Replacing Smallblock Valve Stem Seals VetteNet How To: Replacing Smallblock Valve Stem Seals Symptoms: Recently I needed to replace the valve stem seals on my 1986 Corvette. The L98 engine had approximately 86K miles on the odometer. Some of the symptoms that lead me to performing the work appeared over the years. For some time I was experiencing a Service Engine Soon (SES) condition when cruising at 64-75mph. The SES light would come on and then go off. The error code was a code 45. The code 45 indicates a rich exhaust, and is triggered by the O2 sensor. I also noticed when changing the spark plugs that a couple of the plugs had black, oil deposits built up on them. The two plugs showing this were the ones closest to the firewall. This apparently is where the engine runs it hottest. Along with these symptoms, over the years, upon a cold start of the engine, there would be a noticeable cloud of blue smoke, that would clear once the car was running. Due to the smoke and rich exhaust, over time this condition would clog the main catalytic converter. Tools Required: 1. Access to an air compressor. 2. Air compressor hose attachment that screws into the spark plug hole(s). 3. Torx bits. 4. Standard & metric sockets. 5. Valve spring compressor. NOTE: Purchase the valve spring compressor type that fits over the spring and compresses the spring by turning a knob. DO NOT get the type that acts like a pry bar, as this one will not fit. There is not enough room to use the pry type on the L98 motor. 6. Valve seat oil deflectors (set of 16). NOTE: These are optional, depending on if you need to adjust the valves with the motor running. Parts Required: 1. Valve stem seal kit including seals for both Intake and Exhaust. 2. Replacement set of 2 valve cover gaskets. 3. Replacement set of 8 spark plugs (optional, but recommended). 4. EGR pipe clamp (obtain from GM dealer). Approximate Costs: 1. Spark plug air compressor attachment: $6.00 2. Valve spring compressor: $20.00 3. Valve stem seal kit: $10.00 4. Valve seat oil deflectors (opt): $5.00 http://vettenet.org/vlvseals.html[10/1/2011 8:58:15 AM]
Replacing Smallblock Valve Stem Seals 5. Spark plugs: Varies, $8.00 to $40.00 6. Rocker arm gasket kit: $8.00 Estimated Time to Perform the Work: 1 to 4 days. Figure on the car being out of service for several days. Performing the Job: Step 1: Begin by removing the rocker arm covers. To remove the left side cover, you'll only need to loose the bolts holding the cover in place and gently work the cover off the head. To remove the right side, you need to remove the EGR piping. The EGR piping is the pipe wrapped in what looks like aluminum foil. It is connected below the distributor, with two torx bolts, and to a lower fitting by a circular clamp. Take care in removing the EGR pipe clamp, it may break. If it does, not to worry, an replacement can be obtained from your GM dealer for $2.67. I recommend replacing this clamp. Now remove the coolant intake hose to the plenum. Coolant will leak out, so be prepared to clean this up. Unscrew rocker arm cover nuts and gently remove the right cover. Step 2: Now that you have the rocker arm covers off, you can begin replacing the seals. Start by removing a spark plug from one side, leaving the others in, and screw in the air compressor attachment. WARNING: Do not tighten the attachment too much in the spark plug hole, because it's a pain to remove if you do!!! Supply air to the cylinder via the spark plug hole to hold the valve closed. Now remove the nut holding the rocker arm, doing both the intake and exhaust, and lift the rocker arm away. Note that the exhaust valve is the one that is lined up with the outlet to the exhaust manifold. The pushrods can remain in place. Position the valve spring compressor over the spring, and compress the spring enough to remove the retainer clips. There are two clips, and they are easily removed using a magnet once the spring is compressed. Remove the retainer and spring. Now you are ready to replace the two seals. There will be a small o-ring seal, and either a rubber "stopper" looking seal, or rubber cap seal, depending on which valve you are doing, the intake or exhaust. Step 3: Once the seals are replaced, you will replace the spring, still in the valve spring compressor, onto to the valve. Replace the valve spring retainers and clips. Once both intake and exhaust are done for that valve, you can release the air pressure from the cylinder and replace the spark plug with the new one. Replace the valve tappet and loosely tighten the bolt. Repeat these steps for each valve until completed. Step 4: Adjust the valves. Refer to a manual on adjusting the valves. There are two ways to do this. One w/the engine running the other not. If you decided to do w/the engine running, then you'll need the oil deflectors. Step 5: After the valves have been adjusted, replace the rocker arm covers with new gaskets, tighten down covers, but DO NOT OVERTIGHTEN. Replace all hoses removed. You're done! Start the engine and listen for a any loose valves. If you hear a ticking sound you'll need to pull the rocker arm covers again, and adjust the loose valves. You might also http://vettenet.org/vlvseals.html[10/1/2011 8:58:15 AM]
