Jun. 17, 2024
Good engine performance depends on valve condition. Worn guides or stems and burned or badly seated valves allow gas to escape under compression , resulting in poor starting and loss of power.
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Valve springs , too, can affect engine performance. Over a period of time they weaken, causing the valves to `bounce' on their seats as they close.
Support the cylinder-head assembly firmly on a suitable bench or work surface. See that there is sufficient space to store parts as they are removed, and cardboard boxes and clean newspaper available to keep them clean and safe.
Undo the nuts or bolts securing the inlet manifold to the side of the cylinder head; remove it, complete with carburettor if possible.
On some engines, the carburettor is unbolted and removed before you can gain access to the manifold nuts or bolts (See Exhaust manifold gasket replacement ).
Put the manifold/carburettor assembly in a clean, safe place preferably on a sheet of newspaper.
Similarly, remove the exhaust manifold from the side of the head and place it with the inlet manifold.
On some engines, the inlet and exhaust manifolds are fitted and removed as one unit.
Undo the nuts or bolts securing the thermostat housing to the cylinder head. Ease off the cover and lift out the thermostat.
If necessary, unscrew and remove the temperature-gauge transmitter from the side of the cylinder head.
Turn the cylinder head on its side and support it on blocks to remove the valves. Place a valve-spring compressor over the valve nearest the front of the head.
Removing the collets.Compress the valve spring until the two split, tapered collets round the top of the valve stem can be removed. Take care not to drop them, they are easily lost.
Release the compressor slowly until it is free, then remove the valve-spring assembly and withdraw the valve from the head. Place all the valve parts together for examination later. Discard the oil seals (if fitted).
Repeat the valve-removal procedure on the remaining valves in the correct order, and place the components in their order of removal on a numbered sheet of clean paper, or push them into a piece of cardboard.
Alternatively, use the old cylinder-head gasket to&#;store the valves in their correct sequence.
Each valve must be refitted in its original position on reassembly, as individual valves, valve guides and valve seats wear in different ways.
Remove all carbon deposits from the cylinder-head combustion chambers and valve ports , using a suitable scraper, such as a blunt screwdriver, and a wire brush .
Take great care to avoid scoring the surface of the valve seats or the machined face of the head, particularly on an aluminium-alloy head.
Clean the machined cylinder-head face to remove any remains of the old headto store&#; use the smooth side of a hacksaw blade, or a paint scraper.
Again, take care not to scratch or damage the face.
Scrape until the face is smooth and flat. Modem head gaskets have a resin-coated finish which sticks the gasket to the surface and is often difficult to remove. Make sure you remove all of it.
Cleaning the valve head using an electric drill held in a vice.Clean the carbon from each valve in tum. Grip the valve stem in the chuck of a stand-mounted electric drill &#; or vice-mounted if necessary. Turn at slow speed, if possible, and scrape off the deposits carefully with a screwdriver.
The valve head can be smoothed using very fine emery cloth. Remember to keep the valves in their order of removal.
Inspect the face and edge of each valve, looking for grooves , pits and for other signs of damage. If the valves are burnt, bent or damaged, renew them.
Check the valve seats in the head, looking for grooves, pitting and particularly for cracking.
Slight pitting can usually be removed by grinding. More serious pitting is removed by having the valve seat recut at an engineering shop.
Wire-brushing the combustion chamber.Clean all carbon and dirt from inside the inlet and exhaust ports, using a cup-type wire brush mounted in an electric-drill chuck. Protect your eyes with goggles.
Stubborn carbon particles can be removed by gently scraping with a blunt screwdriver, followed by the wire brush.
Check valve guides for wear by first refitting a valve into its respective guide, then raising the valve slightly off its seat.
Try moving the valve head from side to side. If the movement at the valve head is more than 0.007 in. (0.2 mm), the valve guide or the valve stem may be excessively worn - check the manufacturer's specifications, given in a service manual, or consult your local dealer.
Cylinder block with liners
Hold a block of wood over the cylinders to prevent the liners rising.If there is too much movement, repeat the test using a new valve. If this has less movement, the old valve stem is worn and the valve must be replaced. If there is still too much movement, the wear is in the guide and the cylinder head should be taken to an engineering shop for the replacement of all the guides.
Check the valve stem and guide by trying to move the valve from side to side in the guide.If the guides are an integral part of the cylinder head, they can be reamed - opened out - to a larger size to take new valves with oversize valve stems. This work should also be entrusted to an engineering shop.
