Help: Yay I Think I Need Head Gaskets

[FMOS]

I'm going to take a wild stab and say the valve train is the same as the LLY's...

If so, thats probably the easiest part... All you do is back off all of the rocker adjuster bolts, then loosen the 5 bolts in the valve train "rail" and it comes off with the rockers and whole nine yards. Valve bridges just sit on top of the valves nicely. Push rods come out nice and easy. Putting it back in you just put the valve bridges and pushrods back in the same spots they came out of, torque down the whole rocker "rail" according to the procedure then use a set of feeler gauges to set your valve adjustment.

I'm not speaking from experience on the installation part because I'm not there yet haha. Only tough part will be rotating the motor so you can set each rocker... but I think you can do them all in two crank positions... just need to know which position is piston 1 TDC intake and piston 1 TDC exhaust. And I think you slide the feeler (.012 or .011") in between the valve bridge and the rocker and then tighten the adjustment bolt down until it is snug, then torque the locking nut.


Here is the adjustment procedure.
http://www.duramaxdiesels.com/forum/showthread.php?t=6154

And this is the "which rocker to adjust in which position" table.
http://www.duramaxdiesels.com/forum/showthread.php?t=6149

 

[CancerPipe]

Been studying those. Looks like were on the same page. Now I just need some guidance on the injector cups. If I wind up doing it myself I may actualy buy the tool for future use. Thanks man.

 

[ripmf666]

Been studying those. Looks like were on the same page. Now I just need some guidance on the injector cups. If I wind up doing it myself I may actualy buy the tool for future use. Thanks man.

If you look around in the specs area it will tell you almost everything, When you install the cups with new o rings add some red loctite at the bottom of the cup to the head side and some on the o rings and becareful with getting the first o ring started in the hole you can tear them easy.In the tool crib area I think I posted the part number for the tool needed and you can find them on ebay.

 

[CancerPipe]

So its just regular locktite? Thanks guys.

 

[bullfrogjohnson]

Are you going to do them in the truck? I have done a set and will pull the motor on the next set I do.

 

[super diesel]

You will need a 272 (high heat) lock tight IIRC. I don't know if it does any good when were running hard though. This is what GM uses and Eric M. recomended it to me. This design is interesting that the aluminum surounds the SS cup. As heat rises, the aluminum will expand quicker and more than the SS cup tip. I know the head has coolant surrounding the inside and around the cup, but I had blown 5 of them in mine I found when I tore it down . I've gotten the injector hold downs and studs from SoCal sinse then (not installed yet) to help prevent this. Unfortunately they wern't available at the time I did the rebuild. Got to dive back in .

On edit: May want to verify on the 272 loctite for one. #2. One place it can be had, is at www.mscdirect.com P/N 97031702. RED is what I used.

 

[CancerPipe]

Thanks for the help mike. I ran into some REALY good luck today. It turns out my diesel mechanic (local guy that works on everything and stands 100% behind his work) is the diesel repair teacher at the vocational school. He said they hadnt had any duramax's in his class yet and wanted to know if i would mind. He said he's not going to let the students work on it, but teach them as HE does it.The best part is the labor is free. Thank you hamilton county school board. So I have about 650 in parts including new injector cups, and a maximum of 1200 at the machine shop if they have to completely rework the heads, 500 if they just need to be cleaned up, checked for cracks/leaks and surfaced. Lol and my boss is going to let me borrow a work truck to drive while i wait, which comes with a fuel card. I need to buy a lottery ticket....:nana:

 

[Kat]

Well that is good news :nanawoot:

 

[bullfrogjohnson]

good news

 

[CancerPipe]

And of course it happens when i get all geared up to do it myself. My garage is nice and clean now. I had thought about putting studs in it but dont wanna push my luck. Out of curiosity what are the major factors that contribute to head gasket failure? The truck was worked hard in its past life, but its lucky to see 11000 pounds with me.

 

[FMOS]

500 to get the heads checked out? Crack/leak tested and surface ground for me was 110 bucks CDN. Talked to him today he said he ground a few areas that were borderline but the valves did not need to be recessed because things are at spec... minimum spec, but he said if I'm putting on slightly thicker gaskets all will be well.

Thats sweet about getting it done at the school. Might take a few weeks but its all good.

If it was me I would toss in the head studs while your at it, especially if your going to be running it hard.

