Club 80-90 Forums

Bentley (both Bus and Vanagon versions) say the adjustment should be two clockwise turns after the valve adjusting screw makes contact with the valve stem. Some folks think the adjustment should be 1/2 turn. If the lifter was dry and you were to preload the lifter 1/2 turns,In practice what happens if you don't preload the lifter enough is it will take too much time to pressurize and you won't get enough valve lift. This will cause the engine to labor and sound noisy. The noise is often heard coming from the camshaft (center of the engine).

The lifter will pump up to the correct oil level no matter what you set it to but a sufficient initial setting is important in order to prime the lifter: two turns of the 10mm valve adjusting screw with 1mm threads will preload the lifter ~1.5mm (remember the 1:1.3 rocker ratio). This is about half the distance that the piston inside the lifter can travel. If you use too little preload you will be stressing the lock ring that holds the lifter together. If you use too much preload, the plunger may bottom out at first, then if the lifter pumps up the valve may not close properly and compression, performance and valve life will suffer.

How about 1.5 turns instead of 2? In practice, this seems to be as acceptable as the factory recommendation and a feel good insurance against the ills that other people have experienced over the years following the factory recommendation. In my experience, 1.5mm of adjustment after the engine has run for a while ends up as 2mm. This is good news because it continues to support the ease of valve adjustment vs. solid lifters.

What happens if you only adjust them 0.5 turns? The lifter won't achieve 2mm of travel and you then upset the rocker geometry accelerating valve train wear.

When I first learned to adjust hydraulic lifter I used the following procedure before following the steps in Bentley:

1. Run engine at 11pm for 30 minutes to pump them up
2. Adjust valves cold first thing in the morning

Over time through research and experimentation, I realized that it's best to adjust them with the engine warm (VW even says that a solid lifter engine can be adjusted up to an oil temperature of 50ºC/122ºF).

The steps I prefer to follow are:

1. Change the oil and filter
2. Run engine for 5 min and let it cool for 5 min
3. Perform a valve adjustment sequence. For each valve...
* Record # of turns that keep the screw is in contact with valve (save for comparison later)
* Perform leak-down test on each cylinder with no tension on springs (record state of valves)
* Adjust valves to 1.5 turns

T'Onion wrote:John
Why ? you say its running sweet as so why mess with it ???

oil and filter mate thats all you needed to have done. the tappets if set correctly shouldn't need touching.

toomanytoys wrote:If you are daft enough to try and fit hydro's without filling them with oil first then the only way to clear them properly is with 6thou of clearance (as per normal solids) but they will make one hell of a racket and prob break........

I didn't say the tappets weren't a bit rattly tho did I - I have highlighted in bold the relevant bit above

So, my "new to me" VW recon (at some time in it's past) has passed it's 2000 mile confidence test
Uses no oil or water and the inside of the (new) tail pipe is still perfectly clean ! (running on LPG helps )

So, time to check the hydraulic tappets and do an oil & filter change.

I knew how to do it, back them off at TDC to barely making contact, then 2 turns in, but I double checked in my Haynes anyway.

All went OK, only took 30 mins, until I tried to fire it up !!
No compression at all, it just span over like there were no plugs in it !!

I nearly pood myself, thinking I had done summat wrong and bent a load of valves

Checked on the WIKI on here and read that they should be done with a warm engine !!
It did not mention that in the Haynes !!

Set them to barely making contact again and ran it at tickover for 15 mins.
Set them 1 point 5 turns in (as recommended on the write up in the link from our WIKI) and all is OK
Seems to tick over better and is generally quieter and smoother sounding.

Big sigh of relief !!

I write all this purely for the benefit of any future "searches" on here re this.

T'Onion wrote:Sorry John , I thought you got a second hand running engine , not a new one