Broken piston

Have a 2014 with 87000 miles, oil changed every 5000 with full synthetic and Toyota filter. Started engine after sitting 3 days in 30 degree weather and very nasty knock o right bank. Thought it was cam chain tensioner. Took it to an independent shop that specializes in Toyota. Ended up pulling coils and plugs on right bank. No compression on #6 cyl. Bore scope shows that piston isn't going up and down. Trying to decide how to proceed. Obviously out of warranty. Anyone heard of Toyota stepping up on something like this. Everyone I talk to says this is unheard of. Appreciate any help.

 

Any damage to the top of the piston? If so, maybe a valve got sucked. Some Tundras did suffer valve spring breakage.

 

Looking for a bore scope to do some troubleshooting before I make a decision

 

If the piston isn’t going up and down, you don’t have a broken piston per se, you have a broken connecting rod. I’ve never heard of that happening on a 5.7.
Toyota will not be stepping up on a truck that’s well beyond the warranty period.
Is there more back story here? If not, freak occurrence.

 

Seems very odd that it would be fine when you shut it off but has catastrophic damage restarting a few days later.



I don’t know what good a borescope is going to do if the piston isn’t moving. That broken rod in all likelihood has smoked the bottom end. Is there a puddle of oil under it?

 

No back story. Babied most of it's life. The reason I'm thinking broken piston is the knock doesn't seem to be bad enough to be a broken rod. I am thinking the crown of the piston broke off. Just a hopefulI guess .Will find out when I tear it down.

 

That would be a really odd failure.

 

So you think it broke at the wrist pin? Or that the top of the piston could separate from the bottom part, even though it’s all one piece?

 

Just a theory that piston crown broke off. Noise doesn't sound like anything striking the block. No holes in oil pan. Nothing external. Neverexpecteda Toyota to fail like this.

 

Was this towed to the shop?

 

For that to happen it would require a ring or the piston itself to essentially weld itself to the cylinder wall which would be pretty odd to "just happen"

 

Broken piston almost guarantees a ruined zylinder.

Seek ye a used engine. If any are out there.

 

Odd for it to "just happen". Search all Toyota forums (not)plenty of rod /wrist pin/piston failures on the(supercharged) 5.7. Not at a high level but are out there.

 

Really

 

Links would be great if you can provide any. I’m on here and ih8mud and have never seen it.

 

Couldn’t find any confirmed wrist pin failures when I searched. One thread that speculated that was it, but the motor was replaced and never confirmed that failure. Same motor had previously had all 32 lifters replaced for some reason. Soooo, coming up blank on that particular failure, not common it seems.

 

My response to this thread was off as majority were on supercharged engines. So my fault for not paying attention.

 

That would certainly seem more plausible, didn’t see any of those either, but it was a cursory search, not a comprehensive one.

 

Some on tundratalk/solutions. A few PM's where people didn't want to admit they grenaded their engine. Definitely not a "plenty as I said. Thanks for keeping it real.

 

Boost can do bad things to good engines!!

 

Bore, hone, and send it.

 

or if you don't want to deal with it: https://xatracing.com/XAT-3UR-full-build.html



I feel for you OP. Surprised engine failures for something you didn't try to do isn't exactly an easy pill to swallow. If you go used, get one with with a warranty so you can have some sort of confidence it's running without issues. They're also $4-8k which is why I went the XAT route so I'm not dealing unknowns. YMMV. Good luck!

 

Unfortunately it sounds like these motors cannot be bored and honed.

 

Interesting.
Neither price included shipping to the customer.
Keep or use stock parts.

The cheapest option, you send them your engine on your dime.


With all the bells and whistles and they supply the engine, convert to 6.8 liter.

 

Why not?

 

Wow, at that price I might as well grab a spare. Not knocking them as I'm not familiar; those prices just seem like a lot.

 

You can hone anything. Just like you can milk anything that has nipples!

 

So much truth

 

One of our resident Toyota techs responded in one of the existing threads that mentioned wrist pin failure that these blocks are not designed to be machined, bored, honed whatever. There is a coating or plating that’s applied that doesn’t allow that to be done easily or maybe at all.

@empty_lord was the poster in that thread I believe. I am not the authority on the topic for sure, just sharing. He could expand on that if he wishes.

 

#nobodypayslist - pick up the damn phone, there may be pleasant surprises on the other end (though their voices are a bit deep for my liking).

Seriously, though. They've been amazing, and while even a discounted core wasn't in the plans, either, it saved time on having to get the motor pulled, shipped, waiting, risking being told it couldn't be repaired, etc. The premium, for me, was worth it. They also have a short block option, too. Just tossing it out there since you don't know what your getting with a used engine.