Thanks to everone that helped me out with there suggestions.
THE CYLINDER HEAD IS OFF.

Picked it up at the machine shop with the 1200,the guys were all amused about the lil Datsun.

Here's a pic of it in the trunk.

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Heres a tip from an old mechanic. As I have had to deal with many rounded head bolts over the years I have found this to work a treat. For obvious reasons, a single hex socket is best. Put some corse valve lapping paste on the head of the bolt before attempting to loosen it. The valve lapping paste will help it bite really hard into the bolt. It washes off. You don't want any of that stuff inside your engine though.

Thanks Guys.Does this happen often on a series engines?
Could that happen if its been now opening for the first time since made??

Here's a trick used with British motors and motors notorious for getting stuck on head studs. Yeah head studs but I imagine the same principle can work. Put motor back together but leave the head bolts slightly loose. Run engine till head moves or gasket blowout. If that hasn't shocked the bolt free of any binding rust then fell free to do the other stuff

Quote:Agreed, I meant to say that it is silly to take it to a shop [when it can easily be done at home]. I have no power tools and do all my own Datsun maintenance. I have not taken my Datsun to a shop since the 1980s.

go back to my post #12 and weld away son

Dd why say its silly and take it to a shop then provide info on options? Id give it a go, as long as I had a spare head just incase.

try the pipe,wrench or cut the tops off the heads and lift off as dd did.

But then again look at what happened when I tried to remove a damaged over tightened gearbox drain plug.... I gave up.

So when you used the pipe wrench, what happened?

* If the bolt did not turn, use a piece of pipe to extend the handle. Longer handle = more torque. When you apply enought torque it will turn. I've been in this situation.

* If the bolt head rounded even more so, and the pipe wrench slipped on the bolt head, tighten the pipe wrench. Basically you want it as tight as possible, and just barely able to fit onto the head. As you pull, the wrench will bite into the bolt head.

I had some bolts heads that I cut off with hacksaw (Isuzu engine with corroded bolts which were stuck to the aluminum head). Then pull the head up over the bolts. After that the bolts came out very easy with a pair of vice-grips.

I have Tried Both Long and Short pipe wrench.
Have a six pt socket With 1/2 inch Drive.

For torquing the head bolts, purchase a six-point socket