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ISX

Easy way to set valves

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ISX    58
ISX

I set my valves today, figured I would show everyone how I do it. As long as you know the firing order and valve lash (which are both on the cummins id tag) you can set the valves. This is called the valve overlap method. Basically the pistons have running mates. Running mates are pistons that go up and down together in exactly the same positions, as in they both hit TDC at the same time. The difference is that one of them is on the compression or power stroke, and the other is on the intake or exhaust stroke. To find the running mate, you simply take the firing order and split it in half. Our cummins' firing order is 153624. So splitting it in half would mean 153-624. If you put the second number under the first, you would have 1/6 5/2 3/4 So 1 is 6's running mate and 5 is 2's, 3 is 4's. Since the running mates are 360 degrees out of phase, when one of the hits TDC compression/power stroke, the other is hitting TDC exhaust/intake stroke. This is perfect for setting valves because you can simply watch the running mate of one piston and it will be on the exhaust stroke with the exhaust valve open, when it hits TDC and transitions to the intake stroke, the intake valve will open. Once you see that intake valve move, stop. This is TDC, or as close to TDC as we need to be. The running mate will be on the very end of the compression stroke and the start of the power stroke and the valves will be on the opposite side of the cam lobe since they must be shut during the compression and power strokes. You can now adjust the running mates valves, intake and exhaust. For example. To do the valves on #1, you would watch #6. The #6 will open and close the exhaust valve and once the exhaust valve closes and the intake starts to open, you stop and now you know it is at TDC. Since 1 is it's running mate, you know 1 is on TDC compression/power so you can do both valves on #1. Now look down the line and you will see that the exhaust valve on #2 will be open. Since 5 is after 1 in the firing order, 5 will be the next valves you adjust, and since you watch 2 because it is 5's running mate, you will watch #2's exhaust valve close and start to open the intake, you stop and do the valve on number 5. Basically you will be turning the engine 120* to do each valve. You will do them in the same order as the firing order. Here is the reference order. Do 1 by watching the valves on 6. Then 5 by watching 2. Then 3 by watching 4. Then 6 by watching 1. Then 2 by watching 5. Then 4 by watching 3. The next one you watch will have the exhaust valve open so that will be a clue that you are doing it in the right order. It is a very fast and bulletproof way of doing it. It works on any engine also. Just split the firing order and stack them and you have your running mates like I showed earlier, it always works.

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ISX    58
ISX

Will work on anything really. Engines might have different techniques to set the actual valves but every single engine MUST have both valves closed to build compression and build power during the power stroke. As long as you know the running mates, you are good to go. I went out and looked at my 7.3 since I got the heads off to see if the running mate pistons were the same depth and sure enough, they all were. I do this technique because it is more accurate than the one in the book that you set a few on every cylinder, rotate 360 and do the rest. You also have to have a book to know which ones you can do. You can wiggle the valves and figure it out but that really isn't a good idea. Plus you go to a different engine and your lost once again. The way I show is universal.

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Wild and Free    1,112
Wild and Free

It works but then on mechanical actuated injector engines you add the injector adjustment to the mix and it gets even more complicated. Then you go to Cummins inner base circle versus outer base circle adjustments and your head will spin.:ahhh:But that is on the bigger engines.The STC engines were different again and on and on, then detroit then cat engines and I am getting way off subject here but the simplicity of some engines is great for the do it yourselfers.

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ISX    58
ISX

It works but then on mechanical actuated injector engines you add the injector adjustment to the mix and it gets even more complicated. Then you go to Cummins inner base circle versus outer base circle adjustments and your head will spin.:ahhh: But that is on the bigger engines. The STC engines were different again and on and on, then detroit then cat engines and I am getting way off subject here but the simplicity of some engines is great for the do it yourselfers.

I messed with those PITA's in school. He would put us on one and tell us to set the valves but not how to do it, he wanted us to figure out the mess for ourselves. We worked on some big CAT and after messing with all the others that were Intake Exhaust I E I E I E.. that one was I think I E E I I E E I..so he tried to trick everyone with that. We didn't even do anything to the ISX, just hooked it up to a computer and floored it then cut out all the injectors but 2, which it could hold idle on just those 2 which I thought was pretty neat. Then you ran all these other little diagnostic tests and it would either pass or fail them. I guess that setup is good as long as you can easily get to all the sensors when they go bad lol. Now I remember that CAT having those injectors too. You had to tighten them down to exactly the right torque or they would mess up.