Generally valves should be ground , or 'lapped', into their respective seats to ensure a gas-tight seal . Grind-in each valve (including new valves) by hand, using a valve-grinding tool and valve-grinding paste.
Attach the sucker on the grinding tool to the valve face.On some modern cars the valve faces have a thin coating which must not be removed. When fitting coated valves, use an old valve to grind the valve seat.
For more information, please visit Valve Grinding Tools.
Smear clean engine oil on the valve stem, and attach the valve head to the sucker on the end of the grinding tool.
Smear a thin film of grinding paste round the chamfered edge of the valve head and insert the valve fully into its guide.
Grind the valve in its seat by rotating the grinding tool back and forth between the palms.Rotate the grinding tool back and forth between the palms of the hands, pressing the tool and valve into its seat at the same time.
After a minute of continuous grinding, raise the valve off its seat, revolve it about 45 degrees, then continue the grinding process for another minute.
Repeat the grinding procedure, altering the position of the valve periodically until both the valve-head flange and the valve seat have an even, matt-grey appearance, which indicates that the valve and seat are making good contact all the way round.
If slight pitting remains on the seat, use a coarser grinding paste, followed by fine paste.
When all the valves have been ground-in, remove them and place each in its order of removal.
Wash the cylinder head, combustion chambers and valve ports thoroughly with paraffin, to remove all traces of grinding paste.
Dry the head with compressed air from a tyre foot pump , and blow through all oilways and bolt holes.
Clean all traces of grinding paste from the valves, remembering to keep them in their removal order.
Smear each valve stem with clean engine oil and refit the valves to their respective positions in the head.
Fit the oil seal over the valve stem.If there are oil seals, fit new ones over the valve stems, taking care to avoid damaging the seal lips. Always fit new valve springs.
Place the new valve spring and spring cap in position over the valve stem, noting that the close-coiled end of the spring is usually fitted next to the head.
Compress the valve spring with the compressor tool until the two split, tapered collets can be slipped into position between the spring cap and the valve stem.
Slowly release the compressor tool until both collets are locking the spring cap and valve stem together.
Remove the compressor tool and repeat the valve installation procedure on the remaining valves, in the order in which you removed them.
Clean the piston crowns and cylinder-block face to remove any excess carbon and old head-gasket remains before replacing the cylinder head.
To prevent dirt or carbon particles entering the engine during cleaning, seal oil and water passages in the cylinder-block face with pieces of clean, lint-free cloth as necessary.
The cylinder bores , too, should be plugged with clean cloth to prevent dirt particles falling between the pistons and cylinder walls.
Use a scraper tool, such as the smooth side of a hacksaw blade, to carefully remove all traces of head gasket from the cylinder-block face. Take great care not to scratch or damage the face.
Rotate the crankshaft with a spanner or socket on the crankshaft pulley bolt to bring each piston to the top of its cylinder.
On engines with removable cylinders (wet-liners), hold a block of wood down firmly over the top edge of all the cylinders as the crankshaft is turned.
This prevents the cylinder liners from being lifted as the pistons rise up the bores, and ensures that the coolant seals at the bottom of the cylinder liners are not broken.
When each piston is at TDC , use a soft scraper such as a wooden block to carefully scrape carbon deposit from its crown, leaving a small ring of carbon round the outer edge adjacent to the cylinder wall.
Polish each piston crown with fine-grade emery cloth.
Cylinder block with liners
Hold a block of wood over the cylinders to prevent the liners rising.Clean all carbon and dirt from the cylinder bores and bolt holes, using either compressed air from a tyre foot pump, or a vacuum cleaner.
Make certain there are no carbon particles lodged in the bores.
Clean the block face, cylinder bores and piston crowns with a petrol or paraffin-moistened clean cloth, and then dry them.
Be careful not to risk a fire - do not smoke, for example.
Smear a thin film of clean engine oil on each cylinder-bore wall and then remove the pieces of cloth from the oil and water passages.
