Some Bearing Photos (Not Viper, just an FYI)

[kverges]

OK, let me first get out of the way that I am a braggart jackazz moron fool weasel for bothering to post non-viper bearing photos and GTFO of this Viper Forum. In fact I am a black hole of ignorance and irrelevance. (I do have a Viper, I promise, I can post a photo with a pic of today's paper next to it, but it's at present OK so just putting photos out there if there is any generic interest).

With that all squared away, in one of my other cars I had a rod bearing failure. The engine is the Toyota 2ZZ GTE (Japanese love alphabet soup names) 4 cylinder, 1.8 liter, DOHC, 4-valve with variable valve timing and lift. This particular engine has a dry sump, steel rods, forged pistons and runs 9:1 compression with a turbocharger and set to run about 18 psi boost. Engine max rpm is 8500. I run a standalone EFI engine management system and AiM datalogger, and can log all the basics like temps and pressures, along with ignition timing of each cylinder, knock, ignition retard degrees, cam timing, fuel injector duty cycle, A/F ratio, fuel pressure and more. I get over 350 rwhp and use the car on track with a little bit of modest NASA club racing when the f'ing car works. The data told me what caused the failure. I am not sure I have the skills to read the bearings, but the photos are attached.

Photos may not be the best quality as I used the upload feature and they were take on iPhone anyway. Pics are of all journals with crank in place but all main and rod bearing caps removed then closer view of rod journals 1-4 in that order. I'll try to post some more photos after this post..

[kverges]

And here are the bearing shells on the rod cap side (yes I know #4 is not there, and there was nothing left other than the bit you see in the photo above of journal 4)

[kverges]

Now the rod side of all four bearings after removing the crank, in the order of 1-4

[kverges]

and here are all of the bearings at once, rod and main, with the crank removed

- - - Updated - - -

Ok, what's the root cause?

[Terminator02]

Thanks for posting this. The pictures are very clear. I'm not an engine expert so I have no idea. I'll guess oil starvation leading to debris buildup. But the dry sump makes me doubt it. Misfire?

[zzmike]

Looks to me like the connecting rod bearings were too tight, probably determined by monitoring oil temps at high RPM during track events.

[BlueAdder]

If I am not mistaken this is an Elise or Exige motor :)
Are you the same Kverges who's on the Lotus Talk forums?

As for the issue, I have no clue, sorry.

[kverges]

If I am not mistaken this is an Elise or Exige motor :)
Are you the same Kverges who's on the Lotus Talk forums?

As for the issue, I have no clue, sorry.

Yes. This car has been in mothballs for a while given the failure about 3 hours into a new engine from the last
Failure. Decided to try to fix engine internals myself. I figure I can F it up for a lot less. When it runs it's very quick but when I messed around and went with "pro" built motors the problems multiplied. My luck in the aftermarket has been very spotty but then again I can break an anvil.

[BlueAdder]

Yes. This car has been in mothballs for a while given the failure about 3 hours into a new engine from the last
Failure. Decided to try to fix engine internals myself. I figure I can F it up for a lot less. When it runs it's very quick but when I messed around and went with "pro" built motors the problems multiplied. My luck in the aftermarket has been very spotty but then again I can break an anvil.

I've had the same experience with my Elise. When stock I had no worries at all.
Then, I wanted to go a tad faster so I went for the Radium turbo kit with AEM EMS-4 and the car has been parked for quite a while now. As a matter of fact, I'm currently putting back to stock form (just removing the Turbo) and I'll sell it. I got the ACR-E because I wanted a car that I could track without modifying it at all.

[GTS Dean]

Looks to me like the connecting rod bearings were too tight, probably determined by monitoring oil temps at high RPM during track events.

I tend to agree. Perhaps not enough oil film strength (chemistry) to carry the load, or enough volume to dissipate the localized heat load. If it is a common problem to that engine, (boosted) it could be there just isn't enough bearing area for that loading and you need more frequent rebuilds.

[kverges]

No winnahs yet.

[zzmike]

What do the rod caps look like?

Hard to tell from low-res photos, but I have seen these types of conditions where the mains look fine and the rods are cooked when there is insufficient oil clearance on the rod journals. Usually poor rebuilds. Just a lowly world class GM tech here, so I don't know much, but that is where my money is.

[kverges]

I would post pics of the rod caps but that's not it. Hint: it was not an assembly error including clearance.

[catwood]

I"m going to say excessive heat and being the last rod bearing being oiled. I'd guess that port is restricted more there to push oil into the valve train on the other side. So a pressure drop there on that rod also probably didn't help

[Drlee50]

if your "data log" told you the cause as u stated in the first post--- than you are limited to loss of oil pressure or a lean/ detonation problem.

[kverges]

Warmer. But oil temp is on the list and I also measure oil pressure 2 places, at filter and at head after oil has circulated all the passages leading to main bearings and on its way to cam bearings and squirters.

But I'll spill the beans. After dyno and track tuning of the engine, we were comfortable with the tune. I had also recently added the dry sump for a number of reasons, including to make crankcase vacuum and deal with the slicks and aero grip. So I mounted stickers and decided it was time to start tuning the setup.

Anyway, it appears the sump tank was too small or oil level a little too low, but what you see is the result of low oil pressure for four seconds when loaded up turning left continuously at 1.5G plus. The number 4 rod bearing gets fed with oil the last and suffered the most. What is interesting is the main bearings look very good, but they don't take the high reciprocating loads the rod bearings take. Also the rod journals are fairly small to keep bearing speeds and oil shear manageable at higher rpm. So loss of pressure is particularly bad.

My main point was that, at least for me, it is awfully hard to diagnose the cause of an engine failure by looking at bearings.

In this case it was entirely my fault in that I did something wrong with either managing oil level in the sump tank or having an adequately large tank for the dry sump.