3.2 engine noise (what do ya think it is)?)

[75Carrera]

We installed a '86 3.2 in my 75 Carrera several months ago. The motor has a noticable "rattle" in it that my wrench first thought to be no more than a need for a valve adjustment. That didn't solve the problem. Next we heard there was a possibility there might be something loose in a rocker arm assembly. That too proved not to be the noise source. Now we're opening up the chain covers to see if it's a chain rail or something else in that area. I've heard from several 3.2 owners that this noise is not all that uncommon. Has anyone out there got a better Idea what we might want to be looking for? All input is welcome.

[BeauBlues]

If you hear most noticably when driving it could be your throwout bearing.

[BeauBlues]

Or it could even be your alternator. I had this problem, not too long ago. A good way to tell if your alternater is going bad is if the rattling gets louder when you turn the headlights on.

[BGCarrera32]

If its clicking-clacking and sounds like valves, but is worse when bone cold or mostly goes away when the engine is run hard (like on a track), it could be worn valve guides. Not something a valve adjustment will correct. Early Carrera engines '84 to whenever were somewhat common for premature valve guide wear. If you have anywhere near 70k mi on up its worth a compression and leakdown test.

[Eagledriver]

Rattle often means a loose chain. You might have a failing chain tensioner. I seem to recall mine doing the rattle for a second or 2 when hot and just starting up but it could be my imagination.

-Andy

[RickM]

From what I've read on this board the hydraulic Carrera tensioners are no less prone to failure than earlier ones.

[75Carrera]

Chain tensioners or chain rails are prime suspects. It actually is quiet when cold and starts to rattle when it warms up.

[75Carrera]

My wrench just called and suspects a possible valve guide issue in my #5 (exhaust valve) that appears to have about 60K of movement. This is something he says wouldn't be resolved with different oils (if that's actually what it is). Since it gets louder as the car comes up to opperating temp. He's ruling out the chain tensioner because he says that would usually deminish as the temp came up?.
Except for the rattle he says it won't hurt the car to run with this value guide issue. Do you agree?

[dtw]

Absolutely disagree..if you've got 1.5mm wiggle in your exhaust valve, it is only a matter of time till the valve drops and grenades the engine. Confirm his findings and if borne out, prepare for valve job and top-end rebuild...

[BGCarrera32]

If it was a valve guide, it would get quieter when then engine comes up to operating temp as all the metals are expanding in the heads. Been there have that.

[aigel]

Can't he put a screwdriver / stethoscope and pinpoint the noise? You should be able to tell if it comes from a valve (and #5 to boot) or the chain housings in the back.

I am confused just reading this. Time for a second opinion!

George

[75Carrera]

Well we finally pulled the chain covers and chains yesterday. Guess what? Three of the six chain rails were damaged or loose. By this time tomorrow the rattle should be gone! All the worn value guide speculation was just our fear of the dreaded Porsche "good news-bad news" pattern ... This fix will be easy and affordable compared to a complete valve job! I'm more than pleased to share this happy ending with you all. Thanks guys