Head studs - I'm fixin' them!
 

I figure if I don't publicly declare I'm fixing this car that I've had for ~10 years, I will never fix it. After a lot of work I got it running about 5 years ago, only to find a bunch of head studs were broken.

My goal here is simply to be able to drive the car, a 1980 911 SC. I'm giving myself until May 1 to complete this.

I have the motor out and in my basement. Next up is to order the tools for removing the cams. I had them bookmarked online to order and then lost the bookmarks.

A Porsche mechanic has offered to help but I got this far on my own and I feel like I will let myself down if I don't finish this on my own.

Ok, public declaration complete. Next up, search for the tools again.

Thanks for letting me share.

Declaration noted. Ahhh, errrr, what's is gonna cost you for not getting this done? I'd say, a round of suds and wings for any pelicans that show May 3rd for the Friday night barbecue you'll be having?

Ok, here she is. Sweet!

https://lh5.googleusercontent.com/-l...7/DSC_0224.JPG

tharbert, if you'd like to ride that fancy bicycle to NH on the 3rd, I'll buy you some wings and beer regardless of whether the 911 is finished.

Here is a fascinating album of the 911 with the engine out.

https://plus.google.com/photos/118310977721675433324/albums/5846811309019300865

Here is where the process is at now. Special tools needed.

https://lh6.googleusercontent.com/-H...219_191038.jpg

What's that on the floor? A couple of transfer cases?

All you need is a big socket, and an impact gun, and you can blast those nuts off. I think 46mm? if I remember correct. That way , while you are waiting for the tools to arrive ( which you will need for re-assembly) , you can be getting at those pesky studs. Good luck, doing good so far

impact gun
 

be careful with impact gun. I once broke the end of a cam off(maybe on a 2.2) Installing the big nut. Obviously a learning experience.

Yep, only use the gun to loosen the nut. You will want the tools for re- assembly.

Fred, looks like the cam tensioner has to come off first I guess? Looks like just a few bolts for that? Thanks for the pointer. I'll pick up a socket tomorrow.

Josh the eagle eye. I just counted - three xfer cases in the photo and a bonus bell housing.

It was just about where you are now in the dis-assembly of your engine that I kind of wish I had spent a few minutes/hours/days and checked the cam timing---just to see where it was---before taking it all apart. Good Luck!

I think the socket will fit right in there without interference to the tensioner. I would want the tensioners still on when I went after that big nut with the impact gun. Do not want to take any chances of moving the cam, and bending valves. It should take just a few light blips of the trigger to loosen it.

You might want to loosen all of your rockers and shafts before loosening the cam nut - that's the best way to minimize the chance of valve-piston collisions. Try this order:

-loosen rockers as far as you can
-use impact wrench to loosen cam nut - don't let the engine spin backwards - have someone hold the crank with a breaker bar
-compress chain tensioners with clamp, remove
-remove cam sprocket, washers, retaining plate, etc., etc.

As SCadaddle noted - I did a cam-timing dry-run before disassembling, found the timing was retarded outside of spec, which I since learned is due to chain "stretch". This was a really good way to get comfy with the cam-timing process.
Good luck!
GK

Please don't use an impact wrench on your engine anywhere.

You have to have the proper tools to tighten the nut, so you might as well make the investment up front. Then use them, along with two breaker bars, to carefully loosen the nut. One goes on the crowfoot, the other goes on the cam.

If you use an impact wrench you're asking for the chain and sprocket to resist the torque, because there is no way to hold the cam with a socket over the nut. That's asking for trouble with the chains and the sprockets, to say nothing about the possibility of snapping the nose off the camshaft.

Also, a 46mm socket isn't exactly cheap. If I had it to do over I would buy Stomski's tool, it looks like a slick solution.
911 Cam Nut Tool
http://www.stomskiracing.com/images/SR051wht.jpg

O.K. so I made up a little video today to debunk the myth that loosening the cam nut/bolt on 911 camshafts with an impact gun puts too much stress on the chains. I had a few old pitted cams laying around so I used them as guinea pigs.
I torqued up the big nut with the factory tools, then removed it with the impact gun. As you can see, I am holding the cam with only my hand muscles resisting the turning of the cam from the impact gun. It easily comes loose with out much too much force trying to turn the cam. I am quite sure that if my girly hands can resist this force, then the timing chains and sprockets are easily up to the task. I would never recommend tightening them this way.

