When to adjust valves

Topic: When to adjust valves (Read 1880 times) previous topic - next topic

When to adjust valves

July 31, 2018, 12:10:34 am

I have a 2003, 400 ISL Cummings engine with 30,000 miles. The manual calls for a valve adjustment at 60,000 miles or 48 months. A Cummings factory Rep said I should have the valves adjusted since I have no idea if they ever were touched.
QUESTION: What has been the real world experience for an engine like mine that seems to run well with no hesitation?
All thoughts appreciated. Thanks in advance.

Re: When to adjust valves

Reply #1 – July 31, 2018, 12:39:26 am

I have 225k on the motor in my 02 U320. mine is going in tomorrow to have the valves adjusted for peace of mind.. Runs like a champ.

Re: When to adjust valves

Reply #2 – July 31, 2018, 12:56:39 am

I have adjusted the valves on mine 2 times and both times they were very close to spec. 105K, bought at 52K. You will not have peace of mind though until you have it done at a good shop by a good mechanic.

Re: When to adjust valves

Reply #3 – July 31, 2018, 06:36:22 am

I would go by the mileage in the factory recommendation. Time is really not relevant for lash wear.

Re: When to adjust valves

Reply #4 – July 31, 2018, 09:40:54 am

I've been considering having the valves adjusted in my dodge truck.
It's a 1999 with a 5.9 Cummins 24V with 251,000 miles. Owned since new, and never put a wrench to the engine. Still runs as strong as ever and no smoke, uses less than a quart of oil between changes. (5,000 miles).
Been a great engine.

Edit:
I realize that it's not an ISL but it is a real world example of how long a Cummins can run with only oil and filter changes.

Re: When to adjust valves

Reply #5 – July 31, 2018, 09:49:40 am

Dee,I don't understand the factory reps thinking,you have an engine with 30k miles and you don't have to get the valves done
until 60k,what's the difference what has been done in the past,at 60k get the valves checked.As said above,time is not a factor.

Re: When to adjust valves

Reply #6 – July 31, 2018, 10:32:36 am

Yes, it's mileage not time. One of the big reasons for valve adjustment is valve timing and the degree duration the valve spends on it's valve seat. If an exhaust valve is tight (has less than specified clearance) it will spend fewer crankshaft degrees on it's seat and since this is one of the ways the valve is cooled (valve heat conducted from the valve face to the valve seat in the cylinder head), it will run hotter than it should. The hotter it runs over designed specifications, the more prone to failure it is. In other words, the more time an exhaust valve spends on it's seat, the more heat it will transfer to the cylinder head.

Uneven clearances will result in different valve timing for each cylinder. This may result in poor idling (but poor idling can also be the result of poor injection pump calibration or bad injector spray pattern) with each cylinder producing a slightly different amount of power plus higher emissions being produced.

While valve clearance may not be as critical for an engine like a 5.9 Cummins in a light PU, installing any engine in a large, heavy vehicle and pulling long grades in hot summer weather does stress the components. If operating clearances and temperatures are within specifications, the engine can handle this load and will normally live a long life.

Pierce

Re: When to adjust valves

Reply #7 – July 31, 2018, 01:40:25 pm

I had mine adjusted recently and the exhaust manifold bolts broke off in the head. Expensive as it was done at an official Cummins shop.

Keith

Re: When to adjust valves

Reply #8 – July 31, 2018, 02:01:10 pm

Quote from: Keith and Joyce – July 31, 2018, 01:40:25 pm

I had mine adjusted recently and the exhaust manifold bolts broke off in the head.

Keith,

Please expand on this as I have never had to pull an exhaust manifold on an M-11 (if that is the engine you have) to adjust the valves. Did you have a bad/cracked manifold also?

Mike

Re: When to adjust valves

Reply #9 – July 31, 2018, 02:02:42 pm

Don't think the 2 had anything to do with each other,did your bolts just start breaking or what?

Re: When to adjust valves

Reply #10 – July 31, 2018, 03:17:24 pm

When the coach was in the shop they found two bolts had been broken off for some time although there was no indication of this in sound or running. The head had to be pulled to get the threads out. One of the bolts had fallen and wedged further down on the engine. It was obvious that it had been broken for quite a while. I also replaced the center manifold as it was damaged. Not usual for these M11 engines.

Keith

Re: When to adjust valves

Reply #11 – July 31, 2018, 04:32:21 pm

We're the bolts on number 6?

P

Re: When to adjust valves

Reply #12 – July 31, 2018, 04:36:00 pm

Broken exhaust manifolds are not uncommon on the L engine either.

A good idea anytime you are in the engine room to look for either missing bolt heads and/or black (soot) anywhere in the engine room. All the black should go out the tail pipe, so any trace of it in the engine room indicates a problem.

Re: When to adjust valves

Reply #13 – July 31, 2018, 07:30:48 pm

Not to move to the left, but I show Brett's CAT had the valves adjusted & the injectors timed in 7/5/2010. The mileage was 151,000
I'm not going to worry about her since we're at 170,000 and she sounds like a FAST KITTY!

