My 944 Sounds Like an Old Washing Machine..?

[M1Jenkins]

Just got my ol' 944 back from a complete engine rebuild from a timing belt failure. New belts, pumps, seals, wiring -- you name it, it's been replaced.

After my lengthy and expensive rebuild I want this thing to run great. And it does, pulls hard and drives great.

However the engine is making some noises that are slightly concerning. First is at idle the engine sounds like a washing machine. Woosh,woosh,woosh (it's an N/A so nope, not a turbo )

Secondly is that over 4,500rpm, the engine sounds sort rattly. Is this common for these cars after rebuilds? I'm not planning on redlining it till after 500 miles or so. But it still sounds off. I'll upload videos here soon.

[Bradical]

It's possible that they did not properly align the balance shaft pulleys when the balance belt was installed. It's fairly easy to accidentally set one of the balance shaft gears improperly by using the incorrect keyway, if they did that and then set the timing marks- one of the gears would be 180deg out and it might exhibit the symptoms you mentioned.

[DeadPorsche944]

Originally Posted by Bradical

It's possible that they did not properly align the balance shaft pulleys when the balance belt was installed. It's fairly easy to accidentally set one of the balance shaft gears improperly by using the incorrect keyway, if they did that and then set the timing marks- one of the gears would be 180deg out and it might exhibit the symptoms you mentioned.

Agreed. I have a friend who races 944s. Their's was put in 180 out and they kept breaking alternator bolts. Got it swapped, no more problems. It's hard to notice at lower RPMs

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[dgcantrell]

Yep.. I'll also recommend checking the timing on the balance shafts. It's easy to not get them right or off just a little. It does take a bit of finesse to get them right since there is a lot of slack in the belt when you initially start applying tension to them with the roller. I always turn the engine over by hand two times and making sure all the marks are aligned before even considering firing it up. And I fire it up without the belt covers on it the first time to make sure nothing crazy is going on.