Hydraulic tappets, easy to replace / test

[tvr4ever]

One of my hydraulic tappets is making a ticking noise when accelerating and the revs are below 2000 rpm. The mechanic checked the manifold gaskets, they are OK. The problem is likely one of the hydraulic tappets.

Are they easy to get to, take out and test, maybe replace ???

I have been doing some reading on hydraulic tappets in the RV8 and they mention a tappet preload. Can someone with more technical knowledge than me explain what this means.

What are the things i have to lookout for whit a job like this (if it can be done).

And...., where do you get a replacement set, and how much are they.

Over to the experts.

[GreenV8S]

In practical terms, you can't test them other than by replacing them. And that means a new cam, which to would sensibly be fitted with a new drive gear set, and before you know it you're looking at the thick end of a grand parts and labour. On the other hand it might just as well be a worn rocker or pushrod, or perhaps just a blowing exhaust. Does the noise vary with throttle as well as revs?

[350Matt]

The tappets are down in the vee, which means inlet manifold off ,with both rocker covers, the preload means that when the valve is on its seat the pushrod still loads up the piston in hte middle of the tappet.
This is set by measuring the gap between the top of the piston and underside of its retaining circlip.
It can be varied by the use of shims on the underside of the rocker pillars, swopping pushrods around or fitting adjustable pushrods.

If you do have a one noisy tappet its one of two things, either the gallery inside the tappet is blocked so its getting insufficent oil to pump up and take up the gap. - So strip, clean and re-fit

Or the part for that valve either rocker/ pushrod end/ vlave stem / cam lobe are heavily worn which means theres too much slack for the tappet to compensate for

Either way its manifold off time

Matt

[crackedfinger]

If you are using thin oil yo could try a different grade, may help?

[tvr4ever]

crackedfinger said:

If you are using thin oil yo could try a different grade, may help?

I'm using Castrol Edge 10W60 (used to be called Castrol RS 10W60), i have been using this for years now, regular oil and filter changes every 6000 miles.