CONSIDER DO YOU NEED TO GRIND VALVES ?
A . to begin with do a compression check and note what cylinders are low 20 or 30 %,(example some are 85 and some are 120 lbs.) AND THEN
B .examine the movement of the valve lift before deciding to remove head see? if valve motion is moving like the higher reading cylinders valves,? movement look good" is the cam worn off? if so fix cam first
Is or has the valve clearance become too tight (by adjustment or wear?)if so "adjust if possible first ....see notation #2B down page below (then recheck compression)
IF AND WHEN YOU DECIDE TO GRIND VALVES
ON OVERHEAD CAM MOTORS YOU PROBABLY WILL NEED TO TAKE THE CAM /S OUT 1ST
engines with push rod motors (not overhead cam) i recommend caution if loosening any rockers are removed as some motors like Chevy v-8s and inline 6 motors have a certain way to set them ARE ROCKER ARMS IN THE WAY OF HEAD BOLTS?
when you remove any rocker arms pick one and determine(count as you loosen) how many turns the nut takes to be loose enough to get the socket squeezed into the head bolt then use this figure to turn any other rockers(when loosening). I usually only take as many rockers loose as i have to and then tighten them to the exact same amount of turns as you used to loosen the rocker arms (better a fraction loose then over tight)
1.To begin remove the head then clean it good
2. remove the valves springs ( use tool or make one)
3.place valve springs in box in a line maybe number the springs
leave the valves in the head in the same holes ( do not mix them up)
after this see if you can wiggle the end of the stem where it sticks through( valve guide) the head sideways if 1or two are really loose like .020 thousands beware you may to need have a guide installed at a machine shop for like 10 dollars o.k.?
4. place head on bench or piece of wood have a few small piece's of say 2x4x10" wood handy
5.hook up hand drill 1/4" or 3//8" best, too a suitable plug in a drill that can? run slower than 800 rpm is better i recommend 300 rpm is best
6. determine the size of the valve stem 1/4" or 5/16" 0r 9 MM. go to auto store buy the size of neoprin gas line that will squeeze onto the valve stem diameter tight or snug no more then 4 to 6 inches needed for several grinding job o.k.? cost around 1 dollar
7. get a small wood dowel or saw the end off a soft bolt 5/16" to say 3/8" it should be 3" long or 4" long ( nearly always)
8. take time to clean the valves one at a time if they have carbon caked onto them like wise remove any gunk carbon or rust from around the immediate area of the seat,it helps a lot when grinding
9. don't clean bent valves take them to auto store buy new ones for about 8 dollars each
10. if the car / truck ran good( 4 cylinders) and didn't backfire the intake valves may not need grinding, if v-8 engine they probably do so look at the faces and stems if there bright and show no signs of pitting maybe just grind the exhaust valves o.k.? used intake valves make better millage than freshly grind ed ones do
11. if the exhaust valves are burned bad they may need to be faced/ if there usable at all and to help with keeping efficient grinding time.
12 . i do not recommend buying all new valves as the installed height sometimes need to be set (so use original valves if u can)
and it is necessary to have the new valves Stems grind ed to be the same length as the old ones
so using the old valves might be better unless you know what your doing o.k.?
notation #1Exhaust Valves
BE IT Known !!! that exhaust valves get hotter :..and will wear ,or burn faster than intake valves: and therefore.. are to be expected" to be more likely to leak (power loss) and also and or on occasion be be bent dew to timing jump" if your motor is an >interference type motor< (ask auto zoin )
BUT if YOUR Valves are bent you will still be able to fix your car / engine:you just have to buy new valves, and follow these same methods after installing any new valve it will have/ need to be adjusted to the right length"... pay attention... to factory valve lash specs: if so.
***** notation # 2B Are Valves too tight (learn how to set em)
what i am cautioning is to be aware > how tight a valve assembly is / or has' become: <
This tightness or shall we say over tightness is something called >Lash"< or Stem end clearance.
* CHECK VALVE LASH WITH EACH CAM LOBE ON ITS BASE CIRCLE*
Checking this (lash) is sometimes simple" :on non hydraulic lifters or barrel tappets a quick check
i will mention is simple checking to see if a tiny space is measurable between the
tappet or in some cases cam follower /rocker arm all non hydraulics require a small space
in the line of lift force it is there to compensate for the expansion of hot valve
stem expansion " it (the space mentioned valve lash") it can be .006"(six thousands)
an inch.or it can be .010"(ten thousands) or rarely more,
ok if the valve is over tight it will hold the valve open" and that will cause a low compression(psi)
too mention further the effect
of said over tightened valve lash include 2 symptoms low/r compression and :
if on the intake valve : this causes backfiring into the carb or intake manifold (fi eng-plenum)
on the other hand an overtightened exhaust valve will become overheated
and that is very bad as more damage will concur as result!
knowing if a hydraulic lifter or hydraulic valve adjuster is too tight is a little more complex
let me say check any adjustment nuts if their are any as these type of settings are often described as non adjustable that is not to say they cannot be adjusted or even rarely become to tight occasionally ok..................to explain takes time
just try to see if you can compare any difference to any of the normal compression cylinders... If your car isn't (didnt) miss or backfire and has hydraulic lifters or adjusters
then don't worry" assume there set right ( this is 4 hydraulic lifted valves only)
THINGS TO CONSIDER FIRST
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