<iframe width="560" height="315" src="http://www.youtube.com/embed/-qjNEt2SDqA" frameborder="0" allowfullscreen></iframe>

So, how are you coming along so far?? Heads off yet?

Video is private :\

That's because he's just toying with us, hiding the fact that he snapped the snout off both cams and wants tripm to suffer the same fate........... ;)

I will be watching this thread closely. I have been collecting courage to do the same project. My bucket ( of courage) is about 3/4 full. This thread could be just enough to get me started.

Good luck, and please, more pictures / details of the procedure!!

Does the video work now?

Nope

Still private Fred.

Good think I am better at spinning a wrench than working on computers. I'll figure it out. It is nothing exciting just a quick vid of me holding a cam and taking the nut off. Thanks guys

The video works!:)

Fred, how could you put 150 foot pounds on the nut without the cam thrust washers and the rest of the assembly?

the socket does not clear the tensioner on the left side. there's a tool that replaces the tensioner and keeps tension on the chain. i made one with a long 8mm bolt into an exhaust barrel nut and a short sleeve welded perpendicular to the bottom of the nut. take the tensioner off @ #1 TDC to keep the cam from moving.

Good Luck... prepare for a snowball effect like no other. :) I started mine in late September and just now making the turn to reassembly. My $.02: Take your time, do it right and allow your budget to grow so you don't end up with a half-baked runner. You will find more than you planned on... heads should be serviced, seals and gaskets, maybe you'll find a worn cam lobe (goodbye $600-$1000 if it's just a single rocker/lobe)... and on it goes. I'm having fun learning but boy it's not as cheap an education as the other marques.

I am looking for broken Dilavar head studs for forensic analysis (X-ray diffraction). Will pay shipping to Ann Arbor, MI

Even with the special tools, with pipe extensions and 2 guys I couldn't get the Cam nuts off. I sacrificed the nuts. I drilled a series of small holes across half the nut surface and a quick strike with a cold chisel and it split. The tools worked to reassemble and get 150 ft. lbs.

lapkritis - the engine was rebuilt within 5-10k miles, so I should be good. I also have a friend who is dying to help me as he is going to have to rebuild his shortly.

speedy - I'll pm you. I know I have the broken studs somewhere. You want a whole one, or broken, or both? ;-)

Hey Squirrelly, I've got some broken Dilavar studs...PM me with an address...

Wow, two months ago. Hurt myself and had to have surgery, then worked on another project.

Anyway, I used the beg/borrow/steal method to get the tools and they will be put to use tonight.

Ok, go to the point of removing the bolt for the first rocker arm removal. Then it was late.

Next up, a drift to peacefully remove the rocker shafts and rockers.

Nu-nu-nuh no.....here's a better idea. Find or have machined a piece like the rocker shaft keepers at each end of the bolt, but with an outer diameter the same as the rocker shaft or slightly smaller. Add a long piece of threaded rod and small piece of pipe at the other end with nuts on both ends of the threaded rod and you've got a dandy slide hammer to ease the shafts out! It's a brilliant tool of which I wish I could take credit for!
Follow up cleaning the rocker shaft bores with a gun cleaning kit---the long type for a rifle--mounted to a drill motor. That one I will claim!

Replacing head studs.........
 

When you start to remove the Dilivar studs, your two best friends will be a propane torch and a pipe wrench! Heat the spigot next to the base of the stud until you feel the block on the opposite side of the stud getting warm and then go to work with the pipe wrench. I found that a pipe wrench about 18" long worked best. If you have or have access to an 8mm stud collet tool, it will work on the broken studs. For the unbroken ones, you would either need a larger size collet or would need to cut off the top threads. Good luck with your project! I kept one of the broken studs from my SC engine to remind me why I'm doing this rebuild!

Removing cam nut........1
 

I had the same problem, have the correct tools, but cam nuts would not budge! Did not have a 46mm socket, so I used the 46mm crows foot with my air wrench set on the second lightest torque setting to loosen the nuts. Kept hitting it with a short burst on the air gun until the nut came loose. Worked great, no damage to anything! The cams going back in use the small center bolt so I won't have to fight that battle again!

Don't do it!
 

If you have to, drill out the offending nut on the rocker shaft. Driving them out will ruin the cam housing! I had one that a previous "mechanic" had put in backwards and over tightened to the point of stripping the 5mm end of the screw. Tried everything but finally had to drill out the 8mm end which is the nut. Only had to drill a small distance until the nut came off on the drill bit. With the pressure off, the offending rocker shaft came out easily.