Problem with hydraulic cam followers

[Incorrigible]

I've been trying to cure a bloody annoying top end rattle, and am now wishing I'd never bothered.....

I've removed and inspected the cam followers, and they seem fine. However after bleeding and refitting them they seem to have adjusted themselves. The adjustment is via a one way valve and spring in teh follower centre (as with most of them) but it adjusts the centre out to such a point that I now no longer have any compression (all exhaust valves are slightly open all the time)

Any suggestions short of buying 8 new followers ?? I just need a way of holding the self adjuster in place until its all assembled

[Incorrigible]

Thanks for the replies

Have I definitely re-assembled them properly ?

Dunno, but pretty sure I have, there's only 3 bits after all

What's the inlet like ?

Haven't bothered taking it to bits. I want to get this side fixed first. Also fairly sure the noise was coming from no 4 exhaust, annoyingly I think I've found the cause of the rattle; the belt tensioner is intermitantly going slack which was causing backlash in the cam angle sensor

I've re-assembled them with jizer instead of oil (thinking that would be at thin as oil could ever get) and still the centre remains pumped up, the one way valve prevents the fluid from getting out (does it's job as far as I can see, although my assumption was that they'd adjust themselves down as well as up ) assembling like this would still cause the lack of compression

I've also tried running it with the centre piston with air in it. At least the engine runs like this but obviously I've now got the rattle I thought I was curing in the first place

So to answer your question, it went from a completely unrelated rattle to one I completely understand that I've caused myself

There's a description of some bloke doing exactly what I'm doing (with similar tappets) here he seems to think that the one way valve works both ways but I can't quite see how

Edited by Incorrigible on Tuesday 16th October 21:05

[Incorrigible]

Still in the workshop, but the pub's calling

Think I'll sleep on it

[Incorrigible]

stevieturbo said:

Hydraulic lifters do pump up, to remove any clearance...and then be quiet.

Yeah, but it's a spring that sets the clearance (pushes the tappet onto the cam, ie no clearance)

stevieturbo said:

But on the other hand, most will also bleed down very slowly, if oil pressure is removed, due to the action of the spring forcing against the follower.

Some bleed down easier than others. Some pump up, and need to be bled down manually ( ie, in a vice or press ), although I think these types are less common in modern cars. I know some old Vauxhalls were a nightmare in this respect.

These don't seem to want to bleed down at all, even with a very light liquid in them and in a vice (I've even tried thinners when jizer didn't work)

All I can think, is that I need to temporarily dissable the one way valve during assembly. Then bleed all the air out of the rest of the tappet.

[Incorrigible]

Lotus Elan (new one)

Lifters look really standard though

[Incorrigible]

thong said:

put it back together,then turn each pair of valves in turn to full lift,this will then squeez out the excesive oil you have in the lifters.

That's the problem, the oil just doesn't squeeze out. As I said I even tried using jizer instead of oil to no avail

However, I have found the problem. Over the years (and about 100,000 miles) a very small film of what can only be decribed as "crap" has built up on the very central piston. This was rendering the piston air tight, hardly suprising that oil couldn't get out. A quick whizz with some 1200 paper and we're good to go.

Although just to be on the safe side I used Mechoil to fill them with rather than engine oil (to make sure they would reset)