Should the ZT have a bit more welly than I was expecting?

[Jim Jamieson]

Originally Posted by gizmo_the_great

Please will someone explain what the VIS motors are? My cars done 102K from memory.

If you open the bonnet, look towards the back of the engine (windscreen) On the left side there is one with the second fitted on the right side of the inlet manifold. They have a multi plug wiring harness coming from them.

They control the variable flaps inside the manifold.

I currently run a V6 and the missus had until recently a diesel. both were automatics and the diesel was much quicker off the mark than the V6.

The V6 is obviously much smoother and quieter and power difference was only more noticeable at a higher speed. Bear in mind the diesel has the advantage of having a turbo which the V6 does not have.

Hope this helps

[mininuts]

Originally Posted by gizmo_the_great

variable intake system motors...got it. Look easy enough to replace.

Is there a way to test them before replacing them, just to make sure they do need replacing?

And if they do need replacing, is it the "power" (as opposed to "balance") or both ones that I need from here : https://www.dmgrs.co.uk/products/vis...nce-59-50-each ? Or is there somewhere better to buy...ideally somewhere near Derby where I can just drive to and pick it up rather than waiting for post. I read about A R Griffiths Classic Automobiles, Unit 1, Darley Abbey Mills, Darley Abbey, Derby, DE22 1DZ. A good place to call maybe? Anyone used them?

Mat at DMGRS is a well respected trader on here and he provides a quality and quick service. All his items are top quality and guaranteed too. I've used him several times with absolutely no issues

[SD1too]

Originally Posted by gizmo_the_great

I was surprised it didn't have a bit more acceleration to it.

Hello Ted,

There are two reasons for this: the VIS actuators and flap valves and a blocked crankcase breather.

Your VIS actuators can be tested using either MGR's T4 diagnostic computer, and several club members can provide this service. Alternatively Stocktake offers a repair and refurbishment service for your existing units, and various modifications can be incorporated if you wish including an integral test button. Your third choice is to renew them anyway, but that can be expensive. Whatever you choose, you must check the operation of the flapvalves as well. The balance flap is notorious for sticking which is primarily responsible for poor performance at everyday speeds.

The crankcase breather system has a pinhole restriction in the cam covers which becomes blocked by hardened deposits, usually when oil changes have not been particularly frequent. This pinhole can be cleared if the covers are removed.

If you do both these things your MG will be transformed, I guarantee it.

Simon

[Thorfin]

Originally Posted by SD1too

The crankcase breather system has a pinhole restriction in the cam covers which becomes blocked by hardened deposits, usually when oil changes have not been particularly frequent. This pinhole can be cleared if the covers are removed.

Is there a howto for this?

[SD1too]

Removal of the cam covers is described in Haynes.

Simon

[Thorfin]

Originally Posted by SD1too

Removal of the cam covers is described in Haynes.

Simon

Ok... These are normally done at Belt Change right?

[coolguy]

Originally Posted by gizmo_the_great

TomRS : thanks for the explanation. That makes some sense. My Dad was never a speed freak. More of a quality drive seeker. So maybe that is the reason - it's just not a speed machine.

I have tried it using the manual gears (3 and 4 at least), and there is a bit of a boost for sure when compared to automatic, but all the same, not massive.

Excuse the ignorance, but what are the VIS Motors?

I find the V6 (mine are autos) quite lazy engines. The diesels are just as quick, if not quicker in the lower reaches. My 2.5 X Type Jaguars thrash the pants off the Rovers/ZTs for acceleration from rest, but don't sound quite as good! Btw, the automatic gearbox does adjust to your own style of driving, so maybe you need to "encourage" it!

[TomRS]

Originally Posted by coolguy

I find the V6 (mine are autos) quite lazy engines. The diesels are just as quick, if not quicker in the lower reaches. My 2.5 X Type Jaguars thrash the pants off the Rovers/ZTs for acceleration from rest, but don't sound quite as good! Btw, the automatic gearbox does adjust to your own style of driving, so maybe you need to "encourage" it!

Bottom line is they are slow cars... as you say a remapped diesel is just as quick especially down low.
The Kv6 is nice once you get her into the revs, but truth be told no one drives a 75/zt like a hot hatch (lots of revs)
Its a lovely engine when worked but the cars are too heavy and the car itself is better suited to low down grunt.
I think the V8's, 1.8ts and the CDTi's are the most suited engines for these cars the KV6 especially in its "sporty" 190 form should have stayed away from the ZT.
Dont get me wrong, i love the sound and i own one.. but doesnt change my view.
I think a 1.8t at 200hp or a CDTi around 180bhp would have been perfect from the factory.
Then if the V6 came with 240ish (like the Alfa V6's do) then the V8 with more like 300 i think that would have been a much more effective line up given the weight of the cars.

[SD1too]

Originally Posted by Thorfin

Ok... These are normally done at Belt Change right?

No Sam, I'm referring to the part equivalent to the rocker cover on a push rod engine. Perhaps you're thinking of the plastic covers for the timing belts.

The camshaft cover on the LH bank can be lifted off quite easily, so start with that one. The RH bank cover requires the removal of the black plastic manifold chamber which is rather more involved. However it's all described in Haynes with photographs and if you get stuck you can always ask here!

Simon

[gizmo_the_great]

Guys

You may have wondered what the delay was...well it has taken me until last week to get the VIS motors replaced. I bought both (balance and power) for about £112 and fitted them myself as it was fairly straight forward.

Sadly though, there's no obvious difference. The car still goes like a slug. It's OK once it is up to speed, but accelerating from a standstill is not good at all.

So either the car is just so much slower than I was expecting, and as other users have posted above stating that they are not that rapid maybe that is just it. But I have noticed that even after replacing the VIS motors the MPG is terrible. Average 20.1mpg around town. My BMW 330i sports averages more than that around town. So I am suspecting something is wrong somewhere. But I'm not really sure how to get it checked over given that these cars are not really every day cars like a Ford Mondeo or whatever. Most people I know who know about cars haven't ever heard of 'VIS motors' for example, so they are clearly quite bespoke to these cars.

ANy further suggestions welcome.