any tech questions

[STEVE BURNS]

we are in the process of updating the FAQ section of the website
and need some questions for our team of experts to answer so come on now you must have had problems with your Z/ZXs lets see if we can answer them
POST your questions here

 

[dcweg]

1981 280zx problem

I have owned this car since September 2003. About 2 months ago it developed a bad habit of killing out once it reaches a fully warmed up temperature. It never kills when it's below this point and inevitably does when warmed up. The point of engine temp when it kills is consistent. It almost always restarts immediately with one crank but sometimes 3 or 4. The tach drops like a rock when it kills. When it first started I changed the distributor. Before I changed the distributor the tach would spike to 5 or 6 K when it killed (no engine rev). With the new dist it still kills but the
tach drops. I've checked the fuseable links and they appear to have carbon on the female inserts. They are a harness connection
and that would be a last choice to change out. I've switched the relays to no avail. The coil's been replaced with no change. When it kills and I restart the high beam light on the dash is on. When it is colder than usual (35 degrees F) it does not seem to kill as it does when it is even 45 - 50.
This is driving me over the edge. It's such a great car to drive and is typically so dependable. Oh yes! One other thing I changed that may be relevant is I removed the stock sealed beam HL and replaced with a halogen sealed beam. This was simply an unplug and replug action but I'm sure the amperage draw is higher. My warning guages show no problems.

Any help would be appreciated. Electrical problems are tough. This should be a good start for you techs.
Thanks,
Dan Wegman

 

[Mr.F]

Have you changed the relay which controls the power supply to the ECU? This is located in the inner wing compartment on the RH side of the engine on a LHD car, just behind the strut tower. On a U.K. it is even more hidden in a compartment alongside the battery on the LH side of the car. This unit is renowned from its contacts becoming weak and corroded - it fails in exactly the way you describe and then typically allows the car to be restarted after a few moments rest.

 

[john-h]

Early and late 260

I have a late (1979) 260z I am restoring and a 1974 car for spares. I've noticed several differences in parts from these cars, exhaust, window regulator design, some trim detail brake fluid warning, and I believe the late car can run unleaded. What else will be different? Is the early car really a 240 with a bigger engine and trim changes?

 

[The Z Farm]

Hi John - hope we can help with some details on the differences between a) the early & late versions of the 260Z, and b) between the 240Z and early 260Z. Just hope that we don't send you to sleep before the finish, though ! And no doubt there will be other members who will be delighted to remind me that I've forgotten a lot more besides

NB The rest of answer has been transfered to the FAQ section of the website (Steve Burns)

 

[john-h]

Tech forum

Thanks for the info, the bits I was desperate for were the items common to all 260s except I had to rob an early window regulator and do lots of machining to make it work.
My dad is a member of the independant Porsche club and they run two e-groups for the club side by side, one just technical and one for chit chat, club stuff etc. Perhaps we could use a technical forum in its own right?

 

[owen]

cylinder head

hi i have been told that my 78 260 has a c type head on it and he says it will run on unleaded is this true and can i put a 280 zx head on and run the same carbs and whats involved in putting a 280 zx engine in even if its a auto could i change the fly wheel will my wheel fit a auto crank any help would be appreciated ta

 

[Mr.F]

All late 260Z and all 280ZX heads are unleaded compatible by official statement from Nissan. The 280 N42 head benefits from bigger inlet valves. Late P90 280 head has bigger combustion chamber volume and will reduce compression ratio.

The L28 is a straightforward fit into the 240Z/260Z and can be used with carbs. Ideally a change of needles will be advised to slightly enrichen the mid-range (particularly if header manifold is used). An auto engine will need the flex plate adapter removing from the crank and a spigot bush fitting. All flywheels for manual transmissions are interchangeable with each other and with auto cranks, but will need release bearing carrier matched to the clutch used.

If adapting to mechanical fuel pump, add the "bumper" cam to the end of the camshaft to drive the pump arm.

