Why does everyone say to do the vlaves Intake .010 Exhaust .020 and not what Cummins recommends on the valve cover Intake .010 Exhaust .026??

Some guys claim, Intake .005 Exhaust .013 give better MPG and better turbo spools?

So is Cummins lying to us to make to not allow our trucks to run better? Did the sign a contract with oil compaines to make sure our trucks burn the most fuel..

What you do guys run your valve lash at? See any improvements?

 

Out of spec valve lash will definitely cause a power loss....possibly lower MPG's as well. I've always kept mine at .010/.020 (respectively) just because that's what I've always read and my valve cover also says .010/.020.

Now, some of the folks who have tinkered with this aspect may have found what works best for their engine....who knows. There are other lash specs for a hot vs. cold engine and maybe that's where some of the #'s come from. Myself, I'll keep my .010/.020, and enjoy my almost 20 mpg .

 

I think the exhaust spec was modified from .020 to .026. I can't recall exactly when but I ran across those conversations recently on the forums looking for the procedure.

 

do you adjust them Hot or Cold? And what is the order? Thanks

 

cold

 

Yup! Always cold

 

what are the tools needed to this and could anyone help out with the procedure. I see this "valve lash" discussion come up every now and then but never seen anyone describe the necessary steps. At 110k, I'm sure I am overdue and would like to determine if I have the skills or if its better for an expert.

any advice and/or suggestions on this topic will be much appreciated

 

what i was always taught was consistency. everyone has a different feel for a feeler gauge.

i was also taught to put 5 inch pound on the screw with the feeler gauge between the rockker and the bridge.

so i say equal lash is the most important thing, 20 or 26 on the exhaust shouldnt make much differance IMO, but i always stay with what the manufacture recomends.

 

its actually 6in pounds and cummins does make a special wrench just to adjust the valves http://dodgeram.org/tech/dsl/valve_adj/12_valve.html

 

i contacted cummins on this. cummins designed the 06 early 07 to be 0.020 chrysler changed it to 0.026 to help with the in-cylinder egr. set it at 0.020. i use a different method that is faster so as not to confuse you i am going to paste the following
Once you set the dampener to 12:00 and verify that #1 cyl rockers are loose then adjust the valves in this order.
Intake on cylinders 1-2-4 and exhaust on 1-3-5.

Spin the dampener 360# clockwise back to 12:00 then adjust,

Intake 3-5-6 and exhaust 2-4-6.

I believe the tolerance you want on the intakes are .010 and on the exhaust .020 on your 05. I set them so that I have friction on the feeler gauge. Reset torque on the jam nut to 18 ft#.


You can go in the firing order if you want too but there is no need for it.

The entire job takes around 1-1.5 hours, if its your first time it will be a little longer. Do yourself a favor and get feeler gauges with a 45* bend in them, it makes it a LOT easier.

 

i second that

 

To make sure you are on TDC for #1, watch the exhaust valve rocker on #6. When it closes and your damper mark is at 12:00, then you are on overlap on #6 and TDC for #1. To set it to TDC on #6, watch #1 exhaust rocker, when it is all the way back down, you are on #1 overlap and TDC for #6.

 

Good stuff, thanks.

 

If you are looking to quiet the engine down and maybe gain some efficiency set the valves with the engine up to operating temp and set the intakes .008 and the exhausts to .018. Just drive by the EGT gauge and limit the amount of time your temps are 1200 degrees or better. The cold set and loose lash is to handle the range the engine can generate cylinder temps. Limit thta with your right foot and you can tighten the lash down.

 

Learned something new