Your're right, bad timing can cause an engine to overheat. It's not cause it's running in a rich condition (that would actually cool the motor). If it's too advanced, it will detonate (ping or knock) and can damage the head, piston or even the block.
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Haha, I remember this - happened twice to me. When you change the coolant, the cooling system system should be bled or it can get hotter than normal. For me it didn't actually boil over, but the gauge going up freaked me out. When you fill up the radiator, there is still some air in the engine or hoses. To bleed it, you open up a high spot in the system and run it until the air leaks out, meanwhile keeping the radiator topped up (do this when it's cold, of course). Or just let it cool back down and top it up again.

Many cars don't have this problem, but the 1200 does. Some cars like the old Honda Accord actually had a bleeder valve (just like for the brakes) in the cooling system. The 1200 doesn't.

thats not good to be running cold all the time though, i usually sit and let my engine warm up before taking off just to avoid damage and to preserve the motor

To answer a couple of more questions.

One of the first things that I do to any car that I get to drive any time at all it to put an electric fan on it. I always put it to a relay to keep from burning up the ignition switch but I do make it to where it comes on as the ignition comes on. I want a fan running all of the time. I need to put an elecrtic water pump motor on it also and link the water pump and fan to a thermostat. This was a requirement with all of my turboed motors.

My radiator is a new, very large, three core radiator for an 88 Dodge. The radiator is more than effecient and the temp needle rarely runs up to the cold mark.

Mareo

Hi Ya'll,

Sorry to be gone all week but I've been very busy. Thanks for all the info and stories on head gaskets. It would not have blown if I had taken the time to deal with the first wounds and slowed down a bit to keep it from overheating.

The center bolt closest to the distrubutor is the longest bolt on the A-series heads. I didn't know about it being part of the lubrication system, thanks for that info.

The head war scarred between #3 & 4 cylinders so I had to take it to a head shop and have it milled a bit. While I was there, I saw an A-block head on the shelf so I pulled it down and looked at it. It was an A12 high compression head with the heart shaped coubustion chamber. It was new and had never been bolted on a block yet. He said that it had been there since the 70s. I paid him $75 for it. The head that was on the A14 motor was a sort-of stock A12 head so I just put on the new HP head. It has the round ports. I spent two days with carbon router tips and sanding wheels just a porting away. I didn't take off anything metal that was needed but I smoothed the ports real well and made all of them the size of the manifold gasket port openings. I deburred everything in the chambers but left them alone pretty much.

I put the new distributor on it also and it wouldn't fire. I took it back to Advance Auto Parts and a new one should be there in the morning. So that means that I haven't been able to drive for a week now.

How could a distributor make a motor overheat?

With the Datsun distributors, they have a little triangular piece of plastic that holds three little ball bearings in place that the rotation spark advance plate sits on so the timing can advance when needed. This plastic gets old and cracks, letting the ball bearings come out of place and making the spark advance plate ride crooked. The spark is weakened as a results and the motor runs like it is in a rich fuel condition, which in turn, makes the engine overheat. El Stupido Grande, that's me, didn't stop and let the engine cool down causing severe overheating and the blowing of the head gasket.

Hopefully, tomorrow, Mareo Speedwagon SIX will be riding again.

Mareo

As much as I'd like to take credit for knowing where the odd headbolt goes, alas it was not I who helped out. I'm just as in the dark about them as everyone else.
I don't mean to cast doubt in the minds of others but, are we sure it is the A-12 that has the odd bolt? It seems like the ARP head stud kit that I bought for an A-12 had all of the studs the same. Also, while comparing heads at the machine shop the other day, the A-12 seems to have an oiling hole where the A-14 does not.
I wonder if Gil's A-14 has the "oiling bolt" in the wrong hole and that is why he is eating the #4 intake pushrod. I need to look that engine over again.
Incidentally, I did not build that engine! It wasn't my screw up if that is the case!

You must put the long bolt in the correct hole as this is the oil supply gallery for the rockers. no lubrication = disaster. The long bolt from memory has a letter "T" stamped on it or "13". In addition I think the side (right-left) in which the bolt screwed into could be different, depending which evolution of the A-series engine you have.
It is easy to pick, as the head bolt hole threads in the block start more or less at deck height, except for the hole that the long bolt belongs, as the threads start approx 7-10mm below deck height.

As for the mechanic in tassie, sounds like he is a ruthless bastard, only interested in the dollar.

yes 1200, I believe all the bolts have the same thread size. I wish I could remember who gave me this info. Anyway, they told me that putting the bolt in the correct location would help to prevent blown head gaskets in the future. I believe it is skinnier to let oil flow past it, if I'm not mistaken. You know, now that I think of it, I believe it was dimlight65 that helped me out. Good luck.

i was suprised how easy it was to change the head gasket too, i knew about the diffrent bolt but last weekend when i took an a-14 block from a sunny i noticed that head bolt was in the front right (from standing in front of the car) i mentioned this to my brother in law but thought nothing of it cause i didnt know why it was diffrent, is this a bad thing? is it likely that the thread could have been damaged or do the bolts have the same diameter anyway? and will it have ruined the block in any other way, ie cause no oil somewhere? (keeping in mind the block will be rebuilt and worked before beeing used in a car again)

Hey mario, sorry to hear about the head gasket. Luckily for us, these cars are pretty damn simple to work on. I just did a head gasket on my A-12 about 2 weeks ago, so thought I would share some stuff. Somebody here told me(can't remember who,sorry) Don't forget that one of the head bolts is different from the rest. It's the one on the distributor side in the center of the engine. It's a tad bit skinnier than the rest. It must go back in the same hole. Allows oil to flow past it or something...I don't know if you have done a head gasket on an A-12 before, but it's very simple. It took longer for me to clean the gasket surfaces than to do the actual R&R. Good luck.

You