Slick 60's

Trying to diagnose what sounds like rocker-arm noise on the '71 240 in my '66 F100.

Cold, there's no noise and the motor runs fine.

After driving for a while, the motor develops a loud tick-tick-tick noise though still runs fine.

I've adjusted the valves hot and running while the noise is present, and the noise goes away after I adjust them. #5 intake seems to be the culpirt, though #2 exhaust occasionally makes some noise.

After driving 25 miles or so, the ticking is back. At times, when the engine is warmed up, the noise is louder than other times--also when the engine is warmed up. Occasionally, it's downright alarming. Usally, it's just a persistent tick-tick-tick.

Bad lifter maybe? Exhaust leak? Hope it's not a rod knock. If it was a rod knock, I assume it'd be present when cold. When cold, it never makes a peep.

I went to the machine shop and picked up some new swedged rocker-arm nuts, and will pop them in when time allows. Just wondered if anyone else has ever encountered anything like this?

exhaust leak is possible and many exhaust leaks are misdiagnosed as internal engine problems.

weak lifter, warmer it gets,less its pumped up. although i wonder why it does not leak down when resting overnight resulting in noise on startup.

i would start with an investigation of the exhaust.

on a similar note, my 292, I had rebuilt, is quiet when cold and has an alarming smack on one cyl when warmed up. It is not exhaust, and the old timer that rebuilt it for me is no longer around...or at least no one answers the phone. I am planning to R and R it this comming weekend with the one I bought out of Troy New York five years ago. I guess I will have to figure out the problem with it or take it down to Tim McMaster.

I had a similar problem a few years back and it turned out to be a wrist pin . No noise when it was cold but as soon as it got hot you heard it. Tom

i had the same problem it was a fuel pump

Take a couple of feet of garden hose, put one end near the exhaust and listen at the other. This method will help you locate the noise. When it is making lots of noise and after you have tried the hose trick, use a wooden dowel or a chunk of broom handle and listen by placing one end on the rocker cover and the other on your ear. After you have eliminated exhaust leak and located the cylinder that is clacking disconnect the plug wire on that cylinder and see if the noise changes. Post back. These are always interesting stories.

William-in-St George wrote:Take a couple of feet of garden hose, put one end near the exhaust and listen at the other. This method will help you locate the noise. When it is making lots of noise and after you have tried the hose trick, use a wooden dowel or a chunk of broom handle and listen by placing one end on the rocker cover and the other on your ear. After you have eliminated exhaust leak and located the cylinder that is clacking disconnect the plug wire on that cylinder and see if the noise changes. Post back. These are always interesting stories.

Will do! Where do I listen to the exhaust? I assume you mean at the manifold? I have a stethoscope, by the way. My buddy is a doctoral candidate and swiped one for me.

I had a bad lifter after rebuilding. Same symptoms as you describe. When cold no problem after warming up hear it. I stop the rig and let it sit for an hour or so and it was gone. Had to replace a lifter and no problem. Seems once it was pumped up it wouldn't stay.

Do you have an oil pressure gauge on the truck? A lot of oils lose their viscosity as they warm up. Try a change to 20/50 Castrol and see if it helps. This will hold pressure as the engine warms.

ras4434 wrote:I had a bad lifter after rebuilding. Same symptoms as you describe. When cold no problem after warming up hear it. I stop the rig and let it sit for an hour or so and it was gone. Had to replace a lifter and no problem. Seems once it was pumped up it wouldn't stay.

I'm going to throw a new set in there. I can pick up a dozen for around $40, so I figured why not? At the least, it'll be good experience and one less thing wrong with my motor!

Any tips or tricks to replacing them? Do they need to soak for a day or two?

Update: New lifters in, new swedged nuts on the rocker-studs. Truck is running beautifully, and not making a peep after about 60 miles of varied driving.

Thanks for the update. I was wondering where this would head. Thanks, Lyman.

Well, despite my inexperience with hydraulic lifters, I'm an old air-cooled VW guy, Volvo guy, International Harverster guy...

Let's see if 1500 miles or so passes without incident.

Shade-tree lifter break-in as follows:

1) Copious assembly lube.

2) 1/2 an hour of no-spark turning over in the hopes I could get oil to the cam.

3) Static adjustment.

4) Start-up and idle high enough to shoot oil all over the place--estimate 1500 rpm--for 20 mins.

5) Running adjustment at 170-190F.

6) A long drive in city traffic, and varied speeds, loads, and conditions.

7) Tomorrow, an oil change.

Keep my fingers crossed for the next several oil changes...

I had a 302 that did what you describe, it was the broken off skirt of the #1 piston bouncing up and down in the cylinder between the piston and crankshaft. I caught it quick enough so I did not have to replace the cam bearings. I could have got by by just replacing that one piston but I did them all plus crank and rod bearings. If it does not resolve after adjustment, lifter, or fuel pump change you may be well advised to open her up.

Thanks for everyone's input! Always a gamble when an older engine starts making noises...

I've had some strange ones myself. Had a brand-new Volvo B20 start making what sounded like a bottom-end knock. Pulled the pan, inspected, measured, retorqued, and the noise continued.

After a few days of head-scratching, I accidentally bumped the fan and heard a clunking noise. Turns out the brand-new water-pump had a shaft that rocked fore-and-aft in the housing. I replaced the pump and the motor ran wonderfully--until the fuel-pump studs backed out at high rpm, a catastrohic loss of oil occurred, and the engine threw a rod... But that's another story.

Here's the hoping my 240 will live a while longer!