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Cummins Killer Dowel Pin?

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05-27-2022, 02:00 PM
Eric Herrle
Cummins Killer Dowel Pin?
Does this affect our Breakaways?

Just heard about this.
05-27-2022, 02:29 PM
Steve VW
Cummins 5.9 engines from about 1988 to 1998 had this problem. The dowel pin is installed in the cylinder block and aligns the timing cover as the cover is installed. Over a period of time, in some engines the pin becomes loose and can fall into the timing cover. It may fall harmlessly and end up in the bottom of the case, but may also lodge in the timing gears and destroy the engine, hence the "killer" label. confusion

The only sure fix is to remove the cover and install some form of aftermarket pin retainer.

I do not know of any statistics on failure rates, not sure how common this was. Definitely a serious failure is possible.

Ed has done a lot of work on his 5.9. He knows of this problem and has fixed his. Perhaps he can give us more info. hmm


9708-M0037-37MM-01
"98" Monarch 37
Spartan MM, 6 spd Allison
Cummins 8.3 325+ hp
05-27-2022, 07:24 PM
Goodsign
Eric,

Steve's overview was pretty much right on. It might be helpful for me to add some firsthand experience with the KDP. Several years ago, my wife & I bought a '93 Breakaway(we love it) with a radiator which needed replaced. It seemed like a good time to also replace belt tensioner, water pump, rebuild the alternator, set the valves, etc. The coach with 90,000 miles and with a 5.9 12 valve Cummins ran well and did not use or leak a drop of oil, therefore I hesitated to pull the timing cover to check the notorious KDP. Fortunately my tendency towards perfectionism would not let me neglect my curiosity. Good thing because I discovered my KDP was standing 1/4" proud of the block & required a very slight tap to reseat it. Also as suggested by two friends who are very familiar with this(12 valve Cummins), I also checked the timing cover bolts, a few which can be seen & several which can be accessed by baring the engine over & looking through the gear slots. One shockingly was barely finger tight. I bought a ready-made kit which included a real nice machined piece & recessed allen bolt(about $15.00). However, some people have successfully used the original bolt & made a tab. I cleaned all bolts with brake cleaner, dried the threads, & applied Vibra-Tite Blue Gel; a great product, & re-torqued to specs. There are a number of U-Tube videos which do a good job of explaining & demonstrating the procedure.

Lastly, the one buddy who specializes in the Cummins engine, says he has seen some low mileage engines like mine where the pins & bolts work loose & others which have many more miles & never come out, so do you feel lucky?

Best Regards,

John
05-27-2022, 11:47 PM
Eric Herrle
Thanks for the input.
05-28-2022, 01:02 AM
MWrench
Previous posts by Steve and John were spot on. I was going to investigate this issue on my 5.9L 230 HP Cummins in my 1993 Breakaway. Bought my coach with about 70K miles on the clock. I was familiar with the KDP issue years earlier as there had been issues in the Cummins powered Dodge trucks, I wouldn't say it was a frequent problem but was a random issue that was talked about a lot.

I helped a number of friends get into their Dodge Cummins engine and lock down the dowel pin. At that time there were few sources to get the locking tab or cast aluminum piece. This piece was added under the adjacent bolt and would prevent the dowel from working out, we made our own tab for a few years. We found almost all dowel pins had worked out by 1/8" to 1/4". Some were just like John found, just a slight tap to get them bottomed out. Most required a couple of good hits.

This is a bit harder on the Breakaway as the radiator stack must be removed to gain access to the entire front timing cover. The harmonic dampener must be removed and a new front crank shaft seal installed on the front cover. We never found real loose bolts inside the timing gear area, but some were not quite up to the 18 lb/ft spec.

I did mine about 150K miles when my radiator required a recore. MY KDP was about 1/4" out but required a couple of hard hits on the punch to get it fully in. I had no further issues until I had about 320K miles on it, messing around to bump up the power. Another story!!

If you have a chance or reason to remove the radiator stack or planning to keep your coach a long time, a KDP retainer should be on the top priority. If this is done by a shop it will not be cheap, but a new engine would be much more expensive.


Ed
94 30' Breakaway #3864
30-BS-6B side entry
New Cummins 5.9L, 375+ HP
Allison 6 speed
Spartan chassis
K9DVC
Tankless water heater
05-29-2022, 01:12 PM
Eric Herrle
Any tips on removing the radiator in the Breakaway would be greatly appreciated.
05-29-2022, 02:42 PM
Goodsign
Hello Eric,

Several years ago when we did the KDP, it was just part of a restoration effort which involved cosmetics & some obvious mechanical issues. Our rear bumper was slightly kinked & that annoyed me, & the tow bar was rusty so both were removed, straightened, or refinished. We also removed the rear radiator grill by drilling out the aluminum rivets & also cosmetically refinished it(now polished aluminum). After the removal of the fan & shroud, the radiator set was loosened & lowered with the help of another experienced mechanic(thanks Brad). A floor jack helped too. As I recall, since the radiator was to be re-cored we weren't especially delicate with our efforts. After completing these steps, servicing the front of the engine ie removing the damper, removing the timing cover, & addressing the KDP etc, was relatively easy since all the obstructions were gone.

If you manage to get to this point, you might want to check your exhaust manifold. Ours leaked in three places & had a nasty crack that someone before our ownership attempted to fix. We replaced ours with a DPS two-part manifold(a really sweet piece). By no means a simplistic job but far easier with all of the above removed, since it did improve access considerably.

Ed(M Wrench), who has posted many outstanding technical tips concerning the 5.9 Cummins engines, hopefully would offer a more detailed & proper technique to make your project easier. I subscribe to the "Larry the Cable Guy" school of mechanics. I just "Get r Done". Sometimes that makes accomplishing a task more difficult than it has to be.

Good Luck,

John
05-30-2022, 01:33 AM
MWrench
I have been swamped with projects this last year and haven't really posted much here but will improve soon I hope.

I have pictures of my radiator removal process that I will try to get up this next week. I did a few things to make the removal process much easier but for a one time project you may not want to go thru what I did. The radiator assembly is very heavy and as John mentioned his radiator needed a recore so a bit easier to do with less caution still, a lot of work.

I will also dig thru my archives and see if I have pictures of my first radiator removal, was very similar to how John did his.

More later.


Ed
94 30' Breakaway #3864
30-BS-6B side entry
New Cummins 5.9L, 375+ HP
Allison 6 speed
Spartan chassis
K9DVC
Tankless water heater