ABY Valve Guides PLEASE HELP!

[HMS-S6]

Hi everyone, not been on here in an age - left my job and went self employed and been too busy on others cars!

I have finally got back on to my S6. I discovered the old head was badly cracked so a replacement was found and took to the engineers. One of the main jobs they did was to fit new valve guides throughout. Now the question i have is this:

On the new guides the shoulder (on the valve side) is larger than the old ones in the old head meaning that the washers that go on first do not fit down to the head. I contacted the engineers who told me that this is normal and i was to enlarge the central hole (which is hex shaped for some reason) in these thin washers. Now i don't mind the work to do this but is it correct? Or is there a downside to doing this? Are they wrong?

Any help much apriciated.

[JP]

The aftermarket guides for the I5's come with shoulders in order to achieve correct instal height. There is two routes to take depending on cam profile

1 - trap the shim under the guide so a little less protrudes into the port on a low lift stock cam set up

2 - make the hole in the shim larger so it goes over the guide's shoulder


another thing to note before installing stem seals make sure to put in the spring seat as 99% of the time the shoulder on the stemseals is greater than the hole in the seat.

lastly double check by how much the seats and valves have been cut/ground, if the instal height has changed by more than 1mm you want to tip the valves to allow for proper hydraulic range and add another shim to ensure the spring install height remains correct.