Head Machining

[FMOS]

How critical is it that I have the heads measured and machined if necessary when I change out my head gaskets?

I will have to remove the injectors and injector tubes and from what I understand I'll need some new parts to put them back in correctly... If I can get away without machining I would prefer to do that.

So what do you think?

 

[bullfrogjohnson]

Try checking with a strait edge and feeler gauges and make sure its flat and within spec. I am sure the specs can be found around here.

 

[Josh2002cc]

Honestly I would take it to a machine shop and have someone check it for you. Guess that stems from the saying "do it once, do it right" but others may disagree

 

[S Phinney]

Always have a good performance machine shop check it out. It is good insurance.

 

[LBZrcks]

I would have them checked imo, the piston to valve clearance is very close! Also I would put some solvent or liquid into the intake and exhaust ports to see if there are in leaks.

 

[FMOS]

Ya. Ok I will get them measured up and machined if need be.

But what about taking the injectors and injector tubes out of the heads? First off what the hell are injector tubes? I've been told they protrude past the deck of the head and require removal for any machining to take place. What kind of new parts do I require to put the injectors back in?

This is coming from a guy who says he's done countless Dmax heads, infact he did a set the other day... or so Im told.

I'm getting all setup to do this tomorrow... take the hood off and get the toolbox in position and the compressor revved up and I'll hit it hard thursday morning. So if you guys got any good tips for me let me hear them!

I've got the GM service manual for it, so I suppose that will outline everything that is necessary, but its always better to hear first hand.

 

[LBZrcks]

Is this for your LLY?

IIRC only LB7's have Injector cups in the heads.

 

[FMOS]

Yes, LLY.

I have no idea, never had the injectors out before. Not sure how they are held in, or the seal involved. I know nothing.

I will figure it out when the time comes I guess, I was just hoping to have all the parts I need handy so it can go back together smoothly.

 

[LBZrcks]

Maybe I missed something, but are you just replacing injectors or head gaskets?

 

[ripmf666]

Ya. Ok I will get them measured up and machined if need be.

But what about taking the injectors and injector tubes out of the heads? First off what the hell are injector tubes? I've been told they protrude past the deck of the head and require removal for any machining to take place. What kind of new parts do I require to put the injectors back in?

This is coming from a guy who says he's done countless Dmax heads, infact he did a set the other day... or so Im told.

I'm getting all setup to do this tomorrow... take the hood off and get the toolbox in position and the compressor revved up and I'll hit it hard thursday morning. So if you guys got any good tips for me let me hear them!

I've got the GM service manual for it, so I suppose that will outline everything that is necessary, but its always better to hear first hand.

If you end up getting the head decked they should also recess the valve the same amount they remove from the head to keep your piston to valve clearence the same. I have posted a few pages on what is needed to be done on these type of job in the GM Spec area you will find that his has more info then alldata and some of the printed serice manuals, What I post is right from Gm service info the same as the dealer uses.also you will fing the specs to hwo far out of spec your head can be before needing cleaned up.Are you adding head studs? If not you will need new head bolts, There only one time use.

Specs for the heads are here http://www.duramaxdiesels.com/forum/showthread.php?t=6135

http://www.duramaxdiesels.com/forum/showthread.php?t=6162

There is alot of the specs on this page
http://www.duramaxdiesels.com/forum/forumdisplay.php?f=97&order=desc&page=3

http://www.duramaxdiesels.com/forum/forumdisplay.php?f=97&order=desc&page=2

 

[FMOS]

Thanks, I'll read through those tomorrow.

Yes, got a set of ARP studs.

 

[FMOS]

Sorry forgot to answer back LBZrcks. Im just replacing the head gaskets and putting in some head studs when I do it. But if I need to have any machine work done, the dude at the shop told me to remove the injectors and injector tubes first. But after reading the specs from the last post there it seems like the LLY does not have injector tubes. And I answered on of my other questions as well... I will just need new o-rings and copper washers when the injectors go back in. But the injectors will still need to come off for machining...?

Thanks for the helps guys.

 

[LBZrcks]

Yes if they mill the heads the injectors need to come out, they pop right out most of the time once you unplug them, disconect the fuel lines and remove the hold down.

 

[LBZrcks]

Also maybe your machinist maybe thinks you have a LB7?

 

[FMOS]

Ya most likely.

What about removing the valve train? Pretty straight forward, but when Im putting it back together... is valve lash and valve clearance adjustment the same thing? If it is, then I understand what needs to be done.

 

[LBZrcks]

Ya most likely.

What about removing the valve train? Pretty straight forward, but when Im putting it back together... is valve lash and valve clearance adjustment the same thing? If it is, then I understand what needs to be done.

You might wanna check out this thread also.

http://www.duramaxdiesels.com/forum/showthread.php?t=8856

As Henry was saying he posted a ton of gm specs and instructions

 

[ripmf666]

Ya most likely.

What about removing the valve train? Pretty straight forward, but when Im putting it back together... is valve lash and valve clearance adjustment the same thing? If it is, then I understand what needs to be done.

You will have to remove the injectors to even get the valve covers off,when you install the rocker shaft you will want to make sure you have backed off all the valve lash nuts,If you go and tq the shaft down with it the same way it is from running you can damage the push rods.You will need to redo the valve adjustment Gm calls for 12 thousands I do them at 11. Also with the head studs you will 3 sets of tq's do not back off all the way just some,and wait to do your last run on the tq should wait 24hrs.Also is your head gaskets leaking or are you just doing this to do it.If there not leaking and nothing wrong heads should be fine clean and reinstall just do as the specs I listed says to do and you do not need to go to the machin shop on ly if needed.Also it does not tell you if you do need them cleaned up and lets say the cut 5 thousands off need to set the valves into the heads 5 thousands to keep it all in check.

 

[SBCNX20]

If the gaskets are not leaking then just replace the bolts with studs one at a time and safe yourself alot of work!

 

[FMOS]

The head gaskets are finished. They are leaking. The heads aren't off yet so I don't know exactly where but the coolant system is all pressured up, so somewhere along that interface.

Tell me how you adjust the valves to compensate for having the head decked? Do you shorten the valve stems.... thats the only way I can see it logically working.

 

[FMOS]

Here's an update:

Got pretty well all the BS out of the way, injectors are still in but they are just sitting there, bolts are out and connectors are off, i'll leave the fuel returns hooked up.

Maybe after I eat some dinner I will go take the exhaust off and get the turbo out, its hot bolted already, just need to take out 2 more pedestal bolts and the oil drain.

The thing that stopped us from continuing today was the fuel return lines that hang over the drivers side head... I didn't have the tool to pop those connections apart. I'll get some in the morning and do that. But besides that the valve covers are ready to come off, still gotta take the intake manifold off but I gotta get the turbo out to make that part more simple. Then the valve train and heads. Hopefully I can drop the heads off tomorrow at the place I was talking about it and a buddy is going to look at them.

I got shocks to change and steering components to change this weekend and I'll have to wait until next weekend to reinstall the heads and turbo. I think the biggest pain is going to be rerouting all of the wiring back on there though.

A guy really doesnt know how much BS is sitting in that engine bay until you gotta take it off... like the fuel filter housing, FICM, glow plug module, AC unit...

Am I on track or what haha?? I'd say progess is average, spent about 5 hours on it today.