I have a 355 SB Chevy in the 40 Ford you see in my Avatar. It just started a squeak, sounding like it's at the front of the engine. Forget all the mouse motor jokes I've heard them. It sounds just like a belt squeaking especially like it's bouncing on the pulley a little, in other words not continuous. Let's not get hung up on the belt...or the water pump, or the A/C compressor or the alternator. I took all the belts off and the squeak is still there, exactly as it was. The oil pressure is good and the temp is normal. After it warms up the squeak get less. It seems to go away when you rev it a little and then if you let off abruptly, it makes a definite squeak but doesn't continue, only intermittently. I have searched on the WEB and seen some explanations for similar noise and the most probable is the cam timing gear against the block (which it should rub but may not have enough oil...which is highly unusual) Anybody have an experience with this and a solution?
My first suggestion was going to be timing gear. They make a Torrington Thrust washer/bearing to stop that. The block needs to be machined for that. Many late model blocks already are and need a thrust washer. That is not an answer to your question but it is a place to start.
Are you sure it's coming from the engine and not a loose piece of sheetmetal in the engine compartment? With the belt's off and the front accessories disabled, the squeak should have gone away, unless it's the fuel pump or a bearing problem. Maybe cut the oil filter apart and look for metal shavings.
Rubber failure in the crank damper. Look for a wobble when the engine is running, try marking inner to outer and seeing if there’s relative movement.
Maybe try removing the mechanical fuel pump, if so equipped, and see if the squeak goes away. If you have to run it any length of time you may have to rig up an electric pump or gravity feed fuel to the carb. Also like the idea of checking valve train oiling. Stock rocker arms and valve covers?
I second wheeltramp brian on spraying some lube on the front seal. If that fixes it, you also may want to look at your crankcase ventilation system. If you are building up pressure inside the engine it will pressurize the seals making them prone to squeaking.
Get a 3 ft. piece of heater hose. Put one end up to your ear and fish around with the other end. Cheap stethoscope. You'll know when you're on the squeak. Be careful around moving parts.
If it does turn out to be the timing set, could you please post a video of what it sound's like? I've never heard one squeak before, and it would be good to have that sound in the memory bank.
check for any/all "shields" you might have installed-i.e. solenoid, exhaust manifold, etc. Hold 'em and see if it stops. Had a "knock" at idle on mine-manifold heat shield.
Here is an update. Before tearing it apart to check the timing gear I also checked the fuel pump and looked at the shaft. The shaft was perfect and the pump did not make the noise. The harmonic balancer is just fine. I took the timing cover off and the bolts and bolt retainer were still in position on the cam as I torqued them when I assembled it. The timing gear was perfect, it had been getting oil and no scoring on the thrust bearing. So now what? I am ignoring the suggestions that it is any engine bearing, I have lost rods before and they never ever sounded like a squeaky belt, and cam bearings well, since they have been in so long with no issue I must have the oil hole lined up, and my oil pressure is very good. Anyway, a friend (very good mechanic) says, "I forgot to mention, check the starter and the torque converter cover" While I was doing that I noticed that a bolt on the header flange was loose and the new fancy carbon fiber gasket I put on was blown out a little, I think I found the culprit since the noise started very suddenly, and I was thinking it could be exhaust. I checked all the header bolts.... but didn't check the header flanges because....well I JUST fixed those right?? Stay tuned, I can't confirm this until I get the timing cover, pan and balancer back on.
It's definitely not the timing set. I suspect the exhaust flange gasket, see my update. The squeak sounded just like a squeaky belt that was bouncing, like on a stamped steel pulley that is bent and not running true.
I've heard the same previously when there was a crack in the frame near the motor mounts, and metal to metal moving caused a small squeak. At higher rpms where the engine smoothed out it went away, but at idle it was quieter. A close inspection with a bright light, and mirror discovered the cracks near the motor mounts, and once it was repaired, and reinforced the squeaks went away.
Hope you found it with that loose flange bolt... Something I have done since the 'flathead days' is replace the flange bolts with studs, USS thread into block (or head, in your Chev) and SAE (fine) thread on top, flat washer (SAE, smaller dia. O.D.) and grade 5 SAE nut. Keeps taut, and removes easily later.
When I got into a tailspin from a new problem, My Dad always said go back to the last thing you fixed or place you were doing something in. Wise enough words to live by.
That`s fine ignore if you want, it was just a suggestion if you can`t find the culprit. It happened to me on a fresh rebuilt 340. It sounded exactly like a belt squealing and was intermittent until it wasn`t.; It locked the engine up and back to the machine shop it went. They made it right. That was 20 or so years ago and that engine still rocks today. With all the BS I went through, it`s something I`ll never forget. I hope you find something stupid simple, and not have to go through what I did.
Yuppers ... and in my case you couldn't see the cracks until it was out of the car and even then, face inches away, they were hard to see. Bought an SFI rated one, noise gone.
Ha! When I had my shop I had a customer that desperately needed me to build an engine for his 318 Dodge wprk truck. I was swamped with hot rod jobs, so called a fellow shop owner in San Jose. A week after installing the long block the customer came back in, told of a 'squeak' he had been hearing for 2 days. Engine then froze up, couldn't turn it with starter or lever. I called my friend with the other shop, he had the truck towed and they went in to find #1 main bearing (upper) never to have been bored for oil!!! Siezed that crank like the IRS on a wallet. Yes, they made it good.
Put a reasonable sized piece of wood under the floor pan and use a trolley jack to lift it slightly [then start it] It could be Engine movement related [this should eliminate it] Also What trans??? If Auto.....have you checked the converter to flexplate clearance? [it could be too much forward thrust] Unbolt the converter bolts and slide the converter back, it should have 3/16" clearance [use a drillbit to measure] That's where the shy and elusive 1/2" socket is hiding [we don't have 10mm socket issues in NZ]
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