If I remember correctly, the billet Rollmaster set does not have the 4 advance built into it. So if the installer put it in "straight-up", it is really 4 late. This really stresses the need to degree the cam. http://www.v8buick.com/showthread.php?t=87318&highlight=degree
Ya John, my comments were more aimed at the situation in general, not at you or anyone else in particular.. JW
The Rollmaster was not the issue, you did not install it correctly. Per your post you: "So, I first installed the timing set with the crank gear on the 4* advanced slot, lined up the dots on both gears, then double checked by measuring the actual intake centerline". If you put the crank gear on using the 4* Advanced slot you have to use the tooth on the crank gear with the 4 underneath it that is counter clockwise of the tooth with the dot underneath it . The ONLY time you use the tooth with the dot underneath it is when the crank gear is installed on the crank with the key way with the dot on it.
No, I had it installed correctly. What I meant was I had the tooth marked "4A" on the crank gear lined up with the dot on the cam gear. I was just going off of memory when I wrote that, didn't remember exactly how they were marked. After that, I installed it at the 8* advanced position, and the cam was still way retarded. In order for the cam to be installed correctly, as I mentioned before, I found that installing the crank gear at the straight up position, and installing the cam gear one tooth advanced, the intake centerline came out to 106*, right what I was shooting for. It's been on the engine for two years like this, and the engine runs as advertised with this cam. I agree that I shouldn't have blamed the timing set for this, as I had no way to verify it, but I just found it hard to believe that they could have ground the cam that far off.
Yes and thats 10" The guy called me at my lake house friday and said that he measured the cam at the lifter using a solid lifter and my lift seems to be much lower than advertized. He is checking everything he says to aviod having to tear it down again later. My cam card is missing. This is on my recipt TA Stage 1-455 .418"-.210' //.455"-.224'//113L/S From the catalog .406"-.210'//.441-.224'//113 L/S Seems like a very mild cam and with the stock rockers being 1.55 this would account for the lower numbers he's coming up with. TA must send these out expecting everyone to buy roller lifters. On Wed ( the next time he is open) I will take the new specs and see what we come up with when we degree the cam. The new balancer is right on spec.
John, at the lifter, the int lift should be .262, exh side lift should be .285 TA spec's there cams at 1.6 rocker ratio. X those lifts with your rocker ratio (1.55) Yes it is a 113 LS, but should be installed at 109 for 4* advance. Chris
Chris, to make sure I understand. I should advance the cam 4 degrees to make the lobe center 113 degrees? This is becasue the cam maker builds i a 4 degree advance? The cam card would have helped greatly and probably got tossed when the engine was assembled wit the timing marks straight up (maybe) If the cam is not advanced these 4 degrees and the gears are installed correctly ( marks aligned) do you think the vaccum will come up? I am sure they will not want to remove the front cover but it might have to come off. I hope they can get the oil pan to reseal. As of now I have zero leaks and 40 min run time.
Ken, You want to install it at 109* ILC It's ground (hopefully) at 113*ILC That's where the 4* comes in. I will go thru the whole process of the math, and what the stuff means, for those of you looking in on this that have never done it. Also, your cam can throw you a curve, because of it's size.. see below.. First.. Here's your card.. Now, here is the thing that is goofy about cam cards, on how they are written.. They are designed for the more performance oriented cams, that always have a .050 lifter rise open point for the intake valve before TDC, and a .050 close number on the exhaust that is after TDC.. But on small stock type cams, those numbers at .050 are often on the "wrong side of zero" or.. open numbers after TDC, and close numbers before TDC.. That's why it's -8BTDC on the intake open.. the "-" indicates that it's actually has a .050 intake open point of 8*ATDC. It's written with the minus signs to make the formulas work. To find at .050 duration, you have to add the # of degrees before TDC, + the number of degrees after BDC, + 180 (From TDC to BDC) You need this number to use in the calculation for Intake lobe center. Why 180?... Because the intake valve event is happening as the piston travels 180* of engine rotation. All open and close events are based on the engines piston position, relative to Top dead center,(TDC) and Bottom dead center(BDC). The numbers you get off a degree wheel, for most performance cams, will be intake open before TDC, and intake close After BDC. So adding 180* is required to get the at .050 duration number. Let's look at a typical performance cam with that formula.. We will call this my cam.. It's specs are 232/245/113 When you see something written like that, it's implied that it's : intake duration@.050 lifter rise/Exhaust duration@.050lifter rise/Lobe Center Separation. Intake opens at 7* BTDC Closes at 45* ABDC So, we add 7+45+180 to find out @.050 duration, and that adds up to 232* of @.050 intake duration. It's easier to understand, if I express that in how it's happening.. so, we have 7* before TDC, then 180* from TDC to BDC, and then 45* After BDC.. Or 7+180+45.. 232*- that number represents how far the engine turned, when the cam had the lifter off the base circle of the cam, .050 or more.. this is known as @.050 duration. Advertised duration is typically the same number, but with the lifter .006 off the base circle. That's the 260/276 numbers on your cam card. Anyway.. Then we use our duration at .050 number to find the center of the intake lobe (ILC). We use this formula. Duration @.050/2-intake open point at .050 So, 232 divided by 2 is 116, and then we subtract the intake open number, which was 7. To end up with a ILC of 109*. But in your case, you have to use the "-" sign in the factor So, on your card, -8+38+180 which equals 210*.. now if you add that 8*, instead of subtracting it from 180+38, your going to get the wrong intake duration at .050. Personally, I just look at the degree wheel.. it simpler than trying to add negative numbers.. If it opens after TDC, just subtract that from 180, and then add that number, plus the close number, to find the intake duration. Example.. on your cam that opens at -8BTDC I would add 172+38, to get 210*. 