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Thread: One heck of a '78 280Z

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    Default One heck of a '78 280Z

    Well after a few months of owning my Z i am happy with my purchase she was only $900. But there have been issues with the EFI as much as I would love to keep this thing all original I think it might just be better for me to replace it with something "fresher" from the nissan engine line up. So I am wondering how much can i sell my 1978 280Z engine for with the 5 speed tranny? I would hate to just let it sit and go to waste or have it junked i dont think i could do that. The problems are that it runs rich and i believe the piston rings will need to be changed, (that is why i am thinking of just doing an engine swap) I know that the swap is a a few months away at least. I am trying to save up for the engine i would like to get but was wondering if i can get a decent price for the original one as i could use the cash to go towards the new one. Let me know what you guys think any info will be appreciated.

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    Supporting Member Zedyone_kenobi's Avatar
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    Why not keep it and rebuild it?
    1971 240Z HLS30-38691
    93.9% done and getting better every day
    Now with 100% more DATSUN SPIRIT L28 Power
    1968 Datsun 2000 SRL311-03416

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    I've seen a bunch of L28 power trains for sale, CHEAP. By the time you advertise and deal with all the details of the deal it usually ends up a wash or even costing you money. If your wiring and tranny and diff are all good, I would do a rebuild with some performance mods, or buy an L28 thats already been done. Thats likely the least expensive way to go and still end up with a good result.

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    My dad does not want to change the rings as the time it will take and the garage that we do not have, and the EFI is being stubborn. I was dead set on getting rid of the EFI and doing the AZC carburator install but thats roughly $1000 for EVERYTHING I need but then that still leaves the piston ring problem. So to sum it up, my EFI is acting up and my piston rings are bad and my dad does'nt wanna change them cause of the trouble it is to do.

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    Registered User LeonV's Avatar
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    How did you diagnose "bad piston rings"?
    2/74 260Z

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    It will burn oil but only when you step on the gas, I have searched the problem and talked to a few people who have diagnosed that it is the piston rings. Unless there is something that i've missed or am looking up the wrong thing. The only problems I am having with the engine is it burns oil when i step on the gas (not at idle at all) and it runs rich. But if its not the piston rings that would make me feel a lot better.

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    Registered User LeonV's Avatar
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    How much oil does it burn, and have you done a compression test?

    Running rich is a separate issue, however a constantly excessive rich mixture may cause premature ring failure.

    There is no logical reason to discard an engine without fully diagnosing the issue(s).
    2/74 260Z

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    Registered User EuroDat's Avatar
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    You can try and fing theproblem with your EFI. It is a basic system and generally simple to diagnose. You can also use the instructions on http://www.hiperformancestore.com/Ljetronic.htm. Could save you a lot of money and if the rings are shot, you can use the money on an engine rebuild.
    I ended up lifting my injectors and cranking the engine (without the spark plugs) and found nr3 and nr 4 injectors clogged. There is a recent post about testing the injectors in the fuel injection forum http://www.classiczcars.com/forums/thread46931.html. If you read that it might help.
    Cheers and goodluck
    Last edited by EuroDat; 09-26-2012 at 01:28 PM.

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    In answer to your original question, the engine has about zero value. Scrap at best. Go to a wrecking yard or pick and pull and find a later engine from a zx NA. I've got several good runners and couldn't get $150 for them. Do a little research on it before you get it, but you can get a good runner for $400 or less and that will give you time to save a few bucks to do something more dramatic.

    72 240Z HLS30 49052 110 Persimmons/white stick
    72 240Z HLS30 70087 110 Persimmons/white auto 43K
    77 280Z HLS30 400336
    77 280Z Turbo HLS30 369869
    57 Volvo 444K
    57 IHS120
    85 500 SEC

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    Changing rings to fix a smoking engine is a typical American engine fix from days of old, on the small block chevys or straight sixes or basically any domestic engine from the 50s, 60s and 70s. That's probably why your dad says "needs rings", because that was a common fix-all for old smoking engines. The L engines though rarely waste the rings and/or cylinders. They last for hundreds of thousands of miles.

    As Leon suggests, measure cylinder pressure and/or do a leak-down test. You might be jumping to expensive conclusions.

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    alright, i know today i went and got new spark plugs and plug wires. I'll be putting them on tomorrow. I will run through and look/read those links that you posted EuroDat. My car has 126,xxx that or 26,xxx but going from that looks of things im jut gonna say 126,xxx miles. A pressure test was performed but i can't exactly remember what he said it was. But I'll read through the material that was posted and run through everything, thanks again guys for the answers and help. As for the engine being scrap that kinda sucks but i know in the future there is gonna be a swap done, right now im kinda looking to get this thing running good so i can drive it around and not have to worry about anything.

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    Oh, i forgot to ask. If the rings are not bad then what can be causing this problem? Like i said at idle she runs fine no smoke or nothing but when i rev it up it just smokes it's not like seafoam smoke but it's still pretty noticeable. That is why my dad said piston rings. But again any ideas that you guys have i will look into and test. Thanks again.

