21st century technology

[GAmes]

I'm having a conversation with another 2nd gen 12 valve owner. I pointed out that our manual specifies a clean, dry surface for a new front crankshaft seal. His response was that in the course of over 20 years that the seals may have changed and now require lube. His arguement is the book requires 6000 mile oil changes and other items that are not in synch with today. So, does the new 6.7 front seals also go on dry, free from oil and what are the current factory speds for oil changes?

 

[lpennock]

Current spec on oil changes is 12 month 15K miles. Was 6 months since 2014 (I think this was the correct year).

 

[AH64ID]

My 05 had 6mo and 7.5K schedule B or 15K schedule A.

The 18 is 6mo or 15K miles.

19+ is 12mo or 15K miles.


As for the seal, is the part number the same as the new trucks? If not then you should use the older manual.

 

[GAmes]

As for the seal, is the part number the same as the new trucks? If not then you should use the older manual.

The conversation is if Cummins still specifies a clean/dry surface for the seal or if grease/oil is allowed when installing a new one. My guess is that Cummins never improved on the seal and the requirement for clean and dry is still applicable on new engines.

 

[NIsaacs]

The conversation is if Cummins still specifies a clean/dry surface for the seal or if grease/oil is allowed when installing a new one. My guess is that Cummins never improved on the seal and the requirement for clean and dry is still applicable on new engines.

I did some research and it appears they are still the same, even the part number. Using a 2019 #68426385aa and crossed it to an older Mopar number of 68027026aa it crossed to a Napa. If you zoom on the seal you can read the "install dry"

https://www.napaonline.com/en/p/FPGTCS46174?impressionRank=4

https://r.search.yahoo.com/_ylt=Awr...426385aa/RK=2/RS=3Mrr0wL2c5TF79aOdiSf1zF79AA-

 

[AH64ID]

From the current QSB6.7 service manual.

The seal lip and the sealing surface on the crankshaft must be free from all oil residue to prevent seal leaks.

A bead of sealant is applied to the outside surface of the seal, but the sealing surface is still dry.

 

[bcbender]

From the current QSB6.7 service manual.

The seal lip and the sealing surface on the crankshaft must be free from all oil residue to prevent seal leaks.

A beat of sealant is applied to the outside surface of the seal, but the sealing surface is still dry.

What kinda beat is it... I like a little good rhythm when I'm working in the shop.

 

[BigPapa]

As John posted, from the Cummins S/M for one of our '22 buses.

 

[SSchang]

I worked at CMEP (where the ISB is made) around 2000. I seem to remember that the rear crank seal needed a clean dry crank surface because part of the the seal is supposed to stick to the crank, and spins with the crank. The "sealing" is done between two surfaces of the seal, the one surface spinning with the crank and the other surface not spinning which is mounted to the block.

Not sure if my memory is right, or if the front seal is the same, but if you have a seal you should be able to see if it's two pieces put together.

 

[GAmes]

Thank you very much.

 

[petersonj]

From the current QSB6.7 service manual.

The seal lip and the sealing surface on the crankshaft must be free from all oil residue to prevent seal leaks.

A bead of sealant is applied to the outside surface of the seal, but the sealing surface is still dry.

I have reread this thread and I see no mention of a PTFE (polytetrafluoroethylene) seal. If it is a PTFE seal (which I think it is), it absolutely must be installed dry on both dynamic surfaces. It is the friction between the seal lip and the crankshaft sealing area that creates a permanent dynamic seal upon engine startup. If a PTFE seal is lubed in the dynamic sealing area, then the friction does not occur and the seal will likely fail.

I seem to remember that the rear crank seal needed a clean dry crank surface because part of the the seal is supposed to stick to the crank, and spins with the crank. The "sealing" is done between two surfaces of the seal, the one surface spinning with the crank and the other surface not spinning which is mounted to the block.

There are seals made in this manner (heavy duty rear wheel bearing seals come to mind), but I think the rear crankshaft seals are PTFE seals. But, I certainly could be wrong.

- John