The 8v camshaft thread.

Discussion in '8-valve' started by Phil., Nov 2, 2006.

  1. Phil. Forum Junkie

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    Been reading a few searches but cant quite find an answer people agree on.

    I'm looking to find out which is the best camshaft to use with my 8v PB.

    Spec is: 2.0 bottom end (eventually)
    'Shed head on std valves
    Full Ashley exhaust system
    Modified airbox
    Blitzchip [:$] (+11bhp my ****!)


    I originally thought I wanted a Newman Schrick copy 268 profile cam to retain some civility.

    Then a Kent GS2 was recommended followed by a GS1 recommendation.

    The car is used as a daily driver (all of 10 miles to and from work) and also will see a fair bit of track use so mabey something a bit more agressive like a 272 or 276 would be better?

    Also the Newman cams are advertised as OEM timing marks removing the need for a vernier. Is this strictly true or would I see better gains spending the extra for a complete kit such as Kent or Piper which includes the pulley?

    Opinions please?

    What have people used in their 8v's with what results?

    Cheers
    Phil.

    EDIT: Possibly a 'Bundles in the shed' head.....lol
     
    Last edited: Nov 2, 2006
  2. Bundles Forum Junkie

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    I'm planning on an medium rated cam, such as a newman 268 myself, i too drive my car daily and a fair bit of it is though town, so don't want a car that needs to be thapped to 2500rpm just to tootle around. GVK stuck a newman 268 in his chugger and said it now pulls much cleaner to 6k than before. Might be worth bugging, erm, asking him more details.

    I drove a mk1 with a 302ish deg Kent rally cam in it and it was silly, it behaved almost like a two stroke.
     
  3. Phil. Forum Junkie

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    you see I thought 268 was just about right, might try a 272 if anyone strongly recommended it. I can only imagine what a 302 cam is like, that kind of ON/OFF power combined with a race clutch would make for an 'interesting' drive to work.
     
  4. Bundles Forum Junkie

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    lol, it coughed, popped and farted it's way to 4500rpm (it had webbers too btw) started to go well and then f*cked off at 5k up to the 8200rpm limiter, def not a good road cam. Kent do/did a 320 degree cam that's power band was listed as 5000-9000rpm too!!

    It sounds like your're in the same boat as me though, you don't know a great deal about them (ie what effects diff profiles have on power/revs etc) so don't want to go getting a cam and have it doing very little, but also not wanting to get a cam that ruins the enjoyment of your car on a day to day level. Tricky one huh?
     
  5. philip walker Forum Member

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    The Newman 268 is prob. the best all round cam, for fast road use. The 272 is good slightly more focused is the best description.

    You dont need to use a vernier as I have had then cut to run on stock marks. You can fit a verinier however those customers who have, have reported little or no gain.
     
  6. fthaimike Forum Addict

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    you only use a vernier to fine tune an engine, being able to move less than a tooth at a time.

    mine in the old mk1 2.1 8v is:

    TSR203 - duration = 282.....lift = 11.6.....(Fast Road/Club Sport).
     
    Last edited: Nov 2, 2006
  7. Mike_H Forum Addict

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    You need to be careful with a Mk3. The lambda probe (assuming you've got one) can get very confused by long period cams. I'd think 268 is the max you could go for, if not too much. Suggest you check with others what they've done on a Mk3
     
  8. mr hillclimber Club GTI Supporter and Sponsor

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    That must be a "very" bad set up on the 304. I have a cam similar to that Kent 320 in my 1800 8v. It runs fine between 1,500 & 3,500 on light to 2/3rd's throttle, after that it'll take full throttle from just below 4k to 8,5 +. Thats also on Webers (48's with big chokes).

    I had a similar problem a few years back trying to find a cam for a customers 2ltr 8v. Did'nt like the look of any of the catalogue profiles (ok-ish duration but short on lift) so we had a cam ground based on a G60 profile. It gave a peak of 131bhp at the wheels (the best we'd ever seen from an 8v on K-jet by 19hp) with a strong power curve and total driveability plus a good idle. The cam had 284 degrees duration and 470 tho lift with 64 degrees overlap. Anything much over 70 degrees overlap on K-jet causes a fluctuation with the air-flap and upsets the idle.

