Also if no one's mentioned it, the lash on the valve you are checking should be set to zero.
Degreeing a Cam, or not.....
- Thread starter Kent mosby
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He did that. Kim
I finished checking the Lobe centerlines. I got 109* for the intake and 115* for the exhaust. With my checking without a degree wheel and taking all measurements off the balancer I think the measurements are pretty close for the centerlines. Would this make you comfortable leaving it as is?
If you are going to measure at the retainer, use the same lift point on both sides if it's a symmetrical lobe. The math with work out the same. You can pick .050, .075, .050 off max lift, doesn't matter, the math will get you the centerline number.
I won't bother moving anything for the 1* it is off. Waste of time.
I won't bother moving anything for the 1* it is off. Waste of time.
Do they open and close at the same time as #1?
I thought I remembered he did as I was typin. Gettin old sucks.
I will do this tomorrow as I have a meeting to go to.
I would think number 6 as it’s opposite in the firing order. Kim
That's a good question. Probably going to have a different open and close, start/stop degree cause the crankshaft with be in a different position on those other cylinders.
Can do the check on cylinder #6 if not too much trouble to get that next valve cover off.
#6 is exactly 180° opposite of #1 as to when it fires. (at least it is on the small blocks) big blocks turn the distributor the opposite way, so you are going to have to check this. Same firing order as the small blocks, I don't know right now. Others will probably chine in. (Looks like @oldkimmer confirmed this above ^^^)
After testing .050 on #1, roll the crankshaft over 360° to compression TDC on #6.
Then do your .050 test again on that cylinder.
Then your centerline numbers should be the same between the 2 cylinders.
This gets to be a bit of a brain tease, the numbers of the centerlines should be the same.
You are smart enough to figure it out, when the numbers all start matching up it will make sense to you.
So far, so good.
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replicaracer43
Grumpy Old Man
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In theory yes, but in real life...NO
512Stroker
We are all here because we are not all there.
If the timing events are truly that far off, you have a bigger problem somewhere in the valve train.
PRH
Well-Known Member
If you’re confident in the measurements, you should be good.
Remember, you were trying to verify the cam wasn’t way off, for some strange reason.
You lined up the dots....... it “should” be close.
The 109/115 is a 112lsa installed 3* advanced.
Only 1* off from the cam card.
I will redo all the numbers again tomorrow or Tuesday. Another thought or question. I have both rockers on. Turning the motor over is a big pain and I feel that there may be some spring tension or compression. It is about time for adjusting the valves. Would it be wiser to remove the rockers so that I could rotate the engine more easily? I would not want to remove the heads. I
Can then measure lift directly off the solid lifters. I have an adjustable rod that I can use if needed.
Thank you everyone for all the advice, help and encouragement.
Can then measure lift directly off the solid lifters. I have an adjustable rod that I can use if needed.
Thank you everyone for all the advice, help and encouragement.
512Stroker
We are all here because we are not all there.
Take the spark plugs out.
I can take 7 of them out but one I have to remove headers and that requires undoing motor mounts and moving the motor. What about the rockers?
I'd leave it on number one. There's already way more than enough things to confuse Kent about. Just my simple minded opinion.
512Stroker
We are all here because we are not all there.
I would not remove the rockers.
Rockers off and plugs in you will never rotate the engine as the compression has no way to escape the cylinders.
What the hell kind of headers do you have that you need to pull the header to get the plug out - that aint right.
with a little effort I'm sure you could get the last plug out.
I might take modifying a wrench
I might take modifying a wrench
Didn't think of that.
TTI 2 inch. The #6 plug is a pain in the butt. How about just removing the 7 plugs and the left side rockers? OR Maybe I can back out and remove the adjuster bolt and then I could measure directly off the lifter/rod and bypass all the geometry/ratio etc.??
I will try.
512Stroker
We are all here because we are not all there.
Dont mess with rockers - no need to.
If you are using 11/16 hex plugs find the equivalent plugs in 5/8 hex, it makes a big difference in getting them out.
I use a modified 5/8 long end wrench on # 6
You are doing fine at measuring lift at the valve spring retainer washer.
