Rover V8 Pushrod Pre-Load

[FrenchTVR]

Just about to fit a new cam into my 3.9 V8, along with new followers and valve springs. A couple of people have said to me about the shims under the rocker pillars adjusting the pre-load on the hydraulic tappets. Mine has no shims under the pillars.
So what is the pre-load force supposed to be and how is it checked? I thought the whole idea of hydraulic tappets is that they basically sort themselves out.

[David H]

The easiest way to explain is to point you towards RPI's site:

www.rpiv8.com/engine-4.htm#pre-load

[FrenchTVR]

Well I'll go to the foot of our stairs.....

Thanks very much, you learn something new every day.

[nemo1]

with the cam lobe facing down there should be anything from 30 to 60 thou gap between the top of the piston in the follower and the retaining spring thats with all the pushrods an rockers fitted if you need to adjust the gap there shims available which are fitted under the rocker pedistalls. if you have to fit shims make sure that you put them the correct way round if you fit them wrong it will block off the oil feed to the rocker shaft