OK i hhad posted awhile ago, and never got a good response, i have an 87 f-150 4x4 351w. i have a valve somewhere that taps really bad, well a lifter or rocker, what should i do??? will thicker oil help? or rocker and pushrod? or do i have to do the dreaded lifters? thanks any help would be good.

 

Ok i looked in my motors manual, it says ford offered longer pushrods and shorter 60 thousands to adjust the valves but it dosent say how to check them, anyone got any ideas.

 

I wouldn't install differnt length pushrods. The lifter's are of a "0" lash type and non-adjustable unless for some reason you have a solid lifter cam installed now. Unfortunately you probably will have to do some type of maintenance on it. Some of the "snake oils" work some don't. Depending on the mileage of the vehicle and how often the oil was changed, if you have a clean motor inside, you can do a flush that works for me. "Warning", the engine must have no major carbon deposits inside. You can purchase a quart can of B12 Chemtool, put in the oil, run engine at idle for 30 minutes, drain oil and change with filter. This will remove deposit from inside of lifter, valve guides, etc.
If this doesn't work, then you'll have to remove the valve covers, rotate the engine(remove spark plugs and disconncet battery) until each cylinder comes to TDC. Use a hammer handle and push down on the rocker arms on the push rod side and see if you have any movement. This will tell if you have a collapsed lifter. At the same time of position push down on the spring side, this will tell if you have a broken or weak spring, you can either take measurements for installed height or compare the pressure it takes to move them with the others. Also if you can listen to which side it come from will help to prevent from removing both V.C.'s.
Also measure the height of the rocker arm on the pushrod side and compare with the others. This should give you info if you have a worn lobe.
Hope this helps.
Also check to make sure all the rocker arms are properly torqued and show no signs of excessive wear or side-side movement. You can remove each one and compare them. Do this also while at TDC for each cylinder.

 

Bad lifter, wrong pushrod, loose rocker arm bolt(bad mechanic), oil passage clogged, bent pushrod. I wouldn't let it go too long. I don't think thicker oil is the answer. Pop the valve cover and try to isolate the bad one. You can spin them by hand when the pressure is off and check for a bent one. Running it with the valve cover off to target the bad one is messy but I have had some luck like that. Use a tube to the ear to isolate the noise. If you get close then replace a few pushrods. Label them so you don't get them mixed up.

 

Try using a long screw driver to the ear as a mechanics stethascope this works well for me this will help you isolate the problem to the side and if you are pretty good the cylinder.

 

ok, well when i had the valve covers off before, i had one that i could twist and then none of the others i could, its onlu comming from one side, so im gonna pop a cover and check the bolts for torque, (any one know how many inch pounds?) and if that dosent fix it im gonna put all new pushrods and rockers in, do i need to do anything special becore i unbolt the rocker? or do i just unbolt it, put in the new pushrod and rocker and re torque?

 

When you get it all apart you might try replacing one or two push-rods, then replace the valve cover with two bolts and start it up. This could save you some time and help isolate the problem. You should be able to look at each rocker and see where oil has been coming up the push-rod. You might see a dry one.

 

ok, if i see a dry one what do you reccomend??? someone told me to run some deisel in the oil for about 20 min, and then change it it would break down any gum and possibly clear up something like that, and why cant i run it without a valve cover? will it hurt it for a short time?

 

Won't harm it to run without cover, just not too long. Oil spews and squirts everywhere. You'll see when you try it. Also, I wouldn't recommend anything in the oil to dilute it to desolve carbon particles unless your engine is fairly clean inside. The particles that break off can ingest into the oil pump, galleys and other small orifices.
If it is fairly clean, a light dusting or discoloring of the valve train parts, it's OK. I use B-12 ChemTool made by Berry Manufacturing. It disolves the carbon, not just break it loose. Use about a quart, run engine for 30min, drain oil and change filter.

 

If plugged. I have never tried this but maybe shooting an air hose down the hole of the push-rod. Just a guess.

Unless something is loose or worn it's probably a bad lifter.

If you find a dry rocker, lack of lube might have damaged the rocker and push-rod because of the increased friction. If it's dry and the push-rod isn't plugged then the lifter is plugged. You know what that means. Roll up your sleeves.

If they all show signs of oil then you might still have a lifter that isn't pumping up correctly which will cause your tapping.

It's also possible that the valve, valve guide or valve spring is messed up. If the spring is sprung then the valve doesn't close fast enough and could cause tapping. Bent valve or guide could do this also.

 

ok, well im gonna tear it apart soon, i just havent had time, im hoping its somehting stupid, the truck has 104,000 so im thinking that it is just a worn rocker and pushrod, it dosent skip or anthing so im leaning away from a bad lifter, thanks for the help, i really appreciate it.

 

ok, well here are my findings, i opened her up today, and replaced what i found was the worst rocker and pushrod, my noise in no where near is bad, the pushrod was worn pretty bad, it actually kinda stuck into the rocker, so im gonna go ahad and replace all of them, on that side, and if that dosent fix it when i get time ill do the lifters, oh and i did start it without a valve cover, i should have listened, it wasnt bad at idle but when i started to give it some to hear the noise, i coated my manfold and the framerail of the truck, oh well. live and learn, thanks so much for all of your help.

 

At least you know you got a good heart in there.
Thanks for keeping us posted.

 

yeah, its gonna bw a while before i finish this project, i just had another roll in, i think this is gonna be on the back burner for a while, i now need to get my motorcycle to run. its old but hopefully ill have that done soon.