DIY Overhaul at 232,000 Miles. Couple questions/concerns before re-assembly.


New Member
Love this car, decided to hang my hammer (framer/carpenter full time) for a week and try to save her myself after studying the 2zr engine for weeeeeeeks, to the point my life became a waking fever dream. I'm not a mechanic, have barely done more than plug, filter, oil, tire changes myself. I am, however, mechanically inclined, and have a knack for picking up on things quickly. So I went out and bought myself $300 in tools and prep equipment, and an additional $700-800 in various replacement parts. Been dealing with some newly developed chain slap over the past few months and eventually started getting misfire codes for #1 and #2. Suspected a blown head gasket and confirmed break across the fire rings of those 2 suspect cylinders.

Parts to be replaced:
Timing Chain, Tensioner, Guides, all sprockets excluding VVT Phasers (they are still fully functional and expensive to replace so I'm keeping em in).
Water Pump, Thermostat, Serp Belt
Head Gasket, Head Bolts
Oil Pump
Cam and Crank Position Sensors
Spark Plugs
All Gaskets and Seals and O-Rings accessible during this particular overhaul

Detail work:
Coolant flush and replace
ATF drain and refill (too old to flush I fear)
Valves cleaned and polished and hand lapped into freshly machined seats
Basic cleaning and detail work across the whole top end of engine from the tiny little oil control valve filter to the intake and exhaust ports.

I finished the valves today and have plans to reinstall the head tomorrow morning, but I have a few concerns. First, my machinist took .005" off the head to repair the scarring from the break in the gasket, and the block is likely to lose another thousandth or two. I have searched far and wide for any answer as to what the clearance is between pistons and valves, or the maximum material removable at the head mating surface, and can find none. Can anyone say if this will be okay, or if there is a reference somewhere to this specific concern for the 2ZRFE engine? Second, I didn't leave the crank set to TDC, and it's been rotated a few times anyway to check the viability of the piston rings. Is there even a discrepancy here between the combustion and exhaust stroke if the head/cams aren't even installed? In other words, am I okay to just raise #1 to the top and go from there, or is it possible to be 180 out before the cams are even back in? If so, then how can I determine combustion stroke from exhaust stroke without the cams, on the crankshaft position alone? Thanks in advance for your reply!


New Member
Also, if there's anything else other than the readily available info out there, in cyberspace, that you think I should definitely know... something to look out for... just any advice at all really would be appreciated. The above concerns are really the primary things haunting me...
I have a couple of questions, most importantly do you happen to live in the Chicago area as I could certainly assist?
Getting to the car, I’m sorry to say I searched through my Chiltons manual and was surprised to find no information on machining specs for the engine. Did the machine shop say the block needs to be machined? An old trick for verifying valve clearance is to take some clay or play doh and put it on the tops of the pistons, assembling and rotating the engine slowly by hand. When you pull the heads back off, the marks in the clay will tell you your clearances. If you want to simply play things on the safe side, you can increase the valve relief depths in the pistons with a dremel the same depth as the total amount removed from block plus head.