This is cut and pasted from Yardleys website.[/B] DON'T TAKE ANY MANUFACTURER'S WORD FOR IT!!! DEGREE YOUR CAM!!!! There appears to be two separate camps with regard to which method is the best to use when degreeing a cam. The Crane Cams website recommends degreeing your cam using the opening and closing degrees of the intake valve at .050" as compared to the specifications on the cam card. And the centerline method they mention does not use the formula Jim, Al Fiandaca and Scotty Guadagno use. I'm not sure, but if a serious formula is needed to nail the centerline degree, I would expect a company like Crane to mention it. Jim,Al and Scotty all use the centerline method, where you compare the degree of the centerline to the specifications on the cam card. Who's method should you use? Well, seeing as how Al has a frighteningly fast car, and Jim and Scotty build world-class BUICK race engines, I'll put 100% faith in what they do and recommend. So I suggest you use the centerline method as outlined below. Seriously, when someone asks you where your cam is degreed at, stating the centerline is a concrete way to state the facts: it is 4* advanced at a 110* centerline. So, just WHERE should you degree your cam anyway? Well, information is priceless. You want to find the centerline described on your cam card. Then from there, advancing the cam transfers some HP over to torque, and moves the powerband down. For example, in Dyno2000 it shows: At 0* HP=480@5800 and TQ=501@4500 At +8* HP=465@5500 and TQ=517@4000 You can see where the powerband is now 1200 rpm lower on the HP side, and 1500 rpm lower on the torque side. And it follows that retarding the cam has the opposite effect, transfering some TQ over to the HP side and moving the powerband higher. The results differ by cam, and this cam doesn't respond nearly as much to retarding as it does to advancing. At -8* the numbers don't drop much below the 0* mark, but the rpms move way up over 6000. A waste really. You'll want to mess with a computer program like Dyno2000 to see what affects advancing and retarding your cam have. Or you can talk to others with your setup and see how they have it setup. That's why the Buick Performance Group is such a valuable resource. Here's what you'll need to degree your cam: The specification card (cam card) that was included with your cam. A cam degree kit - which includes a degree wheel and a dial indicator. A wire coat hanger (you will need this to fabricate a pointer if your degree kit doesn't come with one). A piston stop (made from a discarded spark plug - used if the heads are still on the engine). Click here to learn how to make a piston stop. It is advised to use a TA double roller timing chain with the 9-keyway crank gear for maximum adjustability. Here is what Jim Weise and Al Fiandaca explained to me about degreeing in a cam. 1) To begin, install the cam and timing chain, being sure to install the cam straight up (line up the 2 dots on the cam gear and the crank gear). Bolt the degree wheel to the crank snout and affix the pointer to the block using a timing cover bolt hole located at about 1 O'Clock from the crank snout when looking head on at the front of the block. If you don't have a pointer, fabricate one from a coat hanger. It should look like this. 2) If the heads are off the engine, find TDC by sticking the magnetic base of the dial indicator on the top of the block deck next to the #1 piston. Then bring the piston up and watch the dial indicator to see when it maxes out. At the highest reading you'll be at TDC. Set your degree wheel to 0* at the pointer. If the heads are still on the engine, proceed to step 3. If the heads are off the engine, proceed to step 4. 3) With the heads still on the engine, you will need to locate Top-Dead-Center (TDC) of the #1 piston. Here is where the piston stop comes in handy. Remove all the spark plugs, it makes turning the engine by hand all the more easier. The rocker arms and pushrods should also be removed to allow easy turning by hand. You want to find TDC on the compression stroke, so rotate the engine until the lifter on the intake lobe starts to fall back down into its bore, then thread the piston stop into the spark plug hole of the #1 cylinder. Now, rotate the crank clockwise until it stops - you will definitely feel when the piston hits the stop. Mark down the # on the degree wheel that the pointer is pointing at. Then rotate the crank the other way until it stops. Again, mark down the # on the degree wheel that the pointer is pointing at (the number of degrees away from TDC you are). Now subtract the lower number from the higher number, then divide the answer by 2. You will need to spin the degree wheel this many degrees to get to TDC. Then snug up the crank bolt holding on the degree wheel - being careful not to move the wheel when doing so, then take your readings again. You will find you are at the same degree* each time the piston stops when turning it both clock and counterclock wise. If you are only a few degrees off, instead of repositioning the degree wheel, you can simply bend the pointer to where you want it. Now, remove the piston stop. Then you can turn the crank so 0* lines up at the pointer and you will be at 0* TDC. EXAMPLE: 1st reading is 12*. 2nd reading is 24*. 24 - 12 = 12. 