2025 Tundra Engine is down!

Or, the stacked tolerance evaluation did not cover the manufacturing flow extremes.

 

No, We know motors are being replaced because of a bearing failure. The symptom is a knocking motor lol

 

Wrong again. Plenty of failures that happened without “knocking”.

 

Good lord boys, do we even know what we are arguing about ? Lol

 

Well the sky isn’t technically blue either….the motors knock, or seize from a bearing failure. The symptom is the knocking or locked up….is that better.

 

Are they the Teenage Mutant Teenage kind?

 

@UncleBif'sAIvatars

 

Toyota’s ambiguity continues to be justified

 

That's the only kind

 

Stacked tolerances is something I’ve been dealing with consistently as an engineer as we push the envelope for efficiency. I don’t think this is something that is well taught in engineering anymore, if it at all. I wouldn’t be surprised if that is it.

 

Relatively recent mechanical engineering grad here. University of Colorado didn’t really touch on tolerance stackups. Only a tiny bit in my senior design class. It’s much more complex than it seems when you have so many components working together. I remember thinking “oh well you just min max the tolerances” but I didn’t consider pin/hole clearances until I had to do a stack up at work. Now, add in rotating assemblies with harmonic frequencies / non-straightness across bearings… that’s when it probably becomes FEA time using different high/low tolerances… but if you make one wrong assumption, you could be missing something huge. Add in time constraints, lack of resources during covid, confidence/reliability calculations, and of course money. There could’ve been an assumption/calculation made long ago that hasn’t been questioned yet.

 

Lol, what are you talking about? That wouldn’t solve a main bearing failure due to contamination. You would see an upper rod bearing failure and piston/cylinder damage if the actual tune was the problem, multiple people have posted pics of their spark plugs at the 40k interval change and they look perfect. You’d see damaged spark plugs if the tune was an issue. Stop peddling nonsense. Also multiple videos showing the engine swap being done on YouTube, you wouldn’t need to swap the ecu, just upload new software. Modern engines have knock sensors, the ecu would pull timing on its own if it sensed any pinging or misfire. Modern engines will literally go into a limp mode annd self limit if any misfire is detected for a certain period. This was demonstrated when people installed the TRD intakes without the performance tune. The truck went into limp mode and wouldn’t make power, every word of what you posted is just flat wrong.

 

you haven’t been paying attention to the engine tear downs or this thread have you?

 

Yes I have, none of the failures indicate an issue with the tune. The rod bearing issue would be secondary to piston/cylinder damage. Once again you don’t know what you’re talking about. The majority of the issues are spun main bearings, from the oil system being contaminated, specifically main bearing number 1. The contamination has caused spun and damaged rod bearings, but where is the cylinder and piston damage? All I’ve seen is excessive skirt damage from metal being in the oil system, no damage to piston crowns, no metal missing from the combustion chambers, zero indication of detonation and pre ignition. The reason some engines have main bearing failure and some have rod bearing failure, is get this, machining debris being left in seemingly random areas of the oiling system, just like Toyota said.