Replacing Smallblock Valve Stem Seals want to do a compression check to ensure none of the valves is too tight. Lessons Learned and Good Suggestions: Do not purchase the lever type of valve spring compressor, as it won't fit on a number of valves. Do not overtighten the spark plug air compressor attachment in the spark plug hole, as it's difficult to remove. Purchase a replacement EGR pipe clamp, maybe two, as the original one will probably break when removing. There is a special tool required for crimping the new clamp on the EGR pipe, but you can use a pair of dull side cut pliers and brute strength to crimp as an option. The replacement of the EGR clamp was the most frustrating of the work done, as the seal must be good, or you'll hear an exhaust leak. Use shop rags to cover the head openings (oil drainback holes), to protect from dropping dirt/tools/something into the engine, as this would be very bad. Don't overtighten the rocker arm (valve) covers, as this can cause leaks. You may need to use a socket over the valve stem when replacing the lower cap/boot seals, to tap it down to make a snug fit. Two man job, nice to have another pair of hands around. The o-ring valve stem seal goes on the SECOND grooved notch of the stem. Lower one if you want to look it that way. Take note as you remove the old seals. It's likely the old seals will be brittle, and will break apart when removing. Be sure to clean up the broken pieces. Date last updated: June 16, 1995 Copyright 1995 Eric E. Frash - FRASH_ERIC_E@Lilly.com This page is Netscape 1.1 enhanced. http://vettenet.org/vlvseals.html[10/1/2011 8:58:15 AM]
This procedure was done on my wife's 82 Vette. It has a positive valve seal and the common O-ring seal. Most older small blocks used only the O-ring seal. If you only have the O-ring, just ignore the photos with the positive seal. All other steps still pertain. Note: when using only the O-ring seal the oil deflector must be used. Some things to remember before starting: -When air is put in the cylinder the engine will turn so keep fingers and items away from fan. -Once the spring is removed, do not push down on valve stem, it will relieve the air pressure and the valve will drop into the cylinder. -Count the valve seals and O-rings before starting. Many years ago I did a set of heads and had one O-ring left over. I disassembled the heads to find out there were 17 in the package! This is the tool to put air into the cylinders
Do only one cylinder at a time. Remove the rocker arms and be sure to keep them in the same order they came off so they go back on the same valve. The exhaust and intake are identified by the port they are nearest to. Remove the spark plug, screw in the air adapter and connect the air source. Do not disconnect or interrupt the air source until both springs are back on the valves.
Give the side of the retainer a hit with a soft hammer. This will help to unseat the keeper to retainer bond.
Spring compressor installed and ready to go.
Compress the spring just enough to expose the keepers.
Put a magnet near the keepers and use a small awl or pick to separate them from the valve stem. Sometimes the valve spring will not come up. This is usually because the O-ring has hardened in the groove. Use a pick and break the O-ring up until the spring will come off.
The valve spring compressed.
This is an intake that I am doing. Note the two grooves on the valve stem. Now is a good time to inspect the rocker arm studs for any damage.
Work organized and neat. It makes things go smoothly. I already did one cylinder so I have three to go on this side.
Put the plastic protector sleeve over the stem so the grooves don't nick the new seal. Put some oil on the top of the stem to lube the seal.
I apply sideways pressure to the valve stem as I gently push the seal onto the stem. I do this so I don't unseat the valve.
Make sure the seal is down on the machined boss of the valve guide completely.
Before installing the keepers, clean and inspect them. Look for sharp edges, not rounded ones on the raised lip that sits in the groove of the stem. The one on the left is new.
Put the spring over the valve, lube the O-ring and slip it onto the stem. It is now in the first groove.
