Thanks, fellas - <img src="/forums/images/graemlins/kewl.gif" alt="" />

I'm wearing out Texas Instruments calculators tonight trying to figure out if it would be better to advance the Diamante cams or swap back to the Montero cams. <img src="/forums/images/graemlins/lol.gif" alt="" />

If my math is correct, the longer duration Diamante cams have the same lobe separation angle as the Montero cams at 110*, so there's no LSA advantage to be gained from either cam. The Diamante cams do have 4* more duration with a trade-off of 4* more overlap. Again, if my math is correct, the Montero cams have 38* overlap and the Diamante cams have 42* of overlap. Feel free to check the math.... if I didn't calculate it correctly, I'd like to know.

Here's my guess - and it's really a guess - why I'm not getting what I expected:

1) the later closing intake valve with the Diamante cam starts compression with a lower volume of mixture, has a shorter effective compression stroke, is not building as much cylinder pressure as the Montero cam and therefore there is less power is in the available mixture.

2) the added valve overlap is leaking combustibles out the exhaust.

The only way I know to find out for sure is to make the swap, but I sure don't think I'll have time to do it over the next few months - so, for now I'll be content with what I have..... it ain't so bad. <img src="/forums/images/graemlins/wink.gif" alt="" />

Frank