So, I recently bought a 1966 f100 longbed. It originally had a 240 I-6 in it w/3 spd on the tree, but recently(in the last 5 years), he had replaced the motor with a rebuilt 300(1981 block), but retained all the other components such as the intake/exhaust manifolds, carburetor, flywheel, etc. I am treating the motor as if it were a 1966(is this agood assumption or are there other aspects of it being a 1981 that would cause problems with the intake exhaust setup?.

Now for the main questions:

1. The truck runs well, but seems a bit sluggish(low power) at low rpms. I took off the PCV line and that made quite an improvement. It also still has the oil bath aircleaner, should I change this to a fiber element type air cleaner? Please keep in mind that I have given the motor a complete tune up(points condenser, cap, rotor, wires, oil change, and set the timing to 10 degrees. It idles smoothly at 400 rpm(with a slight miss, random?) and accellerates tightly.

2. This engines is making a loud almost screaming noise when rpms are increased above idle speed, the faster it spins the ouder it gets. I would say that it somewhat resembles a jet engine kind of whirring sound, I would also describe it as a tightness kind of sound, if that makes any sense to any of you. I first thought it might be the water pump or the belt was too tight, so I took off the belt, but the sound remained. I have quickly tried to pinpoint the sound to a particular part of the engine, and I think it is coming from the front of the motor, but I can't be sure. I know this motor has timing gears(metal ones right?), so could they be the cause of this winding noise? Are the gears known to be noisy?

Some extra knowledge to help lead you in the right direction: I also just replaced the clutch and pressure plate(no change in noise) but I decided not to replace the pilot bearing(not bushing but bearing) because it seemed in good shape. I think the original trans is quite worn, but the noise is present even when in neutral and the clutch is disengaged.

So if anyone has any ideas please let them fly, and don't pull any punches, i can take it.


thanks,

mike salmon

 

Except for the part about sounding like it comes from the front of the engine, this is how I would describe how my transission sounded a few months ago. The whiring jet sound, and directly related to RPM.

Turned out to be the main shaft in transmission - the little part that fits into the needle bearings in the input shaft was spawled (I think that's a word) - anyway, it was no longer smooth and any unequall turning between the two shafts created the whiring. I suppose that 3rd gear, since it is 1:1 would not have done it, but it was so loud and scary in the lower gears, I never noticed if it did it in 3rd.

You say it makes the noise with clutch disengaged, this would rule my suggestion out if it is REALLY disengaged - maybe you still need some adjustment since you replaced the clutch parts. It would still do it in neutral (if this is the problem) with clutch engaged since your input shaft is turning and main shaft is not.

Also, could it be your throwout bearing? I mention it only because you mentioned the clutch work.

Now if you find that the noise IS up front (timing gears, I think, are phonolic, not metal) and not in trans, then I have to do a Roseanne Rozanadanna on ya', and say ... Never Mind!

good luck.


Raul
w/ 81 F-100, I6, SROD, Carter 1V non-feedback carb, no A/C, no PS, no PB, but it gets me where I need to go

 

That's Phenolic, not phonolic.

Raul
w/ 81 F-100, I6, SROD, Carter 1V non-feedback carb, no A/C, no PS, no PB, but it gets me where I need to go

 

A whirring noice when the engine idles and it gets louder as engine rpm increases. Well I would check and make sure all pulleys are in good shape. If so then check the timing gears and see how they look. Just to be safe check oil pressure and see if its upto specs, if not replace the oil pump. Another thing it might be is the air condition pump, if you have A/C that is. The A/C might be low on oil and need a new oil charge. Not to scare you but it might be the oil pump itself.
To make your life easier see if you can find a mechanics stethoscope. Basically their like a medical stethoscope but that have a long rod that you place on the engine where you think the problem is occurring. It will allow you to home in on the noise!!!


1994 Ford F150
300-6
Highly Modified and more to come!

 

my truck also makes this sound when accelerating it has low oil pressure my truck is a 66 ford f350 with a 240 it had a 300

 

Hello all, So far you have been extemely helpful for me and so the saga continues: today I installed an oil gague and found that at idle (~400-500 rpm) it reads between 17 and 20 psi, around 600-800 rpm it is up to 30-40 psi, then at cruising speed what i would guess was 1500-2000 rpm it is 50-60 psi. The rpm numbers are approximate as I don't have a dash-mounted tach and I quickly used a tach under the hood for the estimates. Anyhow, what are the specs supposed to be for the 300's oil pressure? I have also done some more careful listening around different parts of the motor and the loud whining sound is definitely coming from the front/underneath part of the motor. It is also definitely reverberting within the oil pan as well. I just can't absolutely isolate it, due to the nature of the sound and the fact that the cross member blocks half of my access to the pan.

