Interesting video - 911 head resurfacing
 

All,

I am preparing to complete a top-end rebuild due to a broken head stud on my 80 911SC. Will post here when I get started :cool:

I anticipate that the heads will need to be resurfaced - found this related video that may be of interest:

Resurfaceing the Porsche 911 Cylinder Head - YouTube

Safe and Happy Motoring,

Tom

+ another interesting site: Milling machine | GordsGarage Blog

SmileWavy

It's funny you have both of those videos posted.

After I saw "fiatnutz" youtube clip, I asked Gord of "GordsGarage" if this was something he could do.
As you can see from his blog, he accepted my challenge.

I am very happy with the machining he did. In addition to resurfacing the heads, he also cut down and pressed in my new valve guides. I did the easy part of removing the old valve guides and left the hard work for Gord. Once he installed the new guides, I used a hand cutter and quickly re-cut the valve seats.

I'm hoping to get my butt over to his place sometime in the next month to bead blast and powder coat all my engine tin.

Once I get the engine back together, I plan to pull the motor from my other '73 and get him to do the same head work, hope he's still up for it.

jrbennett, if you don't mind me asking, how did you size your guides to the valves? Did you hone them or ream them? I'm wondering if this is a diy job or if you had to have it done.

thanks for any info.

I really like the videos - they provide some nice clear images of what the head surfaces look like before and after resurfacing :)

Note that in John Edward's video he used a piece of an old cam housing as a way to make an adapter/fixture to hold the head in the lathe chuck. I've got quite a few junk housings if he (or anybody else) would like a housing to make a head fixture.

Welcome!!

I would use the old cam tower method. You would get much better precision and repeatability if you mounted a modified cam tower to a face or fixture plate that attaches directly to the spindle.

.003 run out on a 3 jaw chuck is considered "good."

I had a few new OEM Porsche guides sitting around and I ordered a couple of Canyon brand guides to see what was easiest to work with.

I removed the valve guides by threading a bolt into the guide as found here in Henry Schmidt's post http://forums.pelicanparts.com/911-engine-rebuilding-forum/552404-valve-guide-removal.html#post6506422

Gord machined the outside of the guides and pressed them into the heads (we tried 2 of each brand). He preferred the Canyon ones because they start with a thiner outside diameter and there is already a step on the outside for setting the installed depth.

I then used a reamer to clean the inside of the guides and fit the valves.
I also preferred the Canyon brand guides. The Porsche guides required quite a bit of reaming to install the valves. The Canyon ones basically needed a quick pass with a reamer to ensure smooth install.
So the 2 new Porsche guides were removed and we used the Canyon ones.

Reaming the guides and a quick re-cut of the seats was easy enough to DIY. I don't have the equipment nor the skills to size the outside of the valve guide prior to installing into the head. I've seen several pictures of cracked heads from what I believe is too much interference fit, here's an example http://forums.pelicanparts.com/911-engine-rebuilding-forum/686840-head-damage-during-valve-guide-replacement.html#post6836040

I offered Gord an old cam housing to modify, but he was very happy to make his own adapter. I assure you, he triple checked (if not more) the run out on every head.

Thanks for the great information!

Working in the film industry for Panavision for long time, I machined many different parts.
Runout on our lathe was less than .0004" (had to be for the camera and lens equipment)...so I benefitted from that when doing anything for myself.
I didn't realise how lucky I was at the time...now I do.
Bob