Some piston heads are designed to clear valves, thus you see the indentation. Here's a photo of such design (non-Toyota.)

Given the 1MZ-FE piston heads have such indentation, I'd say that the 1MZ-FE engine is non-interference IMHO. (Otherwise there's no point for Toyota to make it that way.)

 

The Camry model did not run VVT-i in their 1MZ-FE until after the ES recieved it in 99. VVT-i was implemented on the Camry's V6 until 5th generation for the 3.3L 3MZ-FE (2004-06) SE Model only. There was never a VVT-i version of the 1MZ-FE in any Camry V6 model. On the other hand, the 97-01 1MZ-FE V6 for the ES300 gained VVT-i during the 3rd production year of the 3rd generation ES (1999). The first Camry to implement VVT-i in any engine offering was the 2AZ-FE 2.4 starting Gen 5 Camry, 2002. VVT-i MZ series blocks are interference engines per Toyota and Lexus techs. Pre VVT-i MZ series blocks are non. As for the pinky sized rods in the MZ series block and supercharging w/higher boost...that's another story.

 

I hope to add a few lines to that story one day, though in the form of a turbo.

Thanks for the explanation on the ES series.

 

It is not clear for me what those valve pockets are for. One thing I know for sure is that 1MZ-FE with standard valve timing is non-interference but the one with VVT-i is interference. Take a look at the photo of piston with broken rod -- those pockets are practically polished by valves.

 

This guy also cleaned and re-assembly the cam head of a Camry.
http://www.tegger.com/hondafaq/sludg...ng_sludge.html






If you are concerned about sludge on other parts such as piston rings, Auto-RX is a safe and proven cleaner.
Did the mechanic explain to you why that rod is broken? Stuck piston ring?

 

I thought it was an interference engine, This has been discussed before but I cant find the post...

 

Auto-Rx is a proven winner. My uncle still is amazed to this day at what that stuff can do.

As far as intereference/non-interference, that was always a big debate, but there definitely was a point where there was a change over.

 

Yes, along with forged rods.

 

Standard rod will just break, causing block damage (my case?).
Forged rod will push piston and then valves causing cams to break and possibly head case (am I right?).
What is better? (I am not being sarcastic, I really don't know)

 

Forged rods have lighter weight, which reduces power wasted to turn these things. Some of the newer engines such as the new V3.7 in the MDX have forged steel rods and camshafts to reduce rotational mass.
Again, no one makes it. Lexmex and I are just dreaming.

 

I did not know that. Thanks for the info!
That is wrong with 1MZ? It is outdated or something?

 

I am crying.

 

No significant change in MPG, she has gained about .5, currently getting 20.6 vs. 20.1 before it seized. I'm surprised that you didn't get new heads, we did and the local shop installed all of the new head components. I don't recall if new cams were on the parts list because there were so many pieces listed, I think they were. Our warranty from Lexus is only 1 year, unlimited mileage.

 

Update.
Sparkplugs on cylinders 3 and 5 where busted (white ceramics broke). I still trying to think why. I know that cylinder 5 rod broke, but how does it affect spark plugs? My only guess is heat buildup. But ceramics? They cannot handle it?
FYI: All 6 spark plugs are 2 month old. And, no, I did not over-torque them!

 

Yes, ceramics CAN do that. My uncle and I pull about 3 or 4 busted plugs (I think 2 on one vehicle) in the past year, and those vehicles also had sludge buildup.