Engine noise within certain speeds

[rainer]

Hello.
I have a 1916 Touring since some years. At the beginning I had troubles with overheating, it also appeared a bit weak, but over time the engine was running better and better. Now it is running very well, but I notice/hear a vibration when driving between 45-50 km/h (28-31 mph) on high gear. Below and above this speed range this noise almost immediately vanishes.

Is this normal for a T engine? I think this is not indicating bad bearings as this noise is limited to a very small rpm range.

Any ideas and experiences are welcome.

Rainer

[TXGOAT2]

It's probably normal. The Model T has a number of vibration periods of various parts at various frequencies, and at some speeds, these vibrations can come into resonance with the different parts of the car and with each other. The result is a symphony of assorted sounds that varies with engine speed, car speed, and other variables.

[t-time]

We recently had a odd noise at certain RPMs while under load, had a devil of a time locating it. A strange vibrating / chattering sound, investigated numerous things - fan pulley, crank pulley, drive shaft bushing, u-joint, generator and countless other things. After days of frustration it turned out to be the hood vibrating against the radiator shell, new lacing fixed it. Only found out what it was because I left the hood off during a test drive. Live and learn.

[Norman Kling]

My wife says she hears bagpipes at certain speeds in certain terrains. Just a harmonic vibration.
Norm

[ElGranadaT]

So what changed with the overheating? Was this a recently rebuilt engine?

I agree with all who say it could be almost anything- My last very annoying noise ended up being the thrust bushing in the differential - ($$$) after that, it was a loose aftermarket crankshaft fan pulley... it's entirely a process of elimination -

Two questions:
if it's in neutral - and you run up the engine - can you hear it? I've used a long screwdriver to my ear across the engine, a rubber hose and most recently I bought a mechanics stethoscope from harbor freight that was useful.

next question: Wondering if you tried jacking up the rear end to where the tires are just off the ground, putting it on solid stands, chock the front wheels and run it in hi gear with someone at the wheel?
...

all that said...t may just be that cacophony of sounds you get from all T's.

[JBog]

As I have learned, if it’s not making a noise then something is wrong! Or you’re not driving it.

[Jerry VanOoteghem]

What kind of noise is it? A knock? A rattle? It can be difficult at times to differentiate between a body or chassis noise and an engine or driveline noise.

[rainer]

Hi, Jerry.
It is no knocking. Difficult to describe.

Sounds like a "Prrrrrrrr", like a vibration against something. Above and below this resonating vibration almost immediately vanishes and the engine runs smoothly.

[TXGOAT2]

My car has some noises like you describe. I think it's normal, or at least very common. You could go over your exhaust system, engine pans, hood assembly, fan assembly, crankshaft pulley, etc, looking for any loose parts or missing fasteners. I think a common primary source of such sounds is the rear axle, with other parts of the car often resonating at some speeds. Torsional impulses from the engine can make almost any part of the driveline "sing" or "chatter" at certain speeds. Some tire treads can get noisy at some speeds, especially on very smooth pavement. Oiling the springs and the front engine mount may help. Check engine mount hardware for tightness and adjustment.

[Moxie26]

Parking brake rods could be rattling within their guides, giving harmonic vibration

[ElGranadaT]

Finally closing this case up -

Engine knocking ended up being worn no. 1 and 2 connecting rod bearings, probably due to oil starvation while climbing our hill.
No. 1 was a bit over 0.003 in - no 2 about 0.002 - 3 and 4 were also a bit off- but less than 0.002 to start-
Took all down to 0.0015 - A bit stiff on turning but should break in - Didn't really want to dive into the mains until I first tried the
connecting rods.

While there I added an auxiliary oil feed line. Fingers crossed - but hard to know if it really makes a difference without somehow
seeing evidence of a flow - but others swear by it - and it was a snap to install. Regrettably, I couldn't check the flywheel pick up scupper
without pulling the hogshead -and I'm pretty lazy - Does anyone have an easy way to either blow that out or get to it?

[Jerry VanOoteghem]

Finally closing this case up -

What case are you closing up? This was Ranier's thread, wasn't it?

[351cmach]

Hello.
I have a 1916 Touring since some years. At the beginning I had troubles with overheating, it also appeared a bit weak, but over time the engine was running better and better. Now it is running very well, but I notice/hear a vibration when driving between 45-50 km/h (28-31 mph) on high gear. Below and above this speed range this noise almost immediately vanishes.

