246K mile Engine Woes

[alaubhan]

Hey guys,
Within the last two weeks, my 2f has started making some funny noises. Particularly with the belts. This weekend, I started looking at the potential problems, so I did a compression check and visual and audible inspections.
Compression check:
Cylinder 1 2 3 4 5 6
PSI 160 140 130 130 130 140

Visual Inspection:
It looks as though there is a slight wobble in the crank pulley, and there is a small amount of oil coming from the front main seal. This amount is about 1 quart per 1000 miles, does not really seem that rapid. The spark plugs had a decent amount of buildup, so I replaced them and the air filter.

Audible Inspection:
There is a small amount of valve chatter. The previous owner claimed that a valve guide may need to be replaced, so it did not seem irregular. Also, he claimed that a cylinder inspection with a light still showed honing on the cylinder wall, since he used Amsoil since about 90k miles. There is a slight knock, but that may be from the wobble in the crank pulley.

Is it possible the pulley itself is bent? Has anyone had this happen before?
With this amount of miles, I do not want to take the whole engine apart. Does anyone thing replacing the main and rod bearings will assist this situation? The book states the exhaust cam lobes may be worn. I should take off the head to get ahold of the situation? Perhaps to clean off some excessive buildup from the valves and replace the bad valve guide, should it need to be replaced. Any information on this problem would be GREATLY APPRECIATED!

 

[lovetoski]

I'll go in order of simple first...

Front mains almost always leak on high milage 2F engines. Don't replace it just for that reason. If you have to dig in, then go ahead and replace it at that time. Just check oil level frequently. Though, that goes w/out saying regardless the condition of your front main...

Pully could be bent, could be coming loose, could be something else. I'd suggest removing the belts, and going from there.

The compression would be fine, except for the big jump between #1 and #2. Though, if it runs fine otherwise I wouln't worry too much about it. The valve noise might just be that the valves aren't adjusted correctly. I'd start by getting that right, then do the compression test again. Also can do both a wet and dry test and see what differences (if any) you find.

How is oil pressure? Worn bearings usually results in low oil pressure. If your oil pressure is fine, there's less chance it makes sense to open up the engine. If it's low though...

Finally, you can do a used oil analysis (Blackstone labs and others do this) and it can tell you a lot about a used engine. For example - is there coolant contaminating the oil (blown headgasget) or is there enough bearing metals in the oil to suggest premature bearing wear?

Hope this helps.