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Re: 3600 Rod Bearings Why?

I would have to agree with Jeremyfrank14, if you are using the 227-2902 bearing and the maintenance is kept up there should be no reason to change those at 25K. They typically show little to no wear at that service interval, this is especially true if you are running non-shot peened connecting rods.

 

Reference Caterpillar Media Number: SEBD9947

New member

Re: 3600 Rod Bearings Why?

Correct me if I am wrong Mr. Hunt, but my understanding is that the 227-2902(diesel bearing) rod bearing is good to run to 50k hours. The 192 rod bearing is a 25k hour rod bearing for sure. Personally, if I knew that I had the 227 rod bearing, I would scan the rod bolts at the top end and keep running them. I understand that the new rod bolts are not chipped, and that the rod bolt scanner is no longer used, but from my field experience the 227 bearings look GREAT after 25k hours if installed correctly. So if they were installed at the factory, I would not hesitate to run them to 50k hours. Just my .02 cents.

Contributor

Re: 3600 Rod Bearings Why?

Hello again sir, I think im kinda making sense of  this, so youre talking about oxidation in between the bearing shell and the bore of the rod causing clearances to tighten around the crankshaft? I do not have access to this, I am set up in PartStore if that allows access to these items? I have heard of them updating the bolt part numbers and torquing procedure are they having failure issues with the bolts? Thanks again for explaining this.

Trusted Contributor
Trusted Contributor

Re: 3600 Rod Bearings Why?

Cat recommended a rod bearing roll in from the very beginning in the OMM; this is not a new recommendation from that standpoint.  However, the issues that have occurred in more recent years with the oxidation on the back side of the rod bearing shell related to the con rod bearing bore finish, the change to using the diesel rod bearings, which have less lead/tin overlay and some other items have brought this roll in at 25k has been brought to the attention of us all.  A lot of things go into this elevation of this rod bearing procedure and with all of the various conditions in the field, including cleanliness and techs not fully following the procedures either from not knowing or just not doing, makes it prudent to be somewhat diligent to adhering to this recommendation.

 

Do you have access to Cat Engine News articles?  You could get to the website by working with your local dealer in setting you up to do this.  If you don't have this option, send me your email at my email; hunt_al@cat.com and I will send you the latest info on rod bolt torque and rod bearings.

 

Best Regards,

Al Hunt

Contributor

Re: 3600 Rod Bearings Why?

Thank you sir that makes me feel better about running the heads for a while longer. But I still have to ask what is the reasoning for the rod bearing interval? Is cat having issues with them and the rod bolts making it past the 25k mark? Or are they just simply worn out by that time? Also whereabouts would I obtain the latest update information on the bolts and bearings?
Trusted Contributor
Trusted Contributor

Re: 3600 Rod Bearings Why?

The important thing here is to understand the risk.

There is nothing wrong with going past the conservative Cat recommended 25k hour interval to do a top end.  We have lots of experience in the field of going much further when you really have done a good job of monitoring valve face wear.  You can go a lot further before a top end is necessary by using this fave wear information you are monitoring.

 

The rod bearings are a different matter for several reasons; rod bearings themselves, connecting rods, connecting rod bolts, and several other items.  I would strongly recommend rolling in rod bearings following the 25K hour recommendation.

 

Be sure you know the latest with regard to the rod bolt information and the latest rod bearing installation and rod bolt/nut tightening procedure.  This is critical to success of performing this repair.  Cat has several Engine News articles that you should use to guide you with this rod bearing repair.

 

Best Regards,

Al Hunt

Contributor

3600 Rod Bearings Why?

Hello everyone, one of my 3608's is at the recommended 25,000 hour top end overhaul mark and I have a few questions. Is it really necessary to do a top end overhaul when my recession readings are perfectly fine? Also everyone I talk to says you must change the rod bearings at this time as well. This to me seems like a waste as all of the rod bearing changes ive seen on these the bearing shells look completely acceptable usually not even worn through the tin flashing, and tearing into such a sensitive area seems like its just asking for more trouble if the bearings were fine to start with? Just curious folks, Thanks!