Crank / Journal advice

[scouttster]

Ok, I got the oil pan out.. I'm looking at the crank-shaft and the journals, etc.. I do recall someone mentioned scouring or grooves of some sort. Where in there do I look? Give me some advice on inspection of the journals, etc. What to look for? Thankyou.

[sdoan]

Wow! I think that was me, but I assumed the engine was out of the car. Unless you have a knocking in the engine or some other reason to suspect a crank bearing problem I'd leave it alone. Just run good 15w-40 or 20w50 oil (unless it is really cold where you are) and keep it changed it should be fine. Also when doing an oil change - fill the filter with some oil and don't let it start until it has oil pressure (light on dash goes out).

To look at the crank journals you'd have to pull the 4 rod caps and the 5 main bearing caps. To replace the bearing inserts you'd have to pull the crank down. Not really possible with the engine in the car.

[scouttster]

Understood.. Just sort of a driveway mechanic here with book in hand.. So, forgive me if I ask idiotic Q's. Anyway replacing all the gaskets on the front of the engine, they were all shot and leaky. I'm going with a rubber gasket for the oil pan - anyone else use the rubber gasket? Should be fine?
Thankyou for the replys / advice.

[takza]

Usually the rod bearings go before the mains and I think they can be replaced with the pan off....though not too easy if the head isn't off. You can inspect them by removing the caps...look for grooves and wear...use some plastigage? But if you had no knocking...probably leave them alone?

[sdoan]

Understood.. Just sort of a driveway mechanic here with book in hand.. So, forgive me if I ask idiotic Q's. Anyway replacing all the gaskets on the front of the engine, they were all shot and leaky. I'm going with a rubber gasket for the oil pan - anyone else use the rubber gasket? Should be fine?
Thankyou for the replys / advice.

These are great questions - how else do people learn? You should be commended on your courage to tackle this. Another possible leaky spot is the front engine seal surrounding the front of the crank. If it leaks badly, it's probably worth replacing it - even though it adds some time, $, and complication. A trail of shiny dirty oil running down from the seal would suggest it. If it is leaky, it might be worth replacing the oil pump at the same time, though that adds even more expense and complication.

No experience with rubber pan gaskets, is it like thick black paper with a rubberized surface? Probably will be ok. Unless the instructions recommend against it, I'd use gasket sealer on the pan side at least. Make sure all the oil is off. Gasoline or white gas for camp stoves makes a good degreaser. I'd probably glue the gasket to the pan with gasket sealer (unless the gasket will get scraped off by those 2 studs when you put the pan back up), then put a thin film of sealer on the gasket and tighten it down to the block. Rookies usually use too much gasket sealer (think of it as a thin layer of glue or a layer of paint) and tighten the bolts too much.

As for looking at the bearings: How many miles on the engine? Unless you suspect a problem it is probably better to leave it alone - you have to keep all the bearings and caps matched to their rods, you have to retorque the bolts, you risk getting dirt in the bearings, and you risk nicking the journal with the threads of the rod bolt. Then if you replace the bearings you have to plastiguage the bearings which compounds the risks because you have to assemble it and take it apart another time.

After you've got the whole engine back together replace the oil and filter, pull the spark plugs, disconnect the green connector in the wiring that goes to the distributor and crank the engine on the starter until you have oil pressure. Then replace the spark plugs and reconnect the green distributor connector and start normally. I always advise this because I wrecked a rod bearing on an old engine by starting it and waiting for oil pressure - had to pull the crank and have it machined.

Let us know how it goes.

[Petros]

I would not disturb the main bearings unless you have a reason to suspect they are bad, I do not think it is practical to replace the mains with the crank in the block anyway. I have seen rod bearings totally shredded, all the way through the gray metal to the copper base, and the main bearings still within spec. The rod bearings always go first.

The rod bearings can be inspected, or even replaced with the crank in and the head on. Pull the rod caps with them in the down position (carefully mark the caps before you pull them, they have to go back on the same way they came off do not mix them up or even reverse them). Then push the rod/piston up until you can see the upper rod bearing shell (be careful not to scratch the rod journal with the rod bolts), you can rotate the crank a bit to get a better view of the upper rod bearing. the upper one is the one that takes all the wear. Usually the #4 bearing is the worst (furthest from the pump). If you see any copper metal showing through the gray metal bearing material they must be replaced. A few small scratches will not affect much, put if deeply scratch, or if worn through to the copper backing metal, they are toast. Fortunately they do not cost much to replace (about $20-25), take the bearings with you to the parts store so they can verify if they have standard or over-sized bearings.

You can just replace the rod bearings without replacing the mains, I have done it a number of times with no issues. Also inspect the rod crank journals for scratches or pitting. They should be smooth and shinny. If not badly damaged they can be polished with strips of 800 grit wet-and-dry sand paper and solvent until smooth. Make sure everything is clean before you put it back together and torque the rod caps.

Rubber gaskets can be reused if you are careful with the install. Glue it to the pan side with sealer, and then put a very light coat of oil or grease on the top side of the gasket. Clean off all of the old gasket material from the bottom of the block. Remeber to install the oil pick-up (an easy thing to forget, I have done it). DO NOT OVER TIGHTEN THE PAN BOLTS, it will leak (I hate oil leaks) or damage the gasket. Even the torque spec for the pan bolts I have found is too high to risk damaging the gasket. Tighten the pan bolts until you see the gasket just squeeze out a little from the side, and get all the bolts the same tightness so there is even pressure on the gasket. That should do it.

BTW, I would replace the front main oil seal while you are at it. Cheap and easy to reach with everything you have removed.

Good luck.

[scouttster]

Car has 114K orig mileage..
Yes, will replacing the crank seal as well.. Oil leaks bug me! Hate them!
Thanks