Noise from the 930 CIS Monster engine
 

I have a question regarding the "creaking" noise with the Porsche 930 3.3l Turbo CIS Monster engine. The sound occurs is more common when the engine is warmed up, (gear on or idling doesn't matter). The sound is in the most simpliest frequency like one when you would throw nut into a metal can. If it's warmed more like in demostration.

Demostration video via following link: https://youtu.be/p7AgKkqvFLI

Otherwise the engine and the car works perfectly. Maybe the turbo boost is not quite like it use to be and feels like the cylinders not getting enough fuel after 1,1bar pressure.

I have checked all the air hoses, turbo air propeller axle, by-pass, wastegate, spark plugs and cables and everything seems to be ok. Also all of the visible fasteners.

You guys have any idea from where the sound might come and what could be
the issue?

I would appriciate any advce since in Finland the driving season is quite short and I still have a time to get it fixed before next garrage season :)

that sounds like a relay or something other than an engine mechanical part.

nice smooth sounding engine.
were you making the RPM's change or was it doing that on its own.

again, great sounding engine.

Thanx it's even better without that "not so good noise" �� My associate was throttling the gas lever during the demo and rise the RPM's. Any other diagnosis than relay sound?

https://www.youtube.com/watch?v=yoxnN2Nh0Lc

In this video you posted, the fan pulley looks like it wobbles a bit, especially when you give it throttle. Maybe the fan nicking the housing?

That REALLY sounds like the fan blade just nicking the housing. With the engine off, I would look for scraped off paint/coating on the housing. When I've had them nicking - it's usually on the bottom but I did have one that contacted on the top around the 11am position.

That said...wow this car looks absolutely badass!

angela

I have checked the fan housing and unfortunately there aren't any worning of coating or paint in there.

Someone must have had similar symptoms than in my demostration video: https://youtu.be/p7AgKkqvFLI

Any other route causes?

I'm a NFG but it could be the dump valve gaskets being worn. If not get a cheap stethoscope and move it around to see if you can isolate the click sound.
If it is the dump valve this could help:
http://forums.pelicanparts.com/porsche-911-technical-forum/71370-changing-930-dump-gaskets-pictures-galore.html

That could have been the cause but not with this 930, because there is no dump valve. Only diverter valve (by-pass) which I have checked. Although the noise is similar than some dump valve videos that I found in YouTube. Thank you anyways for the quality link!

Any other hints what could be the noise source?

does it only do it when you rev and let off the gas or will it do it at a steady RPM

That sounds like a combustion leak to me. Does the engine have the original dilivar head studs? Regardless, it would be worth your time to remove the lower rocker covers and take a look.

My fan blade has nicked the housing and that's exactly what it sounded like.

It's doing it only when rev and let of. Not in the steady RPM. The head studs should be the stronger ones. Can that kind of noise come from the broken head studs?

Look harder at the fan housing, it's a barely there sound. Loosen the fan strap a little and see if it quits or changes

check the belt on left side is not touching something when u rev. it moves at same frequency as chirp..

Doesn't that sound like the plastic rings in the diverter valve are shot. Each ticking noise is perfectly in sink with the throttle blip. Should pull the covers and replace the plastic rings.

Rahl

Remove the fan belt, start the engine, and rev it a few times, [no more than about 40 sec] If the noise is gone, its fan or pulley related.
Hope this helps. :)
A...

How old is the fan belt? When they get up in years, the belt becomes hard and will actually sound like metal to metal contact. When the engine is warm as in the video, take the fan belt off and run for 30 seconds.
Other places; crank and fan pulley's, alternator bearing, blow-off valve not seated or defective(if you have one) or recirculating valve defective.

The fan housing is just painted and seems ok and the alternator belt is quite new, so I don't think that those are failing.

My plan is now following:

1. Drain the motor oil and check if any metal particles there
2. With the previous step confidence :) change the BOV, drive engine warm and test 30-45s without the fan belt. If not change to noise then proceed to step 3.
3. Remove the heat exchangers and the lower exhaust valve covers to see if any damaged to head studs and cumbusion leak there?

Will update my findings to this thread.

Pls. still advice welcome what components to check?

As stated remove the belt and give it a quick test. Check the spark plug leads to make sure there is no jumping spark under initial load.


Sent from my "Driving Shoe Phone"

diverter valve/BOV
the DV will be open at idle due to vacuum. when you rev it the vac goes away and the valve will close then open again when you let off the gas.

its not the fan housing.

My theory behind the removing of the fan belt, and trying it without it was; to rule out the pulley on alternator being loose on the key!
A...

Hello Guys!

Today I checked two first items from the test plan without finding a route cause :/
It seems now that the noise occurs even when the engine is cold. Always on step to rev. Feels like metal click now. I listened with the antenna the timing chain housings and the lower rocker housings and can't hear the noise source.

1. Drain the motor oil and check if any metal particles there /Done
-->Oil was in excellent shape with no debris in it.

2. With the previous step confidence change the BOV, drive engine warm and test 30-45s without the fan belt. If no change to noise then proceed to step 3. /Done
--> BOV changed to a new factory model tunable OTR and fan belt removed with full alternator & belt test with no result. The noise is same than before.

3. Remove the heat exchangers and the lower exhaust valve covers to see if any damaged to head studs and cumbusion leak there?

So #3 still ahead... I have to admid that I guess that the cruising season is over for me and my 930 :(

Still minor breath of hope in the air... if some of you guys could make the miracle happen and resolve the noise issue with the engine?

The demostration video link: https://youtu.be/p7AgKkqvFLI

i don't think it is anything to worry about.
it sounds mechanical but not internal engine related if that is what you are worried about.
problem is with the mods on that engine you probably have something on there that we don't know you have that could be doing it.

when I say mechanical I mean like the BOV opening and closing, a solenoid switching, a relay, although pretty loud for a relay but you get my point.

you don't say what year or if you are USA. (based on the video sounds like you may be euro??)

Sounds to me like the advance on the distributor. Every time you goose it it clicks. that corespondents to to the when the distributor would be advancing. if its not on tight or right it can hit. Easy enough to check or replace the cap and rotor.

Chris

Something fall down next to the crank pulley?

Replace BOV Gaskets
 

Have you replaced the gaskets under the two silver covers on the BOV? See picture below.



http://forums.pelicanparts.com/uploa...1468984529.jpg


Rahl

The issue still under investigation. Currently I suspect that that there is still something wrong with the power distribution.

Couple of days ago I installed a new spark plugs and cabling and opened the MSD Box. Found rmp resistor unattached form the bottom of the box and yelded it back. Unfortunately all of these fixes and the noise still occurs :/ I tried to localize the source with a stethoscope by listening all surfaces of the motor, but it's too hard to find out where it comes. Feels that the sound comes from the direction of first cylinder but somehow on the top of the motor.

One thing that I noticed was that if set the timing so that the idle is lagging like -8 degs and 4000rpm value +27 degs then the noise almost disapears? If we set it back to +1deg idle and +35deg 4000rpm the noise comes almost at the every throthling. I guess this not very good compromise for the optimal running of the motor. How you would set the idle and 4000rpm advance timing?

Do you guys have any ideas what could be the issue and are you able to what to do next?

I would also like to test and rule out with optional components: Power distibutor, coil and MSD box. Do you have any idea from where we could borrow those for the test or buy 2nd hand?

Items checked so far:

- BOV replaced and vacuum system checked
- Tested the fan pulley alternator without belt
- Motor Oil drained and checked for metal pieces
- Waste gate tested
- Sparkplugs and cabling replaced
- Power distributor opened and seals fixed
- Power distributor cap and rotor replaced
- Timing advance adjusted +1deg idle & 35deg at 4000rpm (vacuum attached)
- MSD box opened, checked and rpm resistor fixed

35 degrees is too much.
set it to 27

I think that the power distributor is giving too high angle and wide range for ingnition advance. Right now it's between 950 rpm to 4000rpm from +1deg to +35deg. If I adjust it to range -8deg to +27deg the noise disapears, but this not very good for the optimal running of the motor

Could there be some worn out parts in the distributor unit?

What intercooler is that? I'm no help but vote removing fan belt check before spending any $ or wasting time.