Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Monty Takes A Deep Breath

For anyone interested in Monty's cam spec, here's a table showing the differences between his current Phase 2s (PH2) and the new Phase 3s (PH3) we're going with.



Newman claim their PH2s have a power band of 2,500rpm to 7,250rpm, the reality was the PH2s proved milder than I'd expected, paired with my Fusion Fabrications long runner inlet these cams gave Monty a very wide and flat torque curve. This gives Monty huge flexibility, I can smoothly trickle through urban environments at 30mph in 4th gear with the engine gently spinning at 1,500rpm. Now hit the throttle and he'll pull cleanly all the way to 135mph in the same gear at 6,750rpm, mid range punch is also impressive.

The engine actually starts to come on cam at 3,500rpm and gives a real VTEC kick at 4,000rpm, however, contrary to what Newman's above cam spec claims the PH2s most definitely do not keep making power to 7,250rpm, mine actually gave up at 6,500rpm giving 173hp until I added a few degrees of timing which I confidently predict places Monty's output at 180hp at 6,750rpm. I'm not complaining as the end result has proved to give Monty very flexible and street friendly manners, keeping the engine speed between idle and 3,500rpm gives an extremely civilised nature that more than equals a standard Duratec Plus 4, but with super exciting thrust from there on all the way to 6,750rpm which makes for surprisingly rapid progress for what is a very vintage looking vehicle.

It's highly likely what I've ended up with here is something of a Duratec sweet spot, none of this is exactly ground breaking as early on in my tuning journey my research pointed to Caterham having long since found the natural Duratec power steps. If we exclude the bonkers supercharged 620R, Caterham give their customers two states of Duratec tune, coming down from the insane 310hp 620R you can choose from 210hp in the 420, or a Monty matching 180hp in their 360 model. The difference between Caterham's 180hp and my 180hp is Monty has a broader and flatter torque curve where peak horsepower also arrives 250rpm earlier, this is almost certainly a result of the two different inlet manifold used, but more on that later.

By now you're probably all wondering if I've already found the 180hp high torque sweet spot, why I'm bothering to take Monty on his next tuning adventure? Well, sometimes I also wonder myself ??? The answer of course is you never really know you've taken tuning too far until you've taken it too far, so I've chosen to accept the challenge of hitting my original 200hp target with the promise to myself that if I don't like the outcome I will revert back to the PH2 cams. The ported big valve head is not my concern, however the worry is PH3 cams could introduce a rough idle (without winding the tickover up excessively high), and they could introduce an unacceptable dip in low down torque?

Saying all that, the increase in duration, lift and overlap when moving from PH2s to PH3s isn't radical; I'd also argue Monty has more than enough torque on the PH2s so the thinking is the PH3s could take Monty past 200hp with no drivability downsides, the new ported big valve head will certainly help here. The key unknown is how the new cylinder head & PH3 cams setup will work with my Fusion Fabrications inlet manifold which is known to start to become a restriction around 200hp.

At this stage in proceedings it's worth pointing out the Caterham 420 makes 210hp on what are essentially Newman PH3 cams, and like the 180hp 360 the 420 achieves this using Caterham's own short runner plastic inlet manifold, but on standard valve sizes and no head porting work.



While Monty's long runner Fusion Fabrications inlet manifold may well start to become the restriction around 200hp, my hope is the new big valve ported head will help redress the balance while also retaining the torque advantage provided by the FF long runner inlet?



Will Monty make the 200 plus horsepower number I'm shooting for, while still retaining good torque and his excellent drivability, or will the Newman PH3 cams fail to play nicely with the FF long runner inlet and hold the horsepower back, while also messing up Monty's lovely flexible street manners I value so much?

As I say: "you never really know you've taken the tuning too far..... until you've taken it too far!"


Wish me luck chaps