my DIY engine rebuild

[kjc2050]

Originally Posted by flaps10

I was mostly poking fun at rear engine cars as opposed to mid engine cars not trying to roast the M96 as an oversize boat anchor. I'll try to stay on topic.

I took it as humorous. Great thread; keep it up.

[Chuck W.]

Originally Posted by kjc2050

I took it as humorous. Great thread; keep it up.

Same here. Love this thread.

[flaps10]

After posting up yesterday I really thought I was going out to the garage to look at some camshafts. I should have known better though, since I've read about the use of some of the special Porsche tools required to properly remove the camshaft cover and remove the cam shafts.

Put simply, if you just remove the camshaft cover the cams will want to fall out and surely they'll get all gouged up in the process. So, tool # 9634 to the rescue.

Now I noticed on 986fix.com and also "project nutrod" that the guys who were kind enough to post up their pictures made their own special tools. So it seemed fitting that I would do the same. Time to go ponder the requirements.

Tool 9634 uses the same lug used to hold the LN engineering cam locking tool, only instead of engaging the key way there are two cylindrical features which lock in the centers of the cam shafts. Time to measure the distance between cam shafts. Now I noticed that on the two web pages referenced that they show the steps they used to create their tooling but don't mention the dimensions. It can't possibly be proprietary since anyone could measure the distance on their own.

Now maybe it's not kosher to publish the dimension so I won't, but it rhymes with 112.5mm. As for the diameter of the cylindrical features, you just need to dig out the socket head cap screws that used to hold your clutch pressure plate to your flywheel. They fit perfectly in the ends of the cams.



Going with that I imagined some tool made from a simple piece of angle. Two tapped holes 112.5mm apart and the clutch bolts threaded in. Then it would need a hole on the other leg of the angle, centered. The biggest hurdle would be getting a face of my new tool to line up exactly with the centerline of the two cam bolts.

I made a shopping trip with my sketch to the local home box store. I came up with a piece of L angle aluminum and after that I needed a spacer. The cheapest spacer I could come up with was a nut that was a slip fit for the M8x1.25 bolt (aka clutch pressure plate bolt) that would hold the tool to the head.

Next it was off to my son's house to commandeer the drill press I left with him. Getting the two cam bolts to line up on the same center as the inside face of my new "spacer" would be easier done than said. Behold:



I needed a rigid way of starting the two threaded holes if I had any chance of nailing my 112.5mm goal. I chucked up a stiff drill bit which I'm going to erroneously refer to as a center drill (it's a countersink tool in real life, but the closest they had at Lowe's). Bottom line, it wasn't going to wander when starting a hole.

Chucking it up in the drill press I brought it down and rotated my table until the rear (non moving jaw) of my vise was right on the money for the tip of the "center" drill. Then I put my angle in, with the spacer (aka M10 nut) faced towards the back jaw. I could then start a hole any damn where I pleased, and then slide the work piece along the vice jaw exactly 112.5mm.

I did that by bringing my center drill down and just marking off the drill point for the future hole. Then I scribed an arc at 112.5mm. All I would have to do is loosen the vise and slide the part down until the tip of the center drill intersected with my arc.

I'm skipping a couple of steps here but this is another look



As you can see, the face of my spacer being pushed up against the rear jaw of the vise assures the holes will be exactly lined up with the lug on the cylinder head.

[flaps10]

This picture is after the holes were drilled but before tapping them for the M8x1.25 bolts. In my previous setup I was aiming for accuracy but could not have drilled the holes through or the bit would hit my vise jaw.

In the pic above you'll see I flipped the part around and set it on a sacrificial plastic spacer. You'll see this plastic again later, when I use it to create the special Porsche tools used to hold the cams in place for timing purposes but for now you're looking at a scrap of plastic. All I had to do was unlock the table of my drill press and relocate the center of the holes I started, then change up to the drill I would us to pilot the tapped holes and blow them through.

Next I tapped the holes M8x1.25, and then verified that they fit the cams (they did). Then I eyeballed the stuff that would need to be removed, marked it with a sharpie pen and took a hack saw to remove the excess metal. Then I grabbed the file and made it presentable at 5'.

I learned a TON from my uncle many, many years ago about taking the time to do things right and making what you couldn't buy. Now, where I used my file to round off sharp edges he would have gone to town and probably would have applied a black crackle finish and some sort of data plate. One of these days I'm going to be as cool as my uncle.

The hole used to sock the tool down in position doesn't have to be a close tolerance hole. It just has to be a nice clearance hole. So I blew it through with a 21/64" bit and then tried to install it.


It works.

Now my tool looks a bit light duty compared to tools you might spend a ton of money on. I would have felt warmer inside had I used 1/4" thick extrusion, but then I'd have had more work to do. And truth be told the cams don't want to jump off the head when you remove the cover. They just want to be held. This tool does that. In fact when I got to the part where I pulled the cams off I had to loosen this tool to let go of the non driven ends of the cams.


I was not horrified with what I found when the cover came off. Yet.

The worst thing I see is the cam journal (which is the inside of the cam cover) in the middle left of the pic. It looks worse in the image than it does in real life. You cannot feel any of the marks you see.

Some more exposure:







Here's that ugly cam journal inside the cam cover. Again, you can't feel any of this that you see. Looks to me like some debris has been pumped through here.

Where I stopped for the evening:

I got all the cam lifters out and I have my request in for an egg carton which I'll get after brunch tomorrow. I loosened all the hardware I could find on cam lifter carrier, but it didn't jump into my hands. I was way tired so called it quits for the day. I cleaned up my tools and the garage.