Here's the situation: I was driving down I-25 on a nice extended straight away with my radar hooked up, and some guy in a 80's 911 and I decided to see what our cars could do. My car is an 87 944S. Around 5500 rpm, I heard a loud click. Immediately cut the engine and pulled over. Brought out the tools and opened the front end up on the side of the highway to find that my balance shaft was seized. So I cut the balance shaft belt out and drove it home. Now I'm assuming that its the bearings, and they were either A) oil starved or B) Just old and worn? I'm confident in changing the belts, but what am I looking at as far as replacing the bearings on the balance shaft? And is this a weekend DIY job? Also, if it is an oil starvation problem, what other problems could i be looking at when I get in there? I have a T-belt kit from 944 online, but this throws a monkey wrench in everything. This is almost a sell the car or keep it depending on cost situation. Full-time student, part-time work, small military stipend!

Semper Fi!!!

 

How could you tell that it was seized ?

 

Nah...figure out what you've got first. You can get the balance shaft cover off without pulling the motor. Until you get in there, you won't know what you have.

But I'm interested in how you knew it was seized too. Are you sure it doesn't spin? What did the belt look like? I assume you stripped the teeth off of it. Are you sure it's the b/s and not something much simple like one of the pulleys that seized? If it is, this is cake to fix.

I'd be real sure before busting open the b/s cover.

 

I have heard of a couple seized balance shaft bearings.

 

I wouldn't think they see anywhere near the loading of con rods or main bearings. But I suppose it is possible.

 

Better get rid of it and fast...also cheap...You know come to think of it you can pay me to take it off your hands lol!

 

The teeth on the belt were basically gone, the upper shaft I can spin with my hand, the lower shaft I can't. Which is why I assumed seized balance shaft. I'm going to dig in there this weekend and see what I find. I'm going to recheck everything again on Friday and make sure that it is seized before opening up the b/s cover. Any recommendations or warnings? Oh, and thanks for the offer Marcus, but I'd by a $500 beater and park it for a year until I commission next year before I sold it. That was the frustration talking!

 

I'm just curious how it ran without the balance shafts turning.

 

I've head of people who race these don't run the balance shafts because they take something like 5-7hp to run. But without them the car will run very rough. The roughness can lead to other problems. Not worth it.

tony4x4nc: It sounds like you'll have to pull the cover and replace the bearing halves inside, then reseal everything back up.
Not a very difficult job, except you have to remove the rear timing belt cover which involves removing all the belts and the crank gear. The parts for the balance shaft will run you about $150, and if your belts and water pump have no been done recently then you should do them too, so that figure could rise.

 

Alright, so I've the front end broken down right now. ....The upper balance shaft turns easily, with 1 finger. Yuo can obviously tell its kind of like a cran in that it will turn to a certain point, then gravity will force the rest of it down. The lower balance shaft will turn if I put a socke on it, doesnt take much force, but it also doesn't make sense that one would spin freely while the other has a significant amount of "drag". Once you stop turning the wrench, the shft stops turning. Is that normal for the lower shaft? This is my first personal 944 timing belt job. So is replacing the bearing halves as straight forward as it seems? Unbotton the front, pull the cover on the side of the engine (I assume drain the oil first?) pull the shaft, replace the halves, lithium grease or some type of lube and button her back up?

 

I would use nothing but engine assembly lube. Any auto parts store will have some, but if you really want the good stuff, I'd recommend Redline assembly lube.

I don't think you need to drain the oil for this job but it can't hurt. There might be metal in your oil from the seized bearing. Be sure you order the correct bearings for your year - the BS bearings changed from 1986 to 1987.

The shaft should spin freely just like your upper one. There is definitely sumthin broke on that lower shaft. Oh, and props for having tools, opening it, and bandaiding it (cutting the BS belt) on the side of the road!

 

I think you need to use a loctite on the covers.
http://www.clarks-garage.com/shop-manual/eng-14.htm

 

Yes, you need the sealant loctite - 574? Also, at least on the later 3.0L engine, the front bearing was pressed into the front nosepiece - it's a full 360-degree bearing shell, not two halves like the rear bearing.

That doesn't sound like a siezed bearing, though - I think Erik's balance shafts required a little bit of pressure with a wrench to get them turning on the rebuild (with new bearings) - like enough to overcome the stiction. That said, opening things up to check them out may not be a bad idea...

 

Keeps getting more interesting......Don't know how I missed it, The balance belt tensioner roller, the one below and to the left of the actual shaft is broken. Which explains a lot, So final question before I go replacing bearings.

FRporscheman says the shaft should spin freely.
924RACR says on the rebuild he had to use pressure to get the shaft spinning.
And someone else I talked to said they've never seen a b/s bearing seized.

From someone who's been in there and changed the belts themselves, do both shafts spin freely? Or is one harder to turn, I can't turn it with my hand, I have to use a wrench with some leverage.

Deos the S use the same bushing/bearing as the Turbo becasue I'm not finding replacement bearings specific to the S

Where do you suggest getting parts? I currently use 944online, but my last transaction wasn't so pleasant.

 

And thanks for all the help guys, greatly appreciated!