Is this normal for a T engine? I think this is not indicating bad bearings as this noise is limited to a very small rpm range.

Any ideas and experiences are welcome.

Rainer

Mine also has a vibration and noise at these speeds also. I myself don't like it but it might be normal from other threads I've read. Like others have said check the basics.

[Les Schubert]

My experience is a noise at about 25 mph and at medium throttle indicates excessive clearance in the center main bearing. I have found this several times over the years

[TXGOAT2]

Les, do you get a knock or rumble or some other noise with a loose center main?

[speedytinc]

I have noticed a rpm range where a harmonic imbalance occurs.
In my case, due to taller gearing, it occurs around 53-54. The motor wont accelerate thru the spot unless I add retard & slowly bring the advance up. Over 55 the motor is back to full power & will continue acceleration. This harmonic power loss position moved up about 3mph with a Scat crank. But still there to my disappointment. The motor has a full balance job. Its a real annoyance for freeway driving. Dosent come into play with normal club touring.

[Les Schubert]

I will call it a light knock/rattle. Upon exploration I have found the center main to have maybe .005” clearance. Removing some shim and it’s gone for many more miles!

[rainer]

First, a Happy New Year to all of you.


Thanks for this explanation(s).

I assume that checking the play of middle bearing and possibly removing shims will require the entire engine to be pulled.

Because the former owner had made a huuuge fault (forgot to add some steel clutch disks to compensate the lower thickness of the installed Jack-Rabbit, so the clutch was out of adjustment range) I had to pull the engine in early 2021 to replace this crazy clutch with steel clutch disks. Hereby I had a look on overall condition but couldn't see anything worse.

But the following gets into my mind, though...
If this is a loose middle bearing and noise comes from resonating, shouldn't this noise also appear when the engine is running in neutral and spun up to same rpm? I can't remember that.

How likely is it that something else in the car is resonating? I.e. engine hood to radiator or towards the firewall? A lot of metal there, and the leather stripe in the hood is meanwhile hard as stone, I'll have to replace it soon.

I would be happy if I don't have to pull the engine soon again, it was a lot of work (also the first time, so it was combined with a lot of fear). For the moment I will try to drive outside this resonating speed, this will at least reduce wear out.

Rainer

[TXGOAT2]

Going over the car and tightening any and all fasteners, screws, bolts, etc, may help. Taking the hood off and going for a drive would show if it's a problem. Taking the fan belt off an going for a drive might help. If you have a generator, it may be a source of noise, either from the generator or the drive gear. Removing it and blocking the hole then going for a drive will show if it is the cause. A loose hand crank could make noise. Oiling springs and radiator mounts and hood tie downs may help.

[rainer]

Thanks a lot, TXGOAT2.

When winter is over, I will do it step by step.

What thickness of leather shall I choose for the hood? As (hopefully) mentioned, I have a original style brass radiator (round pipes), It looks a bit sensible to me behind the upper chamber (where the hood sits on it).

I think about ordering a soft leather stripe at amazon but I have no clue on how to stuff it into the holding clamps inside the hood. Prying them up -- will they move back on release?

[Norman Kling]

A few unusual things which can cause knock. If the engine is oversize bore like .80 thousands, the pistons could be contacting the gasket or the head. This will make a loud clacking noise, especially when accellerating. If the pin through the front of the crankshaft, the pin which you use when cranking the engine is loose, it will make a tapping at idle. If the spark is too far advaneced it will also make a noise when pulling hard such as climbing a hill or when you first shift into high. If the center main is too loose, it would better to pull the engine and add babbitt to the block. Otherwise it will bend the crankshaft up in the center and cause a broken crankshaft. Loose wristpins will make a chatter when neither pulling nor pushing. Just running along at a constant speed. Rods will knock if you are just slightly decelerating. If you have Auxiliary brakes with rods and an equalizer, it will rattle much more than with only the parking brakes.
I can't think of anything else, except loose body parts which would cause knocking.

[Craig Leach]

There are many electronic chassis & engine listening devices available on the market that can be instrumental in locating odd noises & they
can be applied to different places on the car & driven to locate noises.
Craig.