78 280Z N47 cylinder head

[One Way]

The resurrection project will need a complete engine rebuild.  Slowly moving along with the work as time and money permits.  Disassembly requires little money so I have the head removed and prepping it for machine work.  Besides the 3 broken studs,  the rear exhaust was snapped off beneath the head surface when I bought the car, the other 2 I snapped with the disassembly process.  The front cam bearing is seized on a rusty camshaft.  The rear 3 slid right off, the #2 bearing needed just a slight bit of persuasion after several days of spraying Blaster.  #1 is still tight.  Questions for getting head ready for machine work.  Should the oil galley plugs be removed?  Should the freeze plugs be removed?   Do the rocker arm stud receivers need to be removed from the head?  Any hope for a rusty camshaft ? I have already removed the rocker arms, studs, and springs and will be removing all the valves, springs and retainers next free chance I get.  Any recommendations for a good automotive machine shop to do the guides, seats, milling for flatness?  Thanks for everyones valuable input on this enjoyable project, John-Lugoff, SC.

[One Way]

All the valves, springs, and seals removed.  The inexpensive valve spring compressor from O'Reillys worked out just fine.  Definitely in need of a valve job.  Game plan is new valves, guides, and seals with appropriate machine work.  Still have the unanswered questions from above post plus a couple more as I try to prep this head to be sent off for machine work.  2 locating dowels for the cam bearings are still stuck in the head.  Do they need to be removed?  Should the front galley plug behind the timing chain area be removed also?  I removed the 4 plugs on the top of the head.  What is the best sealer to be used on them?  They appear to have had teflon tape sealer on them.  Next chance I get we will tackle the broken studs and hopefully will get some responses from the experienced Z experts on this great website.  Thanks again, John-Lugoff, SC.

[siteunseen]

I've never removed the oil plugs, just the freeze plugs.  Those four allen plugs on the head are casting plugs or plugs for access holes when they built the head.  I tried to remove one once, wouldn't budge then i found out there's no benefit in removing them.  The cam tower locating dowels should be fine, if they get in the way for some reason the machinist will pull them out.  You can take pliers and squeeze them in a little and twist them out but you need to get them back to their proper shape before reinstalling.  I'd leave them be.  Those rocker arm adjusting studs can stay also.  The only sides that I've ever seen flat were the bottom and the intake side.

There's a lot of machine shops in North Georgia area familiar with the L head, truthfully most any shop that's been in business for 25 plus years is familiar with these motors they just haven't worked on one in a long time and have to be talked into it, $$$$ and plenty of time to do the work, at least that's the way it is around here.

I would buy this book if you haven't already, it's a step by step instruction guide that's easy to understand.  https://www.amazon.com/Rebuild-Your-Nissan-Datsun-Engine/dp/1931128030/ref=sr_1_9?s=books&ie=UTF8&qid=1479222354&sr=1-9&keywords=tom+monroe

Here's some good info too, http://atlanticz.ca/zclub/techtips/

[One Way]

Thanks for the response.  I was beginning to think everyone thought the description given was a hopeless cylinder head, but I am slowly moving forward.  The 3 exposed studs came out very nicely with a rethread of the slightly damaged ends, double nut the exposed ends, a bit of heat with the MAPP gas, and some good leverage with a long 13mm box wrench.  I had no problems removing the oil plugs.  Breaker bar and 10mm allen head socket did the trick rather easily.  The plug in the front  is quite large and I do not have the correct allen head socket size.  I even removed the heater hose outlet elbow at the rear of the head but unfortunately damaged the barbed end a bit.  It appears to be standard pipe thread but will have to investigate that further.  #1 cam bearing finally broke loose with a small amount of heat and dead blow hammer persuasion.  Contact surfaces cleaned up nicely with a little ScotchBrite pad.  Rear exhaust stud snapped off beneath the head surface will be an ongoing project.  Got it drilled  starting with a 3/32 and advancing up by increments to 3/16.  Easy out with slight heat has not worked yet.  Soaking in BLASTER.  Hole not exactly centered or perfectly perpendicular but hoping for the best.  Unsure of how much heat can be applied to the aluminum head.  Can the MAPP gas get it too hot?  Thanks for the tip with the book.  The Factory Repair Manual gets a bit difficult to follow at times.  Thanks again, John-Lugoff, SC

[gwri8]

When I took my N47 to the the machine shop I left everything intact.  He Discovered a couple of bent valves and was able to regrind some also.  Just make sure to keep everything together in the order that you took it off, like rocker arms, lash pads, etc with cyl#1, cyl#2 etc.

