Hi,

With +1mm valves on the intake and exhaust, VVT, and Tomei 252 duration 10.8mm lift (intake) & 256 duration 10.0mm lift (exhaust) camshafts is there a possible issue with the intake valves hitting the exhaust valves as the VVT varies the intake cam?

I've searched and can't seem to find a definative or consitent answer. I feel like this was a pretty poular combo 5 or 6 years ago and the miataverse must know the answer!? Or perhaps it's not an issue? I've founf the odd post talking about limiting VVT travel but those cases seemed to be for piston to valve, not valve to valve which I am asking about.

Also while I have your attention, any potential issues controlling the VVT using MS3 Pro Pnp?

Cheers

 

I have +1 valves in my VVT head without issues.

Cam specs I have from Tomei are 252 duration intake and 256 duration exhaust, same lift as what you have listed.

 

Appreciate that, thanks.

Just to confirm, you haven't restricted the VVT movement in any way? I'm assuming not but thought I'd double check...

 

Far as I'm aware we are utilizing the maximum range of the VVT. (But I didn't tune it.)

 

Thanks.

Just in case anyone is curious...
Manley +1mm intake valve weighs 48g, & a used stock valve is 44g. (approx. 10% heavier!)
Manley +1mm exhaust valve weights 42g, and a used stock valve is 42g.