82 Mazda B2000 head gasket woes

[pishta]

had a valve job done on the original head after 278000 miles. The head was in bad shape, pitted everywhere and valves were pretty ugly but it ran pretty good, just no power even after a re-ring. So off comes the head, and straight to the machine shop. $125 later I get a head back that looks brand new, valves blasted and cut, seats ground, and the head was milled down as far as he dared to get a smooth gasket surface. I get the head mounted (1) and noticed a little rocking (Danger, Will Robinson!) but I think its the oil control port (a little hollow alignment dowel that has a small oil orifice) just stiff in the head hole. I get the head installed along with the timing chain tensioner (major PIA) and get it all back together and start it up. Oil comes gushing out of a port that they had pulled the plug on to clean it. I couldnt locate the plug so I bought a new one and sealed it up. Started it up again and I get all kinds of coolant and oil blowing out the gasket right by that oil control port (duh!) Seems the head was cut more than the port was tall so it hung the head up. OK, off comes the head and I drill the stepped hole a little deeper for the oil control port to sit in there properly. I buy a new O-ring and install the head with no gasket and there is no rocking so I figure I got that problem licked. Install the head (2) along with all the timing chain BS and start it again. Now I get the same leak but its on a smaller scale..WTF? I take the head off again and check everything against my old head gasket. Seems the new one didnt compress at all comparing the fire ring thickness. I know I torqued it down correctly, what happened? I measure the head bolts to see if they bottomed out with the .020 cut and they are far from it, but I do notice that all the bolt holes have some oil in the bottoms, actually ALOT of oil as I take out about 5cc's per blind bolt hole with my wifes turkey baster, I guess its mine now! I was torquing the headbolts against uncompressible oil at the bottoms of all the bolt holes! So the head goes on again (3) and now I can feel the torque working on the gasket. I start it up again and I get a little water seepage under the exhaust manifold but it stops after about 30 seconds, I think the block sealer I had in there plugged it or it may have been just runoff. Anyway, runs like a clock now, no leaks. I now understand why they sell a steel .020 head gasket spacer for this motor as you probably mill the head .020 whenever you need to and need the spacer for the oil control port to seat properly. Hope I never have to so that again!

 

[LocuMob]

Ah, the joys of learning. I'm glad it all worked out for you. Nothing like doing it three times to get it right. (i always seem to have to do things three times when I fix something the first time)

 

[Meep-Meep]

Sounds like I'm a bit late, but if you have to deal with that chain tensioner again use a rubber band to hold the thing in the collapsed position. It's a ratcheting mechanism if I recall, and a big PITA, so wrap a rubber band around it then pull it out when the chain is installed.