No matter what mivec you choose, you shouldn't be able to make a piston touch a valve with that setup. So it's just a matter of experimentation and seeing what kind of values those cams like..

Though admittedly, you shouldn't have to run as much advance or retard, typically with bigger cams you run less.

 

I thought our engines were "interference motors" meaning that if the chain did fail (seems like a possibility after browsing the forums) and the cams were to get out of sync with the crank, that the valves could hit the piston.

I know you are talking about making them touch through advance/retard levels, but I wanted to fact check about the interference thing.

 

I'm not worried about the valves hitting the pistons, I'm worried of them touching each other. I even asked Cosworth USA and they didnt have a answer, they said they would have to call the UK and talk to the engineers to find out.

 

You should be fine if your running stock size valves but there are still limits, V2V issues will play a part, if the valves were oversized, and if you are running oversized valves your engine builder or you would of checked V2V clearances to know how far they can go.

 

I don't think on those cams you can run enough advance / retard to make them touch. I've only heard of this on the 280 BCs. Those are 266/266 IIRC. But don't take my word for it, take someone who's actually tuned those cams >.>

 

The Cossy MX1's take a lot of overlap without any issues. I think I've got roughly 32 intake advance and -20 exhaust retard in some places.