Adjusting the Valve Lash on our Cummins 6.7 Diesel Engine

Although this is not a full how to it shows the process for adjusting your valves. Be sure to get the proper service manual pages for this procedure prior to attempting this. Here is a link to the service manual pages we used for this job.

** Something I forgot to mention in the video – Always adjust your engines valves COLD. This engine was at ambient temp about 75 degrees F.

Also, In the video it appears at times the feeler gauges are bending. Like at 5:43 You cannot check proper tolerance with a bent gauge. Later I removed the gauge from the pack and put a bend in it so that it slid in without any resistance. Should have put this in the video because its critical.

Below is the procedure for the 6.7 Engine (2010) from the service manual.

Overhead setting is only required at the interval specified in the appropriate Operation and Maintenance Manual/Owners Manual or when engine repairs cause removal of the rocker levers and/or loosening of the adjusting screws.
Excessive valve lash prior to this can indicate an overhead set incorrectly from a previous repair, worn valve stems, crossheads, push rods, or rocker levers*.
Loose rocker levers and the need to reset the valve clearance frequently can also indicate camshaft lobe or tappet wear. If an inspection of the rocker levers, valve stems, crossheads, and push rod does not show wear, then tappet and/or camshaft lobe wear can be suspected.

NOTE: The TDC indicator is on the vibration damper/crankshaft speed indicator ring.

For 6.7 L engines, align the vibration damper/crankshaft speed indicator ring so that the TDC indicator is at the 12-o’clock position. If both number 1 cylinder rocker levers are loose, move to the following steps. If both number 1 cylinder rocker levers are not loose, rotate the crankshaft 360 degrees.

With the engine in this position, lash can be measured on the following rocker levers:
(E = exhaust, I = Intake)
1I, 1E, 2I, 3E, 4I, and 5E.

Lash Check Limits
mm in Intake 0.152 MIN 0.006 0.381 MAX 0.015 Exhaust 0.381 MIN 0.015 0.762 MAX 0.030

NOTE: Checking the overhead setting is usually performed as part of a troubleshooting procedure, and resetting is not required during checks as long as the lash measurements are within the above ranges.

NOTE: The clearance is correct when some resistance is “felt” when the feeler gauge is slipped between the crosshead and the rocker lever socket.

Measure lash by inserting a feeler gauge between the crosshead and the rocker lever socket. If the lash measurement is out of specification, loosen the locknut, and adjust the lash to nominal specifications.

Valve Lash Specifications (Nominal)
mm in
Intake 0.254 0.010
Exhaust 0.508 0.020
Tighten the locknut and measure the lash again.
Torque Value:

24 n.m
[212 in- lb ]

Using barring tool, Part Number 3824591 (I used A 15mm ratchet on the vibration damper nut) , rotate the crankshaft 360 degrees.
Following the same steps and specifications as previously stated, measure lash for the following rocker levers:

(E = exhaust, I = Intake)
Six-cylinder 2E, 3I, 4E, 5I, 6I, and 6E.
Reset if out of specification.


I hope this is useful information to someone. Feel free to let me know if you have any questions on how we did this.

Check out our website!:




32 thoughts on “Adjusting the Valve Lash on our Cummins 6.7 Diesel Engine

  1. I want to ask everyone who commented on this why it didn’t show how he got it to tdc? You know! Where he stoped at . I’m not complaining I just want to know

  2. Late to the game here, but I just adjusted the valve lash on my 6.7 Cummins yesterday. I had watched this video beforehand, and it was very helpful. The biggest time saver that I found was using the Cummins engine barring tool. It lets you bar the engine over using a male splined socket that engages the flywheel through a cover on the passenger side of the engine. I used a variety of extensions and wobble sockets so that I could bar the engine from the front of the truck, and watch for the TDC marker, which I had marked with a Sharpie, so it was more visible. I was able to do all of the work by myself, in just over three hours, and now my truck sounds much better.

  3. just a FYI you want to change the crankcase filter every 60k or 50k if you do alot of heavy towing. if you dont you will end up sucking oil into the turbo witch will cause some significant damage to your engine.

  4. It's actually quite a bit easier on a deleted truck. Without the egr cooler in the way you have substantially more room to move around. Nice video bud.

  5. hey you never showed us the tdc when it's center how is it supposed to look when it is? but other than that whenever I need to do this I'll be using your video thank you so much! you did a great job

  6. good video, not sure what you mean by just a little bit of drag, but when lash is set correctly the next size up feeler shouldn't fit. I did mine yesterday and when the gap is correct the corresponding gage will have quite a bit of drag. I found when there was just a little drag I could still fit .005 or more in, according to the tolerance though that would still leave you within spec.

  7. Excellent video. I'm considering a RAM3500 diesel and seeing this done is very helpful as I've never worked on a diesel before. Suggestion: Had a friend who was a full time mechanic. NEVER wore his wedding ring when working under the hood but just forgot one day. Holding a wrench in his left hand which was touching the ring, he slipped and touched the battery terminals. Melted the flesh on his finger under the ring in a heartbeat. Be careful.

Leave a Reply

Your email address will not be published. Required fields are marked *