Anyone out there ever siezed a cam in the head?  I went out to start my Sammy last night and it started for a sec, then just quit (kinda normal, it's cranky when it's 2­° outside).  Turned the key again and no compression sounds...Uh oh.  Took the oil fill cap off and had my wife crank the truck.  No valvetrain movement...SH*T!!!!  Well, it's 7 PM, dayum cold out, I'll deal with it in the morning.....

Pushed it into the garage this morning expecting to find a broken timing belt.  Pulled the timing cover off and the belt is intact, except the teeth are stripped off it around the crankshaft.  ???WTF!  I'm beginning to wonder if I snapped a rod and it jammed into a valve, so I loosen all the rockers up, and the cam STILL won't turn.  Took off the timing gear, and it had rotated on the cam and the alignment pin has torn up the rear of the gear.  Took off the distributor, put the bolt back in the Cam, and after putting all my weight into it, the cam FINALLY moves.  It's really hard to turn, and feels like sand in the cam bearings!!!  And the damn head is only 1.5 years old!!! GRRRRRRRRRR.

Well, either I'm gonna put a 1.6 in now, or I'm gonna get one of the hopped up 1.3 heads with the Isky Cam in it.   Anyone got a 1.6L or a cammed head cheap?  

Had a cam oiling passage get blocked on a Honda cb750 ,motorcycle.  Did the same, justabout melted my bearing cap.  

a few months ago i was told by a mechanic who had a tracker that they were notorious for breaking cam shafts. he said he broke his 3 times...

Haven't had mine sieze (knock on wood) but I did notice when I rebuilt my engine that there's no cam bearings on the SOHC engines.  The cam journal surfaces just ride on an oil layer inside aluminum from the head that's been line bored.  Hardly what I'd call the best design out there.  Based on that I'd say if you even remotely suspect any oil supply problems on your rig get it fixed ASAP and don't drive it until you do if at all possible.

I've got good oil flow.  Because I'm running an electric fuel pump, I put an oil pressure switch that cuts the fuel pump out when the oil pressure drops below 7 psi, so I know my pressure is ok.  Not sure what caused this, but I wasn't happy with the rebuild when I got the head in the first place.  Oh well, I'm looking at one of the Sumo 1 heads now

Could be something like too much runout on the cam or a crappy job on the line bore.  Not having some babbit metal bearings doesn't leave a big margin for error unfortunately.

Haven't had mine sieze (knock on wood) but I did notice when I rebuilt my engine that there's no cam bearings on the SOHC engines.  The cam journal surfaces just ride on an oil layer inside aluminum from the head that's been line bored.  .

     I have yet to see an overhead cam engine use replaceable bearings and not a line bored bearing cap setup. They may be out there, but I haven't seen one yet.

Some Datsun engines did/(do?).  I think my 240Z head uses them but I can't 100% verify this till I get home and look.  It seems like there's a bearing piece that's separate on the cams towers on them though.  Not a bad idea if they're in there, they are a pretty bulletproof engine.