12 divided by 2 = 6. Rotate the degree wheel 6* from 24* toward 12* (assuming you left the degree wheel at 24* when doing the little math problem here. Then when checking, I find the pointer stops at 18* on the wheel each time the piston stops. Now I can turn the crankshaft until the pointer is pointing at 0* TDC. 4)With the engine's #1 piston now at TDC, the next big challenge is positioning the magnetic base of the dial indicator solidly on the engine and in such a way as to allow the long rod to drop down through the pushrod hole in the block until it rests in the CUP of the #1 INTAKE LIFTER. (Some like to screw it into the rocker arm shaft pedestal.) NOTE: Some builders like to flip a lifter over in the lifter bore and take the reading off the bottom of the lifter. Others like to position the rod on the edge of the lifter just next to the cup - to avoid the cup from moving and giving you a false reading. I once watched Jim Weise do it in the cup and on the rim of the cup and came up with the same answer each time. It is a matter of personal preference, but I feel the bottom of the lifter and the edge of the cup can possibly result in the slipping and repositioning of the rod of the dial indicator, resulting in frustration and error. 5) Once the dial indicator is positioned correctly, zero out the dial indicator. 6) Now we begin degreeing the cam. Whew! We must start with the lifter on the back of the lobe (called the Base Circle), so rotate the engine until the lifter has dropped all the way into its bore. It will remain there for a few degrees of crankshaft rotation. At this point zero out your dial indicator. SLOWLY rotate the crank clockwise (direction of normal rotation) until the lifter has been pushed up in its bore and the dial indicator reads .050" (fifty-thousandths of an inch). You may "bump" the breaker bar with your hand to slowly creep up on it. We are looking for the point where the lifter has been pushed up by the cam lobe .050" from the bottom of the lobe - or the base circle. The lifter has now ridden on the intake lobe and has been pushed .050" out of its bore. NOTE THE READING ON THE DEGREE WHEEL and WRITE IT DOWN!!!!!!!! This reading is .050" past the bottom of the base circle of the #1 intake lobe. 7) Continue rotating the crank and when the dial indicator again reads .050" NOTE THE READING ON THE DEGREE WHEEL and WRITE IT DOWN!!!!!!!! This reading is .050" before the bottom of the base circle of the #1 intake lobe. 8) Now, with your 2 readings plug them into this formula: 1st reading (intake open) plus 2nd reading (intake closed) plus 180 divided by 2 minus the original intake open# equals the centerline you are currently at. EXAMPLE: My 1st reading was 4, and the 2nd reading was 45. So, 4 + 45 + 180 = 229. 229 / 2 = 114.5. 114.5 - 4 = 110.5 centerline. This was the first reading I took with my cam. I had previously installed it at 6* advanced at the crank. So to get to the desired 108 centerline, I advanced the cam 2* more, to +8 on the crank gear. It came out at a perfect 108* on the nose! You should initially get your cam degreed at the normal recommended centerline. Then advance or retard your cam from there to get the right degree you are looking for. Jim Weise told me he never degrees a cam straight up. Instead, he always puts it in advanced. Even if it takes setting it at 4* advanced to get the normal centerline reading, he'll advance it from there. This is where the 9-keyway crank gear comes in handy. Jim told me that on one cam he did, he had to actually "skip a tooth" between the cam gear and crank gear to get it to degree correctly. WOW! Was that cam ever ground wrong! I personally wouldn't want that cam in my engine. -------------------------------------------------------------------------------- Making a piston stop To make a piston stop, simply break off the porcelain tip from an old sparkplug (one that will fit your engine). Then remove all the center debris (porcelain, copper conductor). Next, if need be, use a drill and drill out any leftover "guts" of the plug. Then tap the center of the plug to accept a threaded rod (you can just cut the top off of a long bolt). The rod must be long enough to extend beyond both ends of the plug "base". You can thread the stop into the plug hole, then screw the rod in until the piston butts up against the rod and is prevented from reaching TDC. I like to use a lock nut on the visible end of the rod to ensure the stop remains fixed in the same spot the entire time I am using it.
This is a very helpful thread for many but there are a couple of things that may need to be addressed. If using a dial indicator to locate TDC(see step 2), remember that the piston will "dwell" at max piston rise for a number of degrees(this will vary engine to engine depending on rod length,ect). TDC will be located precisely in the middle of that dwell time and if using the piston stop method, note that the readings will be X degrees BeforeTDC and X degrees AfterTDC on the degree wheel with TDC being centered exactly between them. Something else that needs to be considered, especially with TA introducing the street roller cams, is when degreeing a flat tappet cam, use a flat tappet type follower and when degreeing a roller cam, use a roller or a matching radius type follower! Using the wrong type follower for a particular cam will produce some very strange readings in comparison to the cam card! To clarify, you will still be able to determine the lobe center, LCA, and lift but the duration figures(advertized & @ .050") will be skewed:eek2: ! Good Luck!
No intention of highjacking the thread just want to relate a story. Or do it like my brother and not worry about it and bend all the valves on your first rotation. True story! I bought a car cheap off him because he wouldn't listen. After that he always paid me to do it because he was too lazy to learn. Of course he is a rich engineer now and I'm a blue collar contractor, so maybe he wasn't so stupid after all. Mikey
That is slick info and super helpful. I would have taken manufacturer's word since I have my first American car.
