valve clearance

looking to see if someone can get me a spec on how far above/below the firedeck valves should set on an ALH motor? the head is at a machine shop and these folks are 100% reliable in the work they do but have never worked on a ALH head. they have checked it for cracks and it is not warped more than .0025.

thank you for your time,
Mike

According to Bentley, the valves and seats should be lapped, not reground or cut.
The problem is too much valve stem at the lifter. Having said that, I didn't caution
the shop that redid my cylinder head - I doubt they see very many of these either -
and the head came out OK.
I guess the takeaway is that they should remove as little material as possible.

This is my experience with ALH head milling, valve seat cutting, valve stem cutting, etc.

A friend took his head to a shop that done a bum job leaving rather deep grooves in the sealing surface ..... fast forward after head gasket would not hold... He took the head to another shop that milled it as slick as a baby's arse.

Now, dealing with the valve protrusion issue, the shop slightly cut the valves and seats and then did the same for the valve stems.

Thousands and thousands of miles later and about 7 years, that little New Beetle is still on the road with that engine powering it along.

info is awesome. thank you everyone

AndyBees,
did the shop cut everything the same amount? to keep all tolerances the same?

One thing that does happen is valve guide wear. A good shop will address that.

Franko6 is well regarded here for his knowledge and work on heads. Try searching for threads by him.

He doesn't post all that much so you should be able to find some good info easily.

First off, Franko6 would have thrown this head to a recycler for scrap after the first machine shop screwed-up the surface with the very rough grind (literally, grind).

The reason the head was off, #3 cylinder was damaged due to a broke-off GP.

Tip: learn the reasons for a flashing GP light.... and none of them have anything to do with a bad GP. (In this case, replacement of the brake light bulbs..[yes the ECU monitors those on each side])

Dmanqso, yes, the machine shop cut each seat and each valve the same, and did the same for the valve stems. They also replaced all valve guides.

In summary: The head, valves, valve stems, and seats were cut beyond any reasonable minimum tolerance specification. IIRC, they took more material from the valves than the seats..... it wasn't a 50/50 thing. Also, if IIRC, the head was milled beyond 0.020 inches.... maybe as much as 0.030. A concrete number just doesn't pop-up in my mind.

I'll tell you how cheap the guy is, I found him a used piston and turbo for $75.00 and he thought that was too much. I got them from Jimbote. Amazingly, that turbo and piston have held up for a long time.... seems this was in late summer, 2010.

Andy, I may not have thrown the head away, but I have seen my share of poor workmanship. And, occasionally, I can fix the other guy's mistakes.

The base line is, if they don't want to spend the money to do it right, they can go anywhere else they want. No problem

Flee,

If I adhered to what VW says, I wouldn't have built the first head. The people who told me you can't rebuild a cylinder head, became a bit of humor. Fortunately for my customers, I wrote my own book. After 6,500 cylinder heads, I can say what I do works just fine. I have so many rebuilt heads over 250,000 miles I can honestly say I've lost count. It is easier to count the ones over 500,000 miles. I don't do them 'as good' as VW. I can prove I make them better than VW.

The shop manual is written for the shop mechanics. The fact that it says to replace a head doesn't mean that the head can't be repaired as Frank has proved.

Lotsa people running around with resealed pumps but you won't find instructions for doing that in the VW manual.