Lift measurements start when the valve begins to move, (and end when the valve stops) not at the .050 ths point like when measuring duration degrees.
Sorry I didn’t read all the comments because sometimes you see something so wrong that guys say and then I would probably have to point something out. I don’t know your whole combo but from your first post you sound disappointed. Not for me every cam I install is 4 degrees advanced. I want low end, and I want 60 foot performance. I with tune the chassis to hook and do what I need. If I can’t make bottom end I won’t get the performance I want. Now as far as dot to dot. I’ve volunteered to go to friends house for free to at least eyeball dot to dot. Most of the ones I found wrong were the guys that eyeballed top dead center. Others just plain looked at the dot to dot from an angle. Now as far as manufacture or factory part accuracy. It’s sucks!!! 10 plus times I’ve found dot to dot so far of a miracle couldn’t get you failed in. That’s about all I can say.
I retested the CL and my 0 on the dampener is within 0.5 degree. My TDC stop was at 12.5 degrees BTDC then rotating all the way around it was at 12 * ATDC. So 0* on the dampener is TDC.
When I did the .050 lift I got 4.5* BTDC again on opening and 57.5* Lift at ABDC for closing. Same as last time. This indicates 10.5 degree retarded opening and 6.5 degree retarded closing. Correct??? Average 8.5* retarded
I got the duration at .050 at 4.5+57.5+180 to be 242 degrees, Close to 246 on the cam card.
When I checked the intake CL, I measured the maximum lift of the intake lobe on the spring retainer, Zeroed the dial and then backed off .100 and then moved the crank clockwise until it reached .030 before max lift and it was at 91*. Rotating past maximum lift and proceeding to .030 after I got 142*. adding them and dividing by 2 I get 116.5 degrees for intake CL. I did it again at .075, I think, and got 68* and 163* summing to 231 and divide by 2 to get 115.5 for intake CL. If we call it 116* then it is 8 degrees retarded from the 108 indicated on the cam card. What is the difference from my other measurements? I had the degree wheel attached to the dampener(thanks @George Jets ) this time. Last time I was measuring with a caliper the distance. Being on a radius I think messed me up and made me think I was close. Am I missing something??? I will have to look at the timing gear receipt and see if it has 8 degree of adjustment before I open the front of the motor.
Tonight I will do the exhaust opening lifts at .050 tappet lift and closing as well. Then I will calculate the exhaust duration . After that I will calculate the exhaust CL and from that the lobe separation.
8 degrees seems like a bunch but I measured several times and the results match closely. I will post the exhaust CL and duration tonight when I get home. Lobe separation also.
When I did the .050 lift I got 4.5* BTDC again on opening and 57.5* Lift at ABDC for closing. Same as last time. This indicates 10.5 degree retarded opening and 6.5 degree retarded closing. Correct??? Average 8.5* retarded
I got the duration at .050 at 4.5+57.5+180 to be 242 degrees, Close to 246 on the cam card.
When I checked the intake CL, I measured the maximum lift of the intake lobe on the spring retainer, Zeroed the dial and then backed off .100 and then moved the crank clockwise until it reached .030 before max lift and it was at 91*. Rotating past maximum lift and proceeding to .030 after I got 142*. adding them and dividing by 2 I get 116.5 degrees for intake CL. I did it again at .075, I think, and got 68* and 163* summing to 231 and divide by 2 to get 115.5 for intake CL. If we call it 116* then it is 8 degrees retarded from the 108 indicated on the cam card. What is the difference from my other measurements? I had the degree wheel attached to the dampener(thanks @George Jets ) this time. Last time I was measuring with a caliper the distance. Being on a radius I think messed me up and made me think I was close. Am I missing something??? I will have to look at the timing gear receipt and see if it has 8 degree of adjustment before I open the front of the motor.
Tonight I will do the exhaust opening lifts at .050 tappet lift and closing as well. Then I will calculate the exhaust duration . After that I will calculate the exhaust CL and from that the lobe separation.
8 degrees seems like a bunch but I measured several times and the results match closely. I will post the exhaust CL and duration tonight when I get home. Lobe separation also.
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