Hey guys i just had some questions about replacing valves.

I'm thinking about attempting to replace my stock bent valves with some other stock ones. I want to try to do it myself with the help of a shop manual and maybe a friend. But anyways i'm not completely rebuilding, just replacing the valves. Does the head need to be machined in any way for the new valves to properly seat even if it's stock valves that are going in? If so, is the process difficult?

 

No machining, but you do need to go through the process of 'lapping' them.
A special 'suction cup' tool is required and it takes a good 2-3 hours to do all 16 correctly.
The process of taking the valves out and putting them in requires a special spring compressor to make life easier. The process is not difficult, but it does take a little bit of finesse.

 

cool thanks for the info!

Does the helms cover all of this stuff? I'm still waiting for it to come in the mail.

Is the lapping basically sanding down the seats to remove imperfections or something? And what exactly does this suction cup do?

 

I just did a quick look through in my GSR Helms and it did not go over lapping.

Lapping involves using two different rubbing compounds (a rough and a fine) and "seating" your valves with their valve seats. You need the suction cup tool to hold the valve while you do a gentle "boy scout starting a fire with a piece of wood" motion with the valve on the seat (with the rubbing compound).
I've got to go to work, but I'll see if I can find some links with some more details for you.

Whatever you do, there should be NO power tools involved! The Helms gets into reaming and reconditioning and you don't want to go there.

Also, you'll need to replace your valve seals when you take out you old valves. The Helms goes over this. It requires (another) special tool. Some people have made their own though.