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Posted by treebonker, Nov 4, 2008
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fantastic, this needs to be submitted as a tech article in the engine section ASAP. If it at all possible, finding links for people interested to buy the products you mention would be awesome (I noticed the summit pinwheel).
Great write up. I had to degree my cam(sohc) but i didnt have the ati balancer. I had some 14mmx1.25 threaded rod, nuts and the supplied adapters with the moroso degree wheel and this is what i cam up with
Was this submitted to the tech articles? I didn't see it.
Why was this left out?
Talk to any cam grinder, engine builder, or racer and youll find overwhelming agreement that degreeing-in a camshaft is a vital step along the route to optimum engine performance. At first that may seem strange because degreeing-in a cam pertains to checking the accuracy with which it was manufactured.
The purpose of degreeing a cam is to insure that the cam is phased correctly with the crankshaft, per the cam manufacturers specifications. Youre insuring that valve opening and closing events are in accordance with specifications, regardless of the cause. Actual valve opening and closing events are influenced not only by accuracy with which a cam was ground, but also keyway position in the crankshaft, crank timing sprocket, dowel pin hole position in the cam sprocket, and accumulation of machine tolerance also play a major role.
It is the exception, rather than the rule, that a cam may be out of phase, but this should be established to insure an accurate performance baseline or point of tune. There are however 4G63 Eclipse cam manufacturers that make it a rule rather than the exception. But nobody cares as long as it's cheap and you got that cool lump-lumpity-lump idle.
Awesome write up, mind if I print this out to have in the garage when I assemble my motor?
I finally got enough post to reply to this. Thanks for taking the time to write all this down. I enjoyed reading this. But I have a few questions. Will dialing in have any effect on stock camshafts? Also, do you think it is possible to do this procedure with the engine in the car?
Very nice write up... Now cut and paste the pertanant info to a tech article...meanwhile i'm saving the webpage to my hard drive
Nice, Thanks! I've always wanted to know how to do this.
This is excellent info.
Why doesn't anyone sell a kit with 2 solid lifters, or something pre-assembled to do this with? I think an enterprising individual should add some DSM-specific parts to that generic degreeing kit and make some $$$
Until then, does anybody have links to some decent inexpensive kits (that you have experience with) ?
nice guide, but looks like its easy to do with the engine out, how would you go about this with the engine in??
im looking to get cams, and have a shop that will do them, might print this out.
Why is it so important to adjust lifters to zero lash? Is it to ensure that the entire valve assembly moves up an down exactly with the cam? If this is the case, why worry about adding just the right number of shims? Why not just add a bunch of shims to ensure that the lifter is constantly pressing against the cam lobe?
And finally, where can I find instructions on removing/installing springs and retainers? (Interest for both that light feeling spring and for future upgrades on springs)
Fantastic write up. Haven't come across a post of this caliber in a while.
When you remove the inner spring and shim it, are you preventing the lifter from compressing at all? If so, how do you turn the motor (where the cam lobe ramps up)?
Same as before, except now the opening of the valve will follow the cam profile precisely.
Ok I think I've been thinking about this the wrong way...
So the purpose is to make sure the lifter is totally secure, so that the rocker has a solid point to pivot against and the springs/retainers/valves move 100% with the lobe?
Exactly....Can't think of a better way of putting it.
Are there any negative effects of running a modified lifter like this? Don't they need to be compressed for oil to flow/splash on the head internals?
You don't want to run them... just use a couple while degreeing the cams, and then put your stock (3g ) lifters back in.
I don't have the links handy, but there are several threads floating around here that talk about the negative effects (or at least the lack of any benefit) of running solid lifters in our motors.
I'm not sure what happened to the original post, but here it is for reference:
4G63 Camshaft Degreeing
Thank you for the updated link.
Just heads up for everyone make sure your lift @ is correct with what the manufacure of the cam has designed them for or your going to be way off.
For example I just degreed my first set of kelford cams and was trying to degree them at .050 lift measurments nothing was coming out corrently.
I found out on there web site there mitsubishi cams are desighed to be degreed at .040 lift or 100mm.
This was all new to me because all the american made cams are desighed to be checked at .050 lift.
My cams both intake and exhaust are now 7/8 of a degree retarted to get the correct lift at .040 reason being so is my head has been decked so many times as well has my block has been decked once.
I used 2 BLE solid lifters and the the morroso pro wheel.
Usually the kelfords are right on the money.
I do beleive the HKS cams are also desighned to be degreed at .040 lift as well.
