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CHECKING HEADS? THE CORRECT WAY?

26K views 82 replies 20 participants last post by  Gearhead2012 
#1 ·
When you guys say max allowable depth for machining the heads! Who came up with the max allowable limit? I would like to see in writing from international Navistar or Ford or Blue diamond where it is that the heads can be machined to this depth or even machined at all. Sure any machine shop can come up with a number and machine the top of the valves to match but I have never seen in writing from ford or international that heads can be machined in fact they say not too. They give a proper way to check heads and clean them im not sure if people are to lazy to clean them the correct way because it takes time i don't know! I have yet to have one set of heads come back that headgaskets have failed after doing proper cleaning of block and heads and checking flatness BY THE BOOK! NOT THE LENGTH OF THE HEAD!!!! I take time prepping my heads and am very meticulous with my straight edge checking the correct locations that international THE MANUFACTURER - MAKER - DEVELOPER of these parts has layed out in black and white on how they want them checked. I do not care or want to hear personal opinion on this just fact. I would rather have a head with all its meat than have it weakened from removal of material. I would like to see this so I can learn.

1) spec sheet from International on max allowable limit to remove?
2) No OPINIONS or I THINK why every head has to be machined WHEN THEY PASS WITH STRIAGHT EDGE AND CAN BE CLEANED PROPERLY!
3) WHY all the head jobs I have done "I have stopped counting" by the book cleaned by the book have had 0 issues!!! and none have been machined!
4) Is it the fact that it makes people feel better to have them machined and have metal removed in most cases that is NOT NEEDED!
5) Because a head wasn't machined because the proper checks where done and it was determined that machining wasn't needed DOES NOT MEAN THE JOB WASNT DONE RIGHT or everyone one of my hundreds of head jobs would have come back.

ON the other side of the coin I cannot tell you how many horror stories ive read on this forum and countless others about I just had my heads machined and my valves hit the pistons that just tells me that that machine shop just did the heads and didn't understand valve clearance to start with and I for one would not want a shop shaving my heads and not understanding the rest of the picture. I would like input from the guys that are in the business on this forum WHO WORK IN MACHINE SHOPS again not from people who know people or have heard something!! REAL MACHINESTS!!

MY POINT IS THIS! FORD AND INTERNATIONAL know way more than us and give us guidelines to follow the same with any other company out there. Doing the proper checks and cleaning will save you the hassle of having to shave your heads!

NO OPINIONS , NO HE SAID SHE SAID JUST FACT
 
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#3 ·
:thankyou2:.... I knew I wasn't going :senile: when I posted threads about this...
 
#4 · (Edited)
Well I like to think I research things very thoroughly before doing them. And here is the FACTS that I found from MACHINISTS on this subject and I apologize I don't have the links handy but here is what the consensus of several machine shops said.

1.) after checking valve to piston clearance on countless heads they found the head has between .007-.009 to deck and be in the safe zone.

2.) the guys who did proper machined work on the SERVICABLE heads with a proper surface finish never had an issue to report.

3.) machinists who took heads down past safe zones because of warp machined and shortened valve stems to give proper clearance. Never had an issue to report.

That being said some of the main issues with powerstroke heads is cracking at the seats. Proper cleaning and a straight edge just won't fix that. Another is warped castings especially in over heat situations, same theory applies that you can fix that with cleaning or a straight edge. I don't know about anyone else but putting a cracked or warped head back on my truck would, well, not happen.

So in my case I had mine magnafluxed and no cracks. One head needed .003 taken off to be TRUE flat and another .004. The machine shop I used put the same surface finish as a factory head or reman head has. To this point the fact is I have had no issues, the machine work cost 175 bux I gave him 200 cause I am ballin LOL. Save myself the better part of 2 grand on machining vs buying new.

So my question to everyone who thinks I did this all wrong and should have bought new, the same machinists on that same forum also measured a handful of remans right from ford, NOT ONE .... AGAIN NOT ONE was flat and some warped too bad to even use. So if these guys at ford and international are so good at what they do why can't they send out a REMAN head that is friggin flat. Did they nix the QC department??? A new head would scare me more than taking a couple thousands of material off to make the head dead flat.

