Why did this rod fail?

gilitos

gilitos

Senior Member
About 100 gentle miles on the rebuild. Newly poured rods on a new Burlington crankshaft. Highly reputable builder known to many on this forum. Full flow filter. Began to knock like heck. This happened a year ago but after all I went through for a no-holds-barred rebuild, I was too beartsick to pull the motor apart to see what happened until now.

The bad one is #2; I also pulled #3 cap and took a picture for comparison. Dipper trays were full of oil and #3 journal was dripping oil when i pulled it apart, so I don't think it was a pump failure. The crankshaft journal is visually okay.

Anybody have an opinion? Should the motor be torn down and rebuilt? Thanks for opining!
 

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Clearance was checked at assembly? Dipper on rod was facing the right way? Piston looks OK? No sign of it seizing? It really sucks when you try to do the right thing and this happens. :(
 
gilitos said:
About 100 gentle miles on the rebuild. Newly poured rods on a new Burlington crankshaft. Highly reputable builder known to many on this forum. Full flow filter. Began to knock like heck. This happened a year ago but after all I went through for a no-holds-barred rebuild, I was too beartsick to pull the motor apart to see what happened until now.

The bad one is #2; I also pulled #3 cap and took a picture for comparison. Dipper trays were full of oil and #3 journal was dripping oil when i pulled it apart, so I don't think it was a pump failure. The crankshaft journal is visually okay.

Anybody have an opinion? Should the motor be torn down and rebuilt? Thanks for opining!
Click to expand...

What did your rebuilder think ???
 
J Franklin said:
It looks like it was too tight. What weight oil was used? check the pump output after it is fixed.
Click to expand...

It really really sucks when you try to do the right thing and this happens.

Too tight was my first thought. What did the builder say? I would have sent it back. Even if it cost a few hundred dollars, but now you opened it he can't see clearance, alignment, etc any more. To have a new person look at it it going to cost thousands more then the shipment.
 
Looks to me like the failed one was poured a little cold. The worker's attention only has to be taken away from the job for a while for the melt to drop in temp. That would explain the broken edges too.
 
If you look at the so called good one, it is starting to change color also. Plus the contact area is not right. I think it is not getting enough oil, like maybe the pump is not working right. If it was mine I would go over every thing. But it looks also like the rods were never done right.
 
gilitos said:
About 100 gentle miles on the rebuild. Newly poured rods on a new Burlington crankshaft. Highly reputable builder known to many on this forum. Full flow filter. Began to knock like heck. This happened a year ago but after all I went through for a no-holds-barred rebuild, I was too beartsick to pull the motor apart to see what happened until now.

The bad one is #2; I also pulled #3 cap and took a picture for comparison. Dipper trays were full of oil and #3 journal was dripping oil when i pulled it apart, so I don't think it was a pump failure. The crankshaft journal is visually okay.

Anybody have an opinion? Should the motor be torn down and rebuilt? Thanks for opining!
Click to expand...

He has full flow oil filter, but no mention of pressure oiling, and he did say his dipper tray was full.

I was also wondering if the cap got installed backwards, but I can't imagine an engine builder making that kind of mistake.

I wonder who did the rod babbit?
 
Lack of lubricant is clear.

1. Does the Rod surface look the same?

2. It appears that there is material build up on #2, so maybe the cap wasn't flush with the rod when assembled?

3. The cap may have been installed the wrong way, not allowing the oil to be picked up. Most likely to me, since I think it uses the "Dipper" to oil the rod journals.

4. If it is an oil pump problem, wouldn't the mains be a bigger problem?

5. If the engine is pressurized, shouldn't the holes be plugged?

I would get with the builder. It clearly isn't any thing you have done wrong, as long as the engine had the oil the builder recommended.
 
How much oil was drained, what was in it, and how did it look?

Were the head nuts torqued often enough to keep them tight, so no coolant got in the oil?
 
Thanks for all the comments. So #3 looks like it may have been on the way out? The babbitt surface was very oily when I disassembled it.; it's not dark or scuffed. I figured that the uneven color was the process of a bearing bedding in.

Caps were all installed in the correct direction.
It's not a pressurized system.
I will definitely talk with the builder but I want other opinions first.
I wouldn't call out the builder unless it was clearly their fault and they didn't work to resolve the issue.
 
Also, I drained about 3.5 qts of oil and it looked fine. It was between the marks on the dipstick. There are now fine droplets of babbitt on the inside of the block around #2. I'll tell you what, that's pretty ugly!! I should post a picture of that for the gallery of Model A horrors.
 
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