When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
ok its my 1984 f150 and i went to adjust the valves due to VT noise and i got the cover off and it looks like studs so from what i read i need to TDC the piston and go one full turn past zero resistance but mine are maxed out already. are they non-adjustable?
if so than when #1 is @ TDC why am i able to move all rocker arms side to side without cycling through the cylinders? they should be tight from the preloaded lifters right?
Yours is more than likely the non-adjustable type.
In that case, you bring each cylinder to TDC, loosen the intake and exhaust rocker arm nuts and then retorque them to 17 - 23 ft./lbs. That's all the adjusting you can do.
If there's still rattling and looseness, your rocker arms/fulcrums/pushrods, etc. etc. may be worn. As the metal slowly wears off, the gap between each increases. Replacing them is the only fix.
If that doesn't do it, it's possible your lifters are worn out and need to be replaced.
However, before any of that, you may just have some stuck lifters that something like Marvel's Mystery Oil may clear up.
yeah i put it back together, i only drive it three or so times a month. if i do anything to it, it looks like comp sells a kit through summit for $300 that gives me lifters,cam,springs,locks,retainers,timing kit,ect... i guess time will tell, thanks for the advice
AB and others: The cam swap thing seems to be pretty regular inquiry. It would be great if someone (AB?) would come up with condensed 'how-to' for a sticky.
they go up and down but all valves are closed when 1 is at TDC i would think some should be open unless the lifters are bleeding down and letting the valves close due to no oil pressure.
Even with the lifters empty of oil, they still should be opening and closing the valves. The oil pressure in the lifters is there more for a "cushion".
A dry, sunk lifter will still open and close your valves, albeit noisily.
thats what i was thinking and the truck seems to have VERY little power so im leaning to the cam lobes are very worn. do you know what the specs are on a oem cam?
According to my Haynes manual stock lobe lift is .249".
Really? A quarter of an inch? Is that off the base circle, a quarter of an inch travel? And a decent, mild aftermarket cam is about .450", almost twice the lift?
Really? A quarter of an inch? Is that off the base circle, a quarter of an inch travel? And a decent, mild aftermarket cam is about .450", almost twice the lift?
What duration is oem?
Lobe lift (.249") * rocker arm ratio (1.6) = valve lift (.3984")
IIRC the stock cam duration is ~268 degrees but it's ground something like 10 degrees retarded.