What's this demonic noise? Options

[Amphicar770]

I posted this in my build thread but since that has gotten kind of long, wanted to also call it out as a seperate topic.

I'm really starting to think I should not be allowed within 59 ft of a wrench.

Went to set timing. No visible marks in fan so I chock one wheel and turn the other with a stick in cylinder # 1 to get to TDC. Confirm that flywheel Mark is at top, I can feel it by reaching around. I mark the fan with whiteout, put spark plug back in and start car. Forgot it is still in 5th but it's on stands so it just kicks out the wheel chock. But wait, now there is some kind of a whine / squeal type sound. Hard to pinpoint but I think it's from engine compartment. Thinking it is the AC belt I first tighten then remove entirely. No use. You can hear what I am talking about here.

http://www.youtube.com/watch?v=tS0hHENOWPw

Feeling like every step forward results in two steps back.

[stugray]

Its a long shot, but I have had a similar noise on TWO 914s when the starter motor remains engaged after the engine is started.

Both times were because the ignition switch was keeping power applied to the solenoid after you (supposedly) released the key.

I dont recall it being such a high frequency noise though.
Unrelated question: why is the idle so high?

[r_towle]

Geez...
Did you drop something down the hold and it's Jammed in at the fan?

Something is rubbing the fan or flywheel if that is now in neutral...

Rich

[BeatNavy]

Unrelated question: why is the idle so high?

I believe that's why he was checking timing - to see if that's what's causing the high idle.

Also a longshot: the only time I ever heard something like that was when there was a big leak at the plenum. Specifically, I had installed the throttle body on the plenum without realizing the washer was underneath, not on top, of the throttle body. It caused a very high idle and a hideous turbine-like sound as it pulled air through the gap between throttle body and plenum.

So in addition to looking for something rubbing also look for a problem with intakes/throttle. Air being sucked in rapidly can cause loud, strange noises (and a high idle).

[PanelBilly]

Sounds like starter motor

[stugray]

If it is the starter it will burn up fairly quickly at that RPM.

I found a GREAT diagnostic tool that is available to us these days.
Record the car running with your cellphone and then go around the car and stick the phone in different places like in front of the fan housing, under the drivers side by the starter, etc. You can see & hear a lot with your phone that you cannot do with your head.

[Amphicar770]

Yes, trying to diagnose fast idle which is why I was checking timing.

Starter is a new gear reduction unit. If that's the case, could explain why it sounds different. It was working fine until now.

If starter is not disengaging I would imagine it will get hot pretty fast at those rpm. As in hit to the touch. Does that make sense? I will have to check as well as using cell phone to try and pinpoint.

Was planning to pull the fan. I assume it is ok to let it run for a few seconds without fan just to see if noise goes away.

Will likely pull plenum next. Everything on it (gaskets, hoses,mets) are new but who knows.

When I was adjusting timing, I did note that noise changes with rpms.

[SirAndy]

Starter is a new gear reduction unit.

Some of them do not extend far enough to fully engage the flywheel on our cars.

Might want to inspect the flywheel teeth for wear.
(IMG:style_emoticons/default/idea.gif)

[Java2570]

I just installed my 2056 build and had a problem with my high torque starter needing to be shimmed away from the flywheel. I didn't try to start the engine but I could hear a weird clicking sound as I was turning over the engine by hand to set the valves. I found it was coming from the starter. I used this starter with no issues on my stock 2.0L but my new engine, it needs a shim or spacer. I reinstalled my old SR17x unit and had no problems. Don't know if it would whine like what you are hearing but that's definitely something to check into. That's not a nice noise!

[wndsnd]

Alternator bearing?

[Amphicar770]

The starter did come with a shim that I installed.

Alternator was rebuilt by a reputable shop with new bearings before being put back on.

I need to try to pinpoint location which is made more challenging by the high rpm. Seemed like it was closer to the right side but not sure about that quite yet.

[ndfrigi]

maybe something grinding inside the clutch?

[Gunn1]

Have you tried a Engine stethoscope? I have had pretty good success with them.

I know your going to think I am joking but I have also used a broom stick/handle shortened to fit in the space as a make shift stethoscope. You wrap your fingers around it and make a fist over the listening end of the stick and holding it up to your ear while holding the other end on the area to be listened to.

As always be careful not to get the stick, clothing or anything else close to anything rotating in the engine department.

Good Luck!

[Amphicar770]

Ok, so I looked all around and starts her up with phone in hand. The Demons are gone. Don't know what they were or where they went but have not been able to re-summon them. Only wish I had not cut the AC belt as that was not the problem but is a pain to replace. Thanks for all the ideas. I'll let you know if problem returns.

[Amphicar770]

Unrelated question: why is the idle so high?

I believe that's why he was checking timing - to see if that's what's causing the high idle.

Also a longshot: the only time I ever heard something like that was when there was a big leak at the plenum. Specifically, I had installed the throttle body on the plenum without realizing the washer was underneath, not on top, of the throttle body. It caused a very high idle and a hideous turbine-like sound as it pulled air through the gap between throttle body and plenum.

So in addition to looking for something rubbing also look for a problem with intakes/throttle. Air being sucked in rapidly can cause loud, strange noises (and a high idle).

Aww c'mon, what kind of a noob would do something like putting the washer between the tootle body and the plenum. I mean really, um, uh, uh oh!

Yup, guess what I just checked and was indeed the problem. Exactly what you described.

Mega thanks. (IMG:style_emoticons/default/pray.gif) (IMG:style_emoticons/default/pray.gif) (IMG:style_emoticons/default/pray.gif)