Continue to move it down until it sits in the second groove. Do Not push any further.
Install the keepers.
Pull up on the compressor/spring and remove the tension from the compressor.
Give the retainer a couple of light taps with the dead blow hammer to seat the keepers. Now go to the next valve. Make sure to clean any pieces of O-ring that fell onto the head before putting the covers on.
Adjusting the valves: Be sure to ground the negative side of the coil to prevent any spark from occuring. Everyone has their own method for doing this; some with the engine running, others with the engine off. I have used the engine off method for more years then I like to tell and it has never failed me. I even do this to an engine after a rebuild while it is still on the engine stand. This is only for hydraulic lifters and low lift/duration cams. Pick a cylinder and using a starter button rotate engine while watching the intake valve. After it closes tap the engine a little more. Back off on a rocker arm until the rocker arm is loose. While spinning the push rod slowly between your fingers tighten down until resistance to the spinning is felt. Now continue to tighten 1/2 to 3/4 of a turn. Practice this a few times and then continue to the next rocker arm. Home Page
Camaro Tech Data My Camaro Pics Parts for Sale Berlinetta Media Camaro Tech Data Berlinetta CD 3rd Gen Links Small Block Chevy Valve Stem Seal Replacement Engines that have higher mileage or are older than 10 years commonly emit a puff of smoke from the tail pipe after initial start-up due to failing valve seals. This webpage will explain how to replace the original valve stem seals with new replacements. A few tips before starting: Use clamp type spring compressor rather than a 'pry-bar' type compressor; Have a magnetic pick up tool ready, Have a small flashlight handy, Be sure to fully seat umbrella (exhaust) and positive (intake) seal fully-press evenly on both sides using boxed wrench for example, & Be sure nothing falls in the engine! Some steps are omitted because they are not needed or required to complete this repair. Examples of this are "Remove the serpentine belt to make rotating the engine easier", "Cleaning the motor as well as possible so debris doesn't fall inside, or; "Inspect all parts & hardware for damage before installing" Some measure of common sense is expected!! ** I don't advise using air pressure to keep the valves in place when changing the Valve Stem Seals. If someone steps on the air hose, the air line breaks, the Compressor loses power or the valves are not in the "best" position, then the air pressure could be lost and the valve could fall into the cylinder. Stuffing or filling the the cylinder will insure that the valve stays up - at all times - until the stuffing is removed. The best type of 'stuffing' I've found is simply and old spark plug wire... It's strong enough to push & pull thru the spark plug holes repeatedly without disintegrating and can not damage the engine internals in any way. How To Remove / Install Valve Stem Seals on a Small Block Chevy V8 Engine http://berlinetta.info/seals.htm[10/8/2011 2:59:54 PM]
Camaro Tech Data 1- Remove all plugs 2- Rotate Balancer to #1 3- Push old spark plug wire ( or equivalent ) into #1 Spark Plug hole 4- Remove rocker arms from #1 Intake and Exhaust valve 5- Compress Spring from #1 Intake (or Exhaust) valve ( You will probably need to tap or strike the spring compressor or spring assembly 'down' with a small hammer or similar tool in order to separate the assembly from the valve stem and free the 2 "keepers" ) 6- Remove keepers ( Magnetic tool is a good idea! ') 7- PULL spring assembly off ( Probably NOT going to just 'slide' off!) 8- Remove and clean any debris from old stem seal 9- Pry Intake positive seal off ( or exhaust umbrella ) 10- Install positive seal( or exhaust umbrella ) 11- Slip spring assembly back over the valve stem 12- Slip stem seal over valve stem ( it sits inside the bottom groove ) 13- Install keepers ( Pull spring assembly up to hold keepers in top groove ) 14- Remove the compressor 15- Install the rocker ( no adjustment at this point - do them ALL later ) 16- Move to the Exhaust or Intake valve for same cylinder and repeat steps 5-16 17- Remove Spark Plug wire from Spark Plug hole Once cylinder is complete: 18- Rotate engine 1/4 turn, push spark plug wire into #8 cylinder spark plug hole & repeat steps 4-17. 