Datsun 120y broken head bolt

[dannobyte]

I'm having some problems repairing my daughters Datsun 120Y.
It originally presented with overheating and coolant loss so I checked al the usual bits (thermostat, water pump, hoses, radiator) and they were ok. I next thought it might be a cracked head or head gasket so I began to remove the head. As I was undoing one of the bolts it sheared off leaving most of the threaded section in the block. Interestingly this bolt was faily rusty loking while the others were black.
So much for the history.....now the questions.
1. Is there any chance that the car will run with one head bolt missing?

and if not

2. How can I remove the broken bolt from the block?

It turned out that the water leak was coming from a couple of pin holes on the um....(not sure what it's called. The front cover of the engine block which the water pump bolts on to and the main engine pulley is in front of. Crankcase cover? timing cover?)

And so to my final question.

3. Is there any way to plug those pin holes with some kind of sealant (Liquid Metal possibly).

Your advice would be really appreciated!

Cheers,

Dannobyte

[DanD]

First things first welcome to the site Dannobyte; thanks for stopping in.

1. The engine will run but for how long is any ones guess? The head bolts are placed/designed to apply even force to the mating surfaces of the block, cylinder head and gasket to ensure a positive seal under all conditions. With one head bolt missing the cylinder head may lift due to expansion and contraction allowing the gasket to fail.
2. You’ll more then likely have to drill a hole in the center of the bolt large enough to use what it call an “easy-out” bolt extractor. This tool is a hardened tapered length of metal round bar that has a spiral machined into its length that will hopefully bite or grab hold of the side of the drilled hole in the bolt allowing you to wind it out. Like I said Easy-outs are made of hardened metal as to be able to grab or cut into the softer bolt but that is also their down fall. They are very brittle and are easily broken if too much force is used during the attempt of removing a seized, broken bolt. The last thing you would ever want to do is break off an easy-out because they are made out of the same material if not harder material then that of a drill bit. In other words you’re not going to be able to drill out the easy-out if it breaks off in the bolt. Basically you would be screwed. If the easy-out doesn’t work I’ve had to use a thin hacksaw blade that would fit into the drilled hole. Cut four equally spaced slices along the inside of the bolt, deep enough that I could use a chisel to collapse the bolt into itself and remove the pieces with a needle nose pliers. Yes that will leave cut marks in the threads of the block but if you haven’t gone to deep with the hacksaw; plumbers dope or Teflon tape will seal the threads.
3. You’ve gone this far to repair this engine don’t trust all your hard work to some form of snake oil that clams to be a magical cure for whatever ales you. Replace whatever is leaking you’ll regret doing anything else.
Here’s a picture of one style of easy out.
Dan.

[DanS]

Thank you Dan. As you can probably tell I'm not too good with cars (computers are much more straightforward. With four teenaged daughters I guess I'll learn as I go.

Thank you again.

Cheers,
Dannobyte

[DanD]

Holy crap man FOUR DAUGTERS no wonder you want to be out of the house and trying to fix this car on your own; it will give you a break from all that estrogen. LOL
I only have one daughter and the wife to deal with; my hat is off to you Sir.
Dan.

[way2old]

I also welcome you to the forum Dan. Although I don't know if 2 Dan's are allowed. I might have to check on that. You might also try a left handed set of drill bits. Sometimes the reverse spinning of the drill bit will break the broken bolt loose and spin it out. Not every time, but I have had good success with them.

The liquid metal is an option for sealing the holes in the engine, but that is dependant upon how thin the metal has worn for the pin holes to come through.

By the way DanD. I have 3 daughters. They are all gone now, but I feel for new Dan.