Edited November 15, 2016 by gwri8

[siteunseen]

If you find a machine shop they could remove that rear stud for you, likely for not much money.  I had the same problem with mine, I kept drilling with step up sized bits until it broke into pieces.  The heat expands the stud then when it cools down it shrinks a little so if you heat it with mapp gas let it cool down before the Easy out.

I buggered the hole pretty good but fortunately my local Nissan dealership had the next size bigger stud that went in perfect.  After reading I decided to use the bigger stud in the front hole too, under the thermostat.  The header I bought from MSA has those two holes bigger than the rest but I'm not sure about the OE exhaust manifold? but you could always drill it out bigger.  Here's the bigger stud from Nissan next to the original size.

 

[One Way]

Starting to do some investigating on machine shop services locally.  I planned on installing all new parts on this head so I really did not label their positions except for the cam bearing towers.  I work for O'Reilly Auto Parts and they give a very generous parts discount to their team members.  A lot of the needed parts are available through them but some others will need to be sourced.Does anyone know the specs on Sealed Power # MR1895 rocker guides/ lash pads?  They are readily available through O'Reillys but searching the manufacturer's website does not give the thickness.  I noticed that MSA offers them in a variety of sizes and if my memory serves me right the .160 was the stock size.  Any experienced input is much appreciated and even though this is a budget project, the cylinder head work is quite critical and cutting corners to save $ is not in the game plan.  Do it right once and be done with it.  Nothing high end performance just a fun driver some years down the road.  Thanks again.  I will be ordering that suggested engine book to assist in the project.  John-Lugoff, SC.

[Zed Head]

You might want to wait until you know which camshaft you'll be using before you buy lash pads.  If you get a reground cam profile, the lash pads will be different than with a stock camshaft.  Also, waiting until the head has been inspected is a good idea too since it's possible that it's warped or cracked or eroded internally.  It might not be worth rebuilding.  The basic process and steps, in order, is/are described in the "How to Rebuild" book that site linked to  (which you really should have bought before you even started.  It's very thorough).

If you find the right shop/mechanic they'll know the details of lash pads and rocker arm wipe patterns and other details.  If you get the wrong one they might try to guess their way through and they can make a mess of things.  Somebody on another forum got a single bad/tight rocker arm and ruined his camshaft.  When things are right they're very durable.  When things are off, they can fail quickly.

[gwri8]

You can download the Tom Monroe book "How to Rebuild Your Nissan/Datsun OHC Engine: Covers L-Series Engines 4-Cylinder 1968-1978, 6-Cylinder 1970-1984"  here:

http://www.nwdatsuns.com/dtech/How_to_Rebuild_Your_Nissan_&_Datsun_OHC_Engine.pdf

But I find a hard copy more useful.

Edited November 17, 2016 by gwri8

[Zed Head]

6 minutes ago, gwri8 said:

You can download the Tom Monroe book "How to Rebuild Your Nissan/Datsun OHC Engine: Covers L-Series Engines 4-Cylinder 1968-1978, 6-Cylinder 1970-1984"  here:

http://www.nwdatsuns.com/dtech/How_to_Rebuild_Your_Nissan_&_Datsun_OHC_Engine.pdf

But I find a hard copy more useful.

It's a perfect bathroom library book.  You can learn something in just a paragraph.

Don't even want to think about mobile phone/super computers in the bathroom...

[sweatybetty]

oreilleys has lash pads??????

[zKars]

It's not that O'rielly's has lash pads, its the Sealed Power makes them and O'Rielly's (and others) are suppliers.

http://www.jegs.com/i/Sealed-Power/844/MR1895/10002/-1

Also the stock thickness is 0.016, but not really. Note the bottom of stockers have an indent where the valves sit, recessed into the pad. Aftermarket thicker ones do not have this recess. You have measure the depth of the recess and subtract that from the overall thickness. I think they are closer to 0.12.