172 is 180-8... If you mark the open and close points on the degree wheel with little bits of tape or chalk, this all becomes much clearer, than trying to grasp it out in space here. Further.. Now we find ILC with the - number.. Formula- Intake open number at .050+intake close number at .050 + 180 divided by 2, and then subtract the intake open number. On your cam.. -8 intake open, 38 intake close+ 180=210 then divided by 2 = 105, then subtract -8 from it.. (in other words add it in) and you get 105+8 = 113 ILC. Now, here's the thing.. when you move the cam's position via the timing chain, you are not changing how big the lobes are.. so you always have to get the same intake duration at .050 when you do the formula.. You have already determined with the first half of the formula that your cam has an @.050 intake duration of 210* This particular cam will always be 210.. so after you move it with the chain, if you don't get 210 degrees in the formula, right before you divide by 2, then your intake open or close measurement is wrong! Example Move it 4* advance Intake open: -4 Intake close: 34 Forumula: -4+180+34- Equals the same 210*, even if the numbers are different. When I would measure it in the engine shop, when the intake open number came up at 4* After TDC.. I would then just write down 176, then find the intake close point, and add the two together. 176+34=210 But regardless, you have to get the same number at that point in the forumla, regardless of where the cam is installed with the timing chain. This is the number one place that folks screw this up.. not precise enough measurements, due to either equipment, or not establishing an accurate zero on the wheel. The complication comes, when you do have to take the wheel off, to move the crank sprocket.. the wheel has to go back on in exactly the same spot.. and just using the pointer is not accurate enough.. ---- Some guys will simply find the center of the lobe, and then go .050 or .100 or .200 on each side of it, average those two numbers, to find the center. Technically, it's exactly the same thing, we are just using the whole lobe, from .050 to .050 valve lift to find the center.. I prefer this method, because it is the most accurate, as well as you get more information on how big the cam actually is. They rarely match the card perfectly. I chuckle when I see folks that say the two methods will give you different numbers. If your equipment is accurate, you will get the exact same number.. you have to.. the center of the lobe is not moving, because your measuring differently.. Now, where to install this cam? First off, all the open and close numbers on the card, are for the cam at zero.. which has always been silly to me.. if you want it in at 4* advance, then give me those numbers, not the zero ones.. Anyway.. On the card, they want you to install the cam so the center of the intake lobe is at 109*. Intake lobe... Intake lobe.. Intake lobe.... Now, this cam, has the center of the intake and the exhaust lobe, both 113* from zero. So, it's known as a 113 Lobe Center Separation (LSA) camshaft. That number is derived by averaging the position of the intake and the exhaust lobe. IN this cam, that 113+113/2= 113.. Not all cams will have an equal distance from the center of the lobe on both intake and exhaust. You can't just blindly use the LSA number written on the card.. It's possible to have a 113 LSA cam, like mine that looks like this.. Intake centerline- 110 Exhaust Centerline- 116 110+116/2= 113 But in cam degreeing, we care only about the position of the center of the intake lobe, from zero.. in your cam, 113*.. .but in mine.. 110* (not the LSA of my cam which is 113). 4* advance with your cam, will be 109* 4* advance in my cam will be 106*... even though they are the same LSA of 113*. Usually it's the LSA number, but sometimes not... depending on the cam.. that's why the graph has individual intake and exhaust lobe centers written on it. Questions... anyone?
Cam degreed sat night. I am told its not in at 109 but at 116. So in your opinion can this be the cause of my low vaccum and poor idle? I think so as we found no vacum leaks the last intake gasket install.
Had the same issue with a 413 cam recently. Put the Rollmaster @ the 2A position and when I checked the numbers it came in at a 119 ICL :shock: :error: :af: There wasn't enough adjustment with the Rollmaster even on the 8A setting. To get it right I had to turn the cam gear CW and put a dot on the next tooth. I put the RollMaster @ 4R and then it came out right. Very glad I decided to degree it in..ALLWAYS degree in a camshaft.
Turned out ther cam was ground so far off it was unuseable. My engine builder installed a Comp cams unit as close to stock stage 1 as he could and it runs fine. Called Mike at TA and he had me send it back to Schnider and well after a dozen calls I never heard back. I did how ever wairt 2+ years to instal it after purchase. Still a call from Schnider would have been nice . Intake and exhaust were on diff lobe centers and the lift was more than .100 off on the short side on the total intake lift was around .340 if memory serves.
:shock: That really sucks! It's getting to the point where quality control doesn't exist what-so-ever.
this makes me madder than a frog without a water tight ass!! :rant: you bought the cam from TA, why didnt they send it to the cam grinder? they have far more pull than a single consumer. doesnt matter when you bought it, time doesnt change how a cam is ground. TA should have swapped it for a new one and then dealt with schneider.
