Degreeing my new camshaft today only 3 questions

[dgie]

I just rechecked my new cam shaft and it the intake centerline is suposed to be 110 degrees but when I checked the intake lobe center it is 113.5. When it is on "0" on the timing mark. The new cam shaft is retarded almost 4 degrees, is this normal?
Also another thing I do not understand is that when I retard it on the crank by moving it to the "R" I am able to get it to 110 degrees and when I move it to the "A" I get 117 degrees. It seems that it should be the other way around. Can anyone explain why this happens? It is my understanding that if it 113 degrees you would want to "A" advance it to 110 degrees, my level of thinking may be backwards here
Also is this a viable way to compensate for 4 degrees difference. It seems that everyone uses cam bushings, can you use the key on the crank to bring it in instead?

[Infomaniac]

That shit happens.
That is why you degree it.
You read my posts about it.
Drill it for a bushing - correct it and put it the rest of the way together.

[dgie]

hey infomaniac, does it make sense that the lobe seperation is suposed to be 110 and I am getting 113. When I change it to "R" it goes to 110 should it not be advancing it with "A"? and are bushings better then using the keyways?

[Infomaniac]

To get the lobe seperation
You have to measure the intake centerline - then measure the exhaust centerline. add them up and divide by two.
That will not change no matter what you do to the crank gear.
If it does there is still something wrong with the method used to measure it.

[Infomaniac]

Load it up and bring it up here.
I will do it for you no charge.

[victorfb]

i think what he is asking is if the offset keyways are a good way to go. i am no pro motor builder so i am not going to say anything on that except that ive seen em. seems like most people use the bushings though.

[Moneypitt]

Djie, quit worrying about the lobe seperation. Trying to measure that without a surface plate, V blocks, and some very accurate indicators is tough. What you need to know is at what degree the intake starts to open, (.050 lifter rise) and where it closes, (same .050), then do the same for the exhaust. The info on the cam card is what you are verifying, you can't change the lobe seperation, just make sure the valve events are happening when the cam card says they should, particularly the overlap 180 degrees from TDC. If the intake .050 rise is on time (BTDC X degrees) and the exhaust is X degrees BBDC and the exhaust is X degrees B 180 f/ TDC (overlap) there isn't much more you can do. As discussed before, you're looking for the valve event to be at least on time (by degree) or a little up. If it comes out straight up, kick it. BUT these measurements are not easy. The margin of error can give some erronous numbers. Do it again, double, triple check everything before you assume something is wrong. The .050 lifter rise is critical, and some what difficult to watch, if the wheel is off 1/16 of an inch all you #s will be off. As you can see, everything HAS to be perfectly measured, and the original setting of the wheel at TDC leaves NO room for error...Keep at it.. It WILL fall in place........Moneypitt

[dgie]

Infomaniac thanks for the offer, I may do that if I can not get it figured out. You mentioned you are going out of town in a earlier post, so I will see if I can not get it figured out by then, if not I will load it up there and you can show me what I am doing wrong. Moneypitt I am doing lobe seperation because thats what they are doing on the video(I may be combining lobe seperation with lobe centerline below). I do not know if it is right but,I better go through what I did to give a better idea of what I am doing. I started by finding true TDC. I did this all twice to verify my numbers. The next thing I did was set the dial indicator on the intake lifter the numbers that I came up with are 65 degrees at .050 and 162 degrees at .050. I added these together and divided by 2 and got 113.5. I then moved it over to the exhaust and came up with 59 degrees at .050 and 155 degrees at .050 I added these numbers together and divided them by 2 and got 107 degrees. I then added the 113.5 and 107 together and divided by 2 I came up with 110.25 degrees. The cam card says 110 degrees lobe seperation, I am pretty close to what it should be, if me and the cam card are talking about the same thing. I then looked at what I got from the numbers above for the intake 113.5 and the cam card says 106 intake centerline (just noticed it) DAMN!!! thats 7.5 degrees retarded...does that sound right :( seems like if it is, I should worry about having something that far off in my motor.
Here is everything on the cam card
Grind # OL 292H-10
Comp Cam
Valve Adj intake .000 Exhaust.000
Gross valve lift Intake .518 Exhaust .518
duration at .006 Tappet Lift
Intake 292 Exhaust 292
Valve Timing at .006
open close
Intake 40 btdc 72
exhaust 80 bbdc 32
Then it says: These specs are at 106 Intake center line
Intake Exhaust
Duration at .050 244 244
lobe lift .3235 .3235
lobe seperation 110.0
[ July 26, 2003, 01:55 AM: Message edited by: dgie ]

