I think I spun a rod bearing.......

[Electricat]

I replaced my rod bearings soon after I got the car, and have driven it around 100k miles since then. I heard some noise when driving it one cold night about a week ago. Oil pressure looked ok, and I figured the noise was just another timing chain slap issue. It did seem a bit down on power, but I thought it just wasn't liking the extreme cold. Changed the oil a few days later, didn't notice any shiny stuff in it. Next time I drove it, the noise was still there, but quieter. The next time I drove it was this morning on the way to church....and the noise is now LOUD! and oil pressure is low. It is sitting in a parking lot on the other side of town now......

I'm pretty sure this is a spun rod bearing...anybody have any input on this???

 

[rubydist]

The noise should be a sharp knock if its a bad rod bearing - is that what you hear?

If so, it will need at least one new rod plus a new crank, or regrind both, or swap in another good used engine.

 

[Eric VerValin]

sure sounds like it to me...

 

[ycode90]

It happens.

 

[Electricat]

Sound is a horrible rpm dependent hammering noise....my dad listened to it earlier, his car knowledge is pretty old school, but he's heard plenty of blown up motors over the years, and says it sounds like a rod bearing to him, especially considering the accompanying loss of oil pressure.

I'll be getting it towed home in the next couple days and tear into it and asess the damage, and at that point I'll have some decisions to make....but I don't much like ANY of the options!! :cry:

 

[SHOtime2511]

time for a 3.2L swap.

 

[VortecGT]

or ill just trade ya for my atx, no really I have a spare motor but if you dont want to do the work let me know!

 

[sperold]

Do more diagnostics in the car, including pulling the pan, before you proceed to the next step. I don't know enought about these motors to give any helpful tips or advice. I know I would fix the one that is in there. You have to take it out even if you swap in another one. So that work is the same. You can pull the crank and have it machined to .010 under or whatever it takes, and buy the new oversized bearing set. I don't know if the piston can come out the bottom in this set up. But if it can I would take it to the same shop and have it resized. That way everything stays in balance as you have all your matched pieces in place. If the piston doesn't come out the bottom, you have to pull the head.
You have already put new rod bearings in a motor and had it fail. The next used one may not be any different.
Time to do something different.

 

[Racer X]

Do more diagnostics in the car, including pulling the pan, before you proceed to the next step. I don't know enought about these motors to give any helpful tips or advice. I know I would fix the one that is in there. You have to take it out even if you swap in another one. So that work is the same. You can pull the crank and have it machined to .010 under or whatever it takes, and buy the new oversized bearing set. I don't know if the piston can come out the bottom in this set up. But if it can I would take it to the same shop and have it resized. That way everything stays in balance as you have all your matched pieces in place. If the piston doesn't come out the bottom, you have to pull the head.
You have already put new rod bearings in a motor and had it fail. The next used one may not be any different.
Time to do something different.

I would not recommend machining the crank at all. Doing so will remove the hardening on the journal, and weaken the crank, making it susceptible to future failure.

If the bearing isn't spun, and the rod and crank are undamaged, measure with a plastigauge and install the appropriate bearing. If there is rod and crank damage, they'll need to be replaced.

Personally, if the crank and rod are damaged, I'd do a 3.2L swap. But that's just me.

 

[rubydist]

... I don't know if the piston can come out the bottom in this set up.....

Pistons do not come out the bottom on this engine (nor any modern engine that I am aware of). The head needs to come off.