Failure, with pics! Honda S2000. Why?

[mechtech2]

Bearings should never touch. Whether 3 miles or 300,000 miles.
So the oiling system is to blame, if the clearances and other machining were correct.
No flow is a blocked pickup or other passages, or a bad oil pump.
Maybe the bypass system is faulty.

 

[TooManyWheels]

One obvious possibility is that the crank's oil passages did not get thoroughly cleaned after machining.

 

[gtx510]

If bearings should never touch journals, how would you use plastigage to measure clearances??

 

[INDYMAC]

Is this the F20 or F22 engine? If it's the F20, maybe it had one of those faulty oil jet bolts that were recalled on the 00, 01 model years.

 

[tlee1234]

poor s2k, hope it all works out!

 

[tlee1234]

whats up indymac, this is tlee1234 from s2ki, this is a cool forum

 

[gtx510]

I'm really curious about the crank grinding/polishing directions if anyone's got more info on that.

 

[widman]

I found huge amounts of crud and polishing compound in the passages of my crank before assembly. I assembled and then found it too tight (too much torque to turn it over by hand easily) so took it apart and tried rod by rod.

That is where I found a defective bearing in my brand new set. A bulge on one end that caused binding.

 

[Kestas]

If you've ever seen the matrix of a ductile iron crankshaft at high mag (~100X), you'd find that it's essentially made of tiny spheres of graphite in an iron matrix. The graphite has no strength and can be considered voids for this discussion. When this matrix is machined, the tool cuts through these holes and forms micro-burrs over these holes. If not properly finished, these burrs can lift up and damage the bearing during service. I've studied this in great detail. I've seen burrs that are long enough to lift up and extend across the bearing clearance thickness.

The accepted way to finish a ductile iron crankshaft journal surface is to grind it in the opposite direction of service, then polish it in the other direction (same as the service direction). Grinding produces the burrs facing in one direction. Finish polishing is then supposed to lift up and remove these burrs, making the crankshaft journal surface suitable for use.

 

[Solo2driver]

Great info, Kestas!!

 

[gtx510]

Thanks for the info, Kestas.
Are the grinding/polishing directions the same for a forged crank?
And do you agree with the RA info in the links I posted?
Have a favorite bearing company or type of bearing?

 

[Kruse]

Originally Posted By: Gary Allan


The crank was machined in the wrong direction on the lathe.

Ask Kestas.


Possibly from foreign material lodged in an oil passage way, but I'm with Gary on this one. I think the crank was machined in the wrong direction and wasn't polished before assembly.

 

[Gary Allan]

The reason for that "spike" from me is that I heard Kestas mention it once. I had never heard about it before, but then again, I don't talk about crank finishing much. In this case, as Kestas stated in his original statement (or so the impression I got), the symptoms met the condition. No apparent issues during initial start ..and a reasonable amount of time "at pressure" to surely have some noise show if lubrication was not there. The onset of the event was within Kestas's indicated time frame for the galling to occur.

The situation was so strange ..and the pro's on site were at a loss ..that this seemed to be an appropriate offering as to the cause. We often get stumped on stuff that we think we've covered all the bases ..and then ..from some oddball obscure corner of nowhere comes the answer. This may be it.

 

[firemachine69]

Dam. I'll guess the OP will be footing the bill for the bearing manufacturer's screw-up?

 

[TooManyWheels]

Why/how would one journal be machined in the opposite direction from the others? I'm having a hard time envisioning that.

 

[firemachine69]

Had to be the monday shift, I suppose...

 

[Hirev]

The Honda 2000 engine cranks are forged steel it does not matter what direction the crank is turned in the crank grinding operation as long as oil feed hole(s) is deburred.

What did the other bearings look like? How about the thrust bearing, how does it look?

Were the machined parts washed and scrubbed out after machining operation(s)?

 

[Hirev]

Went back and reread original post. What was machined on this engine before the failure. And how did the bearings look on the engine before rebuild?

Did any bearings actually spin in their bore before or after rebuild? I see the bearing tang intact on #4. That is actually one of the worst looking bearings I've ever seen on #4 that did does not appear from what I can see to not have actually spun in the rod big end bore. Were these Honda bearings? Has the oil pump pressure relief system been checked for debris to make sure its not sticking in its bore?

 

[mechtech2]

gtx510 - Plastigauge measure the clearance. Most people use it wrong. They lay the crank in the bearings , put the plastigauge on each, and torque the main caps. This is wrong. You have to do only 2 at a time to get the proper clearance check.

 

[mvw2]

If this was professionally done, I with the idea that this could have simply been a part defect-failure. There may only be a 1 in 10,000 chance, but someone's got to get it eventually. You'll really have to see how the bearing failed to see if it was a manufacture error of the part or something else like debris like others have been pointing to.