Hey I just bought a 280zx and it has 175K miles on it, It runs sweetly, but I have two issues


1. should i replace the timing chain? I'm very paranoid about it going since it's so old, and i'm wondering if they are reliable or not, tell me ANYTHING you know good and ESPECIALLY BAD!!! I don't even know where i can go to replace it for less than $500 in SoCal, everything is so expensive!

2. smog i put out enough CO to kill my dog in about 30 seconds, but i'm geussing it's the O2 and Cat con...

Mostly, this is about the timing chain, i'm very nervous!!

 

w00t! Welcome to ZDriver! There's no need to replace the timing chain unless it is stretched or broken. If it is rattling, then you need to check/replace the tensioner. Check all the basics... Timing, EFI sensors & connections (especially the AFM, TPS, and CHTS), and ECU connection.

Have you searched our forum? We have a lot of threads on basic repairs / tune ups. Also... check out our "280zx check list" for buying a Z: https://www.zdriver.com/forums/240z-280zxt-s30-s130-tech-tips-275/280zx-common-problems-checklist-purchase-inspection-16386/

 

well i know that the timing chains on these cars aren't that bad and unless significanly stretched, which i don't think i've ever seen without like tons of miles, hold up pretty good and are even adjustable to take into account said stretch. As far as CO2, I live in a state where emissions is noexistant so can't help ya there, other than to say, these cars are running on sensors that have probably never been replaced so you might wanna consider that too. Oh, and post pics, plenty of pics ^.^

oh yea, almost forgot:

*HUGZ*

welcome to zdriver

 

Yes, about the timing, it (smog rpt) says "FAIL" by ignition timing, so i have no idea what that means, i did do an overhaul on a HT4100 but after that i quit cadillac and that's why i decided to convert to the In-line 6, so pardon me for being new to Z's. and somewhat overall ignorant

 

So... have you checked the timing?

 

Sorry, i only have one picture but i bought it for $1250, i have maintenance records from a lady who did not hold back any amount, until she sold it in '00. since then it's only put on about 25K. Everything works, (sans radio) surprisingly well, even the door panels don't have cracks, not a spot of rust except for a little bondo on the top left area by the dash, hardly noticable, and that is a paint job done in '92.


so far so good

 

no, i haven't checked it becuase......goodbye pride.....i don't know how.

 

haynes manual is your friend

 

Well...

#1... Buy yourself a 280zx Haynes Manual. Really... do it tomorrow.

#2... Timing: Mark the timing "V" on the crank pulley w/ liquid white out so you can see it. Loosen the two 10mm distributor base bolts, get a timing gun, hook it up, shoot at the crank timing plate, adjust the distrib till it hits about 8 degrees.

Pic:

 

Oh snaps! GypZ beat meh!

 

I got a FSM from the wonderful wide web so haynes has nothing on me, thanks a bunch. btw I might as well give you the results, just in case it can help...

15mph
1644RPM
HC meas 317/(138 max)
CO meas 10.59/(.98 max)
NO meas 51/(1136 max)

25mph
2660RPM
HC meas 319/(110 max)
CO meas 10.53/(.78 max)
NO meas 966/(75 max)

 

i would still suggest a Haynes. the FSM is great, but a Haynes manual goes into much more detail about how to properly do things. i wish they made one for the z32.

 

Might want to look up TIMING in that wonderful FSM then. Have you changed the oil, plugs, cap, rotor, and plug wires? Those will all affect your emissions. Also, run some SEA FOAM through the fuel system. It does wonders too.

 

Yes i've changed them out, except for the rotor, but will that relaly reduce CO emisisons? that seems totally odd if it did...Sea foam? Hopefully kragen has it

 

Timing is the biggest emissions factor on the 280zx. If you have a shop willing to put the car on TEST mode, just turn down the timing & check it. Run some sea foam through it tho w/ less than half a tank of gas.

 

1 - If so equipped with an O2 sensor Replace First Period!!!! $17 or so
2 - Get a Service Manual or Haynes Less than $20
3 - Change plugs $8-$10
4 - Cap AND Rotor Button at the same time $20
5 - Spark plug wires $?? Cheap NGK's they are blue and numbered
6 - Get a cheap timing light $30 or less
7 - Timing - Check it, Set it...we will help when you are ready to do it. $ Free
8 - Look for any vacuum leaks and fix them $ Free to $5

Just these things will do wonders and I bet you will pass your smog test. Yes, these cars CAN be reliable and the engines are strong but the stuff on them is old...replace the old stuff and you will be happy with the car...they are a hoot to drive. I **** and moan...and flip flop apparently about my Z's but I still love driving them.

 

if i can go 10 years on a factory timing belt on my z31 without it stretching or getting dangerously worn, then i doubt the timing chain will ever stretch under normal driving..

 

This motor has the most stout timing chain I've ever seen in a relatively small displacement motor.

Mine has over 250K HARD miles and is perfectly fine.

If somebody actually drove that car hard enough in 175K to significantly stretch the chain... The motor is already toast... And I seriously doubt that to be the case.


Rod.

 

The key here is timing CHAIN. Most modern cars have a rubber or polymer timing BELT. A timing belt stretches, wears, cracks and breaks = new motor, which is why they recommend they be changed every 60,000 miles for about $500...

The 280ZX motors were originally designed in 1964. No rubber components were used INSIDE the motor in those days. The timing chain is a DOUBLE chain. In 20 years, I've never seen one that actually needed replaced. I've heard about it, but it's most likely the result of an ignorant owner who just didn't know any better.

Even when it does stretch, there are two additional "positions" that can be used on the cam gear to "take up the slack". I figure, if you can get 250,000 miles out of the first position, then 250k out of #2 and #3 each means you probably shouldn't have to replace the chain until around 750,000 miles. Which is highly possible with these motors. Once you hit that kind of mileage, take a 93 octane fill-up and call me in the morning! We'll be here to walk you through the replacement steps!

 

With that in mind, the chain isn't that much money and if I tear a motor down that has more than 100K miles on it I just put a new chain in.

Hoov got lucky with his timing belt. My friend bought a Z31 and had a new belt put in right away. 2 years later it snapped. Less than 40K miles....

...parts car... now she drives a Ford SHO!