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) makes since" too measure a regular valves height with spring installed (not bent) the new valve must not be taller or longer by much (hint not even 1 thousandths generally more) with new valve replacement 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.? and sand the stem ends to shorten them to whatever the old valve is on example (exhaust valve not bent from same engine when possible or a machine shop must be asked to measure the thing being any valve old or new when installed has not to be too long' understand ? and new valves sometimes... well! must be checked ! to be no longer when ground in and installed with spring/s hear this" notation #1Exhaust Valves
put your(the) valve keepers out of the way in a corner where they wont spill ( stick on magnet?)and then begin next to grind valves ,after cleaning ,and if necessary facing ( see pic) of exhaust valves, if you have the valve grinding compound "? is it water based ? ( ask auto store?) or is your grinding compound grease based?) if water based get a small bowl of soapy water nearby and a paper towel or cotton rags ,....water based compound is simpler and dont smell bad.! if you have the grease based grinding compound then you will need some charcoal lighter fluid or lamp oil or some petroleum ( like kerosene) don't use much of the stuff you might catch on fire and maybe you should have a small art brush to dab it 1st.. Turn head so you can see valves like on its side use a wood shim to block it so it wont roll get the dowel mentioned and put it in the 300 rpm capable drill ( best)Battery drills? it can takes hours to do 1 head if valve/s badly burned so a 15 minute battery drill isn't necessarily effective here" 2. Then put the short piece of the neoprene (rubber hose) onto the dowel push it on say 1/2" too1 inch ok? (do not use a drill bit to turn the hose! use a dowel or metal shaft only) using wood be careful not to over tighten( see Note #3 below 3.Then push the other end onto the end of a valve ( start at one end) or just do the exhaust or do all in order you decide "! 4 . Take the tube or bottle of valve grinding compound in one hand' then lift the valve by pushing on the end where you have the hose and drill that will give space to put some grinding compound into the seat(valve) area ,i recommend putting small dabbs ...say.. like 2 drop dabbs ..onto the seat or the edge of the valve face in a radial fashion first probably not as much as 1/8 a teaspoonful ok? Thar's a reason to use small amounts(grind compound) because it will get into the valves stem and ruin the head......so dont get it on the stem at all just the face and seat " 5 .pull the valve with the drill back into the head until the valve just touches the seat 6 start the drill slowly at first keep the valve pulled to the seat for the first 30 seconds then let the valve lift for 1 instant then repeat the same if possible stay around 100 rpm for a minute after say 2 minutes then began to let valve lift off ( just 1/16"to 1/8" max) every 5 seconds let the slight pull pressure( 1/2 a pound approximate is fine for 90 % of the process but the end shall increase the final cut pressure to 1 too2 lbs pounds if the connection allows) you are using to keep the valves face and seat together with the compound grinding between the 1 rotating surface( valve) and the stationary valve seat .: grind for 5 minutes.... then look at the valve... lift it enough or out thy taking the hose off the stem wash it see if the valve is showing a perfect grey white circle around the middle of where the seat is contacting the face when its smooth and say 1/32 to 1/16" an inch(wide) for intakes valves and or 1/16-1/8" th an inch for exhaust valves (wide)? You may clean both surfaces of the used compound with towel and appropriate liquid ( i use the tip of my finger covered by the rag or towel that is wet in water or petrol respectively as needed ) Then put the drill and hose onto the next valve in order too be ground "ok? if your ?using petrol dont catch fire with sparks or drill ...cigarettes ***CAUTION **** if you do blame the product and you i warned you here to use the water based grind compound 7. one thing is it could possibly take you 10 to 25 minutes to grind a real bad valve or if you didnt face the exhaust valves first ( see face valve illustration instructions) If your valves is smooth and grey in a narrow line all the way in a circle in 6 minutes of grinding you are very lucky . >point here is to change the valve compound every say 8-10 minutes of grinding< and use 1/2 pound pull force to grind with ok"? Don't try to pull more pressure then 1 and a half pounds because your hose will mess up and the grind will be to coarse and wont seal near as good"! so engine wont be as good ",,, Remember if the grinding compound is too course it may gouge the finish also dont let the valve bounce off the seat higher than the recommend 1/8 " because compound will sling into the stem and mess the stem and guide up pretty bad, avoid that, watch for it ,use compound sparingly if prone to ok? and have a little oil on the stem itself not the seat 8.when done grinding but before putting the springs back on? look (test your work) if you have any doubt about the surface squareness of the seat or on heads with high millage ? or ,over heating before? ,( if car over heated ask machine shop if that model head needs checked for cracks and warpage nix this last statement if engine ran cool with thermostat installed ) remember a cracked head isnt likely to work if it is so....but some times certain heads do/ can have the tiny cracks and it isnt harmful it all depends, so ask a head pro shop ok? Grinding compound it shouldn't take you a whole tube of compound( 3 dollars) for 1 or 2 heads, but if they are impossible it can ".i use permatex brand but that are other brands! When all the valves are done first wipe excess compound out with damp rag or paper towel then spray each valve port and guide out with carburetor spray(1 at a time dont get confused on position) and put oil on stem then new seals ( if) and springs and retainers everything just as it was before you may use paint to number the pieces with dots or something so you know or make cardboard rack with numbers however just dont mix stuff up certainly not the valves ok? several small cleaning rags or paper towels at hand moistened ?yes ?soggy no" small bowel of soap water or can of charcoal lighter fluid if using grease base grinding compound **** note #3 if using a wood dowel be certain it is rotating without a wobble if it tightens crooked get another piece of dowel: center it in the drill chuck not to tight here ok ? ***** precaution" a simple suggestion is to keep things in order and dont let anyone mess the order up or u b sorry!
