It might very well be that I'm using the search feature wrong, or Tapatalk and my phone are making things difficult.

 

At any rate, I've picked up my P79 head from the machine shop and am preparing to chase the threads on my block prior to installation.

 

Can someone advise me on which thread pitch to use in my tap set.

 

Thanks in advance.

 

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Thank you for your research!  I will take this into account for sure.  I have blown some compressed air into the bolt holes on the block to ensure all FOD is out of the way, shone a light into the holes and verified to the best of my ability that the holes are free and clear all the way to their stops.  I will also measure the threaded lengths of my new set of head bolts to verify any variations vs the old ones.  My new set is a Nissan turbo set, ordered through a local dealer.  I'm under the impression that these bolts have an updated torque spec of 5 or so more ft-lb than the earlier ones?   It would be good to know if the thread lengths are the same. I am going by Tom Monroe's book, it does not appear to elaborate, however I will read ahead a bit to see for sure once I head out to the garage today. 

I will also measure the bolts I removed at the time of disassembly.  If I were more seasoned, I would be able to tell if this engine has been rebuilt, as all internal components seemed pretty clean for the age and all seals were annoyingly sealed with gasket shellac.  The freeze plugs looked brand new. 

My depth gauge 'pointer' is actually a metal strip measuring about 3/16" across, with a square profile at the end.  As someone else has pointed out, the bottoms of the holes are conical rather than square.  That means that the tip of my depth gauge would have sat slightly short of the very bottom of the hole at its centre.  If you use a piece of wire as a depth gauge, you measurements may come out 1 or 2mm longer than mine.

Run the bolts in to their holes without the head and measure the distance from the bolt head to the block.  If it's less than head thickness it's as good as it needs to be.  In manufacturing, precision and accuracy cost money.  There's no purpose to having all of the bolt holes the same depth so that spec would not be set that way.  

I've only ever seen two length head bolts*, and the positions are pretty easy to figure out... Long ones go through the cam towers and the short ones go everywhere else.

Five long ones for five cam towers.

*I did see in the 1972 FSM where they referenced three bolt lengths. So that's either a feature of the early cars, or a typo. I've never worked on one that early, so I can't verify the lengths.

 

I ran all the aforementioned measurements, and could find no reason to suspect I had a problem. Cylinder head to deck thickness was in line with bolt head to deck distance(with washers taken into account), so I moved forward.

Head bolts lubed and torqued in 20 ft lb increments to 65 ft lbs with no binding or complaining.

Made it as far as just before you get the front cover on and begin installing and setting the oil pump and shaft. Now to put a beer in my hand.

Thanks to all that helped. It's much appreciated.

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10 hours ago, Reptoid Overlords said:

Head bolts lubed and torqued in 20 ft lb increments to 65 ft lbs with no binding or complaining. Now to put a beer in my hand.

Excellent! Sounds like great progress.

I don't know if it's really necessary, but I re-torqued my head bolts after about 100 miles or so.

Edited September 1, 20195 yr by Captain Obvious

11 hours ago, Captain Obvious said:

I don't know if it's really necessary, but I re-torqued my head bolts after about 100 miles or so.

I ended up gong with a Fel-Pro gasket.  They claim no re-torque is necessary.  I've had mostly good experiences with Fel-Pro, but no experience with their head gaskets.  A lot of people I trust say they have no problems.  Let's hope that's the case. 

The only issue I encountered yesterday during head install was that some oil I used to lube the valve train found its way to the base of the head and contaminated the gasket behind cylinder #6.  I cleaned it really good with some isopropyl alcohol and made sure It didn't happen again before I started getting bolts in place. 

11 hours ago, Reptoid Overlords said:

A lot of people I trust say they have no problems.  Let's hope that's the case.

Agreed. Hopefully no revisit.

I used an OEM Nissan gasket because after all the problems I had with my motor, the last thing I wanted to do was mess around with the head gasket again. Not saying that's any better or worse than what you used, but just that "if it's good enough for the dealer"...

And there is a note in the FSM about re-torqueing, with the assumption that your using an OEM gasket of course.

I figured what could possibly go wrong. Go wrong. Go wrong.