Have a bad knocking sound coming from my 79 f250 400 camper special. Just started doing this today, it'll knock faster as rpms go up and slower at idle. Also it'll spit out white smoke on startup regardless of temperature. Just had the oil changed and oil filter changed, what could it be?

 

Depends on where its at. If it just started puffing smoke on start up id say more than likely its in the head, bent or out of adjustment valves or loose rockers . If it smoked in tune with the throttle id say broken rings or maybe a spun rod bearing. If you still have old oil run a magnet through it and see if you got metal. You can use a length of 2x4 to pinpoint the source. Move it around the engine and listen through it. If its up in the heads pull the valve covers. Get the proper feeler gage and adjust the valves properly. You can run it without covers to look for out of sorts movement. If its in the bottom you can unbolt the engine mounts and jack it up to pull the pan. Look through everything. Unhook the battery and turn the engine with a breaker bar. Look for heat scorched bearings or weird motion to the rods.

Its hard to do things like this on the net . If i had hands on its easier. I dont know your skill or instincts. If you grew up tinkering on old stuff trust your gut. Maybe even make a youtube video with your phone. Move it up n down all around the engine bay. If the truck runs worse now start it and remove 1 plug wire at a time. Which ever wire doesnt change the sound is the hole your problems in.

 

X2 on what Jayzdaddy said. Hard to do on the phone or interweb. If you dont get it figured out pm me your # since im real close to you. Maybe I could come help you figure it out if you want.

 

Sounds good, yeah I'm gonna look at it probably this weekend or next week since I'm busy this week. I'm gonna look at it and try to see if I can't figure it out myself. But I understand it's hard to tell online, just figured I'd ask. I'll get in touch if I need help, thanks again both of y'all!