When thar is a smooth grey white line (circle) extending around the total circumference of the valve and no major pits that completely cross that line you may then clean and put it back into the head and proceed to the next valve this valve is finished grinding . Notice that if their is only half a grey white (50%)circle present showing on the valve face( not seat) then you should know that valve is bent or warped ,and you may have to get a replacement (valve) same goes for the seat face their should be a complete circle of grey white metal showing the full circumference ( not halfway) of the seat if not then you will most likely have to do 1 of two things 1 . if its a cast iron seat ( not inserts) you might just need to grind more 2. if its those hardened seats mentioned elsewhere you may need to perform the additional task of squaring the seat as described in the paragraph on squaring hardened seats .(step 5) now to mention how to test how good any freshly grind ed valve procedure is !!!! you can do this TEST procedure ( see pics) take a pencil ( no2#) is perfect ( not to sharp dull is fine ) ok too test any valve grind ed job with a pencil with the seat and valve perfectly clean and dry of anything take the pencil and mark lines every ( like 20 degrees) across the grey white grind ed line space(on seat) , draw the pencil lines radially only the seat circle is pencil lined ok? then put the proper(mating) valve into the head and push it down till it touches the seat LISTEN UP HERE" to do the test right the valve will be twisted only a short twist say 1/4" or 25 degrees back and fourth in this limited fraction of motion it is necessary to push downward as hard as possible with out loosening the slight twist control coordinate ( 25 degrees) back and forth....use fingernails to help to hold the valve edges tight twist valve 10 times in this slight back and forward motion ( pushing down) is enough and the valve is removed look at the lines you drew on the seat now has every line been smeared, by the valves contact ,partial twist if so the seat and valve are perfect go on to next one if only half the lines are smeared check the valve to see if its bent ? and retest maybe if say? only 3/4 to 7/8 of the lines are smeared the seats probably crooked or carbon worn on one side you will have to perform and additional procedure to level that seat ( see pic and carborundum square method) or the valve will still leak probably bad ( unacceptable) between the two tests you can figure out which valves "mite need more work "but if you know the cylinders that were normal to begin with ( because you measured compression) then this will not be the case with thos particular valves so it helps to know where your leaking ones where to start with",... BENT VALVES ? The other thing is.. if your repairing a head that jumped time on the belt or chain ect?. then you may be buying some new valves? for the exhaust valves in question? most likely all or half will be bent from timing jump! those heads usually wont need this pencil test but the new replacement valves still have to be lapped (ground)in to the seat the same grind method applies ok BROKE OFF VALVES Valves break when the are out of time or when they are rusted to tight to move (stuck) The most common cause is when a timing chain or belt or cam gear slips or malfunctions it is possible that a head can be ruined when broken valves are jammed between the moving piston and the surface of the head also pistons and even blocks sometimes are ruined if obviously when that happens you need more then a valve job ALTERNATE TEST OF VALVE SEAL SURFACES AS FOLLOWS!!! Prussian blue for a valve test Prussian blue may be used to see how your valve job is going to test valve seats get Prussian blue? put very thin layer on on the face of the valve then turn that valve 1/4"inch(20 degrees) if the seat shows a clear line of blue extending its full perimeter contact pattern it is assumed to be ok unless there are areas where you don't see blue then you have a worn valve seat or miss match of grinding progress or warped condition on the seat or valve its self or the just need grinding if slightly or also repeat this dye test to determine proper contact of meshing faces ok? using Prussian blue may be tricky so practice or you will not know how but don't despair most likely you will be able to manage to get your valves in working order! Malfunctioning Tappets or rockers Followers / cam lobes ect IM mentioning this because occasionally" and aside from say.... over tight valve adjustment ' its worthwhile to know that hydraulic tappets or hydraulic adjusters even, solid tappet" clearance cause some problems that mimic or promote valve leakage . if a hydraulic lifter pumps up to much and do-sent return to the proper length> it holds the valve inappropriately open< and that will be enough to.. effect the fuel mixture on that cylinder possibly even other cylinders(flow pressure question) If so a miss or partial miss will be noticeable (loss of power and balance) if it is the intake valve that's delayed or not shutting