If your not sure call or email the cam maker.
I'm going to bring this back from the dead. The linked article is refrenced in several different threads but is no longer active. I wanted to ask if anyone had a copy or knew where to find it. Thanks
Still looking for the new link if anyone has it
I know this thread has been dead for a long time, but I was able to dig up the article through the way-back machine.
The pictures are long gone, but the text is still available. Personally, I'm saving this information in this thread so when I go looking for it later, I can find it a bit easier, but I also figured some others may benefit.
Alright, I copied and pasted this and cleaned up the formatting if the information ever goes lost again. It is not mine, and I don't really care to fix the "all-caps" since what I've done to find and re-publish this information is far more then I've found anyone else doing.
TALK TO ANY CAM GRINDER, ENGINE BUILDER, OR RACER AND YOU’LL FIND OVERWHELMING AGREEMENT THAT “DEGREEING-IN” A CAMSHAFT IS A VITAL STEP ALONG THE ROUTE TO OPTIMUM ENGINE PERFORMANCE. AT FIRST THAT MAY SEEM STRANGE BECAUSE “DEGREEING-IN” A CAM PERTAINS TO CHECKING THE ACCURACY WITH WHICH IT WAS MANUFACTURED.
THE PURPOSE OF DEGREEING A CAM IS TO INSURE THAT THE CAM IS PHASED CORRECTLY WITH THE CRANKSHAFT, PER THE CAM MANUFACTURERS’ SPECIFICATIONS. YOU’RE INSURING THAT VALVE OPENING AND CLOSING EVENTS ARE IN ACCORDANCE WITH SPECIFICATIONS, REGARDLESS OF THE CAUSE. ACTUAL VALVE OPENING AND CLOSING EVENTS ARE INFLUENCED NOT ONLY BY ACCURACY WITH WHICH A CAM WAS GROUND, BUT ALSO KEYWAY POSITION IN THE CRANKSHAFT, CRANK TIMING SPROCKET, DOWEL PIN HOLE POSITION IN THE CAM SPROCKET, AND ACCUMULATION OF MACHINE TOLERANCE ALSO PLAY A MAJOR ROLE.
IT IS THE EXCEPTION, RATHER THAN THE RULE, THAT A CAM MAY BE OUT OF PHASE, BUT THIS SHOULD BE ESTABLISHED TO INSURE AN ACCURATE PERFORMANCE BASELINE OR POINT OF TUNE. THERE ARE HOWEVER 4G63 ECLIPSE CAM MANUFACTURERS THAT MAKE IT A RULE RATHER THAN THE EXCEPTION. BUT NOBODY CARES AS LONG AS IT'S CHEAP AND YOU GOT THAT COOL LUMP-LUMPITY-LUMP IDLE.
2. PART REQUIRED
· AN ACCURATE DEGREE WHEEL FOR THE CRANKSHAFT.
· A RIGID POINTER THAT CAN BE ATTACHED FIRMLY TO THE ENGINE AND INDICATE POINTS ON THE DEGREE WHEEL.
· DIAL INDICATOR TO ACCURATELY MEASURE CAM LIFT.
· TOP DEAD CENTER PISTON STOP.
· 2 X MODIFIED HYDRAULIC LASH ADJUSTERS W/ 10MM SHIMS OR SOLID LIFTERS.
· 2 X LIGHT CHECKING SPRINGS. (USED WHEN CHECKING PISTON TO VALVE CLEARANCE)
A GENERIC CAM DEGREE KIT WILL HAVE EVERYTHING WITH THE EXCEPTION OF HLA'S.
3. SETTING ZERO LASH
HYUNDAI HYDRAULIC LASH ADJUSTER (HLA)
SETTING ZERO LASH IS THE SINGLE MOST IMPORTANT PROCESS FOR CAM DEGREE-IN. YOU MIGHT AS WELL JUST DROP IN THE CAMS IF YOU'RE THINKING OF SKIMPING THIS. ANY ERRORS AND YOU'LL BE SCRATCHING YOUR HEAD DURING THE REST OF THE PROCESS. THIS CAN BE DONE MANY WAYS BUT WHEN USING HYDRAULIC LASH ADJUSTERS THERE'S NO EASY WAY.