 

[STEVE BURNS]

Any one want to do a dash removal guide for the Z and ZXs as I know its a pain

 

[Tony 260Z]

With helpful pointers from Mr F., this summer we swapped the 2.6 lump in my 260 for a P90 2.8 from Ken at ZXS. No problems, easy swap. My 240 carbs were already running a bit rich, so we didn't play with the needles at that time. I think that'll happen when I finally get round to fitting my 2" SU's and have her rolling-roaded.

Unleaded no problem, but she lurves four star and octane booster!

TL.

 

[john-h]

Timing settings

My 260 is in standard trim and I'm in the process of preparing it to get on the road. It needs the carbs balancing and the mixture setting but it starts reluctantly and runs o.k. but does not respond to the throttle well until it has run for a little while. The car is a late 260 and Haynes states that the timing should be 17 degrees but the previous owner has crossed this out and written 10. I want to eliminate this so I car set up the carbs. Can anyone tell me what it should be?
John-h

 

[Mr.F]

Whilst 17 degrees might be a bit excessive for modern pump gas, 10 degrees advance would relate to the 280ZX set-up and electronic distributor. I would try 12 degrees as a starter and see if you can safely advance with power gains and no detonation from there. The advance curve in each distributor differs - are you using the original points distributor or the 280ZX electronic upgrade (or other?).

Also, go back to basics and ensure that cam to crank set-up is correct and that the oil pump / distributor drive is correctly installed. As noted in a previous post, the Haynes description is derived from an incorrect edition of the Nissan engine manual - see How to Rebuild your Nissan OHC or the June 1984 edition of the Nissan manual for the correct description.

 

[john-h]

Thanks Mike,
Everything is unmodified so it is using standard points. I have set the timing to half way between 17 and 10 to get it to run but I wanted to eliminate the timing so I can concentrate on setting up the carbs.
John-h

 

[Tony 260Z]

As an add-on to what Mike says, it was the oil pump/dizzy-drive line-up with the crank that I could never get to align properly on my original 2.6. In the end this led to the conclusion that someone must have worked on the engine in the past and done something wrong, so the 2.8 was dropped in.

I have electronic ignition too (lumenition optronic) - far fewer misfires and easier starting! I understand the 280ZX dizzy set-up is the way to go though. I'll get around to it one day.

Only prob I have now with performance is that she's still a bit flat when accelerating just off-idle. I think I read once that that's not unusual in carbed Z's and both my 2.6 and 2.8 have done it. I think it's down to a slight lag in the SU carb piston's reaction time. If anyone knows a cure I'm all ears!

I got the "How to rebuild" book at Mikes suggestion and it is much more detailed than the Haynes. I don't have time to do that much tinkering but I'm confident I've got a good book for when I do.

TL

 

[dcweg]

I submitted a tech problem on 12/28/03. Within a few hours, Mike Feeney responded with his thought on the problem. I changed the EFI relay as Mike suggested and the problem is resolved. Thanks Mike. I appreciate your assistance in fixing this irritating problem.
Dan W

 

[Mr.F]

Thanks for the feedback Dan - always good to know a problem is resolved!

 

[dcweg]

Hello Mike,
My hi-beams come on at will these days. Sometimes I can shut them off but usually not. The warning light on the dash will show a headlamp problem. When I go to the relay box and tap on it the beam may go to low or not. It's random. Is this likely to be the
headlamp sensor under the glove box? Both me headlamps are new halogens.
A second issue is the cruise control. All the switches will illuminate and function. It will not set the speed however. I've checked the servo valve and the solenoid valve and they check out vacuum wise. The actuator diaphragm is fully functioning when I blow into it. Is there anything that is typically wrong with these ACSD's that
I may go to or is it always a crap shoot? Maybe I should try replacing the relay for it.
D.W.

 

[Mr.F]

On U.K. cars, intermittent headlamp functions are more often than not traced to the column switch.

We have no U.K. spec. cars with cruise over here - it was not a 280ZX option, so my knowledge in this area for the 280 is very limited - I don't even have a circuit diagram for this one!!!!

Sorry!