Odd Engine Sound

meatcastle · 09-29-2009, 04:35 PM

Can any help me figure out what this rattling sound is that gets louder with increased throttle (and how to fix it for that matter)?

youtube link:

YouTube - 944 Engine Noise?

Its hard to tell where exactly its coming from because of the noise but if I had to take a guess it sounds like its coming from around the area where the Camshaft is.
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Also, does anybody know what the Inner Diameter and Outer Diameter (in mm) of the top A/O separator hose is, measuring mine gets 17mm ID and 25mm OD (+/- 3mm) but they don't seem to sell that size on this site...am I screwing up the measurements or does pelican not have it?

Thanks!

Icey1174 · 09-30-2009, 04:09 AM

Almost sounds like lifters ticking which is pretty much the same sound the fuel injectors make and they are right next to the cam. My guess would be the injectors but it is hard to say without being there. I did have my cam off and the lifters out when I was replacing gaskets. All my lifters were good so I know my noise is from my fuel injectors. The higher the RPMs the more noise as the injectors are firing more often. Anyone with any other input?

FYI, my new fuel injectors are just as loud as the old ones.

John_AZ · 09-30-2009, 05:31 AM

It does sound like both lifters and the injectors.

If you are near an oil change, get a can of SeaFoam at WalMart and use it for 50 miles of so. Do not leave it in the crankcase for a long time. Change the filter to a Mahle (Pelican) and put in a 20-50 (10-40 if in cold weather area) oil with ZDDP. Valvoline VR1, Brad Penn.

Clean the injectors with a can of Chevron HD injector cleaner and a couple of tanks of premium.

GL
John_AZ