    From memory it was a Piper ground cam, it was based on one of their G60 GPA profiles ground to suit a solid spec head. They do another with a little more duration and a lot more lift (over 500 thou !) but thats just overkill for road use still on a plenum type manifold.
     
  9. mr hillclimber Club GTI Supporter and Sponsor

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    :thumbup:
     
  10. Bundles Forum Junkie

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    Nice one, any more info you could give? where did the power come in from? where did it end? how did it idle? etc :)


    Hmm, i never thought about that but can see how it would effect it, valve opens sooner after the bang, lambda detects the lesser burned mixture and leans it out :thumbd:

    Hmmm, anybody got any more thoughts on this? or any experience on this?
     
  11. fthaimike Forum Addict

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    Idles lovelly & feels really strong from low down & tails off just after 6k (limiter is at 6300) 3.5-5.5 was on full cam i would say.

    (click my vid link).
     
  12. Mike_H Forum Addict

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    There's a similar discussion on another thread...related to 16v Mk3 cams. It's been suggested that the MAF sensor gets confused too (or maybe it's instead and I got all the new fangled electronic stuff mixed up.) Give me K-Jet any time ;)

    You definitely can't go 282 on your standard management.
     
  13. fthaimike Forum Addict

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    i fitted a k-star to my old k-jet motor
     
  14. Bundles Forum Junkie

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    That's some tidy driving there mike :thumbup:

    Seems to pull nicely too. Have you not thought about raising the limiter? My limiter and indeed the limiter on my old rocco (same engine as mk1) was at 6700rpm.
     
  15. fthaimike Forum Addict

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    I did think about it but the last build of the engine managed 123k of v hard driving hitting the limiter every time without any prob's, only thing that happened was a cracked piston from over fueling so i feel more confident where it is at the moment.
     
  16. jam35 Forum Member

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    my mk2 gti 8v 0n kjet is trunning a kent gs2 cam and second and 3rd gear are a joy it just pulls and pulls and pulls! it doesnt seem that much quicker than my m8s standard 8v digi but it definetly is !

    can someone tell me the duration and lift of my cam?

    thankyou

    james

    my car is also runnign v poor it was running rich then the garage messed with it to lean it off now its running pants! does the car ned to run richer too compensate for the cam?? last but not least my car is developing a serious tapping noise only when cold(5mins idling) spoke too my dad and he presumes one of the hydraulic tappets could be dry. is this costly? he seems to think so
     
  17. Bundles Forum Junkie

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    Kent GS2 Specification:

    Power Band - Cam Lift(mm) - Valve Lift(mm) - Duration - Timing - Full Lift - VC (mm) - LTDC
    2000-6500 - 10.94 - I 10.64 E 10.59 - 290 Deg - 35/75 75/35 - 110 Deg - I 0.30 E 0.35 - I 1.83mm

    :)
     
  18. Barkstar Forum Member

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    A general rule of thumb says anything over a 276 is a bit too uncivilised for commuting/shopping etc. It's an often made mistake to over cam, you know lots of 'I've fitted a hairy cam lads' but just like loud exhaust they can soon get really tiring. And fitting a wilder cam to a grunty 8V can be counter productive. Talk to the cam manufacturers about your spec and what you'll be doing with it. Me I have the same dilema and will be going conservative, having done the pig in traffic route in the past.
    Barkstar[:*:]
     
  19. fthaimike Forum Addict

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    Mine does sound a bit like a tractor but she ticks over lovelly at 900rpm.

    Bundles my later gears are longer (4+E).
     
  20. Admin Guest

    Hello Phill! Hope your doin well.(Im that guy with the silver golf...;) )


    Anyways,
    I have a simular set up myself and am running a schrick 268, it pulls all the way up the powerband (comes on at about 3'800) but it is also civerlised enough to pull away in any gear at 1000rpm. A good anytime cam.

    And my brother has a Newman 272 (You can get one from philip walker ;) ) that was cut as a schrick profile, it runs simular just a bit better at higher revs, still civerlised enough for a daily driver tho'.

    And both the schrick & Newman cams run on the original timing marks. When I had my car remapped at stealth vince said a vernier my have helped - but it would be very small gains - not wearth the money IMO.
     

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