Cummins ISX broken valve in #6

[harleytobey]

So I am looking at a 09 Signature with 81k miles on it at a price point way under wholesale. It has the ISX 650hp Cummins. Should I walk away, or should I still consider it if the $$$ under wholesale would help with the recommended engine repair, head, turbo, pistons, etc. Do ya'll think the "Fix" works, or will it be a on going problem?
Thanks! Mike

[palehorse89]

Post from 2015 on a Trucker's Forum:

Have a 2009 motorhome with an ISX 650, 2nd owner. Turbo went out at 11,000, repaired under warranty.

Broke a valve off in #6 at 19,000 miles again under warranty, now at 44,000 miles it again broke valves in #5 and 6, liner in 4 also needs replacing. Cummins admits that they have a problem with the engine breaking valves and have new heads and valves to "fix" it. Bill is right at $29,000 and so far no word on Cummins covering any of it. Cummins NW says they have seen 4 of the ISX's do this, 2 MH's and 2 class 8's so it's not uncommon.

Some more reading: http://capitalremanexchange.com/cummins-isx-history/

[2-Nickels]

I bought an 09 MH with and ISX 650 knowing the problems existed. I negotiated the price less the repair and took it right to Cummins NW. Following the repair and upgrades I have not had a moments troubles.

[08Navigator]

Update...here's what I found so far...

Drive side turbo Fins and other melted balls of aluminum in the header.

Intake side of turbo clean

Timing gears look in order...however due to poor quality control, and errors in tolerances - notice the spring loaded injector cam gear..covers up the manufacturing errors that would be audible at idle..

Plastic Valve cover? Really it's plastic! Maybe used pop bottles?

High end parts made in Czech Republic...NICE touch! Maybe used coke cans?

Piece of steel in intake manifold - how many cylinders are damaged is now your guess.

Valve stems all in place.

Parts made in China under valve cover.

Failing rad pressure test...ouch

Going to dig more...I already have a theory on the cause of the failure....we will see!

[palehorse89]

Posted this in another ISX thread.......... http://www.irv2.com/forums/attachmen...0&d=1536235453

Post #18 http://www.irv2.com/forums/f115/09-s...ns-409663.html

[randomledder]

Plastic valve covers and oil pans have been around for years, not a cummins exclusive. The concept gear keeps the gear train quiet. The engines without any concept gears have an annoying rattle. I don’t have a dog in this fight but just thought I would mention it.

[08Navigator]

Thanks for making me laugh...LOL....I got a dog in the fight...and literally it is a "DOG" . You have missed the point....Just because something has been used for years doesn't make the product high quality. In addition, if Cummins would have line bored the cams in the correct locations they wouldn't need the "cheap" noise fix...again poor quality control / manufacturing...see attached picture of an ISX with out the cheap fix. They got the pictured one right. Sorry, no one will ever convince me that I have a high quality industrial product...I got a POS from a lousy company... LOL....I have a harbor freight generator with more than 1100 hours on it...and I have never changed the oil and it has yet to blow up!?!?

[hypoxia]

This is interesting. Not many DIYers that get into the engine.

[randomledder]

Just to correct you the engines without the concept gears are the lower spec engines. They only added the expense of the concept gears to the higher horsepower engines. Just some friendly advice. Im not sure if you have access to QuickServe for the manual but back off two bolts on the concept gear before you pull it off. I assume you have the timing pin and wedges to pin the crank and time the cams when it goes back together?

[Mr_D]

Was at a chain Cummins/Allison shop yesterday. They had a reman ISX 400 for $24,500. Then there's the cost of pulling the old and installing the new. Pretty easy in a class 8 truck. Not so easy in a MH.

[08Navigator]

Originally Posted by randomledder

Just to correct you the engines without the concept gears are the lower spec engines. They only added the expense of the concept gears to the higher horsepower engines. Just some friendly advice. Im not sure if you have access to QuickServe for the manual but back off two bolts on the concept gear before you pull it off. I assume you have the timing pin and wedges to pin the crank and time the cams when it goes back together?

Thanks for correcting me! If I own the Higher spec engine, and it ran 1100 hours, 48,000 miles....my goodness what do you get with the lower spec motor? 550 hours or 24,000 miles , which ever comes first? LOL Cummins, being the consumer minded organization they are only charges $1200.00 a year for Quick Serve to access the ISX service manual..one can buy a PDF file that lasts a life time on ebay for $14.95 Havent needed a manual yet...

The wedge and pin deal to set the cam timing...lol...another cummins procedure. .that's for the Service Monkeys at Cummins...you know the one that took a hour to find the slide out button and lower the leveling gear...I bet Cummins sells those kits for $500 bucks to each Monkey...I think at Cummins school they couldn't figure out how to use the attached $20.00 tool.

I will say Cummins went the cheap route by not providing a $1.00 Woodruff key to locate the gears on the camshafts...I think the engineers were so slow they didn't understand adjusting the timing via offset keyways so they made the cam gears fit in any position. Well I guess they did save the machine costs for the machining they key way in the gear and the camshaft...and of course the keyway itself...Again...as cheap as it gets...plus they get to sell wedges and pin kits to the Monkeys

Thanks for the tip on the springs! ..I kinda figure that out as I was making pullers for each gear.

[08Navigator]

Update on project..slowly getting to the bottom line...Drive side of turbo took a hit, blades nicked. The Variable Turbo is no longer Variable LOL...Actuator arm seized. Going to have to rebuild. Good new is nothing went thru the charged side...Major bonus! I will not need to clean intercooler....which would be a pain on the side mounted radiator coach.

[08Navigator]

Had to make a couple gear pullers for the tapered camshaft gears...little hydraulic pressure with a porta power between cam face and my puller bolted to the face of the gear.... Popped them right off...Removed cams...I did not like the looks of the Valve camshaft bearings...maybe par for disposable motor...48,000 miles is a lot of miles...particually with 10 oil changes ( one per year...Averages 5000 miles per oil change) not sure..More on bearing to come...I love how Cummins touts this engine as a DOHC ...sounds sexy...to the consumer...like a high performance motor.. Don't be fooled ...It has one camshaft for the valves. The other camshaft simply operates the fuel injectors.

[palehorse89]

I am following your post's with great interest! You are doing a wonderful job and Thank you for posting and for the picture's!
Have you come to a conclusion as to what failed as of yet? It is really sad with only 48k well maintained miles on it for sure!!
Is the head off yet?