Any how I will report back if I ever have a failure because of machining my heads :thumb:
 
#8 ·
This is why im posting this. If he checked new reman heads with a striaght edge the way ford said too not lenght wise but from intake to exhaust or the 13 points to check I find it impossible that a new head would have a .004 deviation on the deck there just is now way. As for seat cracks this is also inpectable and makes a head replacible in my book.
But back to my question I want to see from international where heads can be decked to this spec. Again all I see is do not machine heads. My point is im still learning because im not on the machining siad so I really dont know. Maybe they got paperwork I have not seen this happens alot.
 
#5 · (Edited)
Dale, Todd has very valid points. These heads are well known to develop cracks in the seat areas and as said checking with a straight edge does nothing to tell you about that. Ford sells only reman'd heads now. Are you telling me these heads have NO MACHINE WORK? So if Ford sells nothing but reman'd heads they must be machinable.

Look through Jared's thread on machining the 6.0. He does work in a machine shop that does 6.0 heads every day. Namely Blackwater engines. Lots of god info and pics there on this very topic.

Congrats on your success rate with these and I know what an awesome tech you are but if my heads come off they're going to the machine shop.

Have you ever measured the PTV clearance on a stock motor. If not could you do so on your next head gasket job? That will give us a good reference for how mach is safe to take off the heads.
 
#6 · (Edited)
Right on Jug, I love these discussions when WOMs(word of mouth) are questioned. There are plenty and educated arguments can only educate and benefit all members. These forums spawn WOMs and these discussions are so beneficial.

Though I must add, I don't know where I stand on this one. Machine work and head jobs go back as far as the performance industry, so pretty much industry standard, I cannot offer insight on this thread, just excited to learn.
 
#7 ·
you can buy new heads from international i dont care what ford offers... international says no machining period. It's just a vt365 engine that has been out for a long time now and they make new parts for it
 
#10 ·
This thread was not started to flame but to learn so please lets keep it professional and fact based. Ty im still learning everyday and that will not stop ever.
 
#11 ·
Just because Ford/International don't approve or give info on machining heads, mean that it can't or shouldn't be done.

I've never seen documents stating what the allowed tolerance of removing head material, but simple math by the machinist will give how much material can be removed from the surface before he needs to machine valve to piston clearances.




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#12 ·
All good points Rich but all to often I hear send the heads to be machined before they are even checked the proper way. I just dont believe in removing material to weaken the head when its not needed. And when material is removed from any metal it weakens it, Valve seat cracks are a different story.
 
#14 · (Edited)
Taking .010 or .015 off of a head deck surface isn't going to weaken it enough to worry me Dale. All of these machining practices are tried and true methods that have been done for decades, not new tricks. Milling heads to raised compression in performance motors has been done as long as people have been hot rodding motors, and that takes a lot more than .010 or .015 off the deck. I had my 428 Cobrajet heads decked enough that the intake needed to be machined to make it all line up again. Would Ford recommend that? No, but again time honored hot rod techniques. If we were all about listening to Ford we wouldn't be pushing these poor little 6.0 motors to 600 hp and beyond.

Don't forget Ford also chose to put G-05 coolant in these engines and tell us to change it at 100k. That was great advice too, right? Sorry, but just because Ford says something doesn't make it gospel.
 
#16 ·
This why I started this to learn why people do what they do. It was international that said dont machine them not ford that info was passed to ford and I understand that things are said that dont always apply but in this case I dont think they would make it up. Anytime material is removed from anything it is theoreticly not as strong and will deminish its ability to get rid of heat. Even on this small of a scale. My point again is if the checks where done correct and they passed why machine the heads.
 
#15 ·
I don't see how removing .008" is gonna weaken any 6.0 head. Four pieces of paper is around .008".

Dale, is there a Ford/International procedure for checking cracks in the head, other than a visual? Do they allow Magnaflux or Dye Penetrate?


I can see why the dealer just replaces heads with new, down time. It's far easier and time saving to just replace head, than it is to send heads out to a shop and wait for results of cracks or machine work.


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#17 ·
Yes we can spray heads with dye then clean it off if there is a crack the dye will bleed out of crack after its cleaned. We can see crack with black light. I will listen to you on tje heat tranfer part as you know way more than me on this machining part I am learning teach me!
 
