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dfknoll

Buying a 72 240z. Have questions.

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Hey guys.  I am going to apologize immediately because it has been a while since I posted anything on a forum, and I know all of these sites have different procedures and rules as far as posting goes.

 

 

I am purchasing a 1972 240z from one of my customers (I am a car salesman and he asked me if I wanted to buy a car while his wife was signing paperwork).  He is the original owner.  The car has just over 50k miles on it.  The entire car has been race prepped to run in SCCA races.  The engine was built by Bob Sharp and it has a lot of first gen performance parts on it.  The car has been stored in a heated garage since it was purchased, but just like every car from this time period it has some cancer in the metal.  The good news is that I was a sheet metal welder, so replacing the sheet metal doesn't worry me.

 

 

On to my first question.  The car has not run since 1991, and the current owner told me that I should check with some knowledgeable people (aka you guys) on what steps I should take to turn over the motor.  He knows his stuff when it comes to working on the car because he did most of the work on the car back in the day, but he also said that I should start doing my own research in order to get myself more oriented with the whole restoration process.  He did mention something about taking out the spark plugs and  pouring some penetrating oil in to loosen up the engine in case it was stuck.  So, what steps should I take to turn this baby over?

 

 

Thanks in advance!

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Search around the interweb using words like "resurrecting old 240Z" or similar and you might find some write-ups about it.  They are out there.  There are other considerations besides just stuck cylinders too, like a dry valve train, sticking valves, gummed up carburetor innards, etc.   If it has carbs then you'll need to determine the quality of the old fuel, it tneds to evaporate and leave tarry material behind.  People often get the old engines running then have a lash pad pop free because a valve stuck open.  

 

And, much of the advice you'll find is for getting an engine to start after sitting for a long time but the advice might not actually be the best for getting the engine to start without causing long-term damage.  If you really want it to come back to life and last another 100,000 miles you'll want to examine things closely before even trying to crank it.  For example, that rust in the cylinders has to go somewhere after the pistons break free.

 

Just some thoughts.  I'm always surprised at how people will throw a battery in try to crank an engine over without considering what's happening to all of the age residue.

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Pictures!

 

Couple years ago i had something similar do to with my z when i picked it up. I never tried penetrating fluid but i did drop a bit of oil in the cyls and manually cranked it after it sat for a bit. Did an oil change, and a few other cleaning related things. i can assure you that you will need to just go ahead and order a carb rebuild kit and replace the fuel pump. I didnt even bother putting fuel in the tank. I put a line into a fuel can. Clean the tank out for sure.

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Here she is.  Like I said, the current owner is a wealth of knowledge.  He is the original owner and said he remembers having Datsun factory reps coming out to their club meetings and having them show the guys how to work on the cars and how to do performance modification and stuff like that.  I am really excited to dig in to this thing.  It will probably take me at least a couple of years to finish it up, but I want to do it right the first time.  Don't like doing anything half ass.

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Welcome to the hybridz.

 

First check if it has oil.

 

Depending on how frugal you are either drain the oil and replace it, or undo the drain plug for just a few seconds to get a sample.

 

Inspect the sample for contaminants like water or metal debris. If it has debris, stop now you are going to have to do a whole check list to see how far the damage is.

 

Either top off the oil or fill the engine back up with oil.

 

Pull out the spark plugs to make the next bit easier as well as set them aside to inspect for damage.

 

Get a breaker bar onto the crank and bar it over, if you need to know the rotation (clockwise or counter clockwise) find the timing marks on the timing cover and turn it so the numbers decrease.

 

If you find any hard spots stop. That either means you have a nasty ring ridge in the cylinder or the timing is off or a broken valve is stopping the cylinder from rotating.

 

If you don't find any hard spots, give it a few rotations.

 

Take the valve cover off, look at the valve train for oil distribution, if it looks dry, give it another few turns.

 

If the valve train is getting oil then great, time to put in the spark plugs and check for compression, if the valve train is not getting oil then now is the time to stop and consider if you want risk the motor as is or if you want to save whatever value is in it and replace the oil pump etc.

 

Check the motor for compression by rotating the crank and listening for hissing from the valves as you rotate the head.

 

Once that checks out now you can use the starter to do a compression test.

 

Run a compression test to check for numbers. If a cylinder is low you can isolate the block from the head via a small capful of oil into the offending cylinder. If the compression goes up your rings are questionable, if the compression stays low looks like your valves may not be closing correctly.

 

Engine bay shot would be pretty cool, those bob sharp racing valve covers are pretty rare if it has one.

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Finally picking my z up tomorrow. I need to change out the coolant because I'm pretty sure it's no good anymore since it hasn't been changed since 91. Should I use green anti freeze or do you recommend something else? Does anybody know how much coolant the L24 takes?

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HybridZ is a great site (and my personal favorite), but there is also a ton of good info on some other sites you may want to check, particularly if you're doing restoration-type work:

 

http://atlanticz.ca/zclub/techtips/

http://www.classiczcars.com/

 

Also, you'll want a factory service manual for your year and model.  They used to be available on xenons30.com, but no longer.  Search 240Z FSM and you may get lucky.  You may have to pay for one, but it will be worth it many times over.

 

Looks like a nice find -- good luck with it and have fun.

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  They used to be available on xenons30.com, but no longer.  

 

Still there.  They reformatted the site to make it more difficult to find things.  You have to wait a second for the tiny menu bar to load then intuitively hover and click your way to the info.

 

nicoclub.com has them also.  They've maintained the original primitive site, after you click your way thoguh a couple of modern looking pages.'

 

http://www.nicoclub.com/datsun-service-manuals

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