jay.jay
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Registered: 28th Dec 10
Location: Gloucestershire
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whats bad about them compared to the blank ones?
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corsadonk
Premium Member
Registered: 4th Jul 09
Location: Marlborough, Wiltshire
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You only re-move matrial not add, so you don't gain any lift i,e the valves don't open wider. But you can change the duration so they open for longer.
They are fine for mild tune, but for more power you'll need proper high lift cams.
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shaunmods
Premium Member
Registered: 12th Mar 07
Location: Glascote, Staffordshire
User status: Offline
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Meant to knacker your lifters arent they?
Personally I'd go for ones profiled from blanks just to be safe
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jay.jay
Member
Registered: 28th Dec 10
Location: Gloucestershire
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ah right cheers guys, knew there was somethin not quite right with them, which company is best? i.e piper kent etc. looking to get some in a few months dont wanna pay through the teeth tho.
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Alex_Rally
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Registered: 6th Sep 09
Location: Tyne and Wear, gateshead
User status: Offline
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ive got some for sale mate
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gazza808
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Registered: 30th Jun 08
Location: Peterborough
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quote:
Originally posted by corsadonk
You only re-move matrial not add, so you don't gain any lift i,e the valves don't open wider. But you can change the duration so they open for longer.
They are fine for mild tune, but for more power you'll need proper high lift cams.
this is completely wrong!
when you remove the material from the base diameter this gives you more lift
also theres nothing wrong with using them on a solid lift profile as you'd have to shim etc any ways,
with hydro lifters they take a beating as some times they have to extend to much to take up the new gap
but if it's a mild set for you x16xe or c20xe, if the cam doesn't need piston mods to work then a regrind will probably be just fine for that profile.
[Edited on 04-04-2012 by gazza808]
[Edited on 04-04-2012 by gazza808]
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jay.jay
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Registered: 28th Dec 10
Location: Gloucestershire
User status: Offline
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Ah right, so would you choose reprofiled over blank if it's just a mild build? Will be using throttle bodies eventually but just gonna use powerbox etc for now
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possy
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Registered: 10th Feb 10
Location: wigan bhp vaux
User status: Offline
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i have a set off piper bp285s for sale and some autosprint ones to
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corsadonk
Premium Member
Registered: 4th Jul 09
Location: Marlborough, Wiltshire
User status: Offline
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quote:
Originally posted by gazza808
quote:
Originally posted by corsadonk
You only re-move matrial not add, so you don't gain any lift i,e the valves don't open wider. But you can change the duration so they open for longer.
They are fine for mild tune, but for more power you'll need proper high lift cams.
this is completely wrong!
when you remove the material from the base diameter this gives you more lift
[Edited on 04-04-2012 by gazza808]
[Edited on 04-04-2012 by gazza808]
How can it give you more lift, if you have removed metal from the cam? More lift is the valves open wider/deeper into the engine, which is why you need deeper pockets in your pistons. The reprofile/long duration cams like I said they open for longer, letting more fuel and air in, and out giving more power.
Hi had some piper BP285's in my old XE, which are high lift cams which can only be made from blanks, and I had to machine the head so they would turn in the head. They're the first ones that can't be make from OE cams on the Piper prices list. Making them hi lift, which also need machined pistons. 
I still think you're on about duration, and not lift.
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gazza808
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Registered: 30th Jun 08
Location: Peterborough
User status: Offline
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Your going to loose this argument, I've built a few cam grinders in my time now
Take one of the individual cams off a sam shaft,
Now look at it, the peak is what provides the lift,
Now if you grind down the low point it in theory makes the peak bigger compared to the overall diameter,
And the lift pumps up to take out the clearance caused by the grinding,
There fore giving you more lift.
Some cams need to be made from blanks because there's just not enough meat on them to be made from standard cams.
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