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tonyprks · Joined: 12 Sep 2004 Posts: 13

a camshaft drive or a balance shaft drive?

Sleykin · Posted: Sun Oct 17, 2004 2:50 am Post subject:

Not exactly sure what you are asking but the 87 924S has both a camshaft and 2 balance shafts driven from the crank...2 drive belts.
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Glenn Neff
Medford, OR
87' 924S

The Fife · Joined: 17 Mar 2004 Posts: 241 Location: San Antonio, Texas

If you look in there and only see 1 belt, you've got problems!

9fitty1 · Joined: 28 Oct 2004 Posts: 3

well that is a matter of discussion. if the timing belt isnt there...well...
but if the balance shaft belt isnt there then your car could run ok. I know of many cars that have run without the use of balance shafts, but if you arent racing there is no need not to have then. i think you just need to look a little harder. good luck

The Fife · Joined: 17 Mar 2004 Posts: 241 Location: San Antonio, Texas

I've thought about getting a balance shaft delete kit before. Does it really free up much power?

Manning · Joined: 29 Feb 2004 Posts: 151 Location: Akron O-Hi-O

I don't have any dyno sheets to say yes or no, but apparently it doesn't free up enough power to be worth doing. Porsche tested the 924/944 GTP motor it eventually ran at Le Mans with and without balance shafts and determined and power gains running without balance shafts was so insignificant that they decided to run WITH balance shafts just to be safe. I would imagine if Porsche thought the gains were insignificant on an engine making the power the GTP motor did then you really won't gain anything appreciable on a motor putting less than 140 hp to the ground.
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Michael Manning
1988 924S Undergoing weight loss program

The Fife · Joined: 17 Mar 2004 Posts: 241 Location: San Antonio, Texas

Good to know. Oh, and people recommend changing out the o-rings at the front of the engine when you're in there doing the water pump... well I'm wishing I did mine since it looks like the lower balance shaft ring is starting to leak a bit.

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

The balance shafts use about 5hp, accoding to tests by Porsche.

Fife, not changing all of the oil seals on the front of the engine when you replaced the belts was a MAJOR mistake. Motor oil weakens the rubber that the belts are made of.

So, now you have to take everything apart again, and replace the belts again.

Make sure that you change ALL of the front of engine oil seals this time.

The Fife · Joined: 17 Mar 2004 Posts: 241 Location: San Antonio, Texas

The belts are bone dry, it's coming down really slowly behind the belt covers (not enough to drip). Another thing to do while I'm doing the motor mounts...

Manning · Joined: 29 Feb 2004 Posts: 151 Location: Akron O-Hi-O