I will try to keep this fairly short I have an 1981 ford f150 4x4 with the 4.9L 300 inline 6 and I replaced the original engine with the engine from an 1981 f100 that was rolled on its roof. Don't know exactly how many miles we're on it but I took very good care of it. I put about 200 to 250 miles on it since the swap and all of a sudden it started ticking. Called a guy who knows a lot about engines and I found two bent pushrods both were the intake rod of cylinder 6 and 3. The guy I talked to said I should be ok using the pushrods from a spare 300 I have, maybe I should get new pushrods, and I tightened the rocker arm nut down like the guy said and after about 5 minutes of the engine running they would start ticking again I am afraid of over tightening cause the ticking keeps coming back. I got two new rocker arm nuts because the originals looked like they were loosening on the stud because when I tightened it down and let the engine run it starts ticking again and the nuts are finger loose. I also noticed less of the stud bolt was showing above the nut. Is this a lifter problem or something or am I doing something wrong. Is there anything that would cause this issue out of the blue. Baught the f100 about 15 years ago with 5000 miles on a rebuilt engine it could have 100,000 thousand on it but not positive I do have new lifters if this is the case but I have two guys stumped at why this has happened. Is this a ford thing, I know the 300 engine is a very tough engine. Any help will be greatly appreciated.
I don’t know how he told you to adjust the rocker arms but in the car running, you will have to buy some deflector clips the clip over the oil port on top the push rods as you will have to do this with the engine running valve cover off. Any rocker that is loose and has play when its in the closed position will need to be snugged up so if you grab the push rod you have no up and down play but can still spin the rod with a little resistance. If you can’t spin it then its to tight. If it spins freely then it is to loose. Only do this adjustment with the rocker arm in its relaxed position with the valve closed. You can use a breaker bar or long ratchet on the crank to spin the engine and change position of the camshaft. Now once that’s done put on your deflection clips and start the motor. If you hear any ticking shut it off and check again. Once you have no ticking with the wngine running slowly spin the rocker nut counter clockwise until you hear it start to tick, then go clockwise until it stops, again slowly. Turn off the engine and go clockwise one more time 3/4’s of a turn on that rocker. Oil may spill over the lip with the cover off. So keep a pan underneath, maybe some rags around the head to catch it as long as they won’t get pulled into anything moving. Also you want to do this with engine cold. If it starts to heat up you don’t wanna get burnt by 100+ degree oil so stop and let it cool. Also during the process since you may lose some oil, check and add accordingly.
Hopefully you haven’t overtightened and collapsed a lifter. If it had bent rods and you keep having issues you might have to get new bolts/studs for those rockers or have someone inspect the valves make sure they are not bent or sticking.
Here is a link for the clips. You can only use this process on hydraulic lifters which you have. If you ever have cause to work on something else verify you’re hydraulic and not solid or roller lifters.
https://www.summitracing.com/parts/mrg-1015
I was told when the engine is warm tighten the nut till the rod barely moves up and down then with engine running go 1/4 to 3/4s of a turn more. But after five minutes or so it starts ticking again. Ended up taking one lifter out to look at it to be sure it was ok and the lifter looks just like a new one does with the piston all the way up and hard to push. Plus this other guy said that I shouldn't be able to put the nut on with my fingers but I can, does that mean i need new studs to. I know a decent amount mechanics but i have never messed with this kind of issue this has always been a strong running engine until the accident
Cold is best on adjustments. Metal expands when its hot, you don’t want to have to wait for your car to warm up to stop clacking. And yes on older vehciles you can finger start the cap. You wanna tighten the nut until the rod CANNOT move up and down AT ALL but you can still spin the rod with a little resistance. If you can’t spin the rod it’s to tight. And you want to do this preload adjustment with the engine off. Then follow what I told you to do with the engine running.
PS on the preload make sure the rocker arm is completely relaxed, if the valve spring has started to compress at all you wanna rotate the engine until the valve is fully closed.
Well so far so good haven't had a lot of time to tinker with but if is running smoothe and no ticking haven't taken it out on the road yet but will soon. Thank you for your help