Re: Engine Rattle on Cold Startup

[NitroDann]

Sorry. Fair point. getting a little focused here haha

Dann

[Black miata]

Thanks for the help guys.

Got it looked at by MX5 Plus and they said it is the shutter valve that has broken so will get that replaced and see how it goes

It started to get worse the longer i drove so thought i would take it in to get looked at

[NitroDann]

By shutter valve you mean the idle oil pressure valve in the head?

Dann

[93_Clubman]

Think they mean the shutter valve actuated by the just left of centre round black topped VICS shutter valve actuator with the vacuum line to it pictured here:
http://www.fototime.com/%7B8CADB2F1-31C ... icture.JPG

[NitroDann]

Im not familiar with VVt heads.
So This is part of vvt or what? This is the valve that controlls VVT valve oil pressure?

Dann

[93_Clubman]

No VVT on NB8A, just VICS - VVT was introduced on NB8B along with VTCS.

My understanding on the NB8A is the shutter valve actuator controls the VICS butterflies in the intake manifold via the shutter valve.

[NitroDann]

Sorry I skimmed through and didnt read v i c s.

Dann

[Black miata]

Hey guys,

I have gotten the new shutter valve installed which has fixed one issue but i have not come across another .

When cruising at 60km/h well any speed and I lightly put the accelerator down there is a fast paced rattle coming from the engine.

The motor has only got 2,000km's on it since the rebuild.

The MX5 is currently at the mechanics with the top of the engine dismantled but they can not track down what is causing the noise. They have looked for the defect that i am aware was common on the NB8A's but its not that.

It was quiet but after the install of the shutter valve it has gotten worse.

Has anyone has this issue before at all or herd of it?

Thanks heaps

[93_Clubman]

Has the timing been checked? Appreciate timing on NB8A is not as easily adjustable without a modification as NA6 & NA8, but might be worth a check.

[Black miata]

Thanks for that Clubman

I have had the whole engine pulled apart and everything looked at. Timing, Injectors,air fuel ratio etc etc and still can not find the issue.

I have been told that it is only at a certain rev range at around 60km/h.

Do you have any other ideas at all?

[93_Clubman]

When cruising at 60km/h well any speed and I lightly put the accelerator down there is a fast paced rattle coming from the engine.

I have been told that it is only at a certain rev range at around 60km/h.
Do you have any other ideas at all?

Given the advice the noise seems to becoming from the engine, it would seem to rule out the heat shield for the headers, which commonly comes lose at one or more mounts, especially on NA6 & NA8. But seeing as all else so far has failed to identify the source of the noise, it would be worth checking the heat shield if this hasn't already been done, or if it hasn't already been removed. Heat sheilds at the catalytic convertor & the bullet muffler also rattle if they come lose, but they're further away from the motor.