[Moneypitt]

Djie, It appears that you are mixing up the numbers you're getting. The 110 lobe centers has nothing to do with the cam timing. It only establishes the relation of intake lobe, to exhaust lobe profiles. I notice that they're using .006, (6 thousants) lifter rise. This is way off industry standard of .050, but ok use their way, Now verify the intake opening degree, is it correct to the card, if yes, continue on. Check int closing, then exhaust opening/ closing. You will find that what ever error (early/late) will be steady through the cycle. This is where you adjust the cam timing, up, back, or where ever you want it. The cam grinders usually get their numbers REAL close, and any changes required are usually because of our valve train related parts, ie: chain and gears, or gears. Here is where you decide how to use the three way lower gear. Bushings, in my opinion, are not necessary in these type engines, as chain streech will change the timing of the cam a little anyway. Just verify the info on the cam card, but the lobe seperation has no bearing on the actual cam to crank timing, which is what we consider inportant.(just don't be late, a little "up" helps.)...Moneypitt

[Moneypitt]

Re checking your card #s, it shows an 8 degree overlap..Int opens 40 BTDC, 8 degrees later, at 32 BTDC the exh closes. This is the event that must happen on time (w/ the crank) to benefit from this engineered overlap. So check this 40, 32, and adjust as needed, or even if its right on, you can still kick it 4 to allow for future chain streech. Even the double roller chains will streech, usually only 2 or 3 degrees, so you'll still be up 1 or 2 a year from now. (stock type chains streech, and never stop streeching.) These 2 #s 40/32 need to be that, 40/32 or 42/34, 44/36, but not 38/30, on you wheel, see it now???

[dgie]

man this is a little more complicated then the perfect world in the video, they do not explain any of this. In fact the info that came with the cam said just check intake centerline and match that to the card and that will tell you if you are dead on, advanced, retarded, etc. When I do that at .050 like they say in the instructions I come up with 113 degrees when it is suposed to be 106 degrees. :confused:

[Moneypitt]

The cam card is giving you info @ .006, not .050 as the instructions indicate. Try .006 lifter rise and see where the intake is. (40 BTDC). I don't know what you're checking to get your lobe sep #s, unless you can verify EXACTLY when(what degree) the intake is at .006, or is it at .050. You see there is a large difference here.
Just forget the lobe sep. and check when the valve event is starting, at either .006, or .050.The cam card says .006, although that is not the industry standard. See if the numbers play with either lifter rise number, And forget the lobe seperation mystery, once you figure out the right lifter rise to work from, you can go back to this unnecessary lobe center verification, and call the cam guy with some actual info as to valve timing. I don't think the opening and closing ramps are the same profile, so trying to determine lobe center from a given point of lifter rise / fall is, in my opinion,
in-accurate. Again just check the valve event against absolute TDC......Moneypit

[dgie]

I was just on realoldspower.com and they said that I might be checking the exhaust lifter instaed of the intake, is the intake lifter not the second lifter back on the right and the exhaust the first one back the right on a 455 olds. This is looking from the front of the motor to the back

[dgie]

Interesting stuff moneypitt.I will check those figures tomorrow. I am still wondering about the question above about which is the intake and which is the exhaust on a 455. I just assumed that the second one is the intake lifter, do you know if it is?
[ July 26, 2003, 10:04 PM: Message edited by: dgie ]

[dgie]

I just got a response on realoldspower and it turns out I am on the wrong damn lifter :mad: The intake is the first not the second like the chevy's Hell I figure they are all GM products, go figure. I cant wait until I start checking for coil bind, that is going to be real fun...