jungle_runner

this afternoon i pulled the front diff and oil pan in about 1.5 hours

i don't even want to say how long it took me the first time

tomorrow i will work on the bearings ... i got prices from the local autozone ... they come in packs of two and the prices range from $4.99-$8.99, not bad

i just put the new cork oil pan gasket on less than a week ago and i haven't driven anywhere ... do i need to buy a new one? can i just lace it with a thin film of silicone?

will i be able to pull the rods through from the bottom so that i can check the pins?

i found this great thread on how to replace the top half of the bearings when going from the bottom: https://www.yotatech.com/forums/f123...ce-not-102568/

Country Hank

This may sound wierd, but have you checked the bell housing bolts to make sure they are tight? I bought a truck with a bad "Rod knock" once for $100, tightened the bell housing and drove it for 2 years. The bolts came loose and allowed the tranny to sag a bit and the clutch (or torque converter) was knocking against the bell housing.

Karlton

I wish you luck and I'm curious to find out if replacing the bearings solves your problem. I considered trying to replace bearings from underneath, but I was advised that if the bad bearing had spun it would most likely be necessary to recondition the rod and the crankshaft. In my case the rod journal on the crank was a real mess. I had a machinist grind my rod journals. Aside from the potential for the rod and crank to be out of round, there is also the possibility that the oil passages in the crank may contain tiny bits of bearing shavings that could lead to premature failure. The guy who did the machining on my crankshaft and rods was very helpful, pointing out how I should go about cleaning out the oil passages in the crank to ensure that no old bearing material fouls the surfaces of the new bearings. But hey, (and I'm not being sarcastic) swapping out the bearings from underneath certainly sounds quicker and cheaper than yanking the whole engine out! Good luck!

bigtrucknwheels

good luck!

PlugItIn

if the crank is bad, the engine has to come out. But it is by far quicker and easier to do the bearings from the bottom...youll be able to get the main and rod bearings from underneath fairly easily. There are a couple of threads about this out there somewhere...

jungle_runner

country hank, thanks, i checked but nope, i wish!

karlton, a spun bearing probably means that it's no longer in it's seat in the rod cap or end cap?

bigtruckwheels, thanks!

the good thing is that once i replace the bearings, i can start the engine before putting the dif back in.

i noticed allen key screws on each side of the bearing ... something tells me i should leave those alone and just work with the bearings for now ... it's pretty easy to get top half of the bearings out ... the first rod bearing i did (#4) just slid right out from the top of the rod cap

PlugItIn

a spun bearing would not be lined up right in its seat. The half moon shaped would be turned as to not "seat" in the half moon of the block or the bearing cap. If that makes sense...it blocks the oil passages and is very bad.

Karlton

As PlugItIn describes ... the bearing spins in it's seat and then the oil hole doesn't line up and blocks oil flow. Very bad.

Those allen screw things are plugs for oil channels that lubricate the bearings. The channels are drilled diagonally through the main and rod journals. The guy who machined my crank had me remove those plugs, clean all the oil passages with fuel and gun cleaning brushes, then wash the whole thing with hot soapy water, dry it off, blow out the moisture with compressed air, then replace the allen head plugs using thread lock. This was just to make sure that any loose bearing material would not be lining the oil passages when the motor went back together.

But all of this is not really feasible from under the truck!

I would think you'd be able to tell if a bearing is totally messed-up. Same with the rod journals on the crank.

jungle_runner

i've never seen bearings in my life ... i had an image of ball-bearings in my head ... anyhow, the noise is coming from the rear of the engine, so i pulled main bearings 4 & 5 and rod bearings 3 & 4

there is a lot of little pits and main number 4 looks like it was worn a lot more in the middle than the sides ... main number 5 has some pretty obvious scratches ... i definitely think these should be replaced, but it's hard to believe that this could cause the knock

remember, i went over a concrete embankment where the frame was jarred on the concrete, i drove around about a mile and parked at in-n-out burger, the engine cooled while i waited for my order and when i restarted, there was the knocking

so even though i'm going to replace the bearings, if the jolt had anything to do with the knocking, which is very likely, then this n00b would guess rod or piston pin, but hearing from you guys is better than my guesses

also, once again, using a mech's stethoscope, i pin pointed the knock to the block, back near the 3/4 pistons

thanks for reading

PlugItIn

youd be surprised how little it takes to get a knock...if you had plasti-gage you could measure your bearing size and see how bad they actually were...your engine still has oil pressure, right? Because i'm trying to think of what could cause this from a sudden jolt...

jungle_runner

plugItin, i'll go get some plasti-gage right now so i can see which i need to replace and which can stay ... but i should probably replace them all ... especially all the main bearings or else the crankshaft could bind (i've read)

the bearings toward the front of the engine don't look as bad ... but check out that beautiful gouge in main bearing number 2

and for all you other n00bs out there ... don't try to rotate the crankshaft with the rod caps off

PlugItIn

i would replace em all...make sure your crank is ok too...

jungle_runner

yeah, i agree with you that i should replace them all and check the crank. i think i can afford to replace all the bearings, but to check the crank, i have to buy a dial gauge (according to the FSM), i could probably figure out how to rig it upside down with the crank still in the engine, but i'm running out of time and money

i will post my plasti-gauge results later today so i'll know how bad they were, then i'll replace the bearings and hope for the best, i'll start 'er up again tomorrow

thanks

PlugItIn

just make sure theres no deep gouges in the crank itself...that bearing was pretty bad

jungle_runner

ok i will look at the journals closely ... i was just reading a mechanic's automotive training book (Modern Automotive Technology by James E. Duffy) and it said that bearings are made with softer metal on the inside and with steel on the outsides so that they absorb the abrasion of dirt particles

so all of my main bearings were within spec, although i didn't support the crankshaft with a jack to take the weight off of the caps, so they may be close to the edge ... only the number 2 rod bearing was at .004in (definitely out of spec)

anyhow, i'm going to replace them all and if that doesn't work i'll have to take it to a mechanic because if i pull the head, i'll have to mill it and i don't have that equipment, might as well just take it in

thanks for the tips guys, keep 'em coming

screech

I am really interested in this repair, hows it coming along?

grant526

My buddy blew the head gasket in his 93 with a 22re last fall. We rebuilt the top end, put a new timing chain, guides and everything on and got it back together. when we started it, it had a knock too. Turned out that when the gasket blew, and it allowed coolant into the crankcase and oil pan, it ruined the crank bearings. So we ended up pulling it and nearly completely rebuilding the engine at Thanksgiving. But it runs and sounds GREAT now!!!

Good Luck with it! Sounds like you're on the right track!! : )

screech

yeah the bearings blew because it caused the oil viscosity to become lower than required, causing the bearings to flow to easily and any dirt that was in the oil would scrap the bearings.
If that doesnt help think of you taking a water hose to two pieces of metal with a little itty bitty gap. when you apply water and pressure the gap tends to become larger allowing larger than normal items to flow through them.

PlugItIn

I disagree...the bearings were worn down due to time, running motor dry of oil, not changing oil at regular intervals, or antifreeze/water in the oil. There are a couple more things that would destroy bearings, but those are some of the common ones. Once the bearings wear down beyond limits, oil flows very easily through/around them and that causes loss of oil pressure throughout the entire block/oil system.

And JungleRunner, these cranks very strong. They are forged and some of the strongest factory cranks made IMO.
Just my .02 cents

screech

totaly agree plug it in, totally.
Possibly, now just hypethically speaking though the water/oil mixture will more so increase a bearing going bad. Water oil mixture flows much easier than just an oil mixture causing the low oil pressure fault.