How much is to much?

[ddavisaf]

Diagnosing a knocking upon start up. Nasty little sound. Tore it all apart, and I'm sitting with the engine in the car, pistons and crank still in. Front case and balance shafts are out.

Dropped the oil pan and found a ton of copper shavings. Okay, we have a bad bearing now. Checked the crank for play and there was none at all points of rotation. Checked the Rear Balance Shaft bearing and noticed some signs of damage, but not enough to account for all the shavings. Checked the connecting rod bearings by placing the pistons just below top dead center and tried to move them and could not. Checked the rod caps and there is no front to back play and there is a very small (and by very I'm talking about 1/64") side to side play on all rod caps. I'm going to go double check all of this right now. I've never actually paid attention to whether or not this or normal. Maybe some of you guys have and could let me know
Also, if everything is good so far, what else do you recommend I check?
Front balance shaft has no play. Timing was dead on when I took it all apart. Oil pressure was normal.

 

[bryanwheat]

Diagnosing a knocking upon start up. Nasty little sound. Tore it all apart, and I'm sitting with the engine in the car, pistons and crank still in. Front case and balance shafts are out.

Dropped the oil pan and found a ton of copper shavings. Okay, we have a bad bearing now. Checked the crank for play and there was none at all points of rotation. Checked the Rear Balance Shaft bearing and noticed some signs of damage, but not enough to account for all the shavings. Checked the connecting rod bearings by placing the pistons just below top dead center and tried to move them and could not. Checked the rod caps and there is no front to back play and there is a very small (and by very I'm talking about 1/64") side to side play on all rod caps. I'm going to go double check all of this right now. I've never actually paid attention to whether or not this or normal. Maybe some of you guys have and could let me know
Also, if everything is good so far, what else do you recommend I check?
Front balance shaft has no play. Timing was dead on when I took it all apart. Oil pressure was normal.

did you actually pull the main caps or just check for movement, sounds like a bearing being that it is copper. I f you haven't pulled the main caps, i would reccomend pulling them and checking out the bearing surfaced visualy. Other than that have you checked possibly a spun cam journal, shouldn't be copper colored, but could be discolored from heat possibly, i would look into the first thing, but if not that than check into the cam journals.

 

[ddavisaf]

Okay, I pulled off the crank girdle. Checked the bearings and they all look good. Slight scoring in the middle, but no other signs of damage.
Cam journal bearings were good. Took the head to a machinest downtown and everything checked out okay. He said there were no problems in that area.
Now, one thing I noticed with the girdle off. When I checked the crank for play I checked for all around play, front to back and side to side. With the girdle off there was alot more movement front to back than before. You could see where the crank was not sitting in the main bearings "flush" so to speak.
I know I have a bad bearing. I just can't find the damn thing. I'm going to put the girdle back on and rip out the pistons now. I can see the bearings on the pistons as they sit right now, and I don't see anything that would equate to the amount of shavings I saw in the pan but it's looking like this is my only course of action now.
Are there any other avenues I should explore?

 

[Big Woo]

1: Make sure you check all three balance shaft bearings.
2: remove all rods and pistons, inspect all bearings, big end rod housings, and crank journals.
3: Inspect all main bearings (uppers and lowers) crank journals, and housings.
4: Look for a diacoloration in the metal around the big end of the connecting rods, and around the main bearing saddles. Many times the extra heat created by a bearing problem will discolor the material immediately around the bearing shells.
5: Is there any possibility that the material found was never cleaned out of the oil pan during a previous rebuild?

There must be some side play in the connecting rods where they ride on the crank journals. The book lists 0.0039 to 0.0098 as standard, and specifies a service limit of 0.016

 

[ddavisaf]

1: Make sure you check all three balance shaft bearings.
2: remove all rods and pistons, inspect all bearings, big end rod housings, and crank journals.
3: Inspect all main bearings (uppers and lowers) crank journals, and housings.
4: Look for a diacoloration in the metal around the big end of the connecting rods, and around the main bearing saddles. Many times the extra heat created by a bearing problem will discolor the material immediately around the bearing shells.
5: Is there any possibility that the material found was never cleaned out of the oil pan during a previous rebuild?