completely its worse as a noticeable effect when this is on the intake side of things(valve) WORN OUT CAMSHAFT ?EFFECTS such things on the intake valve side will cause popping through the plenum or carburetor sometimes even backfiring , ITS IMPORTANT not to mix up any valve parts taken from the head or engine Know what the wear is on your camshaft if the cam is in the block such as when you have a push rod engine then attempt to measure and inspect how much each lift movement of the cam lobe is actually lifting all intake lobes and each exhaust lobe must lift only as much type check the lifts of the 2 types of lobes as exhaust lifter usually higher then intake lobes determine which lobe type your comparing if a worn out cam lobe is found then you will need a new cam and set of tappets on older motors tappets can be stuck in the block anyways dont mix up the tappets put any removed tappets in a box place them back the same way and direction if you are using a new cam use new tappets if you are installing a used cam (not recommend) then the same lifter must be installed onto the exact same lobe as in the replacement as a rule i would say its possible to change a 4 cylinders cam but 8 cylinder cams wear more then 4 cylinder cam lobes ect.
To remove valve springs" first remember if the spring keeper fly's off "! when removing the spring it will hit you in the eye!!!(ouch) and it will most likely destroy it so wear plastic glasses when removing the valve springs. Ok first off DO you have a valve spring compressor tool? to work on heads JC Whitney has them for like $20...if not you might make your own tool from steel in my illustrations their are some examples, i assume no express nor implied indication of the safety of any tools show , for or not for usage"! .. Using valve tools can be demanding difficult and you can possibly get hurt, so don't let anything slip or hurt your" body parts" like your eyes ok? If you? have no drill or electric? see hand tool for hand grinding, it works but takes all day and practice . Keep head work on floored area the valve keepers are hard to find if they are dropped or fly off . I showed a piece of chain" in illustration of spring tool pics ok? ...The chain is to be used with one of the two pry fork type tools, you can make out of 5/16th x 1.1/2" steel bar stock it will need a small hole about 3 inches from fork end to put a 1/4"screw through this attaches through the chain link itself and the chain which will be screwed snug to the head by using the screw holes already made onto the head providing a fulcrum point to pries the springs into the compressed position" where you may then remove the keepers with a small magnetized screwdriver ( sometimes only use this for like removing springs while head is on the motor) you may then remove the keepers with a small magnetized screwdriver greased) or your fingers . The small steel pipe in the pic is for valves set down in the head casting and you have to use a screwdriver with grease to hold the keepers when trying to put them back onto the valve stems when working on those heads where the valves are set low into the head also it might be mentioned to compress springs it mite be possible to place a small jack under a car on top of the pipe thing ( in pic or) use a length ( say 4-5' feet)2x4 and prize down onto the valve spring with the pipe tool you-ll need something pretty heavy to hold the one end of you prizeing ( ie 2x4 wood) device such methods will require a suitable helper sometimes if so. remember if you grind the valve a lot ( ie more the .010) you might need to grind some off the tip of the stem so it isn't to long for the necessary clearance perimeters of certain nonadjustable valve clearance head designs ,but most of the time not Be certain to check all installed valve clearances before starting you motor where applicable ( ask a machine shop man if he thinks your motor has hydraulic tappets that can compensate for changes in valve height . VALVE SEAT WIDTHS ARE IMPORTANT A useful Paragraph about the valve seat width", ok "after or before grinding valves the way im showing" with the drill and hose ? your achieved result has a dimension", in other words you are possibly going to have to alter the finished or prior width of the valve seat to come within a (necessary) width parameter ok"? For most valve sizes on common car engines im going to suggest 2 possible sizes for the 2 types of valves ( intake and exhaust) the finished valve width that is very close too this width> 1/16" <for intake valves or not over >1/8" <or less for exhaust valves . For instance 1/32 is way to narrow for intakes and 3/16 isn't going to work for exhaust widths its to wide. Also these sizes are for car or small truck valves bigger then say 3/4" in diameter ok lets say for instance that you ground the valves and it looks like now the intake side seat is just under 1/8" WIDE NOW , (especially of cast iron seats) your going to need to reduce that to 1/16 or just under ok ? Wear some safety glasses when doing this...One simple way this can be done is with a small