How to degree a cam.... April 25, 2014, 10:38:33 PM How does this process work? I've seen the task done on TV one time, but really paid no attention at the time. Who here has done it? Quote Selected
How to degree a cam.... Reply #1 – April 26, 2014, 10:53:04 AM This is what Ed Curtis posted on the Corral:CAMSHAFT DEGREEING - .050” LIFT METHODFirst of all, install the camshaft with the timing sprockets at ZERO, dot to dot on the timing set.Find top dead center: If the heads are off the engine, use a piece of flat stock or heavy angle iron with two holes in the ends that match up to the head bolts holes in the block, diagonally opposed from each other. This will form a bridge across the center of the piston to be used to set the degree wheel to TDC.We have a small threaded hole in the middle of our strap/bridge that we use as an "adjustable" piston stop. Having the bridge threaded with a bolt and jamb nut, TDC can be checked at different places of piston travel. It's verification that the TDC procedure was accurate. A piston stop threaded in the spark plug hole of the head may be used if the heads are still on the engine.In order to verify the correct TDC, you must get the degree wheel set perfectly on each crankshaft rotation. Install the degree wheel onto the crankshaft and make a timing pointer. Most times a simple steel wire coat hanger is easiest to use to manufacture a pointer. Mount the timing pointer in a spot where it can be adjusted and be read.To check, you rotate the crankshaft clockwise and follow the degree wheel numbers the pointer indicates. When the crankshaft hits the piston stop, write down this number. To verify your degree wheel is mounted properly for an exact TDC number, the noted figures should be the exact same number on the counter-clockwise rotation.Example. If you get 40* BTDC on one rotation, and 40* ATDC when rotating the other way, the pointer will be dead nuts "zero" when you remove the stop. If the numbers are off, say 35* and 45* then bend the pointer to the mean number (45*+35*= 80*) (80*/2 = 40*). The pointer should be at 40* to be at TDC. Then recheck. It is critical to verify TDC or all the numbers you get are useless.Once TDC is verified and the degree wheel is mounted accurately, you can check the cam timing events.Use a thin double sticky tape and attach a flat ground washer to the top of the lifter. A typical ARP head bolt washer is perfect for doing this. This little tip is what gives the drop indicator a solid flat surface to measure. Sometimes the edge of the lifter can't keep the indicator in the right spot to get good measurements. On assembled LSX engines, a special tool manufactured like an inverted golf tee may have to be used.Attach the drop indicator to the block or some SOLID place that will not allow for any movement.Be sure the travel of the indicator is parallel with the travel of the lifter. If it's not, the numbers will not be accurate. This set up may take a while but think of the indicator as your push rod so you don't want any wobble of angled movements. The indicator tip should always be on the flat of that hardened washer you just taped to the lifter body.Once you're happy with the entire set up, it's time to look at numbers.Set the indicator at ZERO on the dial.TDC verified.Indicator at ZERO.Fixturing tight and solid.Now rotate the engine slowly clockwise. Watch for the indicator to get from "ZERO" setting to the .050" lifter travel. Read the number the pointer shows on the degree wheel. Write it down. Do this at the .100" -.150" and .200" lifter rise numbers. This is strictly for validation of any and all of the numbers.Now do the same on the opposite side of the lobe.This can be done on the down travel side (staying with clock-wise rotation of the crank) or reversing the rotation, if your crank turning is such that you will not loosen up the degree wheel. If the degree wheel is bolted to the crankshaft using the balancer bolt, you don't want to risk loosening the bolt and screwing up the degree wheel location.Once you have all your numbers.The .050" number should be the same as the cam card. If not... they should be off the same amount from each side and that's when you make adjustments on the timing chain.Examples.You read 2* BTDC and 42* ABDC at .050 tappet lift on each side. PerfectIf you read 4* BTDC and 40* ABDC you are advanced 2* too much and need to make an adjustment.Now... If you read 4* BTDC and 44* ABDC don't panic. Notice you're at 2* off on each side of the lobe (4*-2*=2) and (44-2*= 42*). This is a set up error but you're still right on the mark. Quote Selected
How to degree a cam.... Reply #2 – April 26, 2014, 03:28:18 PM Comp Cams:http://www.compcams.com/technical/instructions/files/145.pdfA positive stop device is easy to make and I posted about it in this thread on page 4 and post #35 & described how to make it in post #38:http://www.foxtbirdcougarforums.com/showthread.php?34313-Porting-the-Edelbrocks-Heads-and-Lower-Intake/page4Darren Quote Selected
How to degree a cam.... Reply #3 – April 26, 2014, 09:25:09 PM Dang I hate that . I need a "slide the cam in, line up the timing chain, and go" kind of deal. LOL. I'll do some studying aand focused reading on these you guys posted later when I'm more relaxed from the day. Thanks a lot. Quote Selected
How to degree a cam.... Reply #4 – April 27, 2014, 10:05:52 AM Vinnie,Slide the cam in, install the cam plate, install the cam gear, install the cam gear on the crank, line the dots up on the gear when installing the timing chain, and button the motor up. For the most part degreeing the cam will net you some power but if done incorrectly it will do the opposite. From what I understand by most engine builders is that the quality of the timing chain and gears is what matters. I always buy Comp Cams sets and get one that has multiple indexes for cam timing. This is due to my engine builder degreeing the cam in every motor he builds whether its a high dollar one or a the run of the mill motor (like mine). I watched him do it and it was like me changing spark plugs it took him just a few minutes to do it but it would have been a couple of hours for me.When I put together the 331 for the Coupe I degreed the cam twice to find that "straight up" i.e. the dots on the gears lined up was in fact straight up. Ed Curtis wanted the cam installed "striaght up" so that is where it was installed. I called my guy and confirmed I was doing it right and he laughed and said that if I was just going to install it "straight up" then I should have just put it together and gone on with my business. What I gathered from that call was that a cam and timing gear set from a reputable place like Comp Cams or a reputable cam guy like Ed Curtis is that when you line the dots up on the timing set it will be just about dead on.Anyhow, if you have never done this I would highly recommend that you go through the pain in doing it at least once just so you understand how it works. The two biggest things you will need will be a degree wheel and a dial indicator with a magnetic base to get TDC dead on. You will need a pointer for the degree wheel but I just get a coat hanger and cut it up and make one as that wire is pretty stiff and works well.Degree Wheel:http://www.summitracing.com/parts/cca-4787/overview/Dial Indicator with Magnetic Base:http://www.grizzly.com/products/Magnetic-Base/G1480Is the dial indicator with base is not the best out there but it works for the couple of times a year I use it.Darren Quote Selected
How to degree a cam.... Reply #5 – April 27, 2014, 10:29:46 AM I am really good with that. Quote Selected
Topic: How to degree a cam.... (Read 1024 times)
previous topic - next topic