As an aside: I also changed the oil. I used 10w-40. Is this too light for these motors? I only run straight 30 weight in my 60 oldsmobile and that does it wonders. The oil looked good when I changed it at its 3000 mile time and I didn't see any signs of metal in the oil or anything like that. So what oil do you reccommend for 300's.

Is this loud winding sound characteristic spun bearings since I have fairly good oil pressure at speed, or is more likely that my oil pump is starting to fail as one of you suggested or my timing gears are at fault. I guess I could remove the distributor and spin up the oil pump with a drill or something, that might induce the noise without the engine running.

However, If I do need to change the oil pump or get to the bottom journals of the motor, what is the easiest method for removing the pan? Will I have to jack the motor up to get enough clearance?

Thank you for your help ahead of time, it is areal blessing to have this resource at our disposal.

mike

 

Mike: comments in between questions. Larry


> Anyhow, what are the
>specs supposed to be for
>the 300's oil pressure?

The oil pressure is fine. Book specifies...at 2000 rpm....40 to 60 psi. Anything over 15 at idle is good especially as old as this engine is. Mine get 16 at idle and about 42 when at 1700.

>I have also done some
>more careful listening around different
>parts of the motor and
>the loud whining sound is
>definitely coming from the front/underneath
>part of the motor.


My bet is that the previous owner put in a set of metal timing gears. They whine like crazy, even being helical cut gears.
They are noisy but the usually last a lot longer than the phenolic gear set that factory installed. I took out the set I had in my 300 and replaced with NYLON set about 2 months ago. Lot quieter.
>
>
>As an aside: I also changed
>the oil. I used
>10w-40. Is this too
>light for these motors?

Get away from 10w-40. Too many viscosity modifiers which have a tendency to gum up ring lands and such. 10W-30 in Winter and straight 30 weight in summer will do ok.

>I only run straight 30
>weight in my 60 oldsmobile
>and that does it wonders.
> The oil looked good
>when I changed it at
>its 3000 mile time and
>I didn't see any signs
>of metal in the oil
>or anything like that.
>So what oil do you
>reccommend for 300's.
>
>Is this loud winding sound characteristic
>spun bearings since I have
>fairly good oil pressure at
>speed, or is more likely
>that my oil pump is
>starting to fail as one
>of you suggested or my
>timing gears are at fault.
> I guess I could
>remove the distributor and spin
>up the oil pump with
>a drill or something, that
>might induce the noise without
>the engine running.

If the oil pump was squealing (which is doubtful as it's submerged in oil) it would have snapped the shaft already as the friction levels went up. but the only way I can see the pump squealing is if it were lined up incorrectly upon installation...
You have good oil pressure. Go ahead and rule this out with a drill attached to shaft and spin it up independently of engine. I would wager no squeal when you do this.

Main bearings when bad will whine/rumble and you will have a concurrent DROP in oil pressure as the clearance opens up. And as they wear, babbit will shear off and either score the journal or get dropped into the oil. You said you that when you chnged the oil there were no shavings, etc in oil...so I would rule out mains or rod journal bearings.

Timing gear whine is speed dependent and will increase in pitch with RPM increase. If they are slightly off line with each other the whine will be increased. Plus metal gears are inherently noisy in the first place.

Like I said above my bet is on the timing gears being metal.
>
>However, If I do need to
>change the oil pump or
>get to the bottom journals
>of the motor, what is
>the easiest method for removing
>the pan? Will I
>have to jack the motor
>up to get enough clearance?

1.)Your gonna have to remove the radiator to jack up the engine.
2.)Undo the motor mount bolts.
3.)floor jack and 4x4 on top of jack, place under oil pan and jack up CAREFULLY till the mounts are about 2" above the frame.
4.) place short pieces of 2x4 btwn the motor mounts and the frame.
5.) drain the oil.
6.) remove pan, scrape all mating surfaces of gasket material and clean with parts or brake cleaner
7.) remove and replace oil pump (prime pump before installing)
8.) install in reverse order using NEW GASKET and oil.




>
>Thank you for your help ahead
>of time, it is areal
>blessing to have this resource
>at our disposal.
>
>mike