I'm beginning to think this wasn't a math problem after all. I think you need to retitle the question. It has little to do with math and more with understanding and following instructions. The understanding and following instruction is the issue. This is my tough love year, my apologies for an offense this my cause. Buy the book, How to rebuild your SBC. These 4 pages of step by step and pictures will guide you thru this. Who knows, maybe your cam and lifters will survive the experience.
Just treat each cly as #1 cly and there is no math. Like one airplane mechanic told about radial engines. They are easy to work on. Just a bunch of one cylinder engines tied together is all it is.
Its set, #1 TDC, and it was math 18436572 720/8=90 1843 first 360 6572 second 360 So i watched 1 and 6, they are opposing Done! Now as far as that adjusting chart posted in this thread, does the engine have to have been run and lifters all pumped up before the adjustment.
Doesn’t matter. Hydraulic lifter get adjusted the Same way. Tighten slowly as you spin the push rod with your fingers. Stop just as the pushrod stops spinning. Add 1/4 turn. That’s how I do it anyway. Lifter on the base circle by the way.
Some guys (I guess who don't know math) either look up "valve adjustment" in the shop manual, or if not available, just adjust the rocker that is NOT opening a valve. Oh, and the BS about having to readjust them after you get it running, is only for guys who can't do a "cold" valve adjustment. Many later cars won't run with one or both valve covers off (too many accessories/brackets removed)
In looking for this chart and not being a died in the wool Chevy man I was looking at an old Motors manual . It showed at during 1961 a change from short travel to long travel hydraulic lifters in v8s
Well, we now know it wasn't a math question. We also know it was not to figure out what the lobes of the cam are doing at various parts of a 360 degree spin cycle to lift or drop a valve. Quite frankly I wasn't sure what was being asked at the time the OP posted it. I'm sure most were as confused as I was. And I'm sure your help is appreciated.
The guys at MOPAR already figured this out for ya. This will work exactly fine for adjusting your valves on your small block chebby.
Bearing in mind that the OP was asking what valves are "depressed" when the #1 cylinder is at TDC on the compression stroke, and also considering the identical relationship of the cam to the valves regarding opening and closing, I'm going to have to disagree with the above part of your comment.
Yes, "depressed". And looking down the barrel of a cam shaft I'm going to see something in that collection and positioning of lobes and try to make sense to the cylinder, #1 cylinder they represent and the position they are in to open or close a valve. Forget the fact he's trying to adjust valves. Although he is. 360 degress of the circle, 16 lobes. Assuming the separation is the same intake/exhaust, we can us 8 as a number focusing on intake valves. Now I never gave a fiddlers fart to why anyone would want that information, but I did see a complicated picture of what it might represent. Could be wrong here but, not knowing what lurks in the minds of men, I guessed it was a relationship thing of some kind they were set to discover. -"which of the other valves are depressed" But all and all, it was valve adjustment. Should have just said that in the first place.
@NoelC So you ARE referring to 360º of camshaft rotation. Most of us who build engines and use a degree wheel put it on the crankshaft, which requires consideration of 720º of rotation in order to adjust valves, or in the case of the OP's question, to know which valves are in what position at a given cylinder's TDC. By the way, using your method of "looking down the barrel of a cam shaft" is well and good for an inline engine. You will discover a valve-bending error of dividing 360º by eight if you're dealing with a 90º V8, because four of your "360º divided by eight" results will have to have an additional 45º (of camshaft rotation) added or subtracted, depending on whether you are counting clockwise or counter.
Can’t really trust that chart when they’ve got the y block dist. at the front and the flat head has 2 # 3 cyl
"When #1 cylinder is TDC on compression stroke, which of the other valves are depressed. " The real sad ones??? What's missing is clarity. Clarity on what was being asked for. Maybe even a why it's being asked. But if only reading the statement as a question, which other valves are depressed, I took that at face value he wanted to better understand positions pointed around the 360 degrees of a base circle. Depressed and opening, depressed and closing, or just riding the diameter of the base circle. My way is well and good if your trying to understand how it can breath and pass gas at the same time it sits and does nothing. Or maybe your trying to draw the profile for comparison. Quite frankly align the dots will make most quite happy and they never see a degree wheel. As far as adjusting valve clearance goes, a degree wheels not even needed for that, my post #47. My only mention of the degree wheel was to locate positions around a circumference. Hopefully that clears up an confusion on my reply.
The sequence 18436572 indicates the order of operation of the cylinders in the engine. In this case, when cylinder No. 1 is at the top of the compression stroke, the valves corresponding to the next cylinders in the sequence (8, 4, 6, 3, 5, 7, 2) will be in the depressed position. I used to have problems with any math problem, I asked do my math homework, found someone who do my math homework and it was the right solution. Over time, I began to understand this subject. It feels like I just had my brain changed.
#1 running mate, in this case #6 will be on compression so both valves closed or not depressed…. quick way to find running mates, 1843 6572 Put the second half of the firing order under the first half, boom! Running mates.
Jeez, Johnny! You have to watch what you say. There are people like @Bandit Billy and @Budget36 on here with delicate sensibilities.
Maybe this will help.......... Now, a little mental exercise.......how many of these engines have the same physical firing order but only seem different because the manufacturers numbered them differently? Look at the physical location of Chevys #1 and #8 cylinders. Then look at the Ford #5 and #4 cylinders. Chevy #4 and #3 and then Fords #2 and #6 Chevys #6 and #5 and Fords #3 and #7 and last Chevys #7 and #2 and Fords #8 and #1 Its the same physical pattern because of the 90 degree crank positions are the same, they just assigned the numbers differently.
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