Cummins 12valve Killer Dowel Pin (KDP) fix

[USMCRockinRV]

Finally MADE the time to put my mind at ease and secure the KDP - which has the potential to crack apart the Cast Aluminum Casing.
This also allowed me to stop the small leak around my Crank Seal and replace my Timing Cover Seal...
4hrs and I was back on the road with my mind at ease the dreaded KDP can never Strike

[milkmania]

good info

never heard of such

KDP Information & Repair

The "Killer Dowel Pin", or KDP, is a concern on 1989 to 1998.5 12 valve Cummins engines. A steel dowel pin is pressed into the cast iron block during assembly. The pin properly aligns the aluminum timing gear housing to the engine block during assembly. Over a period of time, vibration can cause this pin to back out entirely. When this occurs, there are basically 3 possibilities. One, the pin can fall out, bounce off the cam gears and end up in the bottom of the timing gear housing without causing any damage. Two, the pin can dislodge and be forced against the aluminum timing gear housing, cracking it before exiting or falling to the bottom of the case. And three, the worst case scenario, the pin vibrates loose, becomes lodged between the timing gears, and causes catastrophic failure. In this instance, the pistons slap into the valves and your engine literally demolishes itself.

[Tango]

Ya...the KDP issue is common to all 4 & 6BT's and can eat the motor in a heartbeat if not corrected. It is nothing more than a simple, pressed in, steel dowel pin who's primary purpose is to help position the front gear cover gasket. Problem being that it can work it's way loose and fall into the timing gears destroying the cover and/or gears and /or block. Nasty lttle sucker when it goes bad.

There are several different solutions. One is to simply remove it and throw it away (which makes that gasket very hard to position). Another is to fab a small cover plate which is bolted in place (there is a free screw hole right next to it...use permanent Locktite) The third (which I chose) is to peen the case next to the pin to keep it from falling out and creating havoc.

Damage is far more common then Cummins or most diesel techs wish to acknowledge and it absolutely should be addressed on every engine.

[USMCRockinRV]

I was going to jig / pin it but I noticed I had a leaking Crank anyway... So off it all came - 105° heat index and humid... LOTS OF WATER!!!! LOTS... Haha

[bansil]

Bus shop said they did this before I got it, know way to know except take it apart myself

I haven't done it because it looks like it would take several days to just take the front apart

[opus]

You replaced the oil pump while you were there, right? ;)

[USMCRockinRV]

Ya' know - I probably should have but it looked new. Don't know that it was - but the Timing Cover seal had signs of it having been off before - KDP wasn't tabbed paint was knocked off the pulley bolts so I figured it had been changed. You got me thinking though...
Haha... I might just swap that joker out next spring regardless~

[opus]

Sorry, didnt want to make you not sleep for months and months on end. LOL!

Its easy enough to get to though, isnt it...

[USMCRockinRV]

Heck yea... LOL
Actually I don't dread at all getting back in there - they should put the radiators in all pickup trucks on the side - hahaha
I love opening my bus and my engine is RIGHT THERE... No Fan, No Shroud, and No Radiator~

[opus]

[USMCRockinRV]

Not sure too many realize - that's a Gorgeous Sight... Hahaha...

[Kubla]

there is another way to fix the KDP, it was used on my 95 dodge PU, involves drilling a hole in the front cover (done with a jig), tapping the hole and running a bolt long enough to go in front of the pin into it, a lot easier than removing all the stuff on the front of a Pickup engine