1st Gen Killer Dowel Pin

[cumminsgetme]

Don't think that you first gen guys are excluded from this problem!! Latham (new TDR member) and I replaced the gear case on a 90 model cummins that had spit the pin through the case. The case broke clean in two places leaving about a 2" piece of the case being held only by gasket maker Once the case was removed we were able to simply pull this 2" piece away from the rest of the case... again: the only thing holding the broken 2" section was gasket maker!! If I owned a first gen I would take preventative measures immediately. The reason for this is that the cam in a first gen is not designed to be removed in frame . So your options are, pull the motor or completely remove the front end. I mean completely remove the front end!! To do this you will have to loosen the front fenders and pull them away from the truck about 2" in order to remove all front end body work. The problem arises from the vertical support member in between the radiator and condensor. When finding out we had these two options we called the owner of the truck (Latham's dad) and told him of the scenario. His comment was "it's a farm truck with 550K miles, grind the damn brace off!!" That's right 550K miles. I hated to grind it off but we weren't left with many options and he wanted the truck back as soon as possible. Something that we found interesting was the that the cam gear was advanced 4 teeth relative to the crank. My only guess is that someone had been in the motor before and didn't line up the gears properly when going back with the install. We asked his dad if he wanted us to reinstall the cam properly lined up. He said that the truck ran great and wanted the cam installed the same way it came out (4 teeth advanced). For the truck having 550K miles the cam was in extremely good shape. Overall the job went real well, getting the pump off of the gear case on a 1st gen is much easier than a 2nd gen and it was really nice having all the room under the hood. I haven't heard of too many 1st gen trucks having this problem so I wanted to pass on the info to ya'll. I plan on posting pictures sometime this afternoon, however one of you may have to walk me through the procedure.

 

[KEENO]

Thanks for the insight "Cumminsgetme"!



Wowzer! This sounds extreme!



KEENO

 

[R.E. Miller]

Just when you think it's safe to play again.

 

[RamAZ]

Gear Cover.

Just had the gear cover on my 92 replaced a couple of months ago for the exact same thing, I posted it here and nobody seemed to believe me. It happens, costs about 2K to be fixed at Cummins Southwest. CSW did the job in a couple of days, I'm really pleased with thier workmanship.



Runs fine now.



Jim

 

[R.E. Miller]

Sorry for being stupid

How do you fix the lil' dowel pin-o-death problem? I understand about the whole disassembly process, but what do you do that will eliminate this from happening again?



Also, do you need a cummins education and tool kit to perform this?



Now I am scared, but in the name of bonding with one's truck, you can't get any closer then tearing into it's heart

 

[4020Deere]

I find it very hard to believe that the truck would even run with cam timing being off 4 teeth. In most diesels that have gear driven camshafts, even being off 1 tooth can cause valve to piston interference. Heck, I've seen a brand new diesel engine that was off only 2 gear teeth on cam timing and it bent half the pushrods the first time it was started, as a result of the valves kissing the pistons.

 

[jlatham]

4020



I found it hard to believe to. The only thing that I could think of was that the cam had been stamped wrong from the factory. I had to have a 1st gen rebuilt back in 95 because the KDP came out and fell between the cam and crank gear breaking the cam in half also twisting the crank. There wasn't to many salvageable parts left after that. Anyways the company that rebuilt the motor didn't line up the timing marks on the cam crank and pump. I couldn't figure out why it wouldn't start. As you can probale guess I was plenty mad after having to take the front of the motor off to retime it. After that she fired right up. But they did rein burst me for some of the money. Also the company that rebuilt it some how forgott to put a gasket on the side plate of the motor. I had to take the pump off just to put a gasket on. At this time I was really PO when I could have done all of this on a motor stand instead of it being back in the truck. If I would had known that it was going to be that much trouble I would have done it myself.



Needless to say that motor wouldn't crank up with the timing marks off granted they were off a lot more than this other pickup Its still a mystery to me why the timing marks are off, luckily its still running.



Warning to all of the 1st gen owners this is the 3rd 1st gen truck that my dad and I have had to replace the gear case or in one instance rebuild the motor. Trust me it isn't cheap to rebuild one, maybe the prices have changed since then. I hope me nor any of you have to find out









Justin Latham

 

[cumminsgetme]

R. E. Miller,

The case which is reinstalled is an updated version that is necked down and will not allow the dowel pin to pass through it. I will not install a new case unless it is the updated version. I also use locktite and anything else I can get my hands on to hold the pin. There are several methods floating around the forums to prevent the pin from coming out, if your interested in these do a search in the 12V forum. If you have any problems finding these fixes, let me know.



4020 Deere,

I also was shocked to see the cam advanced 4 teeth. However there were two other people who witnessed the removal of the cam. I'm sure they'll chime in if you would like to hear it from them. Once I figure out how to get pictures posted you will see that I have the cam gear marked in two places, one mark for the pump gear and the other for the crank. Had the cam lined up properly there would be no need for the second mark, you would be able to line up the cam and the crank by the stamps provided. I have even gone so far as thinking that it was mis-stamped, however I highly doubt that's the case. I would have preferred to reinstall the cam properly aligned by the stamps, but that was not what the owner wanted.



RamAZ,

I don't want to upset you by letting people know how much the KDP job "should" cost, but I also don't want anyone on this forum to be stuck with a huge bill from these shops. I am fixing these gear cases at 1/3 the price you paid. This includes replacing the front main, all gaskets, parts, and labor. I'm not posting this in an attempt to get more business, as I am not in business, just a 23 year old college student who loves to work on trucks. I just don't feel that it's right for repair shops to take advantage of customers who may not know what the job is really worth.



-Cord Reynolds

 

[4020Deere]

Don't get me wrong, I'm not calling anyone a liar or anything, it's just VERY strange, that's all. Like you've said, something could have been stamped wrong too. I'm just speaking from my experience working for one of the major diesel engine manufacturers and seeing over a hundred diesel engines built and tested per day. We occasionally get one that has a problem such as that, and believe me, the results are pretty bad. I've seen alot of scrapped parts and entire engines that were brand new! I agree it would be interesting seeing some pictures if given the opportunity.

 

[cumminsgetme]

I can't figure out how to get the pictures to appear in the post, but this link should work. #ad
The first pic shows the dowel rods before being lifted and band together. The second pic will show the mess that was made due to the vertical support in the way. I want to stress that this is not how I normally do things (grinding what ever might be in the way), but was told to do this by the owner. He needed the truck asap, there was no hoist available and he didn't want to waste time with removing the fenders. In the top right corner of the frame there is an arrow, click this to get to the next picture. Here it shows the two marks that were made due to the 4 teeth advance. I guess it's a possibility that the gears could have been mis-stamped, however during assembly the installers would have to know of this mis-stamp and assemble it advanced. The truck runs great, actually better than before. This dosn't surprise me because the valves had not been adjusted in a LONG time.