Re: When to adjust valves

Reply #14 – July 31, 2018, 08:49:03 pm

Quote from: Keith and Joyce – July 31, 2018, 03:17:24 pm

When the coach was in the shop they found two bolts had been broken off for some time although there was no indication of this in sound or running. The head had to be pulled to get the threads out. One of the bolts had fallen and wedged further down on the engine. It was obvious that it had been broken for quite a while. I also replaced the center manifold as it was damaged. Not usual for these M11 engines.

Keith

When mine was in the shop after buying it. The shop saw the same thing on my 1998 M11 450HP. Warped exhaust manifold that pulled a bolt out. The consensus was that as these engines are buried in the back and a lot of RV pilots never touch the down arrow on the Allison shift pad to keep it from lugging and building very high EGT's. In addition, The 3 piece manifolds these engines have can twist up like a pretzel.

You wouldn't believe how quickly the pyrometer on the 16 litter Cat in my Kenworth W900 would rise if I let lug for too long. I often used the pyrometer to gauge when to down shift.

Re: When to adjust valves

Reply #15 – July 31, 2018, 08:57:37 pm

Quote from: bigdog – July 31, 2018, 08:49:03 pm

When mine was in the shop after buying it. The shop saw the same thing on my 1998 M11 450HP. Warped exhaust manifold that pulled a bolt out. The consensus was that as these engines are buried in the back and a lot of RV pilots never touch the down arrow on the Allison shift pad to keep it from lugging and building very high EGT's. In addition, The 3 piece manifolds these engines have can twist up like a pretzel.

You wouldn't believe how quickly the pyrometer on the 16 litter Cat in my Kenworth W900 would rise if I let lug for too long. I often used the pyrometer to gauge when to down shift.

Amazon.com: VEI Systems 1800 deg-F digital EGT/pyrometer/exhaust-gas.... Well worth it for the piece of mind.

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: When to adjust valves

Reply #16 – July 31, 2018, 09:09:58 pm

Quote from: bigdog – July 31, 2018, 08:49:03 pm

You wouldn't believe how quickly the pyrometer on the 16 litter Cat in my Kenworth W900 would rise if I let lug for too long. I often used the pyrometer to gauge when to down shift.

Our Allison/CAT combo does fine (so far), but I miss a pyrometer & boost gauge, just in case.

Re: When to adjust valves

Reply #17 – July 31, 2018, 09:35:56 pm

Adjustment Done today.. Also had them replace the 2 O'rings on the harness that goes through the block.. $504.00 out the door

225k Peace of mind.

Re: When to adjust valves

Reply #18 – August 01, 2018, 07:09:27 am

See my earlier post on broken exhaust manifold bolts. The manifolds shrink as they cure with time at temp, and the joints on multi-piece manifolds can freeze solid, causing bolts to break.

Re: When to adjust valves

Reply #19 – August 01, 2018, 07:18:45 am

Quote from: amos.harrison – August 01, 2018, 07:09:27 am

See my earlier post on broken exhaust manifold bolts. The manifolds shrink as they cure with time at temp, and the joints on multi-piece manifolds can freeze solid, causing bolts to break.

X2 on manifold bolts-- had 2 break on SOB with 454 chevy engine manifold warped 02 sensor gave bad reading and engine went into limp mode. On more positive note A shop in Custer SD called Dakota West (west of town about a mile) removed broken bolts and replaced manifold. At the time (3Yr ago) their shop rate was only 60/hr compared to chevy dealer at 100/hr

Chris

Re: When to adjust valves

Reply #20 – August 01, 2018, 07:20:43 am

DavidS where did you have it done?
Chris

Re: When to adjust valves

Reply #21 – August 01, 2018, 07:24:52 am

Does anyone know the difference in exhaust gas temp before and after replacing muffler with resonator?
Chris

Re: When to adjust valves

Reply #22 – August 01, 2018, 09:26:15 am

Cummins Sales and Service 2807 E Alexander Rd North Las Vegas, NV Auto...

Dropped off in the am and picked up in the pm.. very nice guys to deal with..Nice facility

Re: When to adjust valves

Reply #23 – August 01, 2018, 10:12:51 am

Quote from: Chris m lang – August 01, 2018, 07:24:52 am

Does anyone know the difference in exhaust gas temp before and after replacing muffler with resonator?
Chris

Never did a real "before and after" test on my 99, but egt's did seem to run a little cooler at steady speed, and it did seem to accelerate a little better with the resonator.

Re: When to adjust valves

Reply #24 – August 01, 2018, 02:14:00 pm

If you combine the resonator with a lower horsepower consuming fan controller and and bluetech air filter the increase in useable power and mpg is very noticeable. I really liked the additional torque that allows the engine to stay in the higher gears and not downshift nearly as much under load.

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