Crew Cab Update..... No photo's...Sorry

Hey guys. I've been really busy the last month or so. But, I've got the 6.9 crew cab completely torn down and at the machine shop as I type this. It should be ready to pick up next week.

A few guys already know this, but I wanted to share with you all why my headgaskets keep failing on the #1 cylinder. The blocks deck was warped around the #1 cylinder. It needed 7 thousands to get the block flat and square with the crank center line again. The bores are fine and only needed honing..... not an over-bore. The crank and cam are great as well. The heads are supposed to be fine as well, but I'm always worried about a missed crack.

To compensate for the lower deck on the block, I ordered a set of Mahle pistons with the wrist pin 10 thousands higher on the piston. They were specifically made for decked blocks. When used with a standard deck height, the compression ratio will be lowered to 19.7:1. With my milled deck, the compression ratio will not change much.

I decided to go with Hypermax rod and main bearings. They are supposed to be an upgrade to the usual offerings........ we'll see. When time and cash allow...... I'm sending Russ my cam for a regrind. I'm also getting the rotating assembly balanced from the harmonic damper all the way to the flywheel............ AND OF COURSE, A MOOSE PUMP AND MOOSE INJECTORS!!!

I know it sucks without photos, but I hope to have some loaded up this weekend.

Heath

I've got a good imagination. Nothing wrong with that info there. Wonder how your block deck got so out of whack?

Agnem said:

Wonder how your block deck got so out of whack?

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Not sure, but I knew something was up when that dang headgasket let go with just a few thousand miles on it with studs holding it down.

Heath

Thank goodness you finally have an answer! Still sucks, but at least you're not wondering WTH is going on anymore.

Hopefully it's smooth sailing from here

That sucks after all that work, you had to go do it again

There may have been excess pitting around #1 . Having metal that is not as regular as the rest of teh surrounding block deck can cause irregular localized heating which could lead to a localized warpage without effecting the entire bank, or a previously blown head gasket that was run on for a while on #1 could cause irregular heating there.

You do know that Hypermax didnt make those bearings. They just got some good clevites im sure.

Or KINGS.

Thanks for posting an update! There is nothing more frustrating than, after going through what you did with that engine, finding nothing wrong (glad that didn't happen for you)! So it's always a relief and provides some sense of closure to find the root cause.

They did do a thorough check of the block & heads for cracks, right?

The Warden said:

Thank goodness you finally have an answer! Still sucks, but at least you're not wondering WTH is going on anymore.

Hopefully it's smooth sailing from here

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Thanks a lot Tim. Yeah, I hope she'll go another 325K before she needs this done again. I'm glad to find the answer. I suspected a few possible culprits, but I'm glad to be on the way to putting it back together.

Diesel_brad said:

That sucks after all that work, you had to go do it again

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YES IS DOES!!!

typ4 said:

You do know that Hypermax didnt make those bearings. They just got some good clevites im sure.

Or KINGS.

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They probably will come in a blue and white Clevite box with Hypermax stickers on them. But, they were cheaper than buying them from local suppliers and most on-line places.

redmondjp said:

Thanks for posting an update! There is nothing more frustrating than, after going through what you did with that engine, finding nothing wrong (glad that didn't happen for you)! So it's always a relief and provides some sense of closure to find the root cause.

They did do a thorough check of the block & heads for cracks, right?

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Thanks! Yup, very frustrated at the 6.9 for a while. I put a ton of work into it last winter, and had a "new to me" camper to haul for my family to enjoy, and it failed on me. Keeping my fingers crossed for a much improved result this time.

If not, there will be serious repercussions.

Heath

Deck warpage limit

From the Haynes Diesel Engine Repair Manual:

For 6.9 & 7.3
Engine block
Deck warpage limit..............................0.006 in.

My machinist tells me that these block typically require decking .010 to clean them up.

Dohh!! Makes me think now that I should take my 6.9 in to get decked. I was just going to replace the head gaskets, but the deeper I went, the more I found. I see that this is not the first time this engine has been apart.

bbjordan said:

From the Haynes Diesel Engine Repair Manual:

For 6.9 & 7.3
Engine block
Deck warpage limit..............................0.006 in.

My machinist tells me that these block typically require decking .010 to clean them up.

Dohh!! Makes me think now that I should take my 6.9 in to get decked. I was just going to replace the head gaskets, but the deeper I went, the more I found. I see that this is not the first time this engine has been apart.

Click to expand...

Yeah, there is not much room to deck the block on these IDI's as the piston crown is accually out of the block's deck at TDC. The more you mill off the closer and closer the piston gets to the head!!! That's why I went with the "destroked" pistons from Mahle (Clevite). The catalog states they are designed for use in decked blocks. You'll loose just a hair of stroke, but that's better than pistons meeting heads!

Heath

Taking .007" to clean up a deck surface is probably just a hair more than average. Heads are a different story because they are prone to warpage, whereas blocks have enough meat connected to them that they don't really move around much.

It usually takes at least .003" to get the cutter to actually cut the entire surface - if the machine operator is taking his time to setup the machine properly. Taking .007" to make the deck surface parallel to the mains (square decking) would be pretty typical - the worst I have seen here was a 440 mopar that was out by .045" from one end of the block to the other; that's almost 1 entire point of compression.

So did you just have the deck surface cleaned up, or did you have the block square decked?

Oh, and changing the wrist pin location in the piston only affects compression, no change in stroke.

Very good to hear, Heath. Man, it is a good feeling to make some progress. I'm ready to see the crew cabs parked at the campground and the drivers having a much less stressful rally in '12.

bike-maker said:

So did you just have the deck surface cleaned up, or did you have the block square decked?

Oh, and changing the wrist pin location in the piston only affects compression, no change in stroke.

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They were supposed to square deck the block. Don't know if that's what happend or not. The "specification" sheet on the pistons says "destroked .010 inch."

GOOSE said:

Very good to hear, Heath. Man, it is a good feeling to make some progress. I'm ready to see the crew cabs parked at the campground and the drivers having a much less stressful rally in '12.

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I certainly hope so man. If the 6.9 lets me down again, I'm going to the way bike-maker has and the V8 will be swapped for an IH DT360.

Heath

Nice thanks for the update, I was wondering what was going on with your rig. Even though it sucks to spend the extra it should be all right now and you know what you have.