After running my 1950 235 a couple of times now, I can't figure out where the terrible rattling sound is coming from. It sounded like it was coming from under the valve cover, but nothing looked abnormal, and all the tappets seemed pretty close on adjustment. I still need to set them but the random rattle sounds like something else. Poked all around with a stethoscope, but could not locate where the noise was coming from. Get's louder off idle. This video was it's first start in many years, and other than the noise it runs great. My 4100 has 2300 original miles.
Last edited by 4100 Fire Truck; 03/12/201812:19 PM.
The usual suspects could be the fuel pump, water pump, or generator. Did you have good oil flow on the valve train? Have you run any cleaner through the engine to loosen things up? Oil change? Is the heat riser free?
It doesn't sound like a rod, sounds more like somethings loose & hitting a tin. try some easy checks: 1) check the inspection plate on the bottom of the bell housing. 2) make sure the bendix is fully retracting on the starter. 3) remove the fan belt and listen.
The noise sounds like it's in the upper rear part of the engine like a really loose sharp sounding ball bearing amplified by the cover, which is why I looked under the valve cover first. It's not a steady tap, tap, tap like the rockers make. It has an alternator on it , and the water pump, distributor, oil pan, side cover areas sound ok. Valve train seems to have good oil flow throughout. Very strange, keep the ideas coming. I've also been using my stethoscope with just the tube on it trying to figure out where the noise is coming from. Thanks, and I'll keep digging when I get another chance to look. and get some better sound with the cover off.
With the valve cover off, verify that ALL the lifters are moving up and down. Cam lobe pounding on the bottom of a stuck lifter? Just throwing stuff at the wall to see if it sticks!🤷ðŸ¼â€â™‚ï¸ Good luck.ðŸ€
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Back off on the clutch adjustment to be sure the throwout bearing isn't turning all the time. It sounds like you've got a dry throwout, and/or some of the bearing balls have gotten a little square. It's also possible you've got some dry or damaged bearings in the transmission. Jerry
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Back off on the clutch adjustment to be sure the throwout bearing isn't turning all the time. It sounds like you've got a dry throwout, and/or some of the bearing balls have gotten a little square. It's also possible you've got some dry or damaged bearings in the transmission. Jerry
I was thinking the same ....when I asked if the noise changed when the clutch pedal is pushed in ??????
It sounds an awful lot like a noise I had when the starter gear was not retracting. I use a piece of 3/8" vinyl hose to listen for engine noises. I point the end at various points of the engine and find it is extremely directional.
It sounds an awful lot like a noise I had when the starter gear was not retracting. I use a piece of 3/8" vinyl hose to listen for engine noises. I point the end at various points of the engine and find it is extremely directional.
A HUGE THANK YOU to truckernix!!! The starter gear not retracting was exactly what the noise was. The return spring is missing, and as soon as I pulled the starter pedal back the noise went away. So much easier than tearing the engine apart for nothing. I love simple fixes to what seems like a major problem. Engine runs perfect now. I just need to get a spring, and set the tappets sometime on a warm day, and work on the throttle linkage which is binding on the floor and not letting it idle down. Plus the spring doesn't appear to be in the right position either. No pics in the shop manual that I could find. Thanks again for bailing me out.