grindstone about 1/2" -5/8" in diameter (see pic) ok put the stone in the drill chuck ( or dremell tool ect. or die grinder)the idea is to grind a slight amount of seat width away from the inner lower edge of the seats perimeter. TRIMMING SEAT WIDTHS WITH SMALL GRINDSTONE Its a matter of keeping the stone carefully in the hole while the stone is spinning, do not allow the grindstone to come up or out of the pocket while it is spinning, its to risky. If you nick the upper seat it can be damaged severely i recommend a suggested rpm of 300 to 800rpm for cast seats maybe , but a 10,000 rpm die grinder will not be necessary for beginners . i usually start grinding at 12 o'clock( imaginary positioning point) and move the stone in a clockwise direction (circle) taking about 11 -15 seconds to complete the full 360 degrees (circle)... stop the grindstone, then remove it from the pocket (port where the seats at) look at the resulting grind ed spot is it close to the inner diameter of the seat?( suggested width) if so fine if not ? continue repeating the grinding as stated keep a very firm grip on your drill or whatever you hook to your grindstone(use) move slowly and deliberately as possible do not let you stone come to close to the 45 degree of the good seat angle instead keep you alignment within 20-30 degrees is better (for reasons) once again for hardend seats use as high a speed as possible like or more and probably go with the 30 degree "throating" angle otherwise youl waste your stone, also keep loose clothing away from your tool. Cast iron grinds easy so don't over trim that seat and dont mix up your valves while Thar out ( paint numbers?) and chances are you wont need to do any "INTAKE" valves with HARD SEAT inserts AT ALL they will probably be close enough to correct width ..... thanks "
i am including a suggestion for marking timing marks that on overhead cam engines will need to reassembled the same way to the correct marks
i will mention here any push rod engine is not effected timing mark wise but the distributor will need to be marked on those (most likely) as you sometimes have to remove it to remove head/s
of course newer engines don't have distributors they have coil packs ect .
i have used paint of various types but i always clean a small spot near my intended marks
with something like carb spray you can most likely use acetone or turpentine , maybe finger nail polish remover , this will insure the paint stays on the timing gear or belt and the area near the mark
(block / casting gear or cog)
keep most of your paint marks to the visible side so you wont turn the belt backwards by mistake
IN general take time to find out what the marks are supposed to align with by looking in a manual for you engine or ask auto zone . maybe visit a library get a copy made or draw a good picture as if you are working on a v6 0r v8 with a lot of cams and balance rs you will really have to
know where each one is marked
On small 4 cylinder motors with no in block balance rs or maybe a single cam you can probably get by with just painting the marks onto the chain link and gear or on to the belt and its cog for belt
type drives(cam).
I will say in the absence of timing alignment marks: it is possible to make your own with paint .
TRY TO FIND THE MARKS (timing)
A lot of the time i will begin my work (valve job) by turning motor to top dead center on the number 1 piston this usually brings the timing marks into there normal position were you can verify exactly where each of the 3 or 4 marks are aligned(on gears). If you find the cam or cams aligned but cant see the crank mark just wash a spot on the chain and sprocket with solvent ( mentioned earlier)
A FEW MOTORS DO NOT ALIGN AT TOP DEAD CENTER SO BEWARE
Paint a spot of paint across 1 tooth and onto the mating chain use the tooth and mating link as to be careful to use a small enough paint spot as to not be confuse to which link it is on ok?
USE FAST DRYING PAINT OR MAYBE WHITE NAIL POLISH.
THIS MARK DETERMINING OR MARK PAINTING SHOULD BE DONE AFTER ANY COMPRESSION TESTING AS THE MOTOR WILL NOT BE MOVED UNTIL YOU HAVE TO RE-INSTALL
THE HEAD/S TO THE BLOCK ( DO NOT MOVE THE CRANK WHILE OR DURING HEAD REMOVAL ****
when you are ready to re instal the heads you can move the marks just a little to get them to the same spot use you hand and a wrench remember to put the cam back into the same position before
putting or bolting the cam onto the head or when the cam is already bolted to the head ( overhead cam engines)
**** if your motor is an interference motor don't turn the motor over keep crank and cams the same spot when separated
Have 2 cams on a engine or 4 cams? mark them put a paint spot on the front and rear ones or a tag wired with ef if - er=ir ect
dont mix them up . ( ie front exhaust cam front intake cam, or if you have a 2 head motor the back 2 cams)
After you have you marks then take the bolts holding the head on most likely you will need to
remove any overhead cams OK LOOK AT THE CAM CAPS THAT ARE BOLTING THE CAMS ON SEE THE NUMBERS AND ARROWS ON THE TOP OF THE CAP ? HUH? No ?
