Oof, already 1 month in. At this rate, Xist might finish his shed before the HiHy is back on the road!
The heads are at the machine shop to get valve seats & valves touched up, along with resurfacing. ETA for this simple job is 2-3 weeks
It would have been 4-6 weeks if I let them cut valve stems/swap shims to adjust the valve lash (so I still have that fun to look forward to doing myself when they come back). I was really hoping to have this ready for a 4th of July camping trip, but at this point everything would have to fall perfectly in place (and I'd have to do my part to hustle as well).
The good news is everything was in spec, although 1 valve stem was at the minimum thickness (.2154) according to my mic. I asked the machine shop to measure it with their mic and they came up with .2155. Seems pretty incredible to me to have 270,000 miles and still have every single valve stem and bushing in spec...
The head that had the clean combustion chamber, presumably from a blown head gasket, was warped less than I could measure (0.0015 is my smallest feeler gauge). The front head, which looked a lot nicer, actually was more warped at ~0.0015. I could not get the 0.002 feeler gauge under the machinist block so that's good (0.002 being the specified limit).
The valve guides/bushings, which I expected to be worn to the limit, were actually well within spec of a new guide and way inside the maximum acceptable oil clearance.
I'm currently struggling to pull the block without the transmission attached. There is 1 transmission to block bolt that I can't turn a wrench on nor can I get a straight shot on it with a socket. I donated some blood when this wobbly broke:
Once the block is out, I'll tear it down and inspect. I had assumed it would be worn enough to warrant a 0.5mm overbore, but maybe I'll get lucky and can get away with standard size rings on a fresh hone. I'd normally just bore it anyway, but parts in general are not easy to come by these days and this 3MZ-FE was used for a relatively short period of time in the US by Toyota standards (2004-2010) making unusual parts even tougher to come by. Well good quality parts like Mahle pistons or Clevite bearings (Toyota doesn't make oversize pistons). I can still find Chinese-made DNJ overhaul kits, but that would be a last resort...
That's kind of a shame - the 3MZ is really a good engine - much better than the 3.0L 1MZ it replaced (which itself was a good engine despite being infamous for sludging with extended oil change intervals). But Toyota introduced the even better 3.5L 2GR-FE in 2005 - just 1 year after the 3MZ - and by 2008 it replaced the 3mz in all but the Highlander hybrid (which would get an Atkinson-cycle version of the 2GR in 2010)