valve preload just checking

[diabolov]

Morning all,

Thought I'd check and adjust the preload on the valves as the old girl sounds a bit more
1940 Radial Aero engine trying to start then 4 grannies happily knitting.

So I know how from the ajsimmo's wiki and the manuals but I've got a few choices as to when,
Richard Atwell suggests run the engine for 5 mins then let cool for 5 in his article on Hydraulic lifters,
the manuals, including the VW ones just say how.

Experience please.

[itchyfeet]

I do it cold myself, even if the lifter is drained it has a spring inside so it kept at full height, it takes gentle feel to get it just touching when it is drained but not hard if you know what you are trying to to do. That maybe why they say run it to pump them up to make it easier for Mr. clumsy.

I also do 2 turns as that's VW spe, lots of people think they know better of course.

Expect it not to run for a few hours after setting preload, as you release the preload it will probably suck oil or air in and then when you add the preload again you have now opened the valve until the oil and air can leak out again which takes time. This is something never mentioned in manuals.

When valves are open you get no compression. If you do try and start early it will probably run on three or two cylinders and sound like crap and this worries everybody first time, best wait a few hours and then start.

[bigherb]

Just start the engine to let the lifters fill up with oil then switch it off, don't let it warm up, they should be adjusted two turns with a cold engine.

[diabolov]

Thanks Chaps

M

[kevtherev]

Same here pump the lifters up then I follow R Atwell advice 1.5 turns in.
You can always move it 1/2 a turn if it doesn't stop a noisy lifter
The lifter travel is only 4mm in the bore.
I also purge a stubborn air bound lifter by setting it at a positive lash.

[diabolov]