There must be some side play in the connecting rods where they ride on the crank journals. The book lists 0.0039 to 0.0098 as standard, and specifies a service limit of 0.016

My biggest delima or dilema or problem... how about that...
My biggest problem is the engine is in the car. I don't have the means at the moment to remove it. I won't be able to get my hoise and engine stand until next weekend.
So I won't be able to inspect the crank journals and main bearings completely.
I have my wife uploading pictures on my computer at home today while I'm at work so I'll post some pics of the oil pan and then pics of the bearings.
Discoloration? No for the most part. The center main bearing is toasted a bit, but once again... not enough for what I found in my pan.
What's bothering me the most is the lack of shavings anywhere else in the motor.
So... as to your list.
1: Damage on the rear balance shaft bearing only. Perhaps enough to cause a knock, but not enough for the amount of shavings found.
2: Connecting rods will be inspected tonight.
3: Crank is still in the car, so I can only inspect the the bottom bearings and the crank girdle.
4: Main bearings, center bearing only so far. I need to inspect the rod bearings tonight still.
5: Possible? Yes. Likely? No. There are way to many shavings for that. I'll post pictures later tonight.

 

[gsxtacy]

Time for a new crankshaft, or a 6 bolt swap.

Unless your just trying to keep it numbers matching

 

[gsxtacy]

Actually I would like to point out that my very first "knocking" DSM had the rear BS bearing burn up too.

I did as you are doing/did. I pulled the mains/rods, and found very little to speak about. I bought all new bearings, a BSE kit and all new gaskets, everything I needed to do THAT job, and cleaned everything the best I could. I put it back together and filled it with oil and primed the engine and changed the oil. I got about 5,000 miles out of it before I sold it. Haven't heard from that guy since. Last I heard it was still running.

Sorry about the above post, I just skimmed over the thread and replied.

Hope it works out for you, which ever way you go.

 

[ddavisaf]

Here is a picture of the oil pan and a picture of the center main bearing. So far, there isn't a bearing with more discoloration/damage than this. The rear balance shaft bearing has some discoloration and some nicks in it, but it's not the sole cause of my problem.

 

[gsxtacy]

that looks pretty bad.

what does the side of that bearing look like on both sides?

Can you feel anything grooves/marks the crank?

Take a penny and rub it across the journal.....it should leave a pencil like mark across it.

How about a pic of the Thrust journal area?

IMHO here is where you should make a solid decision. Think how much doing this job twice would cost.

Good luck

 

[ddavisaf]

Well... the sides of the center bearing is where the problem lies. Somehow in my frustration I missed the sides of the bearing...WTF

Due to the amount of frustration (and ignorance) this block has caused me I'm going to swap a 6 bolt bottom end in.

Looks like it's time to start gathering parts.... again
Thanks for your help gsxtacy, Big Woo, and bryanwheat

 

[Big Woo]

Let us know how it is comming along, and if we can help in any way.

 

[ddavisaf]

Well, when I checked the rod bearings I didn't find anything wrong. I checked them when the head was off and the oil pan was on by getting each cylinder just below TDC and push down on the pistons and checking for play. I didn't notice any play at all via this "test". However, upon removing the rod caps, I had found a completely different story.
Cylinder 1 had spun completely
Cylinder 2 and 3 had alot of discoloration
Cylinder 4 had some nice gashes, discoloration, and looked on the verge of spinning.
The center main bearing (show above) has the discoloration on the face of the bearing. On the sides of the main bearing there were very deep pairs of gashes (both sides). On the transmission side the bearing was so deeply cut that it was no longer copper (In a half moon that went over the verticle running gashes). On the timing side of the bearing there were gashes that were still showing copper (also running over the verticle gashes).

Moral of the story:
Be thorough in your diagnosing. One "test" may not be enough to find the problem.

Now, my next question is what would cause the gashes on the sides of the main bearing? Too much crank play?

 

[bjones18]

.....

Now, my next question is what would cause the gashes on the sides of the main bearing? Too much crank play?

Was this a recently rebuilt engine?

I would guess over heating of the bearing surfaces to cause this much bearing damage.... possibly a lack of oil? Certainly, the thrust surface must have a clutch load and no oil film to disintigrate.

Which brings me to my age old facination of crank-walk. Mis-alignment of the upper & lower bearing halves will create a very effective "scraper" removing the oil film at the bearing split (proud-half scraping in the direction of rotation).

How's Nort' Dakota this winter? (I grew up in Fargo :^)