Piper or Schrick camshaft?

[zeecue]

Hello

As i got some money for the holidays, (10.000kr = 1000 UK pounds), i want to buy a 4-2-1 exhaust manifold, and a new cam, but what cam should i buy, Piper or Schrick?

What model cam should i take?

And what does the cam come with?

I am thinking about getting a new filter, and a new rear muffler( maybe a thru-flow layout)

What mods could i do for that amount of money?

Here is the exhaust manifold:

SN Kj

[TeflonTom]

hiya morten..

that manifold is a little on the expensive side in my opinion...

this is the type i bought of ebay

manifold on ebay

works out at less than half that price including delivery...

personally i would go for a piper cam because the schrick ones have very odd profiles. dont bother buying thier lifters either... you dont need them.. just get a set of new 'standard' ones.... i paid less than

[KenONeill]

Are we talking lifters or followers here? I know of several tuners who'd not replace lifters unless you were changing rocker ratio, but but would advise always replacing the followers that bear directly on the cam profile.

[TeflonTom]

since i've got a brand new set here i thought i'd take a photo

they are just normal overhead hydraulic lifters

[pinkskud]

hydro-tappets right?

[TeflonTom]

hydro-tappets right?

they are called many things... lifters, tappets or followers

if you look carefully at the left hand one, in the groove is a little hole.. oil id fed in there under pressure and it makes the pluger/piston (which you can see in the right hand one) move outwards till the slack in the valve clearance is taken up...

i've got a set of old ones here.. in the morning i'll strip one down to show you the internal components:)

[TeflonTom]

right then!!! i'm way to kind to you people

the piston on the right contains an inner piston and a miniture spring. this is the mechanism for adjusting the valve clearance...

the inner piston has a non return valve inside which opens at normal oil pressure and allows oil in but not out again. the oil is fed in via the hole in the outer part(which is made in two pieces them pressed together).

it's not easy to see from the pic, but the larger of the two pistons has a tiny circlip running around the outside which stops it from popping out of the outer housing when under pressure from the oil.

so when the oil goes in, it fills the spaces created inside the the pistons and forces them apart which obviously makes the bigger piston move outwards, and hence takes up the slack in the valve train..

the oil gradually escapes by seeping out through the sides of the pistons and through the feed hole whilst the engine is running and also if the engine is left standing for a while without running. on some engines they can loose all of the oil whilst standing which manifests itself as a rattling on startup hence the phrase 'tappety' which soon goes after the oil pressure has built up.

it's also normal for these to rattle on newly build engines whilst they settle.

the most common misconception about these (or any lifter/tappet/follower) is that the are flat on top... this isn't true. the are ground slightly spherical so that the centre is slightly raise when compared to the rest. this makes them turn whilst in service (probably about 10 revs per miniute) this makes them last longer beacuase it's not allways the same area which is taking a pounding from the camshaft also to aid them in turning, the are placed slightly off centre from the camshaft lobe so that the lobe of the cam bears down on it more on one side than the other which makes it want to spin..

you can draw your own conclusions on wether they are suitable for high performance use, but inho this is where vw have excelledm and the quality of the materials use are very high spec. you can buy 'special' ones from most of the cam manufacturers but they wont be any better than oe spec ones, and besides if you were thinking about revving these things fast enough to break them, you would be converting to mechanical lifters anyway

the only thing i will say is.... if you fit a brand new cam... make sure you fit new lifters because the old ones will have worn in with the old cam and using the old worn ones could wreck the new cam.

i hope i havn't blinded everybody with science again

[KenONeill]

Yeah Tom, that's exactly what I was talking about, but both Piper and Schrick make (at least some) cams from new blanks, and the others are re-ground from exchange units.

Therefore I'd suggest that you need new cam followers, and your photo and description suggests to me that the follower is part of the hydraulic bucket.

[TeflonTom]

i saw this and thought of you

[KenONeill]