Engine and new turbo destroyed! Dropped valve seat! Story inside...

[EMorad]

I know of six trucks that have done this. Mine is in that line up. Mine droped at idle so i was able to save the block. When i had the head off we gave it the works: ported,valve guids, ringed the head and replaced the ex-side valve seats with over sized seats. I talked to three or four shops and they said they are starting to see this problem. Dealer would have fixed but i didn't want it done the same. I wanted the problem fixed for good.

I wish I knew someone local that could fix the heads on the new used motor in the truck. I cant see keeping the truck without a warranty and only 28k on the truck and the chance of this happening AGAIN on a now stock truck.



I was told by several that it isnt "IF" it happens again, just a matter of "when" it will happen. I need to get the head fixed or buy a new truck and sell this one.

 

[RustyJC]

Just a general comment. Valve seat inserts are commonplace on large industrial engines such as those built by our company. Fitting valve seat inserts correctly can be a real challenge since inserts can drop out due to (1. ) insufficient interference fit and (2. ) excessive interference fit. To explain the latter, if there is excessive interference fit, the seat will fail (collapse) in compressive hoop stress once the engine reaches operating temperature - the compressive hoop stresses become even greater with higher HP outputs and EGTs of a BOMBed engine as these cause the operating temperature of the exhaust valve seats to run abnormally high.



Rusty

 

[RTillery]

RustyJC:

You seem to know this valve seat thing pretty well. With an adjustable seat pocket tool, what would you recommend as an interference between the seat ring, and the pocket bore in the head? Thanks for the info!

 

[RustyJC]

RustyJC:

You seem to know this valve seat thing pretty well. With an adjustable seat pocket tool, what would you recommend as an interference between the seat ring, and the pocket bore in the head? Thanks for the info!

I could tell you what we use on various engine models, but without knowing how Cummins' head and valve seat materials compare with ours (coefficients of expansion), it wouldn't mean much.



Here's a counterintuitive lesson we learned, though. If valve seats are dropping out, the tendency is to increase the interference fit, but sometimes (especially with BOMBed trucks) the solution is to reduce the interference fit for the reasons explained in case 2 above. One really has to examine a seat that's in good enough condition to see how it failed to determine which direction to go.



Rusty

 

[MCummings]

no more big mods on a diesel EVER. pricey bulsh!t

Uhm, dude, don't hate the diesels. If you Big Mod ANYTHING, it's pricey BS.





Merrick

 

[EMorad]

Uhm, dude, don't hate the diesels. If you Big Mod ANYTHING, it's pricey BS.

I dont hate diesels, I hate the flaw in the new cummins engines that cost me alot of $$. I just got screwed because I have mods on the truck hence no warranty. It is a known flaw. Had they not had a production error/ design flaw, I wouldnt be out all this.



I just recieved a BRAND NEW Edge ball bearing turbo kit. Brand new in the box, every piece. Paid $1800. best offer over $1500 plus shipping. DD shipped me a whole new kit under warranty



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