So, last spring at a race, I lost the coolant bleed screw on my 95 Civic (D16Z6). Noticed the temperature spike, and immediately slowed down and pulled into the pits. There was steam coming out of the tail pipe, so we replaced the head gasket (with a Felpro from Autozone) at the track, and ran the race the next day with no further problems (or steam).

Fast forward to last December (first time I fired up the car since that race), I noticed more steam coming out of the tail pipe. Pulled the head and straightedged it, and found it to be about .012" out in between the 2 and 3 combustion chambers, and about .005" out near the front edge of the head. Also, the intake manifold gasket had failed where the thermostat bypass hose ports through the IM into the head. Replaced the intake and head gaskets with brand new stock Honda factory ones, and had the head resurfaced back down to being perfectly true. I straightedged the top of the block, too, and couldn't get a .003" feeler gauge to slip under anywhere, so it should be in good condition.

However, once I put everything back together, refilled the fluids, and fired it up, there were massive amounts of steam coming from the tail pipe, as well as coolant streaming out of the mating surface between the head and the block. I killed the engine only after a minute or so, and when I pulled the spark plugs, the #4 cylinder had a ton of coolant in it. When I pulled the valve cover, it was obvious that there was a very large amount of coolant mixed into the oil. So, I've pulled the head off again, and plan on having it pressure tested, although I can't visibly see anything wrong with it, and I was meticulous about re-assembling everything last time, so I can't figure out what could cause this kind of issue. Everything was assembled following the Honda factory manual to factory torque specs (ARP studs to spec with 40w oil torqued to the correct spec for that lubricant, although there seems to be a fairly large disagreement on the internet as to what is the correct spec, I went off the ARP website)

I know the mating surfaces were clean, and it was a brand new headgasket still in the sealed package. Does anyone have any ideas of something I could have missed or not done properly? There definitely wasn't any debris inbetween the mating surfaces. I followed the proper torque sequence on the head studs, doing it in stages as the manual describes. I just can't figure out, if the head was machined back to tolerance, how it could have been leaking the way it was, which was worse than when it was still warped. Any help would or ideas would be appreciated. It's starting to become aggravating, but I don't want to just give up on this motor. I'm going to have the head pressure tested on Monday, and talk to the machine shop (racing engine machine shop) to see if they have any ideas, too. TIA.

 

Pressure test the head

 

could be a cracked block as well..