I found this 911 engine rebuild manual online, too bad no luck for Type IV motor found yet.
I have new SS 2.0 valves to install in my 1.8 heads which means I need bigger seats. Depending on how much the local shop quotes me tomorrow I attempt this myself. ( I do have a few extra heads to practice on)
I'm mostly interested in the valve seat info.
https://www.porscherepair.us/porsche-911-19...nder-heads.html
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You can save yourself some $$ by removing the seats yourself,I used to grind the old valves down till they sat half way into the depth of the seat,weld them to the seat with a TIG, the welding shrinks the seat then hammer on the stem and they pop out easily.
Once they are all out,you can ''core out' the valve guides with a drill and punch them out also,I remember heating the head before so no damage (galling) to the guide bore when knocking them out .
Heat your heads again and freeze the new guides and knock them in ,I machined a tool for this so they only went in to the correct height on the outside of the head.
I used to leave the oversize seat machining to the machine shop and get them to fit the seats,ream the guides and cut the seats to the valves .
As you have the machining skills it is a good start and saves money,good luck which ever way you go.
Once they are all out,you can ''core out' the valve guides with a drill and punch them out also,I remember heating the head before so no damage (galling) to the guide bore when knocking them out .
Heat your heads again and freeze the new guides and knock them in ,I machined a tool for this so they only went in to the correct height on the outside of the head.
I used to leave the oversize seat machining to the machine shop and get them to fit the seats,ream the guides and cut the seats to the valves .
As you have the machining skills it is a good start and saves money,good luck which ever way you go.
You don't have to TIG weld, MIG will shrink them.
Find seats the right size, heat the heads and it's a .007 press fit. I prefer to hammer them in, I have a special drift that centers in the guide.
Good seat are not hardened, cast seats are junk.
Get an extra seat pound it with a hammer it should bend. If it doesn't bend or breaks it's cast.
Seats aren't cut like a finished seat, you have to cut them 3 angles after you install them.
Sounds easy right?...not quite.
Find seats the right size, heat the heads and it's a .007 press fit. I prefer to hammer them in, I have a special drift that centers in the guide.
Good seat are not hardened, cast seats are junk.
Get an extra seat pound it with a hammer it should bend. If it doesn't bend or breaks it's cast.
Seats aren't cut like a finished seat, you have to cut them 3 angles after you install them.
Sounds easy right?...not quite.
QUOTE(Mark Henry @ May 15 2018, 05:57 PM) 
You don't have to TIG weld, MIG will shrink them.
Find seats the right size, heat the heads and it's a .007 press fit. I prefer to hammer them in, I have a special drift that centers in the guide.
Good seat are not hardened, cast seats are junk.
Get an extra seat pound it with a hammer it should bend. If it doesn't bend or breaks it's cast.
Seats aren't cut like a finished seat, you have to cut them 3 angles after you install them.
Sounds easy right?...not quite.
Thanks Mark and porschetub,
I think they are going in a box and being sent down to European Motorworks, I have too much other work to do around here at home. Maybe a project for another motor in the future once this car is up and running.
I'm 95% sure I can do it, but time is more important than saving a few hundred bucks.
Which manuals have you checked, Mike?
The factory workshop manual only mentions the width of the seat contact area with the valve; the intake on a 2.0 should be 1.8 - 2.2 mm; the exhaust should be 2.0 - 2.5 mm. They also talk about the angles that the seats should be ground. (15 deg, 45 deg, 75 deg.)
The Tech Specs book merely says that if the seat is so worn that the 15 degree cut would be larger than the OD of the seat, the head should be replaced.
So it seems like they were regarded as disposable back in the day. You'll have to use your own judgement (or that of someone who knows aircooled engines very well!) to work out the info you need....
--DD
The factory workshop manual only mentions the width of the seat contact area with the valve; the intake on a 2.0 should be 1.8 - 2.2 mm; the exhaust should be 2.0 - 2.5 mm. They also talk about the angles that the seats should be ground. (15 deg, 45 deg, 75 deg.)
The Tech Specs book merely says that if the seat is so worn that the 15 degree cut would be larger than the OD of the seat, the head should be replaced.
So it seems like they were regarded as disposable back in the day. You'll have to use your own judgement (or that of someone who knows aircooled engines very well!) to work out the info you need....
--DD
Mark you are right,I only used a TIG because it was there @ my last job and I wasn't paying for the gas 
,the TIG was only an example ,no its not an easy procedure but up to what I said then get the pro's to do the rest,I built tools to get to that stage but certainly had none of the equipment to proceed further.
Good choice by the OP to go to EM they now there stuff.
,the TIG was only an example ,no its not an easy procedure but up to what I said then get the pro's to do the rest,I built tools to get to that stage but certainly had none of the equipment to proceed further.Good choice by the OP to go to EM they now there stuff.
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