19- Rotate engine 1/4 turn, push spark plug wire into #4 cylinder spark plug hole & repeat steps 4-17. 20- Rotate engine 1/4 turn, push spark plug wire into #3 cylinder spark plug hole & repeat steps 4-17. Continue until all seals are replaced ( thru the 1-8-4-3-6-5-7-2 firing order) 21- Once the engine is rotated back to # 1 with all seals installed and rocker arms temp installed,... follow the steps show here to set valve lash and pre-load lifters ( Or after Installing a set of Rocker Arms ) Small Block Chevy Valve Lash /Rocker Arm Adjustment http://berlinetta.info/seals.htm[10/8/2011 2:59:54 PM]
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Camaro Tech DataSmall Block Chevy Valve Lash Rocker Arm Adjustment My Camaro Pics Parts for Sale Berlinetta Media Camaro Tech Data Berlinetta CD 3rd Gen Links This page describes how to properly install or adjust SBC Chevy Rocker Arms. There are many ways to set Rocker Arms and this is the way that works the best for me! 1) Set the timing mark to 0 TDC #1. So; how do you know if you are TDC #1? ( rotating an engine is MUCH easier when there are no belts installed and all the plugs have been removed! ) Rotate the crank clockwise and watch the rocker arms over the #1 cylinder. If the #1 rockers are moving when the timing mark lines up to the tab the engine is firing on # 6. You will need to rotate the crank another full turn to set the engine to fire on the #1 cylinder. If you get lost or are unsure... remove the number 1 spark plug and rotate the crank a couple more times. A clear indication that the engine is firing @ #1 is that engine compression will be forced from the #1 cylinder spark plug hole, so feel for air being forced out of the hole as you rotate the crank. ( And the #1 rockers will NOT be moving as the timing mark reaches the timing tab!) Once you are sure that the engine is at #1 TDC the following valves/rockers can be adjusted: exhaust - #1, #3, #4, #8 intake - #1, #2, #5, #7 First you must find "zero" lash. This step takes all slack out of the lifter-rod-rocker assembly. This is accomplished by grasping the rod http://berlinetta.info/lash.htm[10/8/2011 3:00:56 PM]
Camaro Tech DataSmall Block Chevy Valve Lash Rocker Arm Adjustment and "jiggling" it so it clanks between the valve and the rocker arm. Tighten down the retaining nut ( by hand if possible) until the push rod can no longer "clank" between the valve and the rocker. THIS IS ZERO LASH! (I do NOT suggest "spinning" the push rod because the pushrod can/will continue to spin after 0 lash is reached!) As soon as 0 lash is reached, turn the rocker arm nut down 1/2 to 3/4's (max 1 full turn) of a turn in 1/4 turn increments. A 1/4 turn increment is recommended to set the lifter pre-load. 3) Rotate the crank 360 degrees and set the other half of the valves exhaust - #2, #5, #6, #7 intake - #3, #4, #6, #8 Note: If you are working with an older engine or used lifters it's possible that the lifters bleed may off pressure. (soak lifters for 1/2 hour in clean engine oil before installation.) You can improperly adjust your valves/rockers if you are not aware of this. You should have oil in the lifters to to get the most accurate setting. If the lifters have bled off their pressure than they will compress slightly after 0 lash is reached. (Once reaching 0 lash you can push the rod end of the rocker with the palm of your hand... this could make finding 0 lash tricky!) Rockers can still be adjusted - just remember that ZERO LASH is achieved as soon as all slack in Lifter-Rod-Rocker is removed! ** Beware of using a socket that makes contact with the rocker arm in ANY WAY. ** Most GM Factory Shop manuals I've read call for a 1 full turn adjustment past 0 lash. Many aftermarket rocker arm companies call for 1/2 turn for final adjustment. A Rule of thumb I use is that if the all parts are new the adjustment is a a bit smaller and if the parts are used the adjustment is a bit larger. I have always had good luck using 3/4 of a turn, but I also reuse a lot of parts!! follow the instructions for your exact parts to be sure! http://berlinetta.info/lash.htm[10/8/2011 3:00:56 PM]
Camaro Tech DataSmall Block Chevy Valve Lash Rocker Arm Adjustment Home http://berlinetta.info/lash.htm[10/8/2011 3:00:56 PM]