FIRST THING YOU NEED TO DO IS DISASSEMBLE THE HLA AND REMOVE THE INNER SPRING. TO GET THE CORRECT HEIGHT YOU'LL BE SHIMMING INSIDE THE LIFTER(REFERS TO HYDRAULIC LASH ADJUSTER HEREIN AFTER) AS THE LIFTER BORE IN THE HEAD IS DOMED AND CAN BEND THE SHIMS GIVING DIFFERENT RESULTS EVERY TIME YOU TAKE THEM OUT. DISCARDING THE RETAINING CAP WILL GIVE YOU ENOUGH SPACE TO GRIP THE PLUNGER WITH PLIERS LATER ON WHEN CHECKING FOR LASH.
8 X 10 X 0.1 - 0.3MM SHIM SET
GET AN ASSORTMENT OF 10MM X 0.05-0.3MM SHIMS. I GOT THE SHIMS FROM A NEARBY RC HOBBY SHOP WHICH HAS 10EA OF 8X10X0.1/0.2/0.3MM SHIMS AND ALSO PICKED UP 0.15MM AS THEY DIDN'T HAVE 0.05MM. 0.1MM(0.004") INCREMENT WILL LEAD TO A SITUATION WHERE YOU FIND IT'S TOO LOOSE AND ADDING ANOTHER SHIM MAKES IT TOO TIGHT. THAT'S WHERE YOU USE THE .05MM OR .15MM IN PLACE OF THE .1MM SHIM.
NEXT IS TO GET AN ESTIMATE ON HOW MUCH SHIMS YOU NEED. INSTALL THE LIFTER, ROCKER ARM, CAM AT THEIR BASE CIRCLE AND TORQUE DOWN THE CAM CAPS. MEASURE THE AMOUNT THE LIFTER PLUNGER MOVES UP BEFORE TOPPING OUT AND USE THAT AS A STARTING POINT.
CHECK VALVE FLIPPED AND SHIMMED
FLIP THE INNER CHECK VALVE(MIDDLE PART IN PICTURE) SO IT DOESN'T RESIST SLIDING DOWN THE BODY. IF INSTALLED IN IT'S NORMAL DIRECTION IT TENDS TO BOUNCE BACK UP DUE TO THE TRAPPED AIR COMPRESSING. YOU CAN PUSH THE CHECK BALL OPEN AS YOU WOULD WHEN BLEEDING THE LIFTER SO EITHER WAY WORKS. 11MM O.D SHIMS WILL NOT FIT AND THE 10MM WILL HAVE SOME SLOP. WHEN IT'S AGAINST THE WALL THE OPPOSING SIDE WILL BE SLIGHTLY OFF THE FLANGE. WHILE IT REALLY DOESN'T MATTER I PUT A SMALL PIECE OF VACUUM HOSE OVER THE PROTRUDING PART ON THE CHECK VALVE BODY TO GUIDE THE SHIMS. STACK THE AMOUNT OF SHIMS YOU NEED, REASSEMBLE EVERYTHING AND TORQUE THE CAM CAPS.
CHECKING FOR POSITIVE LASH
VERIFY THE ROCKER ARMS CAN'T BE TWITCHED AND IF YOU CAN SPIN THE PLUNGER WITH A SLIGHT RESISTANCE THEN YOU HAVE "ZERO LASH". IF NOT THEN YOU WILL NEED TO ADD OR REMOVE THE SHIMS. LOTS OF FUN!!! IF YOU SETUP THE DIAL INDICATOR OVER THE RETAINER BEFORE CAPS ARE INSTALLED AND VERIFY THE RETAINER DOESN'T MOVE WHEN YOU TORQUE THE CAM CAPS, THIS ENSURES YOU DON'T HAVE POSITIVE LASH. YOU CAN EASILY TELL YOU HAVE NEGATIVE LASH WHEN THE PLUNGER SPINS FREELY AND/OR THE ROCKER ARMS WITH SLACK.
ANOTHER METHOD, IF YOU ARE USING LIGHT CHECKING SPRINGS, IS TO USE SPRINGS INSIDE THE LASH ADJUSTER THAT CAN OVER COME THE CHECKING SPRINGS PRESSURE. THERE WOULD BE NO NEED FOR SHIMMING BUT I HAVEN'T FOUND ANY THAT STAYS SOLID WHILE COMPRESSING THE CHECKING SPRINGS. IF YOU CAN GET 2 SOLID LIFTERS IT WILL DEFINITELY BE WORTHWHILE. SETTING LASH AND PRELOAD IS JUST A MATTER OF TURNING A NUT. ANYONE KNOW WHO SELLS JUST 2 ?
