3800 L67 bearings question

[71Chevyguy]

Just looking for some advice from anyone who has dealt with these engines before. I can't seem to get many of my questions answered clearly. I have the engine out of my husband's Regal GS s/c 3800 L67, 169k. We have had this car for a while and have put around 3k miles on it since we bought it. It doesn't have the typical 3800 rod knock, it barely made any noise at all honestly. But I have it out to get the water pump done and replace gaskets, timing chain and oil pump to get it to stop making a mess. No smoke or oil use really, ran perfectly smooth, power was great, etc. The intake gaskets were done as soon as I got it home, so there is no coolant in the oil. Not sure what happened to it before me though. The gaskets sure weren't fresh and it seems that it has stop leak in the cooling system that I have flushed out, that uncovered a radiator leak .What I would notice sometimes is that when hot, and I would pull away from, say, a stop sign. I could hear a rhythmic thump. It wasn't the typical tap from say a rod knock or bad lifter. It almost sounds like someone repeatedly hitting a low note on a xylophone honestly. But this was only like 3 thumps and it would go away. No noise on harder acceleration and none on deceleration or when cruising. It wasn't always, but I did notice it since I am really sensitive to things like that. Most people honestly would just say the engine is silent because 99.9% of the time it truly is. I had some VW diesels that made a similar sound, but it was normal on those haha.

Basically I have the engine out and the oil pan off and there is some metal in the pan, some flakes (non ferrous). Obviously something is going on and I obviously DID hear a little something. Others have told me I am worrying too much, but I prefer to fix it before it sends a rod through the block, if that is what needs to happen. Now my problem is: can I check on the bearings? Do I just do the gaskets and put it back to see how much further it goes? Everything I have read says that the rod bolts and main bearing cap bolts are tty. So basically I can't check on them otherwise I will need to get the block align honed and obviously that goes along with a full rebuild which I am trying to avoid if possible. Just not good timing for that kind of expense right now. Also can't seem to find the rod bolts which surprises me if they have to be replaced if touched. Only ARP studs and bolts that require machining.

I have seen many posts that say just slap some bearings in and reuse the hardware, or I get the typical, the world will end if you don't get a full rebuild with 10k in top quality racing parts. This is just a weekend toy and I do hope to get it maybe fully rebuilt at some point and do some mild mods. This just isn't the time for that. Another option is just to get a used motor that seems to run fine. Then hoping I don't end up with the same problem since these all usually suffer from the gasket failures and getting the coolant in the bottom end, tearing up bearings. Really would be easier if I could just pop the caps off and check the bearings with plastigauge and see where I am at. There is some side play in the rods but it seems even and fairly normal. Haven't had a chance to check it for closeness to spec. But there is no play in the rod bearings themselves. At least not enough to make them move at all in any other direction than directly side to side against the neighboring rod. I am thinking it may be a main bearing, worked on a Taurus once back in the day that made a similar noise, just a lot louder and it was the main bearings in that 3.8 . Any advice on this would be appreciated. Wondering if I should just slap it back together so at least the car is movable and put it off for another time. It did run perfectly aside from that noise I heard occasionally.

Thanks in advance guys, I know many of you have had experience with these engines in a variety of cars so I hope someone will help me make a decision one way or the other. I got the car for next to nothing so I don't mind dabbling with it, just not a full on several thousand dollar rebuild right now. Need it either fixed or movable at this point. I will also see if I can get some pics of the metal, not sure how well they will show up.

 

[CorvairGeek]

The N/A 3800s (and 3300s) are notorious for harmonic balancer failures that cause deep knocking sounds. I would assume (even though it has space for 2 belts) that the L67 is prone to the same issue. Take a look at the rubber bonding the inner and outer portions of the HB. Most people don't catch them until they are making a lot of noise.

 

[clinebarger]

Is there Copper/Brass debris in the bottom of the oil pan?

I personally dislike "Un-crushing" Inserts that have miles of them & put them back in service!!

The Main & Rod fasteners are not TTY, They are just torqued using degree angle.

 

[71Chevyguy]

Originally Posted by clinebarger
Is there Copper/Brass debris in the bottom of the oil pan?

I personally dislike "Un-crushing" Inserts that have miles of them & put them back in service!!

The Main & Rod fasteners are not TTY, They are just torqued using degree angle.



I did read a few instances of that being said about just being torqued that way. Sounds like you don't think it would be reasonable for me to check on them and put them back? I have to fish out what it in the bottom of the pan and clean it off. What I did touch with my fingers looked like aluminum to me, all silver in color, no brass or copper color. Some very thin strips, like the thickness of individual hairs maybe 4mm long and some about the size of grains of sugar. I have to check the drain pan that I drained the oil into and see if anything is in there. Not sure if the oil filter is still around or not, but might be worth a look in there as well.

How do you feel about replacing with new bearings as it sits without visiting the machine shop? Is that a possibility? Or is that just a complete disaster waiting to happen if I wanted to check the bearings? Because if I check them and they are all fine, then that would be an option. Wouldn't consider that if I find one torn up of course.

 

[71Chevyguy]

Originally Posted by CorvairGeek
The N/A 3800s (and 3300s) are notorious for harmonic balancer failures that cause deep knocking sounds. I would assume (even though it has space for 2 belts) that the L67 is prone to the same issue. Take a look at the rubber bonding the inner and outer portions of the HB. Most people don't catch them until they are making a lot of noise.


I will double check the balancer and look closely at it. But it def isn't loose and banging back and forth like in many videos on youtube. It seems pretty solid, but I will re-check. Another thing I want to check is the flexplate, but this just seems to me like the wrong noise for a cracked flexplate. Those make more of an exhaust leak/lifter tap noise from my experience. This was def more of a thumping tone and not any kind of tap or rattle.

 

[sloinker]

I was surprised that all the replacement rods now use a fractured joint on the big end. Kind of freaked me out first time I saw one.

 

[clinebarger]

Originally Posted by 71Chevyguy

I did read a few instances of that being said about just being torqued that way. Sounds like you don't think it would be reasonable for me to check on them and put them back? I have to fish out what it in the bottom of the pan and clean it off. What I did touch with my fingers looked like aluminum to me, all silver in color, no brass or copper color. Some very thin strips, like the thickness of individual hairs maybe 4mm long and some about the size of grains of sugar. I have to check the drain pan that I drained the oil into and see if anything is in there. Not sure if the oil filter is still around or not, but might be worth a look in there as well.

How do you feel about replacing with new bearings as it sits without visiting the machine shop? Is that a possibility? Or is that just a complete disaster waiting to happen if I wanted to check the bearings? Because if I check them and they are all fine, then that would be an option. Wouldn't consider that if I find one torn up of course.


It could be Tin/Aluminum from a Insert......But Brass/Copper follows very soon after if that was the case.

I would probably check Crankshaft Thrust first, The torque converter can & will balloon thus taking out the thrust bearing. L67 & LS4 engines are quite known for doing just that to a 4T65E converter.

I'm weird when it comes to Inserts.......& will NOT reuse a crushed insert that has been ran!

Throwing Inserts in a engine is nothing new & has been done successfully for decades, As long as the Crank isn't scored up, The Journals are round/concentric, & Finish is still good.......No reason at all you can't do it, Given the clearances end up within spec!!