Tweaking 264 and 272 cams

[Eagle Eyes]

What are we trying to achieve when someone tweaks the cams?

I noticed that when i advance the exhaust cam (turning anticlockwise)
the EGT seems to rise at a much lower rate and stays lower.

Is there an optimum EGT that we should aim for?
Or is it a question of the lower the better.

[NISFAN]

Cam timing adjustments have a bearing on EGT, but is not normally the reason why it's done. Each cam type (lift, duration, lobe shape, etc) has an optimum position where the most torque under the curve is achieved. Ideally this is the position you would want to 'dial in'. You can also adjust the torque 'wave' slightly by adjusting the individual cam positions, to say give a bit more torque lower down the rev range whilst sacrificing a bit on top, and vice versa.

[Eagle Eyes]

I suppose the only way to "dial in" to get optimum position is to do dyno runs.
I wonder if there's a garage out there that doesn't charge £70-£100 an hour
for dyno runs.

[JohnA]

Originally Posted by Eagle Eyes

I noticed that when i advance the exhaust cam (turning anticlockwise)
the EGT seems to rise at a much lower rate and stays lower.
.

That's because you're reducing the valve overlap.
In rev/load ranges where the exh/intake pressure ratio is particularly high, this is one of the common 'tricks' to increase performance and reliability.

[Pikey]

Originally Posted by Eagle Eyes

I wonder if there's a garage out there that doesn't charge £70-£100 an hour
for dyno runs.

Doubt it mate - that seems to be the going rate.