YOU'RE 90% THERE. TAKE A BREAK AND GRAB A BEER. WHEN YOU GET BACK INSTALL THE TIMING BELT.
4. MOUNTING THE DEGREE WHEEL AND POINTER
MOUNT THE DEGREE WHEEL SO YOU HAVE SOME MEANS OF TURNING THE CRANK WITHOUT INTERFERING WITH THE DEGREE WHEEL. ROTATE THE CRANK UNTIL NUMBER ONE PISTON IS AT TOP DEAD CENTER. THIS CAN BE A ROUGH GUESS. NEXT ATTACH THE POINTER FIRMLY TO THE BLOCK AND ADJUST IT SO THAT IT POINTS TO TDC ON THE DEGREE WHEEL. IT'S A GOOD IDEA TO SHARPEN THE POINTER EDGE AND POSITION IT AS CLOSE AS POSSIBLE TO THE DEGREE WHEEL. MAKE THE POINTER WITH AN ARCH SO YOU CAN LATER BEND IT TO POINT TO ANOTHER TARGET PERPENDICULAR TO THE WHEEL'S CENTERLINE. THIS IS AN AFTER SHOT OF A QUICK MOCK UP. OOPS, FORGOT TO POSITION CYL #1 AT TDC.
5. FINDING THE TRUE TOP DEAD CENTER (TDC)
PISTON STOP INSTALL
TURN THE CRANKSHAFT OPPOSITE THE ENGINE ROTATION 15-20° OR TO BDC. INSTALL THE TDC PISTON STOP IN THE SPARK PLUG HOLE AND SCREW IN THE INNER PISTON STOP UNTIL IT TOUCHES THE PISTON OR BOTTOMS OUT. CONTINUE TO TURN THE ENGINE IN THE SAME DIRECTION UNTIL THE PISTON COMES BACK UP AND TOUCHES THE PISTON STOP. MARK THE DEGREE WHEEL WITH A PEN OR PENCIL ON THE NUMBER THE POINTER IS ON. TURN THE ENGINE IN THE OTHER DIRECTION, SAME AS ENGINE ROTATION, UNTIL THE PISTON COMES BACK UP AND TOUCHES THE PISTON STOP. MAKE A MARK ON THE NUMBER THE POINTER IS ON.
17.5° FROM TDC MARK
69° FROM TDC MARK
I HAVE THE STOP POINTS AT 17.5° IN ONE DIRECTION AND 69° IN THE OPPOSITE DIRECTION. THE TOTAL WOULD BE 86.5 DEGREES. THIS FIGURE DIVIDED IN HALF WOULD BE 43.25 DEGREES. THEREFORE 43.25 DEGREES FROM EITHER OF YOUR STOP POINTS IS TRUE TOP DEAD CENTER.
DEGREE WHEEL WITH 180° IN BOTH DIRECTION FROM TDC
PICTURE SHOWING THE PISTON STOP POINTS MARKED ON THE DEGREE WHEEL. YEAH IT'S A CHEAPO SUMMIT KIT. UNDERNEATH IS AN ATI DAMPER WHICH MADE MOUNTING THE DEGREE WHEEL A SNAP.
ADJUSTING THE POINTER
STOPS AT 43.25° CLOCKWISE ROTATION
STOPS AT 43.25° COUNTER-CLOCKWISE ROTATION
NOW MOVE THE POINTER TO ALIGN WITH THE 43.25 DEGREE MARK ON THE DEGREE WHEEL(THIS IS THE ONLY TIME YOU WILL BE MOVING THE POINTER AFTER INITIAL SETUP) MAKING SURE THAT THE PISTON IS STILL AGAINST THE STOP. NOW TURN THE ENGINE IN THE OPPOSITE DIRECTION UNTIL THE PISTON COMES BACK UP AND TOUCHES THE STOP. THE POINTER SHOULD BE ALIGNED WITH THE 43.25 DEGREE MARK ON THE OTHER SIDE OF THE TDC MARK.
CRANK TO TDC MARK AND YOU HAVE TRUE TDC
IF THIS IS CORRECT, THEN YOU HAVE FOUND TRUE TOP DEAD CENTER AND YOUR POINTER WILL POINT TO THE TDC MARK ON THE DEGREE WHEEL WHEN CYLINDER #1 IS AT TRUE TDC. IT IS BEST TO REPEAT THIS TO MAKE SURE THAT NOTHING HAS MOVED. REMOVE YOUR PISTON STOP AND YOU ARE READY TO PROPERLY DEGREE YOUR CAM.
