Chasing a squeal, need opinions. [Archive]

BLACKLS5

05-22-2021, 01:24 PM

I've been chasing a squeal in my Dad's '71 4-speed Chevelle and am looking for opinions on what it may be. I sure sounds like it's coming from the front of the engine but I know how noises can travel. Here's what I've done to this point... Eliminated the power steering by taking the belt off, tried two different alternators, changed all the pulleys, took the fan clutch off and replaced it with a spacer, numerous different belts. I thought it had to be the water pump right? It's the last thing on the front of the engine, Nope. It starts about 3500 rpms and it sounds like a dry bearing.

Early in my testing I checked to see if it did it with the clutch in or out. It makes the noise regardless. Neutral or in gear same thing. I thought that would eliminate the throw out bearing but maybe not? I'm getting a bit frustrated as I must be overlooking something simple, I just don't know what. Anybody have any suggestions?

Thanks, Troy

SuperNovaSS

05-22-2021, 01:41 PM

Have you run it without any belts?

Jason

big gear head

05-22-2021, 01:51 PM

I put a new water pump on my Mustang a few months ago. It just started squealing last week. Looks like I'll be replacing it again.

BLACKLS5

05-22-2021, 02:36 PM

Have you run it without any belts?

Jason

I did, but didn't take it down the road. I just revved it up in the driveway. I didn't hear the noise so I assumed it was something that the belts drove, Alternator, water pump, power steering pump or fan clutch. I've tried different belts and have a Gates brand on there now.

PeteLeathersac

05-22-2021, 04:53 PM

'

Does sound stop when engine warmed up or continue squealing?
Do all driven part seem Ok when pulleys hand spun w/ belts off?
Are all belts exactly correct for application, not just length but width/bevel shape?
With everything assembled, do any brackets appear slightly bent/missing spacers causing pulley misalignment?
If able to create sounds w/ vehicle stationary and helper behind the wheel, try listening through a 6' piece of garden hose moving hose tip around to suspect areas.
The water pump is a good thought also if sounds are from clutch area, when was clutch last changed also don't forget pilot if you crack things open.
Best of luck and keep us posted of what you find.
:beers:
~ Pete

.

JoeC

05-22-2021, 07:14 PM

maybe the fuel pump ?

can try to cut open the oil filter to see if there is any metal

also vacuum leak or a carb problem can make a weird noise sometimes

SuperNovaSS

05-22-2021, 08:34 PM

It sounds like it is something driven by the belts and is not the power steering. Why do you say its not the waterpump?

Jason

RALLY

05-22-2021, 09:24 PM

Does the squeal start when the engine is under a load? Or just bringing the engine up to 3500 RPMs when its in neutral? Is the distributor making this noise? Agree with Pete, use the short hose or pipe and listen to all areas of the engine.

BLACKLS5

05-23-2021, 12:41 PM

It does it with the car in neutral and under load. It has GM deep groove pulleys on it now but I switched back to the standard pulleys to eliminate the pulleys as a problem. Although it will spit the fan pulley off at high RPMs with the standard groove pulleys. The alignment sure looks good to me. Is there a sure fire way to check other than eyeballing it? Width and bevel of the belts? I don't know, I've tried NAPA, and O'reillys belts. Tell them what the application is and go with it. Gates brand on there now. Jason, I say no on the water pump because that was the last thing I changed a couple of days ago. I thought I had it narrowed down to the pump. It was the last rotating part on the front of the engine.

Let me throw this out there... I swapped out his 396 a couple years ago with the current 454. With the 396 it had a squeal when you shifted, just when you shifted, so I figured it was a bad throw out bearing. Obviously installed a new bearing when I changed motors and noise was gone. It was fine for a couple of summers. Last summer he mentioned that it started to squeal above 3500-4000 rpms. Would a worn bearing retainer that the throw out bearing rides on cause something like this?

Thanks for the suggestions. I'll try the hose idea or buy a cheap stethoscope to try and isolate the noise a little better.

napa68

05-23-2021, 01:20 PM

To eliminate the TOB discussion, just back off the preload on the clutch fork and pull it away from the pressure plate.

Not knowing what is in there for a TOB, I'll offer this. Many of the TOB's provided in clutch kits are not a very good quality piece. Many are plastic. There happens to be one in my 71 Trans Am and it makes noise (albeit I can change it by playing with the clutch pedal).

I will be changing the TOB in my TA (and any other clutch job I do) with this.....
https://www.amazon.com/BCA-National-614018-Ball-Bearing/dp/B000YPKU2O.

By what you have shared, I don't know if that is indeed your problem. Is there a forum member that is close to you? Speaking for myself, when I get frustrated I get my head spinning. Sometimes a fresh mind, ears, and set of eyes is the best way to solve a problem.

Tim

Damien

05-23-2021, 10:19 PM

Had the same issue recently.
Process of elimination is the only way to track it. Mine turned out to be the alternator, which is still in good working order and the shaft has no movement but was the issue none the less.

njsteve

05-24-2021, 09:58 AM

Can you post a short video of the car when its making the noise?

BLACKLS5

05-24-2021, 01:04 PM

I'm going to call Jody Haag from Jody's Transmissions when I get a chance. He sold me the Mcleod clutch kit and may have some suggestions. Another thing I thought of was that I used a GM roller pilot bearing in one of the two 454's I built in the last few years. Unfortunately I don't recall if it was mine or dad's engine. Some internet chatter says the roller pilot bearings aren't up to high rpm use and were to be used for diesel applications. I'll see what Jody has to say.

