rich, etc.

I do run the engine as low as 700 RPM under load (no shaking or anything!), so I'll also be checking for "dieseling" and coke buildup from incomplete burn, just in case. I know the carb'd engines can handle it, but w/ the knock sensor, it might be affected slightly by lower RPM high load operation, so I'll keep an eye out in case I need to disconnect the knock sensor.

[roflwaffle]

The internet says...

Three conditions can indicate overheating of the spark plug. These are poorly eroded electrodes, yellow or white glaze and burned insulator nose. A defective thermostat, improper heat range or too rich carburetor can be a cause of this plug problem.

Two outa three ain't bad. It could be age, but might as well check if the carb could be running rich.

[roflwaffle]

Originally Posted by Big Dave

I've talked to literally hundreds of truck guys. Bigger diameter tires actually reduce MPG.

The reason is increased rotational moment of inertia. RMOI goes up with the square of the radius. Big tires are OK if you go long distances at a constant speed, never slowing down or speeding up.

I don't drive that way.

Even w/ large tires RMOI is quite small for most vehicles, something like 10Wh/mile assuming a 0-60-0 every mile. Odds are it's an increase Crr/CdA associated w/ the larger tires.

[Christ]

Yeah, but none of the "causes" lines up with anything that's happened (since I've had it) with my engine.

They don't look too bad, aside from the obvious. The burnt ceramic, since I just looked at it again, isn't actually burnt. It's combustion deposit that I can scrape off with my thumbnail. It appears to be a brownish color around the outer edges of the deposit.

[roflwaffle]

If it's not actually burnt then it probably is just wear like Frank mentioned. If it shows up in another set then it might be worthwhile getting a wideband O2 sensor, especially since you could lean it out in that case.

[Christ]

I have to replace the heated O2 sensor anyway, the heater circuit isn't working, and I'm not aware of any quick fixes to make the heater circuit work again.

[Frank Lee]

Speaking of O2 sensors incl. heated ones, is there a good way to clean em? All I've come across is soak em in gasoline. Would carb or brake or MAF sensor cleaners work? Don't want to hurt the dang thing either.