On October 6, 2016 at 2:02 PM, Jeff G 78 said:

Is that corrosion/rot in the #1 chamber between the valves?  I can't tell what I'm seeing.

I guess the dowels were keeping it stuck...

No, not corrosion/rot because it comes off.  I'll guess that maybe it's varnish?  I have run some CRC one tank on occasion and maybe that was some carbon or whatever that was peeling off?  I can't say for sure because the head is in the shop. Looks like something got soaked and wasn't all the way off yet.

I had the same leak.  Also sealed up as the engine got warm.  Interestingly, the head was bowed up in the middle, not the end where the leak was.  Also broke a head bolt and used vice-grips and PB Blaster soaking to get it out.  Very difficult though, it was rusted in.  There was actually a small hill of rust around the bolt stub after I removed the head.

Is that a thread insert in one of your spark plug holes?

 

That is a Helicoil.  I discovered it the first time I changed spark plugs and it came out with the plug.  I about crapped when that happened because I had never seen one before. I've since used Thread lock to help hold it in.

Greg,

I had a Datsun mechanic tell me that I should use that permatex copper gasket spray on both side of the HG. I'm not sure if that's the right thing to do or not and wondering if anyone knows for sure. Would be good info if its correct. 

Good find Zed Head. Is a thread insert the same as a "helicoil"?   

1 minute ago, rcb280z said:

Greg,

I had a Datsun mechanic tell me that I should use that permatex copper gasket spray on both side of the HG. I'm not sure if that's the right thing to do or not and wondering if anyone knows for sure. Would be good info if its correct. 

 

Hmmmmm, I wonder if that's what was on it that made it so difficult to remove?  I'll ask the machinist about that permatex gasket spray when I pick up the head.

4 minutes ago, gwri8 said:

Hmmmmm, I wonder if that's what was on it that made it so difficult to remove?  I'll ask the machinist about that permatex gasket spray when I pick up the head.

I was wondering the same. Its supposed to fill "hot spots" and surface imperfections, so maybe. Can't wait to hear what your machinist says. 

Just curious - does your machinist know to keep the valve train parts associated with the spot they came from?  I've read stories.

I think that most head gasket manufacturers have instructions for their gaskets.  Pretty sure the Nissan instructions are for two flat clean surfaces.  There are three different materials on a gasket - steel, copper and an organic material between the sealing areas.  I'd go with the OM process for OE gaskets.

Edit - found it.

Edited October 12, 20168 yr by Zed Head

10 hours ago, Zed Head said:

Just curious - does your machinist know to keep the valve train parts associated with the spot they came from?  I've read stories.

I think that most head gasket manufacturers have instructions for their gaskets.  Pretty sure the Nissan instructions are for two flat clean surfaces.  There are three different materials on a gasket - steel, copper and an organic material between the sealing areas.  I'd go with the OM process for OE gaskets.

Edit - found it.

Yeah I just read the same thing. Plus, I contacted the mechanic that recommended the copper gasket spray and he did use it every time including on mine 16 years ago. I have 2 coolant leaks at the HG. Tom Monroe in his "How to rebuild your Nissan/Datsun engine" also says to NOT use any sealer on an OE gasket. But that it's okay to use it if you are not installing a no-torque or an OE gasket. Pg 23.

You guys have reminded me of something I need to do. 

Tom Monroe also says to retorque the head bolts as added insurance but do it when the motor is cold, pg. 155.

3 hours ago, siteunseen said:

You guys have reminded me of something I need to do. 

Tom Monroe also says to retorque the head bolts as added insurance but do it when the motor is cold, pg. 155.

He also recommends the use of turbo head bolts which I plan to use on my HG replacement.

Question:  Is it wise to use Anti-seize on the head bolts and exhaust studs?  I'm wondering if it holds up under high heat.  I would like to avoid snapped bolts in the future.