Engine/Transmission (1998.5 - 2002) valve adjustment

[DISPATCH]

i have a 2000 2500 with 145k miles i have not had a valve adjustment done yet. is this somthing i should have done and why does it need to be done in other words what does it do thanks for the help

 

[Rman]

Over time the valve train will loosen. I think I've red cummins suggests 125k intervals for valve adjustment. i don't have any data to go on other than what I've read. Loose valves will cause a number of things, unless they are EXTREMELY out (which you would notice) they won't cause severe damage. Some things they can cause is incomplete ignition resulting in power loss and fuel economy loss. Personally I think loose valves can also erode the lobes on the cam faster, but this is more what i've seen from blueprinting an engine after running it a while. Tight valves can do this as well.



I had a solid lifter big block ford that i adjusted on a monthly basis, so every 125k isn't too bad to me. I've never really messed with the valve train of diesels, they're still relatively new to me. There will be others chime in for sure. Good luck

 

[BKilbury]

hi, does anybody know aprox. price at a shop to perform this? and are the specs / directions for doing it yourself availble anywhere?

rgds, bryan

 

[CFast]

It's pretty easy to do, just like adjusting valves on anything else. I'm not sure where to get the info, i'll try to scan a book at work for the right specs. I talked to some guys at work about this, I work on detroits, not so much cummins. they said cummins doesn't have an interval for the ISB. If you hear the valves, adjust them. If you run them a little loose you'll have more torque, builds more cyl press.

 

[FourBarR]

do a search on 24v adj. it was in one of the tdr mags awhile ago. sorry i dont have the number.

 

[Vaughn MacKenzie]

I've seen trucks out of spec at 60,000 miles. IMO Cummins has a really wide range of "acceptible" specs, if you want a top-running machine I would go with a much narrower range such as . 008-. 010" intake and . 018-. 020" exhaust. You'd be surprised how much a few thousands will affect how it runs and how smooth it is. I always go . 008" Intake . 018" exhaust when I do mine so they're a bit tight (means a bit more lift) with enough safety margin to keep them from burning the seats when running hard (too tight and they expand to the point they don't seat and you've got big problems baby).



Vaughn

 

[No Neck]

Owners manual states to adjust the valves at 100,000 miles on the 24 valve engine. I'm at 97,000 miles right now and Cummins NW mentioned that it needed to be done soon when I had the fuel filter changed last week. They quoted it would cost around $200. 00 dollars.

 

[jwilliams3]

There is directions to perform this task on earlier posts.

Use the search.



The only equipment you need is a 14mm wrench, a 5mm allen wrench.

A barring tool, set of feeler gauges, 10mm socket and ratchet.



--Justin

 

[RCook]

Here's a compliation of instructions for adjusting 24-valve engines - works for me:



Winter finally broke here in Michigan (70 degrees today - was snowing last week) so I finally was able to get around to adjusting my valves since I have 100,000 miles on the truck. Here's what I found - intake valves were from . 012-. 015 (optimum is . 010 (. 25mm) - spec is from . 006-. 015) and exhaust valves were . 021-. 024 (optimum is . 020 (. 51mm) - spec is from . 015-. 030). I was blown away that they were still within spec after 100,000 miles - and I haven't been exactly easy on the engine . I set mine slightly tight at . 008 (. 20 mm) on the intake and . 018 (. 46mm) on the exhaust. A note to anyone adjusting theirs - there is a lot of play in the Y from the camshaft to the valves on the 24v engine. I adjusted mine and then cranked the engine over and then rechecked them - it took about 6 times of adjusting them before the numbers were consistent on the next rev (I've adjusted TONS of valve trains over the years BTW). I continued to adjust them until I was able to get a consistent reading for 2 revolutions after I adjusted them. -Steve St. Laurent –



LSMITH: I have played with settings all over the map and found with my combo . 007 (. 178mm) and . 016 (. 406mm) is the right spot, it frees up the top end tremendously. . 012 (. 305mm) and . 025 (. 635mm) has great low end if that is your bag... ... .



TOOLS NEEDED

22mm or 7/8 socket, and long-handled ratchet, for turning engine via alternator

15mm ratchet wrench or socket, for removing valve cover

14mm or 9/16 wrench and socket, for adjuster nuts. 5 mm hex key, for adjusters



Instructions from Chad Sheets

Back all the adjustment nuts off on all rockers, then run them down with your fingers until they touch (you will only be able to run down the rockers with no tension on them... the ones with tension will have to wait their turn on the next round when you rotate the engine 360 degrees. Zero the gauge out and adjust for ever how many mm or whatever measurement you want to use.



1. Put cyl #1 on TDC by using the TDC mark behind the crank case breather on the front of the engine. You will have to remove the breather... I believe it unscrews. You will see "TDC" stamped at 12 o'clock inside the case and a mark on the fuel pump timing gear. Put that mark on the 12 o'clock TDC position.



2. Remove the valve cover, and mark the following INTAKE valves with a paint marker, 1,2,4.



3. Now mark EXHAUST valves 1,3,5. with the paint marker. You should have 6 rockers marked now.



4. Adjust the INTAKE valves somewhere between . 15mm and . 38mm. , I shoot for the middle of the road . 25mm. (per LSMITH - . 20mm)



5. Adjust the EXHAUST valves now between . 38mm and . 76mm. , again I shoot for middle of the road about . 57mm. (per LSMITH - . 40mm)



6. Give all the rockers a good wiggle before removing the gauge to make sure all the play is out of them.



NOW ROLL THE ENGINE OVER 360 DEGREES AND ADJUST THE 6 ROCKERS NOT PAINTED.