GMC 3911068 Spring,Valve(W/Dampener)

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To replace broken valve springs or defective Valve Stem Oil Seals without removing the cylinder heads, keep these steps in mind: First, take off the valve cover(s), and both should be removed if all Valve Stem Oil Seals are to be replaced. For all seals replacement, remove the spark plug from the cylinder having problem or remove all of them. Turn the crankshaft until the affected piston is brought to top dead center on compression stroke. Start by cylinder number 1 in case of replacing all seals and follow through with cylinders following the firing order. An adapter is threaded into the spark plug hole and an air hose connected to a compressed air source, holding closed valves. Insert shop rags into cylinder head holes to keep debris from dropping into the engine. With a valve spring compressor, compress spring/damper assembly and remove keepers. Lift out spring retainer/oil shield/valve spring assembly along with intake valve's O-ring seal on valve stem and umbrella type guide seal. Wrap a rubber band or tape around the valve stem to avoid it falling into combustion chamber and release pressure of air. Check that there are no damages on valve stem and make sure it moves freely in guide. Lubricate valve stem and fit new intake valve umbrella-type guide seal for intake valves insertion point where it's stuck at top position around a piece of dowel pin that fits inside of it via available range at bottom of spring retainer channel. Install d/spring/damper assembly & shield compressing it enough for you then install n/O-ring seal over v/stem; Position either v/spring retainer or rotator; place "keepers" using dab of grease for retention till pressure is taken off s/tool; Disconnect air hose; put rocker arm(s) & pushrod(s) then that may be followed by reinstallation of valv/e covers; Reinstall spark plug(s) & wires, start engine and run engine also check for any oil leakage or any unusual sounds around the valve cover area. Be advised that these procedures require specialized tooling and should be performed with caution.

Special tools and a source of compressed air are necessary to enable you change broken valve springs or faulty Valve Stem Oil Seals without taking off the cylinder head. Start by removing the spark plug from that particular cylinder (or all plugs if changing all seals). One cylinder at a time, start with number one cylinder at TDC, following the firing order. Put an adaptor into the spark plug hole, then link it up with an airline hose for supplying compressed air. Unbolt the rocker arm nut, remove the pivot ball and rocker arm from the leaking valve and take out the push rod. Supply compressed air to the cylinder in order to retain valves. Bring down valve spring compressors so that they can squeeze springs and hence release them from keepers. Get rid of spring retainer and valve spring, then replace guide seal making sure it is pushed downwards onto top of guide tube. Apply engine oil on valve stems and insert spring back followed by retainer forcing springs to their right places using locking tabs. Disconnect air hose, unthread adapter then reassemble rocker arm along with pushrod, spark plug and finally valve cover. Turn on engine and look for oil spills as well as strange noises near that head cover area. Failure of pressure to hold down valve when closed may suggest either damage in valve itself or its seat or both thus meaning extensive repair by removing head.

To replace broken valve springs and defective Valve Stem Oil Seals without removing the cylinder head, special tools and a compressed air source are typically required. Start by taking off rocker arm cover on damaged cylinder head or, if we're changing all Valve Stem Oil Seals, take both covers away. Pull the spark plug out of the affected cylinder or remove every one of them when replacing all the seals. Make sure that the piston in the damaged cylinder is at top dead center on the compression stroke, beginning with number 1 if all seals are being replaced, and follow firing order sequence. Screw an adapter into the spark plug hole and connect it to a source of compressed air so as to keep valves closed during spring removal process from above. In case there is no compressed air, use nylon rope which is long enough so that it can fill combustion chamber through spark plug hole thereby avoiding drop valve. Afterwards, secure shop rags to above and below valves' cylinder head holes to prevent any ingress of part or tool. Use a valve spring compressor to compress the spring/damper assembly and remove keepers. Then check whether there is any damage on the valve stem and ensure it moves freely in its guide. Inspect for wear on rocker arm studs which may need machining shop replacements or threaded replacements on certain engines. Restore air pressure with respect to keeping the valve closed position; remove tape/rubber band from valve stem lubricate engine oil onto valve stem before installing new oil seal. Finally reassemble components including rocker arms, pushrods, spark plugs and rocker arm covers then start engine checking for oil leaks/abnormal noises at rocker arm cover area.