Historical maintenance in this area: water pump replaced in 2006; have mileage recorded but not handy.
Failure event: Driving at 65 mph. Tach dropped instantly to zero and CEL illuminated. Engine braking dramatically reduced. After stop and attempting restart, cranks very fast and "doesn't sound right".
Diagnosis: No spark Some symptoms of ignition module failure, so swap modules. Still no spark Probe coil and module power to verify fusible link H is intact. It is. Crank with distributor cap removed. Rotor does not rotate. At 200k miles a timing chain failure is much more likely than a sheared camshaft, so get started on that.
The timing cover is cast aluminum and two sided. The inner side is exposed to the timing drive while the outer side provides the back of the water pump. The water pump bolts directly to the timing cover, but some of its bolts go through the timing cover and directly into the block. However, the bolt holes have corroded on the inside, making the bolts very difficult to remove, even though they are not screwed into the aluminum.
There are four usages of bolts: 10mm x 75 mm (4x): These straddle the water inlets to the block. From the factory, two of these have T50 heads and two have 15mm hex heads with ~15 mm long studs 8mm x 70 mm (4x): These go through the water pump and timing cover, threading into the block. These have T40 heads. 8mm x 35 mm (3x): These go through the timing cover only, threading into the block. These have T40 heads. 6mm x 25 mm (4x): These go through the water pump only, threading into the timing cover. These have T30 heads.
Stuff that went wrong:
Broke a T50 bit Broke a T40 bit Rounded out a T50 bolt Rounded out a T40 bolt Wrung off a 10mm stud headed bolt All other bolts through the water pump corroded, nearly seized and extremely difficult to remove.
I had a friend weld an expendable socket to the 10mm/T50 bolt and successfully unscrewed it, although I can't remove it until the timing cover and water pump assembly is out of the car. We will deal with the rounded out 8mm/T40 bolt the same way tomorrow. Getting the water pump and timing cover off the broken bolt is not expected to be what most people call fun.
Needless to say, there will be zero torx heads among the bolts that go back onto the car.
Given how hard it's seized and how close EVERYTHING, including fuel lines, is... I'm going to rent a car this week and figure it out next weekend. I'm pretty sure the 2.8 will have to come out, and if it comes out, it's not going back in. It's not in my garage or I wouldn't be as annoyed about it as I am.
At any rate, it's time to stop relying on 1980's technology.
[This message has been edited by Will (edited 01-14-2018).]
Pictures still to follow... I have the front cover off... it had seized to one of the 10mm water pump bolts. Feh.
The chain guide had broken off and gone between the chain and the crank sprocket, causing the chain to break. The chain itself and the sprockets are in fine shape but that F@$%ing guide is worn-ass out.
The oil pressure tube between the filter boss and the oil pressure sender is seized to the flare nut. Are those available in the aftermarket? I have one I can likely steal from The Mule's original engine, but if I can get one new I'd prefer that.
I was able to rescue the oil pressure tube with some heat on the nut. The car's back together and running now. I've uploaded the photos... I've just been busy and procrastinating about writing the whole ordeal up.
The piece of the guide that broke off went between the timing chain and the crank sprocket, breaking the chain. Replacing only the guide was not an option, and a new timing set comes with a new guide.
Multiple cycles of heating and dousing with penetrating oil will usually (eventually) get the job done. Also, a pro tip: after you get the oil pressure tube loose, pull back the fitting and clean off the tube with some fine sandpaper. Then put a light coating of anti-seize compound on the tube before you slide the fitting back in place. That should make it easier next time around.