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white01    0
white01

Nicely done... :thumbup2: For those of you that have the 12V's or if you want this will also work on the 24V's as well...

mopar...your write up on adjusting valves..i printed it off and is pinned up on a board in the shop...:thumbup2:

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freesimons    0
freesimons

Excellent write up and video. Thanks! I just did adjusted my valves on my 97 cummins 12v using it. I have a question though. I turned the motor over by cranking on the alternator bolt, which is the reverse of the normal engine direction. To set number 1 I watched number 6 but the intake closed before the exhaust open. On the video how were you rotating the engine? The normal direction or reverse?

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ISX    58
ISX

Excellent write up and video. Thanks! I just did adjusted my valves on my 97 cummins 12v using it. I have a question though. I turned the motor over by cranking on the alternator bolt, which is the reverse of the normal engine direction. To set number 1 I watched number 6 but the intake closed before the exhaust open. On the video how were you rotating the engine? The normal direction or reverse?

I am rotating it clockwise from the front by tightening a damper bolt but this is not advised. Using the alternator is the best way and you have to work in reverse so you would watch the intake come up and once the exhaust valve moved you would stop. To rotate the engine the right way properly, you would need a barring tool which goes into the bell housing to turn the flywheel, takes forever but won't break anything, the damper way could break damper bolts or something which is why I wouldn't do it. In reverse the timing would be 426351 and watch the exhaust valve instead. I will probably be doing it this way from now on, using the alternator.

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freesimons    0
freesimons

Thanks again for the clarification. Sorry for being such a noob but could you be more specific on how to set the valves turning the motor with the alternator nut. Would I still start by looking at cylinder 6 but the intake as it transitions to exhaust to set cylinder number 1? What is the advantage of only setting the valves one cylinder at a time then rotating it 120 degrees? I do have the manual and it shows which valves to set when cylinder number 1 is at TDC. Then it shows the rest of the valves to set after rotating the motor 360 degrees. Thanks in advance for your patience in explaining.

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ISX    58
ISX

Thanks again for the clarification. Sorry for being such a noob but could you be more specific on how to set the valves turning the motor with the alternator nut. Would I still start by looking at cylinder 6 but the intake as it transitions to exhaust to set cylinder number 1? What is the advantage of only setting the valves one cylinder at a time then rotating it 120 degrees? I do have the manual and it shows which valves to set when cylinder number 1 is at TDC. Then it shows the rest of the valves to set after rotating the motor 360 degrees. Thanks in advance for your patience in explaining.

No such thing as a noob here! We are all here to help or learn from each other, no matter how simple something may seem, and this is kind of weird anyways which is why I added a video. Anyhow when you turn the alternator the engine rotates backwards from the normal way. Normally it goes exhaust then intake (then compression and power) but since the alternator only turns it backwards (and slips the other way as I assume you found out), the process is also reversed. Going backwards you would see the intake valve open then close as the exhaust valve opens. Right when the exhaust valve starts to open is when you stop, then you adjust the running mate piston since it will be on the compression/power stroke transition which means the valves are shut so you can adjust both of them. The running mates will be the same but you are just working in reverse which means the valves will be working in reverse as well (intake closing as exhaust opening, rather than vice versa if you were turning the engine the correct way). The only reason I do this is because I don't have to find TDC and have a book that tells me which valves I can set. I know if one piston is on valve overlap, that it's running mate has both valves shut and I can do both of them. Then you crank it 120* and do the next one. Once you get the hang of it you can fly through the valves. I will make another video hopefully tonight showing you everything in reverse since I know this is different than the way you are used to (the way it shows in the book). I am going to have to do some figuring using the book method to see exactly where each valve is, but I think the method I am showing you is more accurate since the cam lobe will be opposite to the pushrods whereas the book method has them pretty close. I will figure it out tomorrow though and see how close they really are. Keep asking questions if you are still unsure of something :thumbup2:

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ISX    58
ISX

Awesome! Thanks and I hope you're having a great Thanksgiving. :stirthepot:

I was until I had to go freeze to make you a video :lmao: Naw I needed to make one anyways :thumbup2:

So here ya go. Let me know if you need a better video, that one was a little crappy since it was dark out.

http-~~-//www.youtube.com/watch?v=7PsEtQzdugw

--- Update to the previous post...

I said I would make something to show where the valves are on the book method and after 2 hours of starring at it I think I got it all worked out.

Posted Image

The spreadsheet shows the cam lobe position based on TDC #1 or TDC #2. I made it so that 0* is the center of the cam lobe and the maximum valve lift. In the blue it says valve open degrees on cam, 315 to 45 degrees, that is when the cam lobe is pushing a valve open. So if it falls between that 315-45* range, the valve is open. On the chart I have the open valves highlighted in green.

Now the book method shows a number of valves you can adjust on each TDC, which I have made the text red for the valves you adjust depending on the TDC you are on.

Valve lash should ideally be done when the top of the cam lobe is at the opposite of the pushrod, and since I have 0* as the maximum lift on the chart, the lobe should be at 180* to set the valves as this is the farthest away position.

The valves are 90* apart per cam degrees so to do both valves using the valve overlap method (the one this thread is about), you would want to hit the split difference of the valves, putting them each to one side of the bottom of the cam. The exhaust would be at 225* and the intake would be at 135*. This is exactly where they end up when you do the valve overlap method.

Using the book method, 4 valves are 75* from 180 and only 60* away from opening, whereas the valve overlap method ensures they are all 45* from 180 and 90* away from opening.

Even though the 4 valves on the book method are closer to opening, you still have to turn the engine another 120* for them to start opening.. So it is plenty far away and there is no chance for you to screw up so badly that the pushrod is on a cam lobe :lol:

In other words, either way works fine and accurate and is just a matter of preference :smart:

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Zacharynels    0
Zacharynels

I just did all my valves on my truck. Finally got the feeler gauge and some time to do it. Only a few of the valves were too loose, the rest just needed a little adjustment. I think it took me like 30 or 40 minuets in the cold rainy weather we're having. Found TDC by waiting for 1I and 1E to be loose and adjusted 1 I & E, 2 I, 3 E, 4 I, and 5 E, Marked my Top Dead Center and used Alternator bolt to turn 1 revolution. I proceeded to adjust 2 E, 3 I, 4 E, 5 I, and 6 I & E. Started the truck cold, engine lope seems to be gone now, maybe i didn't have a pissed injector. Still going to pop those and clean soon. Will drive Later in the day and post if it made any improvement in the poor state it seemed to be driving.

Timing is still retarded, so I wont have much to go on as far as improvements.

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cajflynn    7
cajflynn

This is how I set my valves. I thought I was the only one so I didn't say anything.

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freesimons    0
freesimons

I got it. It worked pretty good and it went pretty quick. I was hoping that adjusting the valves would eleminate some knocking upon acceleration. It didn't. It did seem like the rocker arms were pretty loose when the valves were closed. How would I know if the rocker arms are shot?

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ISX    58
ISX

I got it. It worked pretty good and it went pretty quick. I was hoping that adjusting the valves would eleminate some knocking upon acceleration. It didn't. It did seem like the rocker arms were pretty loose when the valves were closed. How would I know if the rocker arms are shot?

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joecool911    276
joecool911

Got my valves adjusted today. Number 6 was tricky to get to and that was the first one to come into phase for adjusting. Quieted down just a bit. Thanks for the tutorial here! Had to start from scratch and figure out which rockers were intake and which exhaust. Going backward turning from the alternator was a bit of a challenge too. Figuring which number was coming up next. I guess you need to go backwards in the firing order too. But I did it without having to go around again by missing one. First time through I'd allow a hour and a half. Next time it'll be a lot faster. I got the go/no go feeler gauge set. 1-2 thousands step that won't go so you know you're right on. Just noticed the updated video that explains using the alternator to crank the motor. Use that video if you are cranking from the alternator! Explains what I had to figure out. Excellent!!!

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