Dharn55

Another update on the saga on my intermix problem and the repair of the engine. those of you who have been following it will remember that I had an expansion plug blow out of the end of a camshaft and have been struggling with that problem. Finally sent the cams out to have the ends drilled, threaded and plugged.

Here are pictures of the camshafts. The first shows four intake cams, on the left is a cam with the expansion plug in place, the next shows a cam with the expansion plug blown out, the next is a cam that has been drilled and threaded, and finally a cam with the Hex plug installed.

Dharn55

Here is a close-up of the cam with the expansion plug in place. In this case the plug has not been “deformed” by my home made tool

Dharn55

Here is a picture of my home made tool. The tool fits in the end of the cam to hold down the cam when the cam cover is removed. The manuals give specific instructions on the depth/setting of the bolts that fit into the end of the cams. I did not think this was critical, not even being aware of the expansion plugs, so I screwed my bolts pretty far in, pressing against the expansion plugs. I believe this was a major mistake.

Dharn55

Here is a picture of the tool inserted in the end of the cam with the plug in place. The hex driver bolt I used is actually small enough to fit inside the expansion plug. I think it should be a larger size head, so it fits into the end of the cam, but not into the expansion cap, However there is not much room beyond the expansion cap. I have not seen the factory tool to see the size of the bolt heads on it.

Dharn55

Here is a close-up of a cam with the expansion plug blown out. Notice the shoulder inside the cam where the diameter of the hole gets smaller. It is only about .2-.2.5” inside the chamfer on the end of the cam.

Dharn55

Here is a picture of the expansion plug that came out, and the cam cover plug. Notice how shallow the expansion pug is, only about 1.8” deep. This cap is pressed into the end of the cam, and the widest part is the top/hollow end, so it needs to go all the way into the end of the cam so that the widest part is beyond the chamfer. You don’t want to reuse an expansion cap as they are pressure/interference fit, and once they lose their shape/diameter reuse is very dangerous. All the domestically available expansion caps I found (from Dorman and other) were 2.5+” deep, so that the widest part would not be far enough in the properly fit, this is because of the shoulder inside the cam. And Porsche will not sell just an expansion cap.

Dharn55

Here is a close-up of the cam with the end drilled and threaded. Notice the hole in the bearing area. This feeds oil to the bearing/journal at the end of the cam, so it is critical that the hex plug not interfere with this hole/oil flow. So the depth of the hex plug is critical.

Dharn55

Here is a picture of the hex plugs. The machine shop used standard, easily available plugs and shortened them so that they would not interfere with the oil passage.

Dharn55

Here is a close-up of the cam with the hex plug installed. Notice the Red Threadblocker used to secure the hex plug in the end of the cam. I am going to modify my home made tool so that it will fit into the hex of the plug to hold the cams. I am not really worried about it pressing against the hex plugs, with the thread and threadblocker it is not coming out.

Dharn55

Here are a couple of pictures of the other ends on the intake cams with. I have had both ends of all four cams drilled and threaded, and am putting hex plugs in all of them. I thought I would be putting the engine back together this weekend, I ordered the last few parts needed and they were supposed to be overnighted to arrive yesterday or today. Found out this morning that Sunset had mistakenly sent them by ground, so i won't have them until next Wednesday or Thursday, very frustrated, the parts were not available at the local dealer. Found them in stock at a CA dealer, but neither FedEx or UPS is delivering on the 4th. So now I am just sitting and waiting.

rb101

Wow, now it all makes sense. Great pics to explain everything. Hopefully it will all be back together soon.

Jake Raby

Very good pictorial.. This is exactly the way that I do the procedure.

You can modify your cam holder to incorporate an 8mm hex wrench so it will lock into the threaded plugs very tightly. In my tool they are allowed to rotate so the cams are held tightly, but the plugs are not damaged.

Impressive!!! Hopefully in the future we can make this not quite so painful for others to do what you have done.. It just takes time.

Ubermensch

This will definitely be very useful for someone in the future. Thanks for taking the time to post pictures and the explanation.

Tippy

Best technical pics ever for this forum. Very informative.

jasper

Yes - I'm impressed - but I have to admit I'm not following the plot so well. Maybe I'm overthinking it.

Replacing the expansion plugs with the hex plugs I get, although I'm not clear if you buggered up the expansion plugs so that's why you're replacing them, or if you are replacing them as an "upgrade".

My real question is.....why the big todo with the cam holder tool. What is it's purpose?


Kudos for pushing the DIY envelope though mate.