COMPARISON AFTER FINDING TDC
EYEBALLING TDC WITH CAM/CRANK SPROCKET MARKS
AFTER FINDING TRUE TDC AT THE CRANK
THIS IS THE BEFORE AND AFTER SHOT OF THE ECLIPSE CAM GEARS ALIGNMENT. THE CAM GEARS ADVANCED 1 CRANK DEGREE WITH THE TRUE TDC AND THE CAM GEARS NO LONGER LINE UP PERFECTLY. I WAS EXPECTING IT TO BE RETARDED SINCE THE HEAD AND BLOCK HAVE BEEN SHAVED. 1 CRANK DEGREE ADVANCED WOULD ROUGHLY MEAN .025" TALLER DECK HEIGHT, WHICH MAY BE ACCOUNTABLE DO TO THE STOCK VS MLS GASKET THICKNESS DIFFERENCE BUT WHAT ABOUT THE RESURFACE JOB?.
6. MOUNTING THE DIAL INDICATOR
MAKE A METAL BASE PLATE THAT YOU CAN BOLT ON THE HEAD FOR THE DIAL INDICATOR'S MAGNETIC BASE. THE MOUNTING BASE FOR THE DIAL INDICATOR CAN BE ANYTHING YOU HAVE AROUND. I ACTUALLY USE A BOSCH DIE GRINDER WRENCH. IT HOOKS TO THE SECOND PLUG HOLE AND THE HOLE IN THE HANDLE LINE UP WITH THE VALVE COVER BOLT HOLES AT THE CAM GEAR SIDE. ONE BOLT AND IT'S ROCK STEADY. POSITION THE DIAL INDICATOR MOUNT SO THE TIP WILL CONTACT THE RETAINER OF THE INTAKE VALVE. YOU'LL NEED TO MAKE A RIGID EXTENSION (COAT HANGER WORKS NICELY) FOR THE DIAL GAUGE SINCE THE RETAINERS ARE DEEP WITHIN THE HEAD. SAND DOWN THE EXTENSION TIP SO YOU DON'T SCRATCH EVERYTHING IT TOUCHES. IT IS IMPORTANT THAT THE INDICATOR PLUNGER BE PARALLEL TO THE VALVE STEM AND LOCATED AT A FLAT LEVEL ON THE SPRING RETAINER. ANY VARIANCE IN THE ANGLE OF THE INDICATOR WILL INTRODUCE GEOMETRIC ERRORS INTO THE LIFT READINGS. BE SURE THAT THE INDICATOR IS SUPPORTED SOLID AS ANY LOOSENESS WILL INTRODUCE MAJOR MEASUREMENT ERRORS.
7. MEASURING TIMING EVENTS AT .050" VALVE LIFT
THIS IS FOR TUTORIAL PURPOSE ONLY AND ARE NOT THE ACTUAL CRANE CAM'S PROFILE. THEY WERE DEAD ON THE MARK.(MUCHO SARCASM...).
REFERENCE POINT AT CAM BASE CIRCLE
ROTATE THE CRANKSHAFT SO THAT THE CAMSHAFT BASE CIRCLE IS OVER THE ROCKER ARM AND SET THE DIAL INDICATOR WITH .500" PRELOAD SO IT DOESN'T RUN OUT OF TRAVEL. ROTATE THE CRANKSHAFT SLIGHTLY AND MAKE SURE THE INDICATOR READING DOES NOT CHANGE. NOW YOU CAN SET THE INDICATOR TO READ ZERO AT THIS POINT. MY CHEAPO GAUGE DIDN'T HAVE THIS FUNCTION SO I HAD TO READ THE NUMBERS AND SUBTRACT.
THIS IS THE STARTING POINT OF MY INTAKE CAM.
.050" OPENING VALVE LIFT
USING THE INTAKE OPENING AND CLOSING AT .050” CAM LIFT, OBTAINED FROM THE INFORMATION ON YOUR CAM SPEC CARD, TURN THE ENGINE IN THE NORMAL DIRECTION OF ROTATION. WATCH THE DIAL INDICATOR. WHEN IT MOVES DOWN .050”, STOP ROTATING THE ENGINE.
5° BTDC @ .050" OPENING VALVE LIFT
RECORD THE DEGREE WHEEL NUMBER THAT THE POINTER IS ON. THEN CONTINUE TO ROTATE THE ENGINE IN THE SAME DIRECTION. WATCH THE DIAL INDICATOR, IT WILL CHANGE DIRECTION AT MAXIMUM LOBE LIFT. RECORD THE MAX VALVE LIFT AND DEGREE WHEEL NUMBER.
