Engine/Transmission (1994 - 1998) 98 12 Valve not going over 800 RPM

[dieselram96]

Want to buy my buddies 98 five speed but now has problem. Two weeks ago he had the dowel pin blow out and break the housing case, but engine still ran and got him home with no problems besides oil leaking out and making a mess. He lost about 2 or 3 quarts. He purchased all the new parts, about 500. 00 and took it apart. He did marked all the gears and put it back the same way it came apart. Now comes the funky part. When he installed the rockers back on he just torqued to the specs but never checked the adjustment of the intakes and exhaust. He told me that everything was marked and put back in the exact same place. The truck now starts but runs pretty rough and will not go over 800 RPM. The question I have here is that if the valves are not adjusted properly would this cause the engine to run crappy and not go over 800 or 900 RPM? The truck is a distance from me and I would go down there and tinker around with it if I felt confident that the adjustment is way off on the intakes and exhaust valves. My buddy is so fustrated that he will not work on it. Input would be appreciated.

 

[Lightman]

Want to buy my buddies 98 five speed but now has problem. Two weeks ago he had the dowel pin blow out and break the housing case, but engine still ran and got him home with no problems besides oil leaking out and making a mess. He lost about 2 or 3 quarts. He purchased all the new parts, about 500. 00 and took it apart. He did marked all the gears and put it back the same way it came apart. Now comes the funky part. When he installed the rockers back on he just torqued to the specs but never checked the adjustment of the intakes and exhaust. He told me that everything was marked and put back in the exact same place. The truck now starts but runs pretty rough and will not go over 800 RPM. The question I have here is that if the valves are not adjusted properly would this cause the engine to run crappy and not go over 800 or 900 RPM? The truck is a distance from me and I would go down there and tinker around with it if I felt confident that the adjustment is way off on the intakes and exhaust valves. My buddy is so fustrated that he will not work on it. Input would be appreciated.

Sounds like the injection pump jumped time if he didn't clean the shaft and time gear where it mates with the pump they can and will slip.

 

[WilsonF]

The valves not being adjusted will make it run crappy, but never sure that's the only problem. If he is that disgusted with it, he might let it go @ a price that makes it worth towing it home.
Floyd

 

[Joseph Donnelly]

I agree that the injection pump timing probably slipped. This is a common occurrence when a bit of oil is present on the tapered shaft. The nut should be torqued to 144 ft-lb. If the rockers and pushrods were replaced in the same positions, the valve lash will be the same as it was before.

 

[wcjp]

Take the truck to your local shop for injection pump nut as previously mentioned. Also have them advance timing a little while they're at it.

 

[Signal73]

he can time it himself without tools by pinning the engine at TDC with the timing pin in the back of the case and pinning the pump under the acorn nut on the side of the pump, then reattch gear to a cleaned shaft. This will set him to stock timing which will get his truck running at least.

 

[Joseph Donnelly]

My favorite cleaner is Mopar 4897150AB non-chlorinated brake cleaner. I put a long M8 x 1. 5 thread bolt into one of the threaded holes in the pump drive gear to rock the gear and get all of it cleaned. Spray gently so you don't blow oil out of the bearing that is just behind the taper, at the front of the pump. Blow dry gently with compressed air, then push the gear into place on the tapered pump shaft. Attach the (oiled) washer and nut, torque to 144 ft-lb. You will need to put a barring tool into the bellhousing/block plate hole on the passenger side to keep the engine from rotating. A barring tool comes with the timing kit, or can be purchased from Cummins, part number 3824591.

 

[dieselram96]

Thanks guys for your responces, I am far from a diesel mechanic and still learning about these engines. The gear on the pump was never taken off so I dont understand why things would change. Maybe someone here could enlighted me on this. Maybe I am missing something here. . Thanks

 

[Signal73]

it is just a taper press fit gear. the P pump uses about 30hp I have been told to turn so after a while it can manage to work its way backwards, retarding timing.

BTW, if the KDP blew out the timing case he would have to remove the gear off the pump to replace the case.

 

[Signal73]

Thanks guys for your responces, I am far from a diesel mechanic and still learning about these engines. The gear on the pump was never taken off so I dont understand why things would change. Maybe someone here could enlighted me on this. Maybe I am missing something here. . Thanks

there is also a nice writeup on timing in this months TDR mag issue number 61 on pg 102 courtesy of Joe D