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tom chelbana · 04-09-2016, 06:56 PM

Spent 3 days doing a valve adjustment on our 04 Essex with a 500 ISM. If you don't have 125K miles when Cummins recommends a valve adjustment wait till then. I adjusted only the intake and exhaust valves because of the tight working area and didn't adjust the Jake Brake or the injectors. Because of drag racing and auto tech instructor plus owning a repair shop I have adjusted valves hundreds of time but this is not the same. Because of space cylinders 1 and 2 you can't see the work area. I do have the Cummins ISM service shop manuals which I don't suggest you take on this project without them. Below are some items you will need and not a complete list but somethings to know.
1 You need a 32mm socket to turn the engine over
2 You will need the extra long feeler gauge to adjust the valve
3 The valve adjustment is .014 inch. on the intake and .027 on the exhaust
4 The valve arrangement is E-I-I-E-E-I-I-E-E-I-I-E
5 All exhaust valves were right on intake were at .010 and had to change to .014
6 Didn't have luck using Cummins method of which cylinder to adjust so used procedure of when exhaust valve going down adjust intake when intake valve has gone down and about to close adjust exhaust valve.
7 You have to hold rocker up to get feeler gauge in. This was one of the point you don't want to make a mistake. I check them 2 and 3 times to make sure they were adjust correctly. A remote start button will make this easier to do.
For 98% of ISM owners this is something to wait till it needs to be done and then take it to someone who knows what they are doing. In a truck a lot different but in a motor home there just isn't any room and you are bending over the whole time.

DAJO · 04-10-2016, 03:58 PM

Thanks for taking the time to do a write up. Then after all the work the .004 probably would not even mattered in the long run but now you know it is right. Been there before.

Iron Man · 04-10-2016, 06:09 PM

Interesting the intake valves were tighter than the recommended gap. I would think they would have a bigger gap.

twinboat · 04-10-2016, 06:21 PM

Valve clearance can shrink due to the valve and seat wearing.

The valve and seat are tapered.

As they wear the valve sinks a bit deeper into the seat.

Noisey valves is not the only reason to check the lash.

Lug_Nut · 04-10-2016, 07:58 PM

I've gotta ask if there was any real adjustment change required. I can understand having a slapping rod, but is this valve check really needed?

Case in Point. I had twin Cat C-18's with duel Turbos in my boat (2008 1015 HP per side). At 250/300 hours the manual stated a valve lash is required. Well, the tech from Cat was working on my engines, they were under warranty, though I knew that adjusting the valves were a pay maintenance item. He said, "The engines are running great, don't touch them. Sometimes you only create issues.

So, is this just a cover the but thing with all these engine maker?

But, doing it yourself? Great work and Kudo's!

Just thought I would pass this happening along. I don't know if valve adjust is required on my ISM as they are overhead cam driven, very little to adjust.

Peter

tom chelbana · 04-11-2016, 06:55 AM

Lug Nut In your last sentence you your ISM engine with a overhead cam that would be your ISX has a overhead cam but not the ISM doesn't. After that slight change in the intake valve adjustment I would agree that it was a lot of work for not much change. It is better to have a slight increase in valve adjustment rather then to tight so with that in mind maybe it wasn't a waste of time. If you just had more space it would wouldn't have been that time bad. I was using a mirror on cylinder 1 and 2 for the intake valves.

DAJO · 04-11-2016, 07:12 AM

Tom, when I was reading the valve adjustment procedure it appeared to me that they were saying that if the clearance was in a certain range that adjustment was not necessary. It left a question in my mind that I would want to check out before doing the procedure. I was also looking at the ISL maybe different. The ISL I think was 150,000 or four years, the four years is the killer.

tom chelbana · 04-11-2016, 05:00 PM

DAJO I read that too but there was a big margin. Being a race engine builder .010 of and inch is a lot. You would still need to do a valve check to see if the valve were in that range. If you are going to check them I think you should adjust them to the proper gap. I takes 3 hours to get the valve cover off.

BRex45 · 04-12-2016, 09:54 AM

I've adjusted at least a hundred Cummins' valve/adjuster/injector/jake setups "back in the day." (Kenworth dealership-Authorized Cummins and Allison dealer)
I never had to hold a rocker up to get the feeler gauge in.

Also rarely found found valves too tight, almost always loose.
We NEVER adjusted valves without adjusting injector, then valves, then Jakes.

These were C, L, M blocks. Non-computerized fuel systems but the basic block/crank/cam setup is the same I think.

tom chelbana · 04-12-2016, 06:57 PM

The rocker arm would slide to the side so I needed to align the rocker to be able to get feeler gauge in. Because Cummins has a couple different valve adjustment spec. I think that the intake valves were adjusted to .010 at the factory since they were all the same. The Cummins service book said the preferred adjustment was .014 so that what I set the too. Because of the tight working area I used a mirror in numerous area so since it was already day two and all the adjustments were so closed decided to skip Jake and injector adjustments. Most CC I have seen with the C12,13 and 15 engines there was only a 2 inch gap above valve cover which would make very, very difficult to even get the valve cover off much less adjust the valve train.