And if I had to take some guesses at why there is head gasket issues... Firstly I think there was some issues with the design of the initial head gaskets they put on the 1st and 2nd gen motors. The ones I took off are just standard issue head gaskets. The new ones that are going on (GM brand) are multi layered, rivetted together units bit rubber or some sort of compound in the middle. Second part of my theory is on the drivers side bank. The front two cylinders might have excess pressure and heat because of the exhaust manifold diameter decrease causing exhaust pressure to back up on the cylinders. And the rear drivers side cylinder because its really tight quarters back in there and it's closest to the turbo, where if your running higher performance it might be subject to a lot of extra heat and pressure versus cylinders towards the front.

Just my theory though, I'm totally full of BS. And I say that cylinder is closest to the turbo because I noticed that the heads/cylinders aren't lined up across the motor, seems like the left bank is shifted back about an inch or more from the passenger side.

Edit: I believe it was my front drivers side cylinder that had the leak because of the way the top of the piston looked compared to all the others. Didn't notice anything on the gasket, but I didn't look very hard.

 

[CancerPipe]

The machine shop has done a good bit of duramax heads, but mostly powerstrokes so i guess they're used to expecting the worst. The 500 was machining the heads cleaning and assembly, but if they're in spec and just need a cleaning its less. There are cheaper places to take them around here, but thats realy the only shop i know that well. I would like to put studs in, but not having them will limit me and keep me from getting to crazy. I would rather blow a gasket than bend a rod untill i can afford a build.

 

[ripmf666]

Guys when you take these you the shop make sure they do not HOT TANK your heads. Or even add to much heat to them they will make them junk.

 

[FMOS]

OOOOPPPPPSSSSSS!!!!!!!!

Whats the deal with that? A know of a ton of aluminum heads before that have been hot tanked. And they turned out fine. What happens on the DMAX heads?

I will have to verify tomorrow for sure whether they were hot tanked or not. He mentioned on the phone today that he has done quite a few duramax heads for a couple different Chev dealerships around Edmonton so I would think he has an idea of what not to do etc.

 

[ripmf666]

Guy off the diesel place had a set of heads repaired and I guess it came that they were heated up to much and when the did the head studs the washers sunk into the heads, and the valve seats feel out, Guy Tripp might add some info in here about what temps can be used and not.

 

[drmatt]

Hot tanking them at 80 or 90*c (180F) wouldnt do that to them, If your seats fell out and the heads were all pooched they must have used some kind of solvent or acid that degraded the aluminum during the cleaning, But the heat would not be a problem, you heat them alot hotter on the engine. Hottanking heads and blocks, aluminum and cast steel is standard procedure for cleaning, Shop must of got a good deal on some new solvent...haha, cleaned the aluminum right out from under all that grease and dirt...hahaha

 

[FMOS]

Everything is going good so far. Got the heads back on the motor and torqued.

Only thing is we kinda dinked the mating surface of the heads. When we were trying to set them down so BS got in the way and it slid around a bit before it dropped onto the alignment pins... We eye'd it up, and it didn't seem too bad. So we tossed them on there. It was almost enough of a scrape to feel with your finger nail though. You guys think it will be alright? The truck is going back together regardless, and if I have problems then the entire motor is coming out and getting built haha.

I just need the exhaust gaskets and hopefully next weekend it will all come back together and run!

Really sucks being 500km away from where I need to work on the truck haha.

 

[ripmf666]

Aslong as you did not hurt the exhaust gaskets they can be reused.

 

[ripmf666]

Hot tanking them at 80 or 90*c (180F) wouldnt do that to them, If your seats fell out and the heads were all pooched they must have used some kind of solvent or acid that degraded the aluminum during the cleaning, But the heat would not be a problem, you heat them alot hotter on the engine. Hottanking heads and blocks, aluminum and cast steel is standard procedure for cleaning, Shop must of got a good deal on some new solvent...haha, cleaned the aluminum right out from under all that grease and dirt...hahaha

To much heat on th eheads in the wrong area takes the temper out of them,Also with the blocks its in Gm service info to not to hot tank the block at all you must use a solvent tank.

The heads that were hot tanked to long they think it sunk the washers into the heads when tqed on.

 

[CancerPipe]

No hot tank for me. I asked and they said they never do their duramax heads that way. Lol on a side note i was asking him if he'd seen many bad duramax heads and he just laughed. He told me he loves them because he can just clean them up, check the seals, guides and springs and send them out, but he's tired of wasting his time cleaning 6.0 powerstroke heads.