I'M SHOWING 5° BTDC AT .05" VALVE LIFT FOR THE INTAKE OPENING. SPEC CARD SHOWS IT SHOULD BE 10.5 BTDC SO THE INTAKE CAM IS 5.5 DEGREE RETARDED.
.050" CLOSING VALVE LIFT
CONTINUE TO ROTATE THE ENGINE IN THE SAME DIRECTION UNTIL YOU REACH .050” BEFORE CLOSING. IF YOU GO PAST EITHER OF THE .050” MARKS, BACK UP AT LEAST .100” AND ROTATE THE ENGINE IN THE NORMAL DIRECTION AGAIN UNTIL YOU REACH THE .050” MARK ON THE INDICATOR.
39.5° ABDC @ .050" CLOSING VALVE LIFT
AGAIN RECORD THE DEGREE WHEEL NUMBER THAT THE POINTER IS ON. CONTINUE ON TO ZERO LIFT AND VERIFY THAT THE DIAL INDICATOR HAS RETURNED TO ZERO OR IT'S ORIGINAL POSITION. THE OPENING AND CLOSING FIGURES SHOULD BE WITHIN ±1 DEGREE. IF YOUR FIGURES ARE NOT WITHIN ±1 DEGREE, GO THROUGH THE PROCEDURE AGAIN TO CHECK FOR POSSIBLE ERROR.
I'M SHOWING 39.5° ABDC AT .05" AND THE CAM CARD SAYS IT SHOULD BE 33.5° ABDC. SO IT'S 6° RETARDED, CLOSE TO THE 5.5° AT VALVE OPENING.
IF YOUR OPENING AND CLOSING FIGURES ARE STILL NOT CORRECT YOU WILL NEED TO MOVE THE CAM IN RELATION TO THE CRANKSHAFT IN ORDER TO CORRECT YOUR OPENING AND CLOSING FIGURES. THIS IS WHERE YOU MAKE USE OF YOUR CAM GEARS. IF THE CAM IS OPENING EARLY, THE CAM IS TOO FAR ADVANCED, AND WILL NEED TO BE MOVED IN THE OPPOSITE DIRECTION OF THE CAM ROTATION. IF THE CAM IS OPENING LATE, THE CAM IS TOO FAR RETARDED, AND WILL NEED TO BE MOVED IN THE DIRECTION OF CAM ROTATION. REPEAT PROCEDURE 6-7 ON THE EXHAUST SIDE. ONCE THE CAM IS PHASED WITH THE CRANK, PER THE MANUFACTURER SPECS, THEN A BASELINE CAN BE ESTABLISHED. FROM THAT BASELINE OF PERFORMANCE YOU CAN DIAL THE CAM EXACTLY TO YOUR COMBINATION.
ADJUSTING THE CAM GEARS
INTAKE AND EXHAUST CAMS WERE RETARDED 6 AND 3 CRANK DEGREES COMPARED TO THE CAM SPEC SHEET. FOR THE HKS CAM GEAR EACH MARK ON THE SCALE REPRESENTS 2 CRANK DEGREES SO I ADVANCED 3 AND 1.5 DEGREE AT THE CAM GEARS.
RECHECK THE TIMING EVENTS.
CENTERLINE METHOD OF CAM DEGREE-IN
UNLESS THE MANUFACTURER WANTS YOU TO USE THIS METHOD DON'T BOTHER. THERE ARE CAM MAKERS WHO LIST THESE VALUES FOR REFERENCE ONLY AND DOES NOT REPRESENT TRUE CENTERLINE AS THE LOBES ARE OFTEN GROUND ASYMMETRICAL.
CRANE CAM P/N 435-0014
OPENING & CLOSING EVENTS WERE RETARDED 5 CRANK DEGREES FOR BOTH THE INTAKE AND EXHAUST. MINIMUM PISTON-TO-VALVE CLEARANCE OF .052” @ 6-8 ATDC FOR THE INTAKE AND .097” @ 10 BTDC FOR THE EXHAUST SIDE INSTALLED STRAIGHT UP WITH MITSUBISHI MLS GASKET, JE 9.0-1CR AND +1MM OVERSIZED VALVES. ADVANCING THE CAMS TO MATCH THE SPEC CARD WILL ONLY GIVE .030” CLEARANCE FOR THE INTAKE. ONLY SOLUTION IS TO USE A CUSTOM THICKNESS GASKET AS FLY CUTTING THE RELIEFS WON’T BE ENOUGH.
