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Engine Specific Info and Questions => IDI Engine => Topic started by: erice1984 on July 27, 2011, 04:31:31 pm

Title: A question for those with prothe cylinder head experience
Post by: erice1984 on July 27, 2011, 04:31:31 pm
I am debating whether or not to take my prothe cylinder head to the local machine shop guy to have him make sure the valves and valve seats are the correct angle for each other.

The problem with this decision is the guy is the only machinest in town and is back logged a long time with work.

So I guess I want to know if it is possible for me to do it or if it is just lapping the valves in place.

I figured that the valves should be the same angle as the cylinder head.

Any thoughts?
Title: Re: A question for those with prothe cylinder head experience
Post by: Mark(The Miser)UK on July 27, 2011, 07:42:33 pm
Quote from: erice1984 on July 27, 2011, 04:31:31 pm
I am debating whether or not to take my prothe cylinder head to the local machine shop guy to have him make sure the valves and valve seats are the correct angle for each other.

The problem with this decision is the guy is the only machinest in town and is back logged a long time with work.

So I guess I want to know if it is possible for me to do it or if it is just lapping the valves in place.

I figured that the valves should be the same angle as the cylinder head.

Any thoughts?
The valves should NOT be at the same angle as the seat. For the best seal and max lb/sqin there should be point contact.[fine line of contact]

EDIT
OK so the VAG instruction manual say's contact should be 2mm for exhaust and 2.4mm for inlet. IMO these values should be listed as maximums.
As a pair of mating faces will from day one  grow as they hammer together, the valves  will move out of spec from day one and begin to compromise my 'blue' point above,  should you whip the head off to check... You get my drift?? ;D
Title: Re: A question for those with prothe cylinder head experience
Post by: erice1984 on July 28, 2011, 12:23:43 am
Quote from: Mark(The Miser)UK on July 27, 2011, 07:42:33 pm
The valves should NOT be at the same angle as the seat. For the best seal and max lb/sqin there should be point contact.[fine line of contact]

EDIT
OK so the VAG instruction manual say's contact should be 2mm for exhaust and 2.4mm for inlet. IMO these values should be listed as maximums.
As a pair of mating faces will from day one  grow as they hammer together, the valves  will move out of spec from day one and begin to compromise my 'blue' point above,  should you whip the head off to check... You get my drift?? ;D

Gracias Mark.

I was talking to a few other people and that's pretty much the consensus.  I was just trying to avoid the machine shop guy I have to pay with cash AND beer to get stuff done in a reasonable time frame.
Title: Re: A question for those with prothe cylinder head experience
Post by: erice1984 on July 28, 2011, 09:09:19 pm
Damnit I pulled an exhaust valve...  2.01mm  lol

Go figure

Looking at ETKA, I noticed that I only have one large valve spring.  :o   What the hell!