WELL YOU WILL HAVE TO MARK EACH CAP AND MAKE AN ARROW OR NUMBER
IF YOU MIX THESE UP YOU WILL RUIN YOU MOTOR OR HEAD
if you are uncertain about a caps position (numbers?)try to match the scratch marks seen on the lower cam
journal they are like finger prints
there may me a set of numbers and a letter like E on one cam (CAP) and a similar number and letter N
if the numbers and letters are invisible make your own letters and numbers do so like this
take a screwdriver or ice pic number the cam holders (boss) starting at one end say 1 through 5 then additionally speaking of twin cam heads put an e or x for the exhaust cam ones? only beside the exhaust cam caps (dual cam requires more marks)
More then 1 cam ? do something similar (last paragraph) for the rear head but keep the parts away from the 1st heads cam/s (store it so you don't mix em)
Cam caps i lay the caps in the valve cover after checking my cap numbers keep them in order to replace the same spot on the cam journals
Take any necessary intake manifold bolts off the head and remove to one side take any exhaust manifold bolts off and remove exhaust manifold to one side
take any brackets off the manifold that bind you from removing the head and connected parts .
IF YOU TAKE A CAM SPROCKET OR GEAR OFF TO GET IT LOOSE FROM THE CHAIN THEN
MARK IT AND THEN PUT IT BACK ON(after) SO YOU DON'T MIX THEM UP YOU MAY USE PAINT TO MARK THEM LIKE CAM 1 OR CAM 2 OR 3 OR 4 WHATEVER
YOU MAY HOLD THE CAM ON A SPOT THAT ISN'T MACHINED TO KEEP IT FROM TURNING WHILE Loosening OF TIGHTENING GEARS OR COG BOLTS DO NOT LET THE CAM TURN WHEN YOU ARE LOOSENING ANY GEAR OR COG END BOLTS IT CAN RUIN THE VALVES if IT TURNS SO BE WARNED DON'T LET THE CAM TURN WHEN DISASSEMBLING GEAR OR PARTS
( a pneumatic impact wrench is helpful removing big bolts if they are tight but should not be used for small bolts like 1/2 0r 13 mm just on 17 mm or bigger ) AND LOOSEN THE CAM GEAR RETAINING BOLT /S BEFORE TAKING ANY CAP BOLTS LOOSE
LAY YOUR HEAD BOLTS IN THE VALVE COVER OR A CAN PUT SMALL BOLTS IN A DIFFERENT CUP OR PAN DON'T DROP THEM INTO THE AREA BETWEEN THE CHAIN AND THE BOTTOM OF THE OIL PAN YOU DO NOT WANT THEN IN YOUR MOTOR"! IF YOU DO DROP ONE IN CALL AND ASK A MACHINIST ABOUT WHAT HAPPENED use a large pair of vise grips to lock the cam and hold it or if you can try to get the cam and gear off with out removing i have used a pipe wrench to hold a cam
but it can slip and remember you cant let the cam turn (on interference engines ) if your can gear has large holes you can sometimes stick a metal bar through the hole to lock it just so it do sent turn ( when loosening cog bolt)
HINTS"
if you are uncertain about a caps position try to math the scratch marks seen on the lower cam
journal they are like2 halves and sometimes are matchable by wear scratches pa terns
if you have damage to a cap or journal you may be able to smooth it a little(slightly) with 320 grit sandpaper stretched around a socket of a very close size (clean all dust after).
CAM CAM WONT STAY PUT ON MARK BECAUSE SPRINGS
If you find the cam when set to correct mark is jumping to a different spot, it will be necessary
to hold or lock it while your finishing positioning any remaining gears / chain ect use a pair
of vise grips clamped to the cam at some spot UN-machined.
CAMS WITH ALIGNMENT HOLES
Some motors like
the GM 2.4 use holes in the cam gears that you stick a bolt or drill bit into to while aligning
beware of the gm 2.4 variable cam gear/s as there are 2 gears stacked and you must not
allow the 2 gears to slip to another tooth or it will not work (seriously)
the 2.4 is a difficult motor to lean their are hidden bolts behind chain tension er ect
On iron blocks and or heads i use permatex Indian head shellac to seal rust spots
even though it may not be altogether necessary it can stop rust from forming on the
metal that will cause pitting and lead to gasket failure (use your own judgement).