8. CHECKING PISTON TO VALVE CLEARANCE
WHEN YOU INSTALL A HIGH PERFORMANCE CAM, IT IS POSSIBLE THAT THERE MAY NOT BE SUFFICIENT CLEARANCE BETWEEN VALVES AND PISTONS WHEN NEAR TDC ON OVERLAP. EVEN IF THEY DON’T TOUCH WHEN YOU ROTATE THE CRANKSHAFT SLOWLY BY HAND, THEY MAY HIT AND DAMAGE THE ENGINE AT HIGH REVS DUE TO SLIGHT “FLOATING” OF THE VALVES, STRETCH IN THE RODS, DEFLECTION IN THE VALVE TRAIN, AND OTHER CAUSES.
THE EASIEST WAY OF CHECKING PISTON TO VALVE CLEARANCE IN AN ENGINE, WITH THE CYLINDER HEADS INSTALLED, IS TO INSTALL A PAIR OF LIGHT CHECKING SPRINGS IN PLACE OF THE VALVE SPRINGS. THESE LIGHT CHECKING SPRINGS WILL ALLOW YOU TO DEPRESS THE VALVE EASILY AT ANY TIME DURING THE ENTIRE ROTATION OF THE ENGINE, ENABLING YOU TO MEASURE THE PISTON TO VALVE CLEARANCE. WHILE YOU'RE HAVING TO REMOVE THE SPRINGS IT'S A GOOD TIME TO MEASURE THE RETAINER TO GUIDE CLEARANCE ALONG WITH COIL BIND, STEM HEIGHT ETC.
WITH YOUR DEGREE WHEEL STILL MOUNTED TO THE ENGINE IN CORRECT TDC POSITION, AND THE VALVES ADJUSTED TO ZERO LASH, TURN THE ENGINE IN ITS NORMAL DIRECTION OF ROTATION UNTIL YOU COME TO 15 DEGREES BEFORE TOP DEAD CENTER OVERLAP ON YOUR DEGREE WHEEL, THEN SET THE TIP OF THE DIAL INDICATOR ON THE EXHAUST VALVE SPRING RETAINER, IN LINE WITH THE MOVEMENT OF THE VALVE. PRELOAD THE DIAL INDICATOR TO ABOUT THE MID-POINT OF TRAVEL, AND SET TO ZERO. DEPRESS THE VALVE WITH A SCREW DRIVER BY PRESSING ON THE VALVE END OF THE ROCKER ARM UNTIL THE EXHAUST VALVE CONTACTS THE PISTON, MAKE A NOTE OF THE READING ON THE DIAL INDICATOR, AND RECORD THE CLEARANCE. NOW, CONTINUE TURNING THE ENGINE IN ITS NORMAL DIRECTION TWO DEGREES AT A TIME, CHECKING AND RECORDING THE CLEARANCE EVERY TWO DEGREES UNTIL YOU REACH TOP DEAD CENTER, ON YOUR DEGREE WHEEL. REMEMBER, SINCE THE VALVE WILL BE MOVING, THE DIAL INDICATOR WILL NOT RETURN TO ZERO. YOU CAN EITHER SUBTRACT THE DIFFERENCE OR RESET THE DIAL INDICATOR BACK TO ZERO EACH TIME BEFORE YOU MAKE YOUR CLEARANCE CHECK.
MOVE THE DIAL INDICATOR TO THE INTAKE RETAINER AND START CHECKING THE INTAKE PISTON TO VALVE CLEARANCE THE SAME WAY YOU CHECKED THE EXHAUST, EXCEPT BEGIN AT TOP DEAD CENTER AND CONTINUE TO 15 DEGREES AFTER TOP DEAD CENTER, TURNING THE ENGINE IN ITS NORMAL DIRECTION OF ROTATION. THE ACTUAL POSITION OF CLOSEST PISTON TO VALVE CLEARANCE WILL DEPEND ON HOW FAR ADVANCED OR RETARDED YOUR CAM IS. REMEMBER, AS YOU ADVANCE YOUR CAM YOU WILL LOSE INTAKE PISTON TO VALVE CLEARANCE AND AS YOU RETARD YOUR CAM YOU WILL LOSE EXHAUST PISTON TO VALVE CLEARANCE.
