From good old haynes... Inlet opens @ 3 deg ATDC Inlet closes @ 35 deg ABDC Exhaust opens @ 43 deg BBDC Exhaust closes @ 3 deg BTDC So, Inlet 212 degrees Exhaust 220 degrees Doesn't say about lift sorry. Cheers
I think you have to specify at what lift the duration is measured at. I.e, I think the Haynes data is based on duration @ 1mm valve lift. I've seen 207 @ 1.27mm for the inlet cam and 215 for the exhaust on an american site. Joe
Joe_G, As you say haynes says "Nil valve clearance at 1.0mm valve lift" above the valve timing figure stated above. Cheers
Wow, I didn't realise the were so low compared to fast road cams at about 260 degrees, no wonder they up the performance when fitting them.
Haynes are such a bunch of strokers, what the hell is the point of giving valve timing at 1mm lift. It's only any use if you know what a comparitive cam is at 1mm lift! IMHO valve timing should be measured at the initial movement of the valve, not once you've already started the next cycle!
Also I'd be interested to know at what lift shrick measure their cams. If it's at zero lash then as a rough guestimate I'd say if you were to measure the standard cams the same they'd be more in the region of 245-250 than the 1mm Haynes version.
VW uses 1mm as the standard value for measuring cam duration. You should ask what the duration is measured at when buying a cam.
Thismis where alot of people get confused too. When micing up a lobe, they take the height away from the width to give the lift. But this is not so as the lobe has to take up the gap first, thus reducing the overall lift.
Also, the lift of the cam only plays a part fo the cams chracteristics. If you look at a schrick they tend to be fat and wide at the lobe, with a steep ramp. In theory if you took one of these with 11m lift and placed it next to a vw cam with 11mm lift, although both cams have the same 'lift' the duration would still be more on the schrick due to the lobes width. Theres alot to think about when choosing cams!!
Fozzie bear speaks some truth, www.pipercams.com explains it all.. Theres lots of stuff on there that joe average doesnt even know about let alone consider !
