Engine upgrade time!

[AgingGeek]

Hey all, so I have been having quite a lot of reliability issues with the 280Z, it keeps running rich and stalling all the time, we've chased gremlins, replaced parts and it works ok for a bit and then the problems start again. It's likely something simple, but to be honest, I've had enough and just want to be able to have faith that I can drive the car and it not keep letting me down.

So, we are ripping out the original EFI and making some upgrades along the way, whilst trying to keep it look as authentic as possible. Here is the current list:

Jenvey Heritage ITB Kit
Link Monsoon ECU & Complete wiring loom
Lambda & Air Temp Sensors
Distributor style pick up
Complete new fuel system, with new lines and swirl pot
Camshaft sent to Kent Cams for a grind

Once that's all fitted, its going to Abbey Motorsport to have the map built on the dyno

I am hoping that once all that is done, it will actually have the reliability I want, and should at least give a decent boost in performance and fuelling (and sound damn sweet too!) I should mention, I have no interest in turbo's, I want that sweet NA roar

Any thoughts, have I missed anything?

 

[atomman]

I wouldn't use the Heritage kit , just the normal Jenvey's , there has been problems with the angle of the injector for the middle cylinders on L series engines .

I'm sure some one else will chime in and know more than me ,

I have just brought ITB's for my 240z and am going the same route with ECU etc etc , was planning on Emerald K6

 

[jonbills]

You've missed the work and parts to make a reground cam work correctly.

 

[AgingGeek]

I wouldn't use the Heritage kit , just the normal Jenvey's , there has been problems with the angle of the injector for the middle cylinders on L series engines .

I'm sure some one else will chime in and know more than me ,

I have just brought ITB's for my 240z and am going the same route with ECU etc etc , was planning on Emerald K6

Ah, thats super interesting, I wasn't aware of that... will go and do some research, thank you!

 

[AgingGeek]

You've missed the work and parts to make a reground cam work correctly.

Could you explain more please? I was under the impression you could go a little more aggressive on the profile without having to replace ancillary parts?

 

[jonbills]

Could you explain more please? I was under the impression you could go a little more aggressive on the profile without having to replace ancillary parts

That depends what 'a little' means. If its more than almost nothing, you'll minimally need new shims. More again and you might need taller retainers to hold the taller shims. More again and you might need new springs to allow the more lift.
And ideally you'd always fit new rockers.
And new valve stem seals.
(And while you're there, check the guides and seats)

 

[jonbills]

I'm sure your shopping list will address the reliability issues, and improve economy, but I doubt it will give you much performance improvement. But perhaps thats a different thread

 

[Fairlineguy]

Ah, thats super interesting, I wasn't aware of that... will go and do some research, thank you!

Better put my hand up here I had problems with the Heritage units as well as a couple of other owners .
Jenvey took them back and replaced them with there standard units which cured the prob

Jenvey Heritage pinging issue .

The problem Pinging whilst setting up new jenvey heritage itb on rolling road Brief story /Engine spec F54 block with kameari flat top pistons (10-1) Ported F42 head Comp cam 480 duration / 460lift Ms2 ecu (wasted spark /batch firing) Last year I ran the same engine in another car but with a sing...

forums.hybridz.org

 

[SeanDezart]

Better put my hand up here I had problems with the Heritage units as well as a couple of other owners .
Jenvey took them back and replaced them with there standard units which cured the prob

I second what Neil says (from experience).

Missing ?

An efficeint exhaust manifold, line and silencer....for that 'roar' you want :

 

[AliK]

Trouble is, with a longer duration grind, you are bleeding off more of the compression dynamically. So ideally you want to up the compression also to get the benefit of the grind (that’s of course including all the things Jon mentioned ).

But if you’re just trying to get more rpms / top end performance, could you get there by carefully retarding the existing cam’s timing to shift the power band? You could move the band say another 500rpm up. But be mindful that it’s at the expense of the low end / mid range torque.

And Sean is right, I noticed a massive difference at the top end by just swapping out my restrictive “turbo muffler” for a straight-through one, on the same manifold and piping! Just changing the muffler brought the top end to life. I do have a 270° fast road Kent Cam grind with all the required mods though. So the engine had the potential to breath better at the top end, it was just being choked by what I had stuck on the end of the exhaust system.

 

[SeanDezart]

But if you’re just trying to get more rpms / top end performance, could you get there by carefully retarding the existing cam’s timing to shift the power band? You could move the band say another 500rpm up. But be mindful that it’s at the expense of the low end / mid range torque.

And Sean is right, I noticed a massive difference at the top end by just swapping out my restrictive “turbo muffler” for a straight-through one, on the same manifold and piping! Just changing the muffler brought the top end to life. I do have a 270° fast road Kent Cam grind with all the required mods though. So the engine had the potential to breath better at the top end, it was just being choked by what I had stuck on the end of the exhaust system.

And I'll add to Ali's comments that you'll want to be running at least 10:1 compression ratio.....and always prioritise torque over max hp !

 

[AgingGeek]

Thanks all for the super useful feedback and info, I went down a rabbit hole with this, and have decided to invest in the full manifold / exhaust rather than the cams Oh, and thank you all for the heads up on the heritage kits, will avoid!