Tappetty noise from engine

[neil1967]

Hello

I have a 1.9 dg 1984 Engine which developed
a loud top end tappetty noise. I removed the
rocker cover and found one of the valves had
7mm clearance at the rocker. I've read a few
threads where it's been mentioned about adjusting
the clearance as a first port of call or should I
be looking for wear elsewhere.
Thanks
Neil

[itchyfeet]

should have hydraulic tappets, adjustment is just an approximate one so hydraulic tappet is in the right area, it then adjusts itself

if this has happened suddenly something is brokem I think.

picture of rocker please?

Any recent work done before this happened?

[Oldiebut goodie]

7mm in the right area? I doubt that it would take that amount up. Are you reading that as 0.7mm?
I posted on my boat engine where the gap was 8mm, I ended up replacing all the rockers as the case hardening had been worn through on that one and excessive wear was showing on others (diesel, but same function). I suspected poor material.
I would inspect the contacting surfaces as a minimum.

[R0B]

Could it be tappet bleed down?

[neil1967]

Hello

Forgot to mention no recent work carried out on engine,
recently went to Scotland and back to Brighton. Noticed
noise a week later.
With the valve closed I estimated the gap at 7mm and I was
able to press rocker to push the pushrod down.
I do all the work on my van except welding.
I've never had to do anything to the engine apart from oil plugs
Etc..I will try and investigate more next few days and get back
with more info...any more basic checks I should look for.
Many thanks
Neil

Ps the recent engine rebuilds threads on here are amazing

[Oldiebut goodie]

This is what I found!

[itchyfeet]

I'd say tappet no longer holding oil.

possibly need to swap it but it means cutting the pushrod tube out and using a telescopic one to replace.

[kevtherev]

Lifter full compression stroke is only 4mm.
Reads like the adjuster screw has come loose.
Or it's utterly battered to death

[itchyfeet]

he said it looks like 7mm, so could be 4mm

cam lift on a DG is 7mm or 6mm if its worn ( I measured it)

as I said picture please, would tell us alot.

[neil1967]

[itchyfeet]

looks more like 4mm to me
duff tappet with no pressure I think.

[neil1967]

Hello

The feeler gauge sizes were .762 .737 .711 and was still
moving freely in gap...
thanks for all the advice.. will read up on replacing tappet.


Thanks once again
Neil in sunny Brighton

[ajsimmo]

Have we established yet if these are hydraulic or solid cam followers? Can't see the question has been answered.
Either way, there's something spectacularly wrong there.
If hydraulic, has the spring inside the follower broken, meaning the check valve doesn't close allowing the piston to stay compressed all the time?
Or the end's fallen off the pushrod!
I'd be taking the rocker shaft off and having a look-see down the tube at the follower(s). If the follower is sitting deeper than it's neighbours, it could have annihilated the bottom face, mushrooming it, in which case it will never come out and it's rebuild time. Not suggesting this has happened, just preparing you for the worst...
Have you tried adjusting it yet, and what setting do you use (as there's no common consensus - VW say 2 turns, some say 0.5 or less! I use 1.5 turns in as per Ratwell). What are the others at?
Fingers crossed for you.

[ajsimmo]

I'm still thinking this one over as I eat my sarnies, and I can't see how there could be that much clearance on a hydraulic tappet, even a failed one. At worst it would be totally soft, and be just touching, maybe showing a little clearance when the pushrod's depressed with thumb pressure. Unless there's a mechanical failure, rather than a "wearing out".
Just a thought, but has the rocker shaft mounting stud come loose, or suchlike? The one next door would also be very loose, but it could be...

[itchyfeet]

If the tappet check ball valve failed and then the plunger return spring got a pounding and broke, there would be nothing holding it up, it would sag down.

Nice sarnies?