I am looking for a valve adjustment procedure for the Cummins 24-valve engine. Many websites have the procedure for the 12-valve engines.
Thanks.
PSiemens
01-02-2003, 10:58 AM
I just did a valve adjustment on my brothers 24 ....
1. Remove valve cover
2. Put cylinder number 1 to TDC
Both intake and exhaust will be loose or free on cylinder #1 when TDC is on that cylinder. There is a TDC mark behind the crank case breather, but you will have to remove the breather to see it.
3. Adjust intake valves on cylinder 1, 2 and 4.
4. Adjust exhaust valves on cylinder 1, 3, and 5.
5. Turn motor over 360 degrees.
6 Adjust remaining valves.
The lash for intake is 10 thou and exhaust is 20 thou. Set valve lash when motor is cooler that 140*F.
Phil
dfancher
01-02-2003, 11:36 PM
Phil,
Thanks for the information. Did your brother notice any difference in noise, fuel economy or power after the adjustment?
Don
PSiemens
01-03-2003, 12:05 AM
A little less clatter. Most of his valves were on the tight side. We will only go 50K next time before doing adjustment. A 100K is just too long. Do you have a barring tool?
Phil
dfancher
01-04-2003, 09:32 AM
The truck has about 90K and I have heard that noise reduction is typical after adjustment. No, I do not have a barring tool. I am not familiar with it. What is it? I assume that it makes the job easier. Any tips or suggestions would be appreciated.
Don
PSiemens
01-04-2003, 08:29 PM
A barring tool is used to turn motor over. There is a plug on the passenger side of the bell housing. The plug is pulled out and the barring tool is inserted into this hole. The barring tool engages the ring gear and a ratchet is used to motivate the barring tool.
Second way to rotate motor is to put a socket onto the alternate nut. Depending on direction of rotation, pressure might have to be applied to serpentine belt.
Seeing as this is your first valve adjustment, you will want to ensure that #1 cylinder is TDC.
The TDC mark is located behind the crank case breather on the front of the motor. The breather will have to be removed. On the 98 1/2 Cummins, breather unscrews. You will see "TDC" stamped at 12 o-clock inside the case and a mark on the fuel pump timing gear. Put this mark on the 12 o-clock TDC position.
When motor is at TDC, both intake and exhaust on # 1 cylinder will be loose.
You might want to use a crayon or some other form of marker to keep track of the valves that have been adjusted.
The valve cover gasket can be reused. Wipe it clean before the re-install. Send me a PM if I can be of any help.
Phil
