I figured I'd start a proper thread about the work I'm doing to my Montero. I work on motorcycles and have built/helped build a few vehicles of mine and friends. I used to own an early Bronco and am pretty mechanically competent, but I still have lots to learn.

My girlfriend and I flew out to Wichita Kansas to pick up this:

(this photo is actually from when hurricane sandy caused a gas shortage in NYC and we had to drive to CT for gas)

A 1988 with under 100K and a supposedly freshly rebuilt and broken-in motor. This Montero was towed behind an RV for much of its life. The seller told us that one day the balance shaft chain went, taking the oil pump with it and seizing the motor. The truck sat in storage for 14 years before he inherited it. He rebuilt the motor, drove it for a couple months, and then sold it to me. We drove the Montero from Wichita to our home in Brooklyn, NY, camping the whole way up.


During the last leg of the trip the engine started to develop loud valvetrain tapping. I was very conscious of the oil levels but in retrospect I think I underestimated the oil consumption during such a long drive; The motor might have been low on oil during a couple stretches of the drive. Bummer.

After getting home and over the course of one oil change and about 4500 miles of city driving (and I mean CITY. NYC driving is about as city as it gets), I began to notice a significant increase in oil consumption and a small oil leak developed. Eventually I was having to add about a quart for every tank of gas to keep the oil level up.All the while, I never saw any smoke from the tailpipe and the leak from below was very slow. Where was the oil going? <img src="/forums/images/graemlins/confused.gif" alt="" />

Once while adding oil with the engine running, I was surprised to see the oil get sprayed upward by airflow exiting from the oil filler cap. I can't imagine this is normal. Could be a sign of exhaust gas in the upper crankcase somehow, maybe a bad head gasket. Also, probably a sign of high crankcase pressure?

After crawling under her for the first oil change, I saw that everything was covered in oil. Looks like oil is being flung around by the driveshaft. I guess this accounts for some of the oil I'm loosing! Also noticed that the oil filter was slightly crushed in on one side. I dismissed it as from the previous owner installing a damaged filter to save a little money.

Then one day upon start-up she suddenly started SPEWING smoke. I thought for a moment it was coolant being burned as the smoke looked white. Also, the smoke would go away after the motor was warmed up. The smoke never smelled like coolant though. I did a compression test and all cylinders were within spec and consistent. I checked the coolant for oil and the oil for coolant. Both checked out ok. Determined that it must be smoke from oil being burned. Replaced the PCV valve for good measure and prepared to change the valve stem seals, thinking they were leaking the oil into the combustion chambers.

While I was waiting to do the valve stem seals, oil consumption got much worse. I monitored oil levels and she was now burning about 2-2.5 quarts per tank of gas. Fuel consumption dropped from roughly 20mpg to 10mpg! Before I could get around to changing the seals I blew an oil filter and oil started dumping from the flange. After doing some research, I guessed that the pressure relief valve in the oil pump might have failed, so I decided I'd have to replace the oil pump. I now had oil getting into the combustion chambers and unusually high oil pressure? Bummer.


After much thinking, I decided to replace the head altogether with a non-jet valve casting from Clearwater. You might notice I also went with mechanical lifters. I don't mind doing valve adjustments. In fact I like it.

Pulled the old head, and just as suspected, found carbon deposits on the piston tops and the intake valves were incredibly gunked up.


Flakey carbon in #2. I'm going to clean the piston tops and vacuum out all of this.


Intake valves 1-4.


Exhaust valves 2-4 do not look good.



Cam and journals show signs of oil starvation.


Also found a crack in the head at the front, around one of the bolts that holds the front chain case.
Not a good look, but could this really affect much?


[img]http://img607.imageshack.us/img607/7640/photokyj.jpg[/img]
Proceeded to pull the front case, tearing the oil pan gasket in the process. Finally got to the oil pump and was surprised to see how clean it was. No visible obstruction to the pressure relief valve. Spring was clean and the valve 'plunger' moved freely. Would a faulty or stuck pressure relief valve be visible? Wondering now if there was a pressure problem to begin with. I should have hooked up a mechanical gauge and tested. But in any case, something caused this oil filter to fail.
[img]http://imageshack.us/a/img163/6827/img0908zq.jpg[/img]
Suddenly remembered this is exactly what the original filter that came with the vehicle looked like, as described earlier in this post. Can this warpage be a result of high oil pressure?

[img]http://imageshack.us/a/img541/5492/img0909p.jpg[/img]
No plated links on the timing chain so I'm marking with a little liquid paper.
(Question: Do the balance shafts need to be "timed"? If so, how is this done?)

This is where things stand today. This weekend I'll be installing the new oil pump and begin reassembly.

All thoughts welcome on any of the above! Tips and pointers welcome too.

Rol