Intake exhaust gasket 280z

chris frizzell

Club Member
Hello all just a quick update on the bane of my lift ie datsun 280z . after 2 years restoring the car it still fights me all the way . i think it toying with me it leads me up the garden path as it runs great for a month and then F-up .the new problem running rough and misfiring and i think theres a snake under the inlake manifold . so haypresto a air leak .so my question is can you fellow crazy people recommend a new inlet exhaust gasket ? ps on a plus point just spent £300 on a nice new billet fuel rail for the effing thing not that it will appreciate it . please if you ever see my wife dont tell her how much money i spend on this bloody car ,because when its running good i love it . Chris
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Chris, I feel your pain! I’ve been chasing air leaks for the past year or two with those exact same symptoms. I also spent (ahem) a few pounds replacing the entire ignition system thinking it was electrical.

A vacuum gauge is your best friend.

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First it was carb insulator joints having loosened themselves, then the rear Z therapy carb spindle cap had over time swallowed it’s mastic and needed redoing, then the brake booster hose had a small leak, then I found the carb domes did not have totally flat bottoms and made my own gaskets to solve.

I have a happier car but one that still doesn’t idle or part-throttle as smoothly as it should - but WOT is just perfect and grin inducing which is 90% of my driving. [emoji1787]

Once I put my (as the neighbours call it) “Mecano” car back together again, I plan to use the Felpro gasket next which very experienced people on the Z scene have told me they swear by.

I have spare Felpro ones I don’t need with the injection cut out if that is what you are looking for. I’ve finally worked out a way to post them safely. PM me if that is what you need, I will be going to the post office this week. They look like they are far higher quality than any gasket previously used in my car.

BTW here is the evidence of some exhaust leaks on my old gasket I replaced the first time ....


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The intake side leaks being clean are much harder to see in the photos but there were definitely sucking noises coming from there.

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chris frizzell

Club Member
the problem is when the car is running parked it fine but when i take the thing out it feels like its getting no gas this is about 2500 revs . i do have a vac gauge and it all look ok . put a new fuel filter on and iam thinking of flushing the line out but a do have good fuel pressure at 37fp . going to extend the fuel line so i can see the pressure gauge from the outside of the car . then i can see if the pump bust ,it does make quite a lot of racket . if that dont fix it i will remove the heat sheild and look for a air leak with some starter fluid . i have just fitted a z story exhaust and used Sean gasket which is not spot on for a 280z due to the injector ports but its probaly not that . may have to re torque the studs . thinking of starting to do brain surgery may be easier than fixing my 280z . ps i may post a vidio of the vac gauge reading for debate thanks for the post Chris
 

AliK

Vehicle Dating Officer
Staff member
Club Member
If it’s any consolation Chris, barring needing the hands of a child, I find working on my Audis way easier than the Z as the ECU / pc software practically tells me what’s wrong! With the Z you have to work it out ;) oh and de-rust everything you can now get to! [emoji849]

If it can’t get past 2.5k rpm it does sound like a fulling issue, but also I’m no expert on L-series injection systems. The electric fuel pumps can be noisy but imho you shouldn’t be able to hear it when the engine is running. You may be getting good pressure at idle but may not be getting the flow when on the move. It’s a great idea to be able to see the gauge while driving.

I did find that after fitting Sean’s exhaust and a few hundred miles, even with threadlock, some of my stud nuts had come loose. It’s always worth going back and re-torquing. With the heat and cycling, the new gasket and everything is settling in I guess.

Keep us posted, would be interesting to know what you find / root cause.
 

Huw

Club Member
Hi Chris.

If the problem is the engine is lacking power then it’s possible it’s one of 4 things.

1. Timing, check the timing, ignition module or dizzy coil pick up
2. Air flow meter, possible the flap is not opening properly or is sticky this will lean out the mix and give similar symptoms to fuel starvation.
3. Fuel pressure Is incorrect but I think you said you have good pressure.
4. Throttle valve plate is not opening fully

Air leaks will mostly show when ideling as the engine will refuse to run properly.
 
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chris frizzell

Club Member
Thanks Huw engine is running fine until you get to about 2500 rev in 2 gear . it hesitates as if its got no fuel then give it a little gas and its back to normal is this purging ? doesnt do it every time but when it happens its like all 6 pots have gone down and judders until you give it some gas . the car will still get up to speed . also it may be the original fuel pump its one of the few parts not new . going to look at the fuel system and pull the filter and run some fuel through the line then after that rig my fuel pressure gauge up so i can see through the windscreen and take it for a run to see if it fluctuates ,with the help of my son. hopefully its the fuel pump and its a quick fix ! or it may be more tails from the garage with ratsun .Chris
 

moggy240

Insurance Valuations Officer
Staff member
Club Member
It does not sound a fuel pump issue as they are designed to over fuel the engine with the regulator keeping a constant pressure for the injectors.
But if a new works then good.
Another thing is to consider is just because you have put a new part on its not guaranteed to keep working.
I put an aftermarket thermostat on my bmw and within a year it kept over heating and thought it can't be the thermostat as I have changed it, the thermostat had gone so ended up fitting a genuine one
 

Bazzateer

Club Member
Not an injection engine but when I first test drove my 260 it would not rev above about 2500. Turned out to be a knackered dizzy. New replacement had it running beautifully.
 

chris frizzell

Club Member
the car does rev over 2500 but sometimes it feels like its getting no fuel and it judders . also its got a new dizzy . its as if all the injectors are starved of fuel may be the pressure regulator . thanks for all the posts any more greatly apprerciated . i will keep posting until it fix . Chris
 

chris frizzell

Club Member
good new all got the z running good .after a little investigation we found a vac leak ,also run fuel through the line which had some crap in it . then swopped out the FPS and heypresto running great . when for a spin and gave it a 2nd gaer rip through a tunnel .sounded awesome , smiles all round
 
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