Hi chaps. iv a reasonable spec engine- 2.0 agg block flowed manifolds newman 268 big valve head 40/35 i had the cam before i started the conversion, so i went for a tame one. now i love the low down power of the engine as it stands, it revs freely to the red, and it idles perfectly. so its the usual question. i want to make the most of the head, as im sure the bigger vales can be working better. but i want to keep the characteristics of this power delivery. i dont want to loose low down delivery. so what are your experienced options? iv looked at the tsr 202' schrick 268/272, but will i really notice that much difference? will a newman/schrick 272 loose that little low end grunt and drivability? (thats why i have an 8v not 16) your help will be much appreciated. as im bloody skint!
Gaining power at the top end invairably comes with a loss at the low end of the power band... how much of that are you prepaired to trade ? I'd say a 272 wont make that much of a noticable gain over what you have, though forgeting the duration, it does have more favourable lift. I would be looking at around 276 duration with 440-450 tho lift to perk it up over what you have to notice a real difference. It should still have good road manners with enough low down power on that duration. My friends 2.0ltr MK2 on K-jet has more than enough low end power with a 284 duration cam. The idle is old school rumpa-rumpa, but as soon as you touch the throttle it smooth's out and pulls rather well, and with enough mid to top end grunt to pull past a hard accelerating Astra GSi 16v. Skint and tuning cars dont go well together though, usually that why we're skint !
Mr H i wish you wouldquote lift in mm not thou' we went metric along time ago! As above no point goin to a 272 IMO.
.. sorry, a bit old school ! 11.2 - 11.5mm is around 440-450 tho lift. The cam I used in the project 8v head is 470 tho, or 11.9mm lift, but you run into valve spring clearance issues at that level (ask me how I know!). I would say a 268 is more for a standard type engine with very few mods (no head work), with 272 more the first basic road cam for use in a modded head. Though more cam can be used, it takes more work to get the results, spring changes/spring seat machining etc.
