PROBLEMS WITH 968 CAM SHAFT REMOVAL
#32
Burning Brakes
Thread Starter
Great pictures! But, I still have more questions.
1. For the #1 cylinder cams (front most lobes), it appears that the exhaust and intake lobes, at TDC for the crank, end up facing one another, with the exhaust lobe pointing to 2 o'clock and the intake lobe pointing to 10 o'clock. Is that correct?
2. With the cams oriented as in Question 1, should the blue links on the chain be just above the "arrow" markings cast into the cams?
3. If #1 and #2 are correct, is this rough setting good enough to bolt the bearing caps down without fear of running any of the valves into the pistons?
On the varicam chain tensioner, I managed to get the old chain off and am about to put new pads on the tensioner, so there are a few questions about this, as follows:
1. The pads can be slipped onto the tensioner from the front or the rear. Does it really matter as long as they are fully slipped on?
2. Should both pads be slipped on from the same direction (front or back of the tensioner). If you slip one pad on from the front and the other on from the rear, then the holes in the end of the pads do not line up. Is this an issue?
3. It looks like it will take three sets of hands to collapse the actuator, spread the cams and chain for clearance, and then slip the actuator assembly in between the chain and cams. It would be much easier, if you could collapse the actuator in a padded vice, and install the tie rods in the pad holes that would keep the actuator compressed. Is that correct? I tried to fashion, out of thick wire, the connector link tool that shows in some of the DIY photos, but the wire was not stiff enough and spread as the actuator was released from the vice. Do I need to buy that tool? Or, is there some way to fabricate one in the home workshop?
I apologize for all the questions, but when I get through with this job, I will capture all my lessons learned so that they can be incorporated into the DIY article. This really isn't a bad job, but knowing how to finesse things would be a big help. So far, I have cummulatively spent about 6 hours of wrench time on the car (probabaly an equal number of hours researching!). I believe that the assembly will go back in much faster and that this job, the second time around, could probably be only a 5 to 6 hour turnkey job!
Thanks to everyone for all the help! Keep it coming......I'm almost there.
Ernie
1. For the #1 cylinder cams (front most lobes), it appears that the exhaust and intake lobes, at TDC for the crank, end up facing one another, with the exhaust lobe pointing to 2 o'clock and the intake lobe pointing to 10 o'clock. Is that correct?
2. With the cams oriented as in Question 1, should the blue links on the chain be just above the "arrow" markings cast into the cams?
3. If #1 and #2 are correct, is this rough setting good enough to bolt the bearing caps down without fear of running any of the valves into the pistons?
On the varicam chain tensioner, I managed to get the old chain off and am about to put new pads on the tensioner, so there are a few questions about this, as follows:
1. The pads can be slipped onto the tensioner from the front or the rear. Does it really matter as long as they are fully slipped on?
2. Should both pads be slipped on from the same direction (front or back of the tensioner). If you slip one pad on from the front and the other on from the rear, then the holes in the end of the pads do not line up. Is this an issue?
3. It looks like it will take three sets of hands to collapse the actuator, spread the cams and chain for clearance, and then slip the actuator assembly in between the chain and cams. It would be much easier, if you could collapse the actuator in a padded vice, and install the tie rods in the pad holes that would keep the actuator compressed. Is that correct? I tried to fashion, out of thick wire, the connector link tool that shows in some of the DIY photos, but the wire was not stiff enough and spread as the actuator was released from the vice. Do I need to buy that tool? Or, is there some way to fabricate one in the home workshop?
I apologize for all the questions, but when I get through with this job, I will capture all my lessons learned so that they can be incorporated into the DIY article. This really isn't a bad job, but knowing how to finesse things would be a big help. So far, I have cummulatively spent about 6 hours of wrench time on the car (probabaly an equal number of hours researching!). I believe that the assembly will go back in much faster and that this job, the second time around, could probably be only a 5 to 6 hour turnkey job!
Thanks to everyone for all the help! Keep it coming......I'm almost there.
Ernie
#33
For questions 1,2, and 3 short answer is yes. As far as the pads. You need a 5 or 6mm allen to unscrew the posts in the variocam assembly and slide the pads on that way. The posts act as a barries so they can not slide off. If you put them on without then they are backwards
You can let the plunger (two steel discs machined connnected by a steel rod) in the oil feed line out and then you can compress it by hand to fit it in between the chain before installing as a unit, cams and all. Make sure you have fully seated the cams in the lower half of their journals before installing caps to tighten. With the cams, tensioner and chains, installing can be tricky. It will seem like they won't fit at first. Are you using the special tool to hold the variocam compressed for installation?
You can let the plunger (two steel discs machined connnected by a steel rod) in the oil feed line out and then you can compress it by hand to fit it in between the chain before installing as a unit, cams and all. Make sure you have fully seated the cams in the lower half of their journals before installing caps to tighten. With the cams, tensioner and chains, installing can be tricky. It will seem like they won't fit at first. Are you using the special tool to hold the variocam compressed for installation?
#34
Burning Brakes
Thread Starter
VARICAM ACTUATOR INSTALLATION
Thanks for the reply. No, I do not have the special tool to hold the actuator in the compressed condition. If I had that tool, putting this thing back together would be relatively easy. Can you provide a source for the tool? I assume that you are talking about the tool that indexes into the holes in the end of the chain pads, right? I actually tried to fashion one out of the thickest wire I could fine in my shop, but the wire was too soft and the bends in the wire straightened out and finally slipped out of the holes in the pads when I released the actuator from my vise.
So, where can I get that small but essential tool!
Ernie
So, where can I get that small but essential tool!
Ernie
#36
Burning Brakes
Thread Starter
TOOL
Yeah, I tried the coat hanger and it was so soft that it straightened out as soon as I released the clamp on the tensioner. But, sounds like your design may have been a little different than mine. I fashioned two straight pieces of wire, each with a short 90 degree bend on both ends. I was able to get the bent wire to engage the end holes in the pads; but, as mentioned above, even with connector wire between both sets of holes, the spring force in the actuator was just to much for the soft wire.
#39
RL Community Team
Rennlist Member
Rennlist Member
I just did this job yesterday (again). I don't have that tool, and I was able to hold and squeeze the variocam while my brother held the cams/chain in the air. It is vital to hold it in the air so the bottom part of the chain can sag - if you lay it on a table, the bottom of the chain will be flat, and then the cam sprockets will sit too low and they will interfere with the lower pad.
I made a tool out of a coat hanger, and it was definitely strong enough. But after making it, I just set it aside and did it the hard way.
I made a tool out of a coat hanger, and it was definitely strong enough. But after making it, I just set it aside and did it the hard way.
#40
Burning Brakes
Thread Starter
The tool to hold the actuator piston in the collasped mode is no longer available in the USA. I had Sunset Porsche look for it, and there are none anywhere. At the factory, they are on back order. Sunset told me that that meant at least 3 to 4 months for availability. Incidentally, the tool is cheap. Only $37 and you also get the pin to hold the cam belt tensioner piston in the collapsed position as well.
#41
I know I'm dragging up a very long dead thread, but I just had to say a big "Thanks!" to Raj. The 12mm socket trick was genius, and made quick work out of the single bolt that stripped on the 968 I was working on yesterday (well, other than the cam sprocket bolt, but that one was easy enough to Dremel the head off of).