Discussion in 'Mech Tech' started by Soggz, Mar 16, 2023 at 7:58 AM.
Straight cut in theory is more "efficient". But they make a terrible racket.
Yes,not the quietest of things.
I Imagine in a race engine, they would be more effective against the endfloat phenomenon.
The heavier performance valve springs push the camshaft harder sideways with the helical cut cam gears. So you get worsening camshaft endfloat and hence timing change on the cam lobes as the camshaft moves away from its initial installed position eating through the end thrust bearing face on the camshaft.
Is that why I’ve seen the cam shaft bearing face on some performance cams welded, and two thrust bearings used?
Also, thicker stronger, lifters with squarer profiles for strength? I think SCAT do a set.
There doesn’t seem much point in welding cams when new ones are cheap.
Double thrust bearings are beneficial if heavier than standard valve springs are fitted but are really unnecessary if straight cut gears are used because the thrust load is negligible.
I don’t know what squarer profile lifters are but they have nothing to do with thrust load whatever they are.
Stop.. you are doing it all wrong ...
Back on cam thrust bearings.
I remember someone on here saying that the case would have to be modified on one side, for the thrust bearing lip to fit, but on inspection of my case ,(and use of the old thrust bearing), they seem to fit perfectly well on BOTH side with no machining, so obviously VW machined the case out for two? So why didn’t they use two?
Just wondering if two would be better…
For a standard engine you don’t need a double thrust but If you have two bearings and they fit, use two but make sure you don’t have less than the minimum cam end float with the engine assembled.
The bearings usually have an locating tab stamped into them to locate with the cut-out in the case. The other case half doesn't have that cut-out so if you had "normal" bearings they wouldn't fit without adapting.
^this. A bit of filing necessary in one case half to fit the pair of bearings.
Both of them go in without filing, though. Both sit flush. Isn’t the stamp out, on a Bearing to stop it spinning?
From the pics it looks like only one casing has the cut-out for the bearing tang. Has one bearing half had the tang removed?
No. Not that I can see.The two halves are from different sets. One is a KS VW and the other, a Silver line.
Do both bearing halves have a tang and both casing halves have a cut-out for the tang? The tang is for location, the bearing crush prevents it rotating.
The other halves of the bearings here, have tangs. But are shorter, with no ‘outer lip’.
I mean the thrust bearings. One Silverline, one KS. do they both have tangs sticking out?
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