#18 ·
GUYS AND GALS i must say i take no offence by people agreeing or disagreeing with me i want to learn! i want this to be a learning thread! IN NO WAY AM I BASHING ANYONE ANY MACHINE SHOPS OR ANYTHING THAT OTHERS DO. everyone has there way to do things if it works do it. I want to learn why people do what they do!!
 
#19 ·
Well I can not provide any more "facts" than what I posted. If you are really after a document from ford, well there isn't one that I am aware of. That being said there is lots of procedures written by ford that are suspect at best and it has more to do with speed of turning vehicles over than doing the job correctly.

As stated taking off a few thousandths of material doesn't weaken the head in any magnitude. Hell machining heads has been done for 80+ years and is a key component if Hot rodding.

The fact is machining a head is perfectly acceptable and often times the correct way to fix the vehicle. I am also sure ford would rather get 2 grand to replace parts than having a machine shop make a couple hundred bucks and them nothing.
 
#21 ·
I had mine machined too,as they were off by.003 and .006 when I did studs,but have wondered eventually with the heat and cold cycles they will be off again.i am in to learn.
 
#25 ·
Gearhead im so glad your here ! i cant wait to read your post eagerly waiting to read it!
 
#30 ·
Here is some info I had saved. Gearhead2012 should have more info.


Cylinder head and valve train

Cylinder head gasket 0.05mm(0.002in) per 51
surface flatness mm(2in)
0.10mm(0.004in) per
Total surface area

cylinder head thickness
Minimum - 95mm(3.74in)

Valve face angle - Exhaust 37.5 degrees
Intake 30 degrees

Valve seat width - Exhaust 1.80-2.56mm(0.071-0.101in)
Intake 1.48-2.24mm(0.058-0.088in)

Vlave seat runout - 0.0035mm(0.0014in)

Camshaft

Gear backlash - 0.179-0.315mm(0.007-0.012in)
Lobe lift - Intake 3.744mm(0.2261in)
Exhaust 5.832mm(0.2296in)

Allowable lobe lift loss - 0.51mm(0.02in)

Cylinder block

Cylinder bore diameter - 94.999-95.001mm(3.7401-3.7402in)
cylinder bore maximum out of round - 0.05mm(0.002in)

Head gasket surface flatness

0.10mm(0.004in) across the total area
0.05mm(0.002in) across and 150mm(5.9in)x150mm(5.9in) area
0.025mm(0.001in) across any 25mm(0.98in)x25mm(0.98in) area


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#34 ·
Well I wonder, how many have had failures after milling their heads?
 
#37 ·
Thanks for that long winded post Jared and taking the time to type it all out, so in your opinion would billet rocker arms and custom pushrods along with a correctly machined set of heads be the correct fix to ensure geometry is correct?

I was unaware the severe tolerance issues with the factory parts - that is just insane.
 
#41 ·
Yeah man, a $2500 dollar set of harland sharp adjustable rockers, and hardened pushrods and that would eliminate one of the huge downfalls of the 6.0. Never mind the 4 head bolts per cylinder, heui injection system and over taxed egr system. Other than all that...6.0's are great! Lol.

Oh, and the plastic lifter retainers that overheat, crack and allow the lifter to spin in its bore wiping out the camshaft. Lol. Other than all that they're great motors!


Oh...and other than the oil coolers that fail religiously. Lol. Other than that they're great motors! Lol
 
#46 ·
Reading all of this I am glad I took my head to the shop I did. Before I took them in there I went and talked to the guy and tried to see how knowledgeable he was on it.

When I went in and talked to him he said that if I wanted him to do the work I had two choices. He would flux them, check them for flatness and if they needed decked he would do it along with a complete valve job, or I could take them elsewhere. He stated if he mills any 6.0 head he required a complete valve job to ensure that all the tolerances are within manufacture specs. He did not want his shops name on something that broke because the tolerances were not there. He had a good point, if you are going to do the job why not do it right the first time. It will be a lot harder and more expensive when your valve kisses a cylinder head. Needless to say I went with him and now reading about how tight these heads are I am glad I did.
 
#48 ·
Well that's it I'm doing studs one at a time and never pulling my heads?????


Just kidding don't yell!!!!!
 
#49 ·
I got some reading when I get home.
 