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    Curious, have you actually driven the car or just revved the motor while in the driveway? Does it puff when you shift? Does it smoke on deceleration and upon acceleration? What color is the smoke? Does it have any kind of smell/odor? What do the plugs look like after an hour drive? (Pull each on-not just one). Do you have to add engine oil and how often? Have you changed the oil recently? Of course if it isn't a driver some of these you can't determine. Am trying to determine if it is even engine oil that is causing the smoke or just overfuel. If it is black and waters the eyes, its fuel. I'm with the others in that it probably isn't a ring problem. Of course it could be, but.................

    72 240Z HLS30 49052 110 Persimmons/white stick
    72 240Z HLS30 70087 110 Persimmons/white auto 43K
    77 280Z HLS30 400336
    77 280Z Turbo HLS30 369869
    57 Volvo 444K
    57 IHS120
    85 500 SEC

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    Im not familiar with the EFI system on the L motors, but a faulty crank case venting system could also make the car smoke at high R's, and could cause a fuel delivery problem as well.

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    We have taking it around for a bit, and the after awhile the plugs were nasty. Black an ashy that's why I went and got new plugs and new plug wires. While driving it it smoked blue out of the exhaust upon acceleration, i have not yet jammed my foot into the gas pedal yet nor do i intend to until im sure what the problem is or more than likely could be. I have not had to add oil yet but ive only drove it once, i will be taking it out again today though. I had gotten new connectors for my water temp sensor and my TVS but haven't been able to see if that fixed the running rich problem yet. When i change the plugs later today i'll take a picture of them for you guys. And 5thhorsemann i will look into that thank you.

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    Had the car been sitting for a longtime before you got it? What you really need to do is download the Factory Service Manual,if you don't have one, and start testing components as shown in the Engine Fuel chapter. Save yourself time in the long run and just go through the tests. There are many causes of running rich and each one can add a little bit of richness. You will most likely not find a single solution to the rich mixture problem.

    And, regarding a new engine, you'll still have the same problems with a new engine, unless you get all of the EFI parts with it, and they are all in great condition. You're on the typical path of a new owner of an old 280Z.

    www.xenons30.com/reference

    p.s. You're way ahead of many people with new Z's since yours actually runs and drives.

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    Registered User Ben's Z's Avatar
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    I have a 77 280z with 93k on the clock. I just pulled my N/A engine because I am doing the 280zxt swap. My engine also smoked when cold under acceleration. I never investigated the problem fully but can tell you that a dry compression test yielded anywhere between 138PSI and 141PSI across all 6 cylinders. Having inspected that engine a little more the other night when I took the manifolds off I believe the motor would have been fine with a rebuilt head. I just had my turbo head rebuilt and the shop did it for 200 dollars. While my 163k turbo block was at the shop they evaluated the condition of the block, and even with all of those miles, and it being a turbo engine, a simple ball hone restored the cylinder walls to satisfactory condition. These blocks are really tough, I doubt this is all from the rings.
    1977 280Z 5 Speed
    HLS30-388451

    Do you know where my Grandpa's 240z is? He sold it around 1994. I think it was a 72. It was orange with black interior and some sort of scissors style aftermarket crank up sunroof. I think it was sold to a fellow pharmacist and I think he was from Egg Harbor Wisconsin. At the time the car had between 32-36k original miles. He sold it for the lowly sum of $3000-$3500. My grandpa passed away a few years ago and I would like to know its whereabouts.

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    yeah i have ran through the FSM about when i first purchased the car, the only thing that i found wrong was the TVS. running rich is an issue i would kind of like to put off for a bit and put more attention on the smoke, i know they are both problems that need to be fixed but i can but new sensors if need be for the running rich issue. And Zed Head yeah the reason i bought it was cause it is a 5 speed manual, it's a damn sexy car and it started an ran. Plus it was only 900 dollars haha. But yeah i have ran through the FSM and came back with the TVS not being correct (corroded connector). I just dont know where to start to find out what is causing the oil to be burnt. I really appreciate all the responses guys again any ideas or thoughts will be looked into and checked out the best i can. Thanks

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    Registered User LeonV's Avatar
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    (1) Fix the rich condition.

    (2) Drive around.

    (3) Report back on how many quarts of oil were burned after driving 1000-3000 miles.
    2/74 260Z

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    Registered User grantf's Avatar
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    Quote Originally Posted by LeonV View Post
    (1) Fix the rich condition.

    (2) Drive around.

    (3) Report back on how many quarts of oil were burned after driving 1000-3000 miles.
    Good advice. Easier and cheaper than a new engine (or worse bad used engine).
    1977 280z
    1974 260z long gone

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    Yup, agree with LeonV, fix the rich condition, it may take a while, I've been trying to fix the rich on my 75 for about 3 months, but it will be worth it in the end.
    75 280Z almost done
    49 Chevy 3100 p/u next project
    96 Dodge 2500 4X4 tows my 5th wheel

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    well she smokes no more, and i think the cause of the richness is injectors, i know for a fact one is the wrong size (it's pink) the rest are a dark green but i plan on replacing all injectors on the beast, then fixing the exhaust. I know this is in the wrong part of the forum and i don't want to switch topics for to long here but are the results with the exhaust system into a straight pipe good? cause mine has holes all over getting into the cab and it NEEDS to be replaced.

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