Balance shaft sprockets broke.
03-19-2006, 06:35 PM
#1
Rennlist Member
Thread Starter
Balance shaft sprockets broke.
The shields on the upper and lower balance shaft sprockets have broken and the balance shaft belt slipped off!
Do I need new sprockets? It doesn't seem safe to just throw a new belt on there. I dont even know how this happened.
I just got the car and told that the belts were just replaced, so I didnt check them myself, because as you can probably tell by now I am a complete idiot.
The timing belt seems to be perfectly fine, luckily.
Should I order new sprockets? Can I just unbolt the old ones if I need to replace them?
Thanks again for all your help, and sorry for asking so many dumba$$ questions.
-Brett
Do I need new sprockets? It doesn't seem safe to just throw a new belt on there. I dont even know how this happened.
I just got the car and told that the belts were just replaced, so I didnt check them myself, because as you can probably tell by now I am a complete idiot.
The timing belt seems to be perfectly fine, luckily.
Should I order new sprockets? Can I just unbolt the old ones if I need to replace them?
Thanks again for all your help, and sorry for asking so many dumba$$ questions.
-Brett
03-19-2006, 11:12 PM
#3
Race Car
That is really wierd. The sprockets themselves should do a good job of holding the belt, even without the front shield or the thrust washers.
I am not sure what to say.
I am not sure what to say.
03-19-2006, 11:39 PM
#6
Rennlist Member
Thread Starter
the thrust washers broke not the sprocket itself (I should change the title).
The middle part of the thrust washer is still under the other washer both the part of the thrust washer that goes beyond the edge of the sprocket is broken.
If you were to look at a Thust washer it broke just inside of where the holes and notch are. Right where it begins to depress.
Sorry if I am unclear
The middle part of the thrust washer is still under the other washer both the part of the thrust washer that goes beyond the edge of the sprocket is broken.
If you were to look at a Thust washer it broke just inside of where the holes and notch are. Right where it begins to depress.
Sorry if I am unclear
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03-20-2006, 12:33 AM
#8
Rennlist Member
Thread Starter
LOL tomorrow, I'll try to take pictures if I get back from golf in time. The balance shaft belt got torn to shreds as well becuase it had slid off the sprockets and was riding them sideways. It was like a disemboweling, not pretty.
I don't see how the balance shaft could be important and the car still run and move becuase it hadnt fallen off recently. I had gone 95+ w/ that belt not on correctly.
I don't see how the balance shaft could be important and the car still run and move becuase it hadnt fallen off recently. I had gone 95+ w/ that belt not on correctly.
03-20-2006, 12:41 AM
#9
Rennlist Member
It's not THAT important, some poeple do delete them for weight reduction. With the displacement of these 4 cyl engines, there is an inherent vibration, and they are there to counteract that. Probably similar to the vibration of bad motor mounts, maybe not even that bad, I haven't witnessed it personally. Car will still drive fine, you just might find bolts falling out eventually or annyoing buzzing. 
You are VERY lucky that that shredded belt didnt jam in your timing belt and throw it off... the timing belt is very important!
You are VERY lucky that that shredded belt didnt jam in your timing belt and throw it off... the timing belt is very important!
03-20-2006, 12:51 AM
#10
Rennlist Member
Thread Starter
I know about the importance of the timing belt thats why as soon as I heard a squeal I opened up the belt covers.
I have seen the horror photos of the bent valves. And I am very grateful that didnt break/jam.
I have seen the horror photos of the bent valves. And I am very grateful that didnt break/jam.
03-20-2006, 02:27 AM
#11
Porsche considered racing 944 motor without the balance shafts and decided the loss in reliability wasn't worth the extra couple HP gained so to me that says tyhey are important. Things like the oil pick-up (weight on the end of a thin tube) may crack from the excess vibration. In the short term the car will run without the balance shafts and you are lucky the camshaft belt didn't jam. The message you car was telling you was to get it properly maintained.
03-20-2006, 10:11 PM
#13
Rennlist Member
Thread Starter
I slid the belt back on today and tightened the **** out of it. It seems to want to slide outward about 1/4" but then it seems to sit there just fine. But uh... It shouldn't move outward.
Any idea why it is doing this.
The plastic cover over the belts is also a bit loose if that makes any difference??
Thanks
-Brett
Any idea why it is doing this.
The plastic cover over the belts is also a bit loose if that makes any difference??
Thanks
-Brett
03-20-2006, 10:19 PM
#15
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About 2 months I guess. I was testing it out to try to dispell the myths about "shaking your engine to pieces". My engine sure seems to be running pretty strong - just ask the Civic Si owner that got spanked. 
I think that when Porsche considered no balance shafts for racing, they were probably concerned with endurance in mind on engines that seldom revved lower than 5 grand RPM, and spent most of their time at redline and WOT for long durations. On a street engine that sees occasional track use, it's pretty much a non-issue as most of the time it sees gearshifts under 3800 RPM, with the occasional romp into the 6800 range.
I think that when Porsche considered no balance shafts for racing, they were probably concerned with endurance in mind on engines that seldom revved lower than 5 grand RPM, and spent most of their time at redline and WOT for long durations. On a street engine that sees occasional track use, it's pretty much a non-issue as most of the time it sees gearshifts under 3800 RPM, with the occasional romp into the 6800 range.