Hi all,

Have a 1991 Longbed pickup with a 22RE running the LCE "tune up" kit and a Doug Thorley header, otherwise stock. Truck had about 132k miles and just recently, it's been making a mechanical grinding or scraping noise.

I've got a stethoscope to try and pinpoint the sound but I can't quite track it. I've pulled all the belts, still there. Pulled the valve cover, t chain and guides look brand new (only 12k miles on em), didn't see any metal shavings in the oil when I pulled the valve cover. Sounds loudest at the distributor, so I thought maybe the distributor bearing. I bought a Spectra Premium O'Reilly's special and the noise is still there.

It's only noticeable or even audible around 1k-1.7k rpm loudest at 1.2k. I can hear most clearly on the front or driverside of the engine bay and I can hear it somewhat on the bellhousing with the stethoscope. It's also loud enough to hear in the cab with the windows rolled up. When I'm in stop and go/ accelerating from a stop.

So I've isolated the fact that it's not the distributor bearing, not the timing chain or guides, not any of the pulleys/ bearings. Considering it's very rhythmic with the speed of the engine and then fades away at certain engine speeds has me confused.

Here's a video I took:

 

is it automatic or manual? I've heard of bad torque converters making a squealing noise at certain RPMs.

 

Sorry, should've mentioned, W55 trans. Makes the noise if clutch is in or out.

 

Is the starter solenoid stuck out?

 

Haven't been having any starter issues, but what's the best way to check that?

 

you can jump the starter solenoid to see if it engages and disengages properly

 

It might be your alternator. If the belt is too tight it will put strain on the bearings and wear it out

 

he mentioned that it made the noise even with the alternator belt off

 

A couple of things to try, put your hand on the starter motor while it's making the noise, You will feel the vibration if the starter is the problem. Pull all the spark plugs out and turn it over by hand, you may feel it grinding somewhere.
Pull the starter off and have a look at the flywheel ring gear, there may be a bolt come out of the clutch and rattling a round in there. To me it sounds like the timing chain, but very hard to tell from the video.
Have a look at this https://old.lcengineering.com/LCTechPages/A Good Intention With A Bad Result.pdf

 

is this the type of sound you're experiencing

 

Try removing the clutch fan!

 

what did you figure out ?