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'72 240Z Rebuild

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I'm about to tear this motor out and then apart.  It's kind of hard to do because it runs pretty good today but I can't trust a 43 year old motor's stamina, so here I go.

 

I think updating this thread with the progression of the build will save my butt from mistakes with the help of the forum.   

 

My plan is to remove the carbs first then the head and then block and transmission.  I know the basics, label and bag everything and clean, clean, clean.  I did my 280 a couple of years ago with step by step instructions from Tom Monroe.

 

I'm feeling a little sick knowing what I'm about to do but these beers are helping.

 

Thanks,

Cliff

 

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I still remember rebuilding my 240z motor 32 years ago when i was 16 and that motor still runs strong today.

 

good luck

 

Steve

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Cliff,

 

I'll watch this thread with interest as I will be doing a bottom end overall myself later this year on my 185K mile engine. My problem is bad oil consumption across the rings. My head was rebuilt in 2002 and pulls very good compression and vacuum, so I will be spared half an overhaul.

 

The only other problem is a worn timing chain and tensioner. I've been slowly accumulating parts and tools for the job, needing only engine block paint and main and rod bearings. Figured I'll have to wait until the crank is pulled to see whether I'll need a regrind and undersized bearings.

 

I took the advice of others on the forum and purchased Tom Monroe's book. My overhaul will be a little different than yours. I am leaving the automatic transmission in place and simply pulling the engine. 

 

One point from your post. Why are your removing the head before pulling the engine? I thought the aft-most exhaust manifold stud is the best point to attach the hoist chain.

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So Cliff, is this the motor that's hauling you to Zcon 2015? If so, we are in the same boat. I was thinking of documenting my 'redo' of my l24, but maybe just throw some comparisons in on your thread?

I'm a little further than you in that my block is sitting here cleaned and rehoned with my crank polished.

You are having a machine shop prep everything?(rods, crank, etc...)

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65 degrees here yesterday.  I cleaned up and out my garage then drove the little car for the rest of the day.  Those new 15x7s with 205-50s make all the difference in the world.  Looks good and drives like it's on a rail.  Anyway, all I did last night was pull the hood off.  But today I'm filling up some boxes and baggies.  ;)

 

DJ that book was crucial when I rebuilt my very 1st car engine, my '77 280.  I'd only took the top end off dirt bikes then in the early 90s I learned how to work on outboard motors by working with a mechanic while I was healing after an ankle fusion surgery.  He turned out to be a good friend that I'm still in touch with today, Dr Brown we call him.  I had a 2.5 liter Mercury V6 with OMC carburetors that would turn 9,200 RPMs with a 24 pitch prop.  8,000 with a 26 or 28 prop (can't remember) was 102 MPH on a handheld GPS I had in a pouch on back of the driver's seat.  1,200 lb boat and motor I raced 1/4 mile side by side "run what you brung".  It was a '83 Hydrostream Vector. 

 

Sorry about that, great memories from then.  Anyway I have to do everything by myself and taking the engine apart piece by piece is the easiest way for me without banging the car up.  After getting the top off I put 2 head bolts in the block and lifted it out with a hoist.  It may take a little longer but I tend to make mistakes when I try to do too much at once.  I let the 280 motor worry me to death, not going to happen with the 240.  I've learned enough with Tom's book and the helpful members on here to have some confidence now, plus the 240 is so basic and simple I can hardly wait to tear into it.

 

I'm going to take the block and head to the machinist in North Georgia.  They're going to set up the valve train and notch my block for the exhaust valves.  Port match and anything else I can afford.

When I take it apart, if there's anything that looks suspect I'll have it checked out by my local machine shop.  

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Very good. Enjoy the pretty weather. 102 mph on the water is "hauling the mail"!

Charles

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my eyes will also be on this thread... my f54/p79 build will progress sloooooowly, as it is being "trickle-funded" so i will have plenty of time to watch and learn.

thanks for posting up for the benefit of us all.

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Finally getting down to the motor.  Hood is under one bed, radiator under another.  Carbs are on an extra intake mounted to a wall.  Everything is coming off pretty easy so far, exhaust manifold is going to be a booger.  I'm getting a friend to come by today and suck the R12 out of my A/C, don't know if I'll be putting all that mess back on.  

 

MSA's got a free shipping deal through the 16th so I'll order my exhaust in the next couple of days.  

 

Oh my aching back!

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progress seems to come with an aching back.

it's the one downside to these low-slung sports coupes - serious 'bend-over factor' when working under the hood. i find myself taking a 'wide stance' to get lower and keeping one palm on the hood latch bracket otherwise just changing the plugs is enough to get me feeling much older than i am...

 

the exhaust manifold is a pita, but once it's off you're just about done. i wrapped my u-joint socket adaptor w/some electrical tape to keep it from flopping around when trying to reach some of those hidden stud nuts, this was a great help.

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Saw this on zcar.  They're standard bore so if you go over not much use.  But might be useful if the bores are good but pistons not.

 

http://www.zcar.com/forum/19-sale-parts-accessories/367049-nos-piston-wrist-pin-set-l24-flat-top-240z.html

 

 

 

Tried to learn what "Ttt" means but all the internet came up with is "third tier toilet".  Not sure why he says that...

 

Also, just because it's interesting - http://www.art-piston.co.jp/en/profile.htm

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I'll have to share this with you guys and see what you all think.

 

I'd thought I found a L series machine shop in North Georgia.  The late John Williams had his shop located behind theirs, or vice versa, they built a shop in front of Mr Williams's place.  It's all up around Road Atlanta race track.  Two guys but only one talks on the phone, he says you need to talk to the other guy but he's never there or in the bathroom or on the roof, blah blah blah.  I called Monday to ask if they would notch my block for me.  The phone guy says that sounds crazy as hell but he'd ask the other guy and call me back.  When he called back the other guy had said that I shouldn't have put larger valves into my E head, I told him it was a very common mod and that I had bought it that way.  Then I remembered reading the 2.6 blocks were notched from the factory so that bothered me too.  Then he say's I'll need .150" lash pads for proper geometry.  Schneider told me that I would get .175" with my cam kit because they REMOVE material resulting in the need for thicker pads.  So that's 3 things that got me to wondering how many L heads they do.

 

I called my Dad for some reassurance, he's a simple kind of guy in the best way, love that man.  He say's that getting the geometry right isn't as hard as I think and his favorite machinist could do it easily.  I read where Madkaw notched his own block and looked at tons of pictures, I can do it myself.  So the question is, I have chosen the cam and the cam company myself, they'll send everything I need, the head has new valves and stems already.  I can get a local guy to take it apart and lube everything up (it's been in a bag for 5 years at least) put it back together with the new springs and retainers that are coming with the cam.  New valve stem seals most likely, they've not had oil on them.  Center the wipe pattern and give it a try.  15 minute drive compared to 2 1/2 hour drive.  Telling my local shop what I want or having the out of state shop tell me what they want?  If you read this THANK YOU for your time and your opinion.  Cliff 

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If the machinist doesn't want to do the work, find someone else. You need and want to notch the bores. Datsun motors aren't the only motors that practiced this notching. I notched my bores right to the limit of the HG fire ring, but you don't need to go that far. If you are careful and take your time you can do this yourself. Just don't go to deep or wide.

Sounds like the machine work is all done and you just need better valve seals and a wipe pattern checked? I would think any competant machine shop could do this. I handed my machinist the "how to modify" book for a references. I just told him that I know he doesn't see these motors everyday and just thought he might want the book to look at.

 

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I would also express a concern about rocker geometry an quality of the rocker arms. Whoever winds up doing the wipe patterns, make sure the wear is square on both the cam surface and the lash pad surface. 

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go with your gut - if something feels off, it probably is.

i've burned myself more than a few times letting my brain tell me to go down a certain path when i had vague misgivings... 

 

now that i'm working on my third head, i'm learning that setting the valve geometry is not that complicated - but it's really important.

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Seems like one of the reasons that people like to work with Rebello or DatsunSpirit is because the owners share what they know and the customer learns something when it's all done.  Your guys seem more like the old, classic, "leave it there and we'll call you when we're done" kind of guys.  Guys that always come in at the top end of the quote range and call you with "problems" found requiring more work.  I think the descriptive word is sketchy.

 

On notching the block, a general trick that I learned from a machinist is to turn the block upside down.  The grinding or filing chips will fall away from the cylinders.  That's if you're planning to leave the block assembled.

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Good news!  I went to my Dad's machinist and he knew exactly what I was talking about.  He told me I may need tower shims to get the wipe perfect.  I have an extra 2.4 block that I'll do the notching to and keep the numbers matching motor OE, rebuild it later on.  When I walked in he slid his glasses down on his nose and says "well I'll be damn, there's Marvelous Jr." my Dad's name is Marvin, I haven't seen that man in at least 20 years.  :D

 

Another funny thing he said was "I thought all those old L heads were scrapped by now".  One more thing Steve"madkaw" brought up that he knew about was notching blocks.  He said he makes templates out of cardboard with the HG when he notches blocks so he doesn't ruin the HG.  So YES, other blocks need notching too, thank you Steve.  Looks like I'm following in your footsteps

 

I feel so much better now I'm going to have a couple of beers and run over the dog poo and onions in my yard, with my mower of course.  I'll get back to the motor removal tomorrow, the weather is going to turn cold again.

 

Thanks again guys, y'all are the best!

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Boy this is a lot easier than before, I'm learning something I guess.  It'd be hard not to when I check in with you all everyday. :)

The head has been off before for sure, I guess for the steel valve seats? and a newer style spray bar.  It has big phillips head screws in the bottom holes so I guess it's a multi car type.  It looks good too.  The head gasket has overly large fire rings so I guess it's for a 86mm bore, it has a copper coating on both sides too.

 

The only 2 bolts I broke were the 2 holding the exhaust manifold to the exhaust pipe.  I drained the radiator and only got a little over a gallon last Sunday.  Today I removed that plug at the back of the block and got a GUSHER of coolant, at least a gallon maybe more, I'll have a catch pan next time.

 

Cylinder walls are as slick as glass, so standard size rings will work fine hopefully.

 

280Z, 1st rebuild worried me sick and took 6 months.  This 240Z will be done in a third of that time and done right, blue block not bar-b-q grill black paint.

 

All the topside is done, tomorrow will be the exhaust pipe then the transmission.  Saturday the blocks coming out and apart.  Then clean, clean and some more cleaning.

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great to hear your progress - and excitement! i'll be borrowing your enthusiasm when i start re-building my f54/p79.

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I'm on schedule but will be as sore as ever.  I decided to drop the transmission onto a motorcycle jack I've used before for holding it to roll around while I pressure washed it.  BAD idea for my 50 plus years old cracked up to hell garage floor.  

 

Getting my Dad's cherry picker tomorrow to pull the block out.  I can't believe I wouldn't wait and get them both together.  Stupid mistake I'll never repeat.

 

This time I'm making a pile throughout the day then going back and bagging and boxing up everything in the evenings.  Seems to be a lot less worrisome.

 

RossiZ I have my console out so if I can take some measurements or pictures just let me know.

 

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Love the idea of the rubber pipe cap over the transmission output. Do you know what size it is?

It's a 2" or something, I'll make sure in the morning and post the size.  That works way better than a baggie and tape.  Even Carl Beck noticed that a few years ago when I rebuilt my 1st Z.  He told someone that was hauling their car on a U-Haul type that holds the front tires only to remove the drive shaft and use that cap on the transmission for a long trip.

 

In the morning, I promise, I'm not about to go back down there now that I'm clean.  It was a couple of dollars at Lowes.

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Nice pictures.  I can see the factory hone marks in the cylinders but also the classic rust line of an engine that's been sitting (my old one has that).

 

I see that you have a chain tensioner block installed.  Like you haven't decided yet how far to tear it down.

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