Rockers - Swipe vs swivel vs roller

[modnrod]

 
Yeah OK, roller wins!
(Apart perhaps from the initial costs).

I'm looking at 2 cams, and the end result is very similar, if not identical in the real world (although I don't know the area under curve figures, so maybe not).

1. Web 86a with 1.4 swipe rockers intake, and 1.25 swipe rockers exhaust (252*@.050, lift is .469" and .419").

2. Web 163 with 1.25 swivel feet intake, and 1.1 swivel exhaust (249*@.050, lift is .475" and .422").

It got me to thinking about the different ratios involved in the rockers and the valvetrain, and the different weights swinging around at either end of the rocker, and how they accomplish the same thing effectively. Just to further confuse the issue, I've used both in the past, although I would only be guessing at which was better because I've never tried one set-up then swapped over to the other type without any other change.

Lots of head-scratching while I'm at work (over Easter of course   *sigh* ) bored stooooopid!
Oh, and yes, I know I'm over-thinking it. Thanks. 

Who has their favourites and why?

[Fiatdude]

You're already dealing with smaller valve on the exhaust -- Why would you want to further restrict the flow by using less lift???

[modnrod]

It doesn't need it on the exhaust.

But I was more curious about the weight the adjuster adds to the nose of the rocker, vs the longer lift arc travelled by the lighter-nosed swipe rocker.

[Fiatdude]

I believe, the only way you can get some of those ratios is offset drilling the shaft and pedestals, so a few of those combo's might not be available.

Flow is flow the more the merrier, and I never found myself with having too much flow in a VW head --

But back to your original question,,,, I've had all three types of rockers and found that the swipe rockers tend to wear out the valve guides a little faster as you get up in spring pressures (OK they were K800's) -- but, I only run roller rockers now just because they look so damn cool setting there when I pull off the valve covers, simple pleasures for us simple folks I say.......