I took advantage of the nice weather this weekend to take care of some overdue maintenance on my 86 744T. I drove to central PA, about 250 miles from NYC. On the way down, I recorded app. 22 mpg.

Over the weekend, I replace the air filter (the old one didn't look too bad, but it was a pain to open the air box, so I figured what the heck.

I changed spark plugs 1 and 2. I tried to change 3 and 4, but 3 would not screw all the way out, and I feared that whoever changed the plugs previously may have cross-threaded it, so put it back in. No. 4 wouldn't budge, so I'm leaving those for now.

Finally, I did some maintenance on the PCV system. The hose from the oil separator to the Y fitting had cracked when I replaced the engine wiring harness (it has been taped up since), so I replaced that.

While poking around I came across a rubber hose that led to nowhere, and upon closer inspection, I noticed that the tip of the Y fitting had broken off. Took care of that with a new Y fitting.

Gas mileage on the way home: 28.8 mpg.

What did I do right? Does a properly operating PCV system make that much of a difference?

Joe

Start soaking the stuck plugs with PB Blaster or Kroil. Make a ritual out of it. Do it often. The one that would come part way out will be easy. Unscrew it some and add penetrant, screw it in. Next day do the same. It will give in with persistance and patience. The other may take longer, but you should be able to prevail. Accept no substitutes for PB Blaster or Kroil. Also add antiseize compound to the threads of the plugs to avoid a repeat of your situation.

Randy

Randy,

Thanks for the tip on P-Blaster. Regarding anti-sieze, the FAQ seems to have conflicting info on its use with spark plug threads.

Is there a consensus (as well as a consensus on the use of a torque wrench) on this?

Thanks again.

Joe

I don't use a torque wrench on spark plugs- I have been installing them since before torque wrenches came into being (grin).

I NEVER install plugs without antisieze.

Randy

Been there. I would have bet the plug thread was crossed on a new purch.

Besides the PB Blaster, remove the plugs when the engine is warm. The coefficient of expansion is greater for aluminum than steel. Work the plugs in and out after a good long soak of several days.

Important: Before installing new plugs, clean up the head threads with a cotton rag lightly soaked with carb cleaner and a cleaned up old plug. When everything is clean you should be able to twist the plug in all the way by hand.

When using anti seize, reduce the normal torque of 220 in-lbs by 40% to 132 in-lbs and, 132 is not much.

Photo: It was a long time since this electrode last saw daylight. The gap was wide enough to measure with a yard stick. The distributor was also very worn but somehow the car ran fine.

--
Tom F Back to three 940s. Mods, RainX. Lien holder on two more (the kid's). Rust in pieces, '78 245

I did some maintenance on the PCV system. The hose from the oil separator to the Y fitting had cracked. While poking around I came across a rubber hose that led to nowhere, and upon closer inspection, I noticed that the tip of the Y fitting had broken off. Took care of that with a new Y fitting.

Those were the major fixs. You fixed vacuum leaks in your system. Any time you do a tune up and replace parts such as plugs and air cleaner it helps. 28.8 is out standing mileage for a Turbo. Manual Transmission?

Thanks, Al. Yes, the car is a manual transmission, and I run Mobil Super 93 in it.

I was stunned by the mileage, too, especially since the trip was on I-80 and most of the traffice was going 75, give or take.

Next on my list is to take care of the other spark plugs and replace the vacuum hoses.

Joe