Type 4 double thrust cam bearings...

If it was going to take days .. I'd totally agree. There's a lot of messing in that article, but some on Samba do like to do that.... perhaps I'm just a rougharse.

But for the time it took to make a receiving notch, about 20 seconds, and the cost of a set of cam bearings for the extra half a shell I though what the hell..

The rest of the fettling was pretry much standard cam fitting for me, but.. might have been lucky.. or perhaps it'll all go pear shaped when I throw it down the motorway

Was more worried when I found pump gears could 'drift' accross and hit the cam

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Obvious question: do you need them? VW didn't seem to think so.

 

VW didn't increase the lift and uprate the springs either... (or fit 123 ignition units ) and they liked the idea on later ones (Waterboxer anyway)

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You probably don’t need them, but it’s probably better to have them. And a lot of folks want them without knowing why.

 

Luxury! Think of those early type 1-ers who had no cam bearings at all

 

Interesting to know where the axial thrust comes from on the cam. Radial load I can understand (pushrods, valve springs etc), but the only axial thing I can think of is the thrust of the helical drive gears.

 

That’s why I said earlier ‘unless the gears are straight cut’.

 

Oh, scoldy . Missed that bit.

‘Tis only the gear thrust that would load the cam back and forth, which is presumably why VW were happy with just a half shell thrust bearing?

 

Cam wear patterns suggest there would be some axial pushing those tappets round to get that arch shape

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But each cam lobe has two overlapping followers and one counteracts the other.

 

But not at the same time so it gets pushed in two directions back and forward?

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I don't think any cam induced thrust would be on the same scale as the thrust from the cam gear?

 

But there’s four lobes each pushing backwards and forwards at different times and opposite to each other. I’m guessing, but I doubt if there is a significant thrust load from the followers – the load is from the helical cut gear.

 

That’s hot!