THE RECOMMEND CLEARANCE IS AT LEAST .080” BETWEEN INTAKE VALVES AND PISTONS AT ALL TIMES, AND AT LEAST .100” FOR EXHAUST VALVES, WHICH EXPAND MORE WITH HEAT. ADD .030” TO THESE FIGURES IF YOU HAVE ALUMINUM RODS IN THE ENGINE TO ALLOW FOR THEIR EXPANSION AND STRETCH.
MOST AFTERMARKET PISTON MANUFACTURERS CUT THE VALVE RELIEFS QUITE GENEROUSLY SO UNLESS YOU'RE RUNNING SOME OUTRAGEOUS CAMS YOU SELDOM HAVE CLEARANCE PROBLEMS BUT STILL CHECKING THE PISTON TO VALVE CLEARANCE IS HIGHLY RECOMMENDED. CONSIDERING HOW OLD DSM'S ARE AND WITH SO MANY SHAVED HEAD/BLOCKS WITH HIGHER COMPRESSION AND OVERSIZED VALVES IT'S PROBABLY A MUST FOR EVEN MILD TO MODERATE CAMS. IT'S CHEAP INSURANCE.
HOW TO TUNE CAM GEARS ON A 4G63T
ON THE 4G63 DOHC ENGINE YOU CAN DIAL-IN INTAKE AND EXHAUST TIMING INDEPENDENTLY OF EACH OTHER TO REGULATE OVERLAP. AS YOU'LL START TO SEE AS YOU MAKE CHANGES, COMBINED WITH THE USE OF A CHASSIS DYNO (HIGHLY RECOMMENDED) YOU CAN FINE-TUNE YOUR CAM'S ENTIRE OPERATION BY ADVANCING OR RETARDING ITS ACTION, SQUEEZING AS MUCH HORSEPOWER AND TORQUE FROM YOUR STATE-OF-TUNE AS POSSIBLE.
IT'S IMPORTANT TO NOTE THAT ADJUSTABLE CAM GEARS HAVE NO DIRECT EFFECT ON THE DURATION AND LIFT OF THE VALVES, THAT'S THE JOB OF THE CAMSHAFT LOBES (PROFILE) AS DICTATED BY THE CAM MANUFACTURER. GENERALLY, ADVANCING A CAM GEAR OPENS A VALVE SOONER, AND CLOSES IT SOONER... RETARDING THE CAM GEAR, OPENS THE VALVE LATER, AND CLOSES IT LATER... SINCE ALL YOU'VE DONE IS "MOVE" THE FIXED EVENT.
ADVANCING INTAKE AND EXHAUST
THIS WILL PROVIDE THE CAR WITH MORE BOTTOM END POWER, AND WILL DECREASE TOP END. ADVANCING BOTH CAM GEARS WILL MOVE OVERLAP EARLIER BUT WILL NOT INCREASE IT.
RETARDING INTAKE AND EXHAUST
THIS WILL INCREASE THE CARS TOP END, BUT WILL DECREASE LOW END. RETARDING BOTH CAM GEARS WILL MOVE THE OVERLAP LATER AND BUT WILL NOT CHANGE THE AMOUNT OF OVERLAP.
ADVANCE EXHAUST ONLY
THIS WILL HELP THE CARS TOP END, AND IT REDUCES OVERLAP.
RETARD EXHAUST ONLY
THIS WILL HELP THE CARS MID RANGE POWER, VERY USEFUL FOR CARS WITH BIG TURBOS / BIG CAMS. BY INCREASING OVERLAP, IT DECREASES LAG SIGNIFICANTLY. DOING THIS WILL BRING THE BOOST ON ALL AT ONCE. VERY COMMON DSM MODIFICATION.
ADVANCE INTAKE ONLY
THIS WILL INCREASE OVERLAP AND HELPS THE CARS BOTTOM END AND MID RANGE POWER. THIS MOD WILL BRING THE TURBO ON ALL AT ONCE, ALTHOUGH IT ISN'T A VERY COMMON MOD FOR DSMS.
THIS IS JUST BASIC INFORMATION ON TUNING CAM GEARS I FOUND ON PROSTREETONLIN. PERSONALLY IT'S NOT WORTH THE TROUBLE AND I WOULD NEVER TOUCH THE CAM GEARS UNLESS I HAD AN ACCURATE BASELINE ON HOW FAR YOU CAN GO WITHOUT PTV CLEARANCE ISSUE.