I f you are working on the ford SOHC V-8 the Gas TYPE chain Tension-er is behind
the timing cover it will be very difficult to squeeze if you remove the gear so if you
have a piece of oak wood you may be able to make a wedge and pound it
against the chain to scotch the tensiner from springing out when you take the top
cam gear off. If it does come out you will have a hard time to get your gear back on.
cam loose .
Pressurized Gas Tensioner
Be aware of what type of Tensioner you have on your engine if it has a gas pressure
type Tensioner you will need to in most cases remove it because you will not be able
to get you chain/s or belts onto the cams as it will expand and make it to tight a fit
If you do take the gas pressurized Tensioner off to reuse it you will need to slowly
re compress it back into the cylinder housing so you can get it in far enough to put
a pin into the retainer hole on the side near the rubber boot to be removed like
a grenade pin only after all the gears and chains / belts are in place and screwed on.
It takes a lot of force to push the Gas pressure Tensioner in : you will have to
put it into a large shop vise and the slowly over say 4 or 5 minits screw the vise
tight until the pin hole is aligned to much weight and you will ruin the end of the
tensioner i have put them under the car and used a jack to slowly compress them
remember to give them time it will need to move slowly over say 4 or 5 minits .
when replacing a rocker arm assembly on the Honda civic 4 cylinder engine, be careful when the
assembly starts to tighten watch to see if the rocker arms are all contacting there
respective valve stems if the high lobe end valve gets sideways it will bend the exhaust valve
sideways BEWARE just push it to the top of the stem so it don't bind as you get it close to pulling down
even as some lobes are high and push on the assembly as your tightening it to the head cam inplace
understand ?
A Nissan 4 or v-6 cylinder uses a hydraulic tensioner if your chain is makeing a zizing
noise when engine heats up it could mean the main bearings are wore out ! a chain job
will not help this you have bigger troubles so check oil pressure" with motor hot first .
Got an older front wheel gm motor with a bad cam? don't want too take the motor out
because of side fender frame? then jack the motor up remove intake and push rods
and all lifters (use vise grips to pull lifters) timing cover and gear .Then slide the cam
sideways till it hits the metal above the box frame (jack the motor a little ) the use
a drill to drill a series of holes in a semi circle slightly larger then the cam from
and through the tin behind the wheel well ,bend the metal back (wheel removed)
and pull the cam out through the flap , it will save a lot
of work and sometimes an engine change. Install new cam and lifters".
Have a leaky crank seal up in side an area where you cannot prize it out with a
screwdriver ? it may be necessary to drill a small hole in the seal shell through
the thin tin shell ( caution don't over drill into the main bearing )
and put a fairly long enough sheet metal screw into the hole so
you can pull on the screw ( seal attached)to get the old leaky seal out
These few cars with a sunken seal will be hard to align the new seal to push it in
i have at these times cut a small section of plastic from the side a plastic pop
bottle and wrapped it around the crankshaft nose(temporarily) so that the rubber the new lip on the new seal can slide over the plastic sleeve like a shoe horn and the new
seal doesn't flip under when you push the seal into the recessed area
always put grease or oil onto a new seal.
LEAKING OIL SEALS AND TIMING BELTS
If the cam seals or crankshaft seals are leaking and your motor has a belt /s
you will need to replace any and all seals on the effected cam or crankshaft
other wise if you allow the oil to continue to leak onto your timing belt
it will sometimes ( depending on the belt) cause the belt to break soon possibly
in as little as 2 months and potentially within a year it could break
best to always use a new belt but if your not then wash the oil of the belt
with degrease r or then use tide soap, or oven cleaner ect.
Time saver when taking certain heads off that "head bolts" can be removed
without first removing cam? simply take bolts out: when ready lift end of head
farest from gear/cog that will allow you to slip the belt off the gear/ cog & remove
head and cam in one chunk, ! leave adjustment alone Unless its loose going
back on? if you mill the head it may become loose so then adjust the belt if
it has a manual belt idler ( see above for info of pressurized gas tension er !)ok
NEVER FORGET TO TIGHTEN THE CAM GEAR BOLT OR BOLTS BEFORE FINISHING THE JOB OK?
If you are looking for more details, kindly visit Valve Tightness Test Machinery.
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