Failure, with pics! Honda S2000. Why?

[Solo2driver]

We all like the disgusting engine failure and sludge pics, so here you go--

From a buddy who will be racing at the SCCA Solo National Championships in Topeka next week, just rebuilt and installed his engine in the Honda S2000 racecar. Drove it only 3 miles (after idling and reving to build pressure and check for leaks/fire, etc. it developed rod knock.

#5 main bearing (which feeds #4 rod bearing) destroyed. He says it had plenty of oil pressure, no filter failure, and no evidence in the pan or oil pump of any indicators why they would fail or starve. Crank was trashed, re-machined and installed again and currently re-assembling engine this week. All clearances were triple-checked, and this is not a noob assembly.

Car with the engine out (second time)--

#5 main bearing--

#4 rod bearings--

Okay oil nerds, let's play CSI: BITOG and see what could have caused this. Break-in oil was dino juice, some assembly lube present on important parts.

 

[chevrofreak]

Did someone check bearing clearances?!

 

[bdcardinal]

incorrect clearances? contamination? i always check clearances with micrometers, and plastigauge when i build a motor, and i do it on all 4 sides. were proper ARP fasteners used?

 

[pickled]

My money is on foreign matter...those bearings are chewed up pretty badly.

 

[Gary Allan]

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

 

[Steve S]

Oil starvation from reving before the oil was warmed up . What does the crank look like and what about the rod and piston are the other bearings o.k.?

 

[Solo2driver]

Parts were taken to a good engine builder and machinist for inspection, found to be all great except for the crank. They are re-machining the crank and re-installing, along with all new bearings.

I'm sure he warmed it up, he had run it for quite some time and then was driving it over to be fully broken in on a dyno later that day when the knock surfaced.

I'll try to get more details.

 

[Bryanccfshr]

Did the block recieve any machining during the inital rebuild?

 

[pickled]

I still think Foreign matter...I had an engine fail just like that and what I found was that a gallery plug was never removed before/after shot blasting prior to machining. It wasn't pretty. The newly painted short block did not reveal it's secret until that wonderful knocking sound appeared and a tear down was performed.

 

[Johnny]

Originally Posted By: Solo2driver
Parts were taken to a good engine builder and machinist for inspection, found to be all great except for the crank. They are re-machining the crank and re-installing, along with all new bearings.

I'm sure he warmed it up, he had run it for quite some time and then was driving it over to be fully broken in on a dyno later that day when the knock surfaced.

I'll try to get more details.


Solo, do you know what kind and weight of dino oil he put in there? Do you know what kind of assembly lube was used? Do you know what oil he races with?

 

[Quest]

My take is also foreign matter, + incorrect/ bearing clearances and/or too thick of an oil and insufficient warm up before putting tremendous pressure on the engine itself.

It could be even as simple as the assembler forgot to put some pre-lube on the bearing shell during the assembly.

Still guessing...

Q.

 

[bobfather99]

Perhaps he was hot-roddin it way too early on in the break-in process...

There are lots of unknowns here:
Break-in oil/assembly lube used
What machine shop work was done to it before the first rebuild(if any)
How high the initial revving went to
Foreign material in the crankcase/bearing surfaces
If there were errors of some kind in the initial assembly

 

[chet2]

glad the guy didnt assemble my engine

 

[Gary Allan]

Quote:
found to be all great except for the crank.


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

Ask Kestas.

 

[Pablo]

What do the other journals look like? Did he get an oil sample?

 

[ProStreetCamaro]

Idle and rev to build pressure? Did he not prime the engine first before the first startup? That is a huge no no.

There are so many things it could be that nobody here will be able to give anything other than a guess. I would have to look at it in person to be able to give any indication of what really caused it.

Could have been a blocked passage, clearance was to tight, not primed before it was started etc etc etc etc etc etc

 

[Jim Allen]

Well, this is my WAG!

Not a lot to go on but if all the bearings looked like these, it looks like oil starvation to me. I remember a customers Jensen-Healey from decades ago that was being raced SCCA. It had a remote oil filter, relocated from the original spot. As I recall, (it was 30 years ago) upon rebuild, the oil lines to the remote filter were reversed accidentally, so the oil flow was reversed in the filter and the ADBV blocked most flow. The engine had oil pressure indicated but almost none of it was getting to the bearings. It lasted about as long as this S2000 engine. I suggest making sure there is oil flow to the top end right after startup, which would indicate proper lubricant flow.

 

[gtx510]

Originally Posted By: Gary Allan
The crank was machined in the wrong direction on the lathe.

Ask Kestas.
Would that still matter if it was a forged steel crank vs cast iron?

http://www.aa1car.com/library/cpolish.htm

James, was the crank polished? Or just ground down?
Were the journals nitrited after grinding?

 

[Kestas]

What is the oil flow in this application? I'll bet the #5 Main is the last to get oil. If there is any problem with debris, all of it would get flushed to the last bearing in the circuit. Look closely at higher magnification for embedded debris on the bearing.

Polishing direction only affects cast ductile iron cranks.

 

[gtx510]

another link
http://mahleclevite.com/it_crankgrind.asp