PS, Connecting Rods and other stuff - A log

[kdjones2000]

I was out at the track mid-December having fun putting the 951 through its paces when one of my Rennbay trackday ball joints had a hiccup and blew out the bottom bits from the control arm.

Also, with the leak on my oil pan gasket getting worse over the past year, plus the rollers for the timing and balance belts starting to sound like a wheat shredder, I figured that it was time over the holidays to make some more love to my car and appease the 944 Gods once again.

First it was off to Pelican and the Por$che dealer to find all of the various bits and pieces to replace:





Surprisingly, the local dealer had better prices for half of the power steering hoses than our host did, plus some of the other bits and pieces. Either way, both Pelican and the dealer should be happy with me helping out the economy

First job was to repair the ball joint. Travis at Rennbay was awesome in quickly shipping me the missing pieces with only a simple phone call. He mentioned that he has had much better success with using the spiral spring keeper that is included in the Rennbay kits than before when he was replicating the strong spring clip that is used in the OEM ball joint. I personally have found that I prefer the original spring clip, but apparently it is fairly common to install that clip only partially, resulting in it coming out under load.

The ball joint that came apart on me was the one with the spiral retaining clip, which had lasted me for slightly over 2 years (and quite a few track days). Travis recommended to use a screwdriver or punch to seat the spiral clip in better, once everything is put back together.



One piece of good news was that the control arm was only slightly banged up with the ~5min of "vigorous driving" that was done on it while I tried to figure out what was wrong (it behaved more like a bad sway bar mount).





The rest of the control arm was unaffected, so I put things back together and problem solved:



With the front end back together, it was time to prepare for doing the power steering rack and connecting rod bearings, without having to get the car re-aligned. The idea here is to use some old front rotors from the car to move the reference plane out beyond the fenders, and then use a laser pointer to reference the angle for the front hubs both horizontally and vertically. This in effect captures the current toe-in and camber settings for the car, once it is jacked up and stationary (You still need to mark the caster settings with some spray paint or other method before tearing everything apart). I did this by using some 5-minute epoxy to secure 2 laser pointers onto the rotors, and bolted them up to the existing front hubs:





Once this is done, I simply marked the locations on the ceiling and the wall inside of the garage. When I put things back together as long as these marks are matched the car should still retain close to the original alignment settings:

[kdjones2000]

With my car having 134,000 miles on it, it was time to replace the connecting rod bearings, as I have heard all about the dreaded #2 rod bearing spinning due to oiling issues. The oil pan gasket was also leaking slightly in the rear, causing oil to drip onto the crossover pipe and causing burning oil at startup:





To get to this you have to drop the front crossmember, which was done after capturing the alignment settings. I ended up using some leftover DOM tubing from out 924 Chumpcar build with some 2x6 wood and a nylon strap to support the engine. A couple of notes here; 1) I had a jack under the bellhousing to protect in case anything supporting the engine failed and 2) I noticed that with the tension from supporting the engine that my cam tower gasket started seeping oil. I ended up tightening the rearmost bolts on the cam tower a bit tighter after everything was completed to try to prevent additional leaks, but time will tell if it worked or not, so far so good:





Good news when the oil pan finally was off, no weird metal particles or other stuff in the oil pan, so the engine continues to get a good bill of health! Just normal varnish and other oil byproducts:





One thing to note on the later cars that I never see documented is that the oil level sender needs to be removed from the oil pan in order to get the pan lowered off the engine block:



Taking the bearings out, the crankshaft journals all looked to have little to no wear:



The bearings were also in very good shape. However, the top half of the #4 bearing did show that the coating seemed to be removed, possibly indicating pre-failure (?). I am a bit surprised that #4 is showing the most wear, however. Has anyone else seen this behaviour?

[kdjones2000]

While I am no concours loving, anal retentive kind of person, and I am not really interested in using all kinds of chemicals to make everything all shiny, I did spend some time cleaning up the various removed items:





A rebuilt PS rack from Autozone, plus all new PS hoses on a cleaned up crossmember:



I also used the Rennbay power steering pump rebuild kit to renew the pump:



One final modification was to make a support to try to help keep the oil pickup tube from fatiguing off. I ended up just making a version of the Paragon support bracket myself, but instead of brazing it onto the tube I used a hose clamp. While I realize that this will not have the same stiffness as brazing to help support the tube, I figured that it was better than nothing:



I ended up using Permatex high temperature sealant on the four corners of the oil pan gasket, and the dental floss trick to keep it in place during the installation. That made putting the oil pan on VERY easy



Some final pictures taken during reassembly:







The timing belt and rollers were the last items to be addressed, and it turned out to be a good thing I did. The idler roller for the timing belt had seized up entirely, and the other rollers were dry and freely spinning. Everything else went as expected.

Closing thoughts on this round of fixes:

1) The alignment trick seemed to work well, although I might still take it and have it aligned. The front crossmember moved slightly to the driver's side upon installation, and I was not able to get the alignment for camber exactly where it had been, even using some pry bars.

2) The dental floss used to tie up the oil pan gasket is a great idea, and I highly recommend it.

3) Rollers need to be changed by ~100K miles. I let mine go a bit too long and dodged a very nasty and expensive bullet.

Cheers, Keith

[968 GUY]

IMHO I think you will be sorry you put that clamp in the oil pan.

[Komenda Fan]

Great write-up, thanks! I haven't had a lot of need (fingers crossed) to turn a wrench on my car as of yet, but its great to have shots like these to see what awaits down the road. Hence why I'm fixing up the garage shop this month.

[kdjones2000]

Komenda, get yourself a good set of swivel type metric gearwrenches, as they will really help you out with things

Originally Posted by 968 GUY

IMHO I think you will be sorry you put that clamp in the oil pan.

While I understand this sentiment, I still think that adding the support will negate the extra weight of the hose clamp at the least, and might even take off a bit of the peak off the fatigue frequency amplitude. Time will tell I guess...