#51 ·
Really its all about budget...isn't it always lol. Like I said, some of the local dealerships just didn't want to foot the bill for a totally reworked set of heads. In their mind, it was almost as much as a new set of heads, and...sadly new isn't always better. I was talking with a member on here who bought a new casting, not from ford, I won't mention who...but it almost immediately began to leak fuel into the coolant from the ever common crack in the fuel passage. Plus those seats are bound to fare no better than the stock ones without seats in them. 5.9 24 valve Cummins, 6.7 cummins, duramax all use valve seat inserts, as do absolutely all the bigger diesel motors. Simply put, if each seat costs $1 dollar (normally between 3-5 dollars) and each motor has 32 of them, and they sold 1 million engines, well they just increased the cost of that by 32 million dollars. They harden the valve seat area of the stock 6.0 heads, but bits just an integral seat, so from a metallurgy standpoint its still cast iron. Hardening it makes it harder, sure...I've only seen a few seats that showed any sign of wear...however hard and strong aren't exactly the same. The seats are so hard they're brittle. The advantage of a press in seat is that its an alloy of a different make up than the iron heads, with different heat transfer properties, different load capacities and certainly different wear tendencies. Was that the right answer? Probably yes, but navistar too is under a budget. Ditto for the fuel system, duramax came out in like 2000 or 2001 and 6.0 wasn't till 03. Also in 03 Cummins went to common rail njection in their 24v motors. It took navistar till 08 to do that. Just examples...heui operates just fine, nothing really wrong with it, and I know I'm way off topic here now, but it all gets back to budget. If a customer wanted me to check out a set of heads and do the bare minimum, I'd pressure test them, measure valve recession, prep the deck surface and check very carefully for straightness and visually check for gasket imperfections. If none were found and there were no other blemishes in the deck surface, and if it was reasonably flat, there wouldn't really be anything wrong with properly prepping the block and head and reinstalling it...but without taking valves and springs out you can't accurately magnaflux it, and the head has to be very very clean and dry for that, so a full wash would be in order...the odds are very very high the seats would be cracked, in which case I'd recommend installing press in valve seat inserts and then the list begins and escalates from there...new valves? New springs? Pull the block and mill it as well? At that point you'd be looking at just an entire new long block, especially if the block and particularly the heads have already been machined, or worse yet cleaned with a burnishing pad, those red scotch bright pad things people put on air drills......yeah, they're the devil. Never use them. Ford and GM both have tech bullitens about them, and how the warranty is voided if they're ever used. They're too abbraissive, and remove metal from the deck surface as they remove gasket material. Have they worked before...sure, but I wouldn't prep a deck surface with one.

That might have been the worlds worst run-on sentence lol...but anyway it all gets back to budget. Do as much as you can afford to do, with a very competent machine shop. If they can do the work, but arent familiar with 6.0's, and don't know where to set the specs, ask me, I'll gladly give some advice. Anyway enough rambling.
 
#53 ·
So I'm probably wrong but is the conclusion it's ok to have them machined but only by someone that knows what's going on?
 
#55 ·
I would tend to say that I wouldn't take anything anywhere, car to the mechanic, heads to a machine shop, me to the doctor - if I thought they didn't have a grasp on what was necessary to remedy the problem. Lol.

All that really really matters is that the geometry of the rocker arms in relation to valves and pushrods and lifters is correct, and such that it won't cause failure, and that the deck surface of both the head and block are suitable to promote good sealing capabilities. Ford has all but admitted the rocker geometry was wrong when they left the factory, I say that because after speaking with our parts manager and head engine builder yesterday apparently ford only offers the .050" shorter pushrod... evidently you can't buy the original length pushrods anymore...that's their response to the problem. I would either find a local shop that I could trust to ensure they'd provide you with a head that had all the proper geometry between valve height, pushrod length, amount milled off the head, valve recession and so on. If you can't find a shop that garners your trust, shipping heads is always am option, either to somewhere that offers a head exchange program. We are currently working on such a program, I'm sure others offer similar processes as well.
 
#54 ·
I don't have any data sheets or facts from International or Ford to offer but thinking that either of them should have the final say on what can or can't, should or shouldn't be done to these engines is engaging in folly. Remember those oil coolers they designed and put on these engines???

k
 
#57 ·
Yeah man, that's really it. That's kinda what I dislike about where a lot of this diesel stuff is