Started up my pickup today to run to the store and heard a noise I haven't heard before. And it doesn't sound good. To me it sounds a lot like a locomotive chugging. The engine is a straight six out of an 81 F150. It's been starting to get cold here lately, and when I started it up it was probably 50 degrees out, really not that cold. Anyways I was hoping you guys could help me figure what this sound is, and how bad the prognosis is. I've tried watching you tube videos of engines knocking or pinging and nothing really sounds the same.

http://www.broiledtatties.com/noise.WAV

It's got plenty of 10w-30 oil in it, when I rev the engine up the sound either goes away, or is most likely drowned out. I let it idle for a couple of minutes today to warm up and the noise was still there.

And for future questions I might have about my truck/engine, should I post questions in the 81 forum for the engine and this forum for the body and cab? Or is it ok to just use this one?

 

So hearing that makes me wonder if you have a miss/dead cylinder. Then I start to think of a bad bearing/rod knock. First I would say to try and rule out a rod knock. Use a mechanics stethescope or 24" long screw driver and check along the pan rail for the loudest area. Double check the rocker arm cover lip as well to see if it is the top end. Using a screw driver, place the handle to your ear to transfer the sound waves. Or worst case use a broom handle. To find a miss, pull the plug wire from one cylinder at a time and put it back on. When the engine doesn't chage you found the cylinder.

 

Finally got around to giving the engine a listen with the screw driver, pretty sure I can hear the rod in the back part of the engine. Tried the dead cylinder check first and that wasn't it.

So now my question would be where should I go from here. Am I right to assume that if I get the rod fixed at an auto shop, I'll also want to get the engine rebuilt seeing as who knows what the broken rod has done to the inside of the engine? If that is the case should I go that route or perhaps spend the extra money and get a new engine. I'm wanting to get my pickup to the point where I can drive it to work everyday, and eliminate a car payment.

What kind of ballpark figure would I be looking at for repair/rebuild vs. a re manufactured engine? I'm leaning towards the new engine just for the sake or reliability. I haven't done anything to put undo stress on the current engine for a rod it to break, which leads me to believe its just getting old.

Any advice would be appreciated.

 

Just out of curiosity I took the rocker cover off the engine to take a peek at the rockers. The third rocker from the back has no oil on it. Thats not right is it? All the others have plenty of oil coating them.

 

Well the rod bearing could be bad and make that noise, not a broken rod. You can drop the oil pan and take a peek inside the crank case with little to no difficulty. Then you will know for sure how bad it really is. Make sure to have a fresh set of batteries in your flash light and wear goggles to keep oil out of your eyes when your under there. Oh and uh, drain the oil first.

If the cylinder walls are banged up bad you will be better off getting a long block. However, get it from somewhere with a good warranty and good references. I have seen some engine builders use 3 different piston sizes in one engine or they make you replace every bolt on accessory/radiator/water pump to the engine in order for your warranty to be honored if it happens to fail. If the engine isn't torn to shreads I would call around to get worse case estimates on rebuilding the one you have. Or pick up another low mileage used engine.

Or you can do both, rebuild the one you have and pick up a used one. Install the used one, tear down your current one and have the machining done to bring it back to a servicable condition and learn how to build your own inline 6. After you figure out how to install one piston, repeat 5 more times. That is if you have never done it before or really don't have the _____ (fill in the blank) to do it.

 

Did you ever figure this out? Having a very similar situation