markS2kcU

I always thought there were 2?

Everytime I have seen cams listed for the S2000 motor the picture shows 2.

Pie_n_Chips

That'll be one for the inlet and one for the exhaust valves.
VTEC runs off more agressive lobes on the same cams, the shift to the new lobes is activated by oil pressure.

A better explaination here

GSi

Bugger, I knew that Even if I didn't I could have come to the correct conclusion given a couple of minutes thought. Would be a mean feat of engineering to swing in another camshaft at VTEC cutover wouldn't it


Must have killed a few too many braincells recently

GSi

Even though my original intent with that question was dense, I've just realised that the question still stands (given my understanding of the word 'cams')...

Aren't the lobes, the 'cams'? situated on the camshaft?

i.e will the new camshaft (singular ) have modified profiles for both sets of 'cams'/lobes?

Pie_n_Chips

[QUOTE]Aren't the lobes, the 'cams'?

GSi

What I was trying (and failing) to say was that as it is called a cam-shaft, that perhaps it's logical to draw the conclusion that the 'nobbly bits' could be called 'cams' ? or am I just trying too hard to dig myself out of a hole now

Pie_n_Chips

SPADE for Rob

edited to correct name need more caffeine

Turtle

2 cams, 3 profiles. 3 profiles? There are two cam lobes per pair of valves on low cam, with one lobe shared by each pair of valves on high cam. Normally the low cam lobes are the same for each valve in the pair but sometimes there's a difference to promote swirl for emissions etc. Vtec killer cams normally just have the low lobes, but ground to the high profile. The vtec followers are replaced with solid ones so you revert to a more traditional valvetrain. Good for vavletrain weight, and allows you to avoid some geometry limitations with the vtec valve train.

As to custom cams. If you're going for more lift than Toda A2's, then you will need to machine the pistons for valve clearance. Worth replacing the retainers when you change the valve springs too, preferably putting soem stronger ones in as they're the weakest link.

-Brian.

foz01

Hi Brian, after much deliberation Piper finally came round

I posted up a question in under the hood regarding valve-piston clearances at TDC and if anyone has machined the std pistons but no replys even after bumping it a few times, either people didn't know or were not willing to say...

scov

I would be absolutely astonished if Piper felt they could make a new cam that would be cost effective for them.

As an example, a mark 1 escort is a straightforward cam on a pretty basic and mass produced motor and was easy to improve with a big market. The S2000s Vtec is a completely different matter in a small market.

(I hope my example does not show may age too much )

David