Steve, I'm real tech savvy but I give it a shot next time I'm there.

big gear head

05-24-2021, 01:11 PM

The roller bearings shouldn't be used with the Muncie transmissions. A bronze bushing is best, but not one of the bushings that has iron mixed with it. If a magnet sticks to it then don't use it. AutoGear makes good bronze bushings, and you can still get them at some auto parts stores. Jody probably has them too.

elcamino72

05-24-2021, 03:42 PM

A 71 Chevelle if it is somewhat stock will have a charcoal canister under the hood on the radiator support. There is a vacuum line that goes to a check valve on the top of the canister. There is a seal this that will dry out and can cause a whistle or squeal. Perhaps this is what you are hearing if you can't otherwise locate it.

ZiggyL78

05-25-2021, 02:41 AM

Did you check the oil ;)

Old cars - Old tactics. Get a long screw driver Put it against every area/part of the motor and put the other end against your ear. It will be noisy but it should tell you if it's at the front of the motor or back. If you can get the car on a hoist you should notice if it is louder underneath. Try the screw driver every where including the timing chain cover, oil pan and trans pan. Might as well try the axle and posi bearings and trans tail shaft while you are there. Disconnect the speedo. If you get desperate pull the trans. It's not that hard when the car is up in the air. If it turns out to be the throw out bearing or bronze bushing you will be pulling the it anyway. If you still can't find it do it all again with a piece of heater hose. It makes noises more subtle then the screw driver.

Good luck.

PS. Check for a smart ass mouse in the glove box ;)

EZ Nova

05-25-2021, 11:30 AM

Ziggy, get with the times. We have a couple of these.

https://www.princessauto.com/en/mechanics-stethoscope/product/PA0008885576

Works a lot better than the screwdriver-to-the-ear method.

On sale now for $7.49

BLACKLS5

05-25-2021, 12:58 PM

I spoke with Jody yesterday and he also said a roller pilot bearing is a no-no with a Muncie due to the hardness of the rollers vs. the input shaft. He said because it does it in neutral with the clutch disengaged it should rule out the TOB and pilot bearing. His records show I bought the clutch kit in 2016 so it's been together longer than I thought. I'm on vacation next week so I'll take some time to go over everything again with a stethoscope before pulling the transmission. Maybe get a friend over to help with a video and a fresh perspective as has been been suggested. Thanks again for the help.

SuperNovaSS

05-25-2021, 01:34 PM

What I do not understand is you said the noise did not occur when the water pump belt was removed. Doesn’t that mean the noise is coming from one of those driven parts?

Jason

BLACKLS5

05-25-2021, 01:40 PM

Yes, but I don't know what else to try at this point at the front of the engine. I'm going to revisit everything when I get a chance.

x33rs

05-25-2021, 01:46 PM

The roller pilot bearings aren't necessary for a muncie since that trans uses a ball bearing for the input shaft. Those roller pilot bearings become necessary on setups like a TKO for example because they use a taper input bearing that can not tolerate a bunch of side to side movement.
I do see roller pilot bearings quite frequently installed in muncie applications though. Seems like many clutch kits just come with it automatically these days.

I'm not sure if this was mentioned, but does the car have a roller camshaft in it? I've had a roller lifter fail (on more than one occasion) and they at first create a chirp that turns into a squeak or squeal. What throws it off is that the sound will transmit right through the front timing cover from the cam button and make it sound like a water pump squeaking.

Just a thought.

BLACKLS5

05-25-2021, 02:57 PM

Yes it does...

x33rs

05-25-2021, 03:10 PM

Ugh...

I hate to say it but might want to pull the intake and have a peek at the cam lobes.

If a wheel has locked up it'll score the lobe pretty quickly and you'll be able to see which one is the culprit, eventually eating it down until the arms of the lifter that holds the wheel pin contacts the outer edges of the cam lobe. Makes a squeak or squeal sound that is hard to locate. Even had one where the engine was still running fine (hydraulic roller), but was making the noise. Had a locked up roller lifter and was eating into the lobe. I can only assume it was still running fine because the hydraulic lifter was still taking up the extra lash it was creating for itself. It only ran for a few minutes after the squeal started.

I really hope that's not the issue but I've seen this more than once.

BLACKLS5

05-25-2021, 03:20 PM

I really hope it's not also but it is something I hadn't considered. I'm going to double check the noise is absent with the fan belt off again and go from there. Thank you.

njsteve

05-25-2021, 07:17 PM

Does it have a thermostatically driven clutch fan? Is the clutch hub bearing on that, bad?

BLACKLS5

05-25-2021, 07:25 PM

Steve, I took the fan clutch off and used a spacer to eliminate that as a possibility.

BJCHEV396

06-03-2021, 09:47 PM

Here's a squeak I had in my Camino 3 years ago.Would start once the engine warmed up a bit.It really challenged me.I used a stethoscope to track the noice down and the old long screw driver trick.The sound seemed to travel.Took off all the belts...still there.Changed the water pump and distributor...still there.I was at my whits end.One day got angry and decided to take the Camino on a long highway ride at 70-75 MPH's.Squeak went away to never be heard again.Here's a YouTube video.Check it out and see if it's a similar noise. https://youtube.com/watch?=0Hx802HyWs&feature=share

earntaz

06-03-2021, 11:49 PM

For what this is worth ... In the past I put together a 427 BBC and installed in a 72' two wheel drive Blazer with a 700R4. Ran just fine and later on when the engine warmed up it had a slight "squeal" in the front of the engine. I used a stethoscope and it seemed like the noise was coming from behind the harmonic balancer. Removed the balancer and the chrome timing chain cover. The area where the seal is installed was not center correctly and the balancer was slightly contacting the metal surface. Installed a factory cover -- noise gone. Lesson learned ... don't used cheap crap from across the pound. :no::no::no: