valve adjustment

[JStieger]

Looking at the engine from the front with the valve cover removed, what are the order of the valves?



First set from front = ?



Second set from front = ?



I want to check my valve adjustment, but the service manual shows the cylinder head upside down with no direction indicator with the exhaust valves having dimples on the heads.



Thanks-

 

[jwilliams3]

@ Tdc



1. I,E 2. I 3. E 4. I 5. E 6. XX



@ 180



1. XX 2. E 3. I 4. E 5. I 6. I, E



. 010" I, . 020" E

 

[ACerf]

I am curious as to why you would want to check the valve adjustment? Are you having a problem?

 

[Steve St.Laurent]

Valves should be checked every 100,000 miles

 

[ACerf]

That makes sense to check them every 100K. I was just curious if he had over a 100K or he was having problems.

 

[Vaughn MacKenzie]

I always check mine by 20-30k and usually they need tweaking. Probably 'cause they're not perfect from the factory. I've seen some off pretty bad on other people's 24-valves well before 100k.



Cummins' window of "in tolerance" is huge IMO (+/- . 005"). Your truck could still be within "spec" but benefit significantly if you make them all within . 001" of each other (which is what I do).



I adjust to +/- . 001" of . 018" exhaust & . 008" intake for a bit more at midrange+ RPM.



If you find your valves outside the +/- . 005" Cummins limits your truck needs a valve adjustment BAD!



Vaughn

 

[JStieger]

I am curious as to why you would want to check the valve adjustment? Are you having a problem?

I am having issues detailed here:



https://www.turbodieselregister.com/forums/showthread.php?t=136945



So I want to rule out all the obvious, "meat and potatoes", kind of stuff before things might get expensive. I have ~56k miles.



I adjusted the valves yesterday and after the truck was a lot more peppier and quieter. I then redid them again this morning because I wanted to check my pushrods. Everything looks good, but I still have the stumble/poof/sputter - not as bad as before the valve adjustment and before rechecking the torque on the valvetrain and injectors - but it is still there. I'll have some pictures in the post above shortly.

 

[rbattelle]

I have a basic question: are these engines interference or non-interference?



-Ryan

 

[nickleinonen]

I have a basic question: are these engines interference or non-interference?



-Ryan

interference. .

 

[rbattelle]

What happens if the valves are way out of adjustment... let's say like . 015" too loose. Other than running like complete crapola, would the engine be damaged in any way?



-Ryan

 

[DValentine]

You would not have interference with the piston and the head... . just the opposite. The valve train would be sloppy and slowly hammering itself apart..... Tap Tap tap... . like a solid lifter small block... out of adjustment.

 

[Vaughn MacKenzie]

I have a basic question: are these engines interference or non-interference?



-Ryan

This is only a concern with belt-driven cams due to potential belt failure. The Cummins cam is gear driven.

 

[JStieger]

You would not have interference with the piston and the head... . just the opposite. The valve train would be sloppy and slowly hammering itself apart..... Tap Tap tap... . like a solid lifter small block... out of adjustment.

I was reading on here or another site that one has to be careful on modded trucks with going too tight because of the extra heat. What exactly is too tight?



The feeler gauges are certainly an art in itself - I had my neighbor who is a heavy duty mechanic show me what he felt was good "drag" on the gauge to set the #1 intake lash and then advised to remember that "feel" and keep it consistent.



I also wish I had those 45* angle guages cause I ended up bending a good set to have a straight shot into the gap... .

 

[rbattelle]

This is only a concern with belt-driven cams due to potential belt failure. The Cummins cam is gear driven.

I know... this thread just made me curious.



-Ryan

 

[DValentine]

The gap you set will be depleated as the engine comes up to tempature. Should be running at zero lash when at operating temp. Notice the exhaust valve is set looser than the intake..... more heat into the exhaust valve. When the engine is running with the pyro at 1250 degrees how much heat to you think sinks into the engine components?



You won't gain much going over the spec. The diesel engine has high compression as you know... . that leaves little room for valve protrution toward the piston. You are adjusting the valve on base circle of the cam shaft..... if you go much tighter than spec... . as your engine heats up the valve will be held off the valve seat. The valve cools (important on the exhaust) as it sits on the seat... in the head with coolant flowing by. If you want more lift on your valve... get a different cam..... you can't cheat by over tighting the valve adjustment.



It is my opinion that the first adjustment is important because of two things... you will be more exacting than an engine tech... putting your engine together in the factory. The second reason is that the first 10,000 miles the cam and lifters are wearing in and lapping together... . the wear is less after they lap in.



Hope that made sense



Dave

 

[JStieger]

It is my opinion that the first adjustment is important because of two things... you will be more exacting than an engine tech... putting your engine together in the factory. The second reason is that the first 10,000 miles the cam and lifters are wearing in and lapping together... . the wear is less after they lap in.



Hope that made sense



Dave

Dave-



That makes a lot of sense - thanks! I swear that my truck idles quieter and smoother now than it did when I first bought it stock off the lot - and that is with my mods now.



I had the PDR cam installed by a shop about 10,000 miles ago, but I don't know where they set the lash to. If they did set it to Cummins 0. 010/0. 020 specs and I was at 0. 010/0. 023 yesterday before adjusting, then that would make a lot of sense.



After worrying about doing this job for a while, I just decided to do it and found in the end it is right up there on the oil and filter change difficulty scale and know after the job is done that everything is under my control/standards!

 

[Vaughn MacKenzie]

Great post DValentine. The only reason I run a bit tight is to get a bit of free power, but it's not much of a gain. As you're saying it does increase the risk of getting the valves too hot. If they're too tight to the point they don't completely seat when the EGTs are sustained that is not good news either.



Vaughn

 

[DValentine]

Vaughn, I know what you mean, and I agree with you to "run" on the small end of the tolerances given. I too, set my valves like that... .



JStieger, glad to be of use. Thats what is cool about this forum. Glad you got it figured out. I didn't catch your sig and didn't see that you had a cam. My opinion on Piers is that things where spot on when it came out of their shop. But as I discussed things wear in. Glad you measured before you adjusted... . its always interesting to me to see how things wear. How do you like the PDR cam? I would like to own one some day. I am sure you are right about your engine running quieter than it used to.



Dave

 

[rbattelle]

After worrying about doing this job for a while, I just decided to do it and found in the end it is right up there on the oil and filter change difficulty scale and know after the job is done that everything is under my control/standards!

That's good to know. I must confess I'm very intimidated by the valve lash adjustment. In fact, I'm intimidated by any process that involves feeler gauges (I could probably spend hours on one single rocker arm trying to get "just the right drag" on the gauge).



-Ryan

 

[JStieger]

How do you like the PDR cam? I would like to own one some day. I am sure you are right about your engine running quieter than it used to.



Dave

Dave-



Love the cam! It is worth a solid 1. 5 mpg over the stock one and makes my 14 cm2 turbo exhaust housing drive like the 12 cm2 turbo exhaust housing I had before the swap. It also seems like I gained a bit more low rpm "pull" than before - especially noticeable in town and on curvy roads that I travel all the time where I don't have to downshift as much as I did before in the same spots. As far as EGT goes - it is hard to tell because of the other changes I did at the same time.



However, now I can't enjoy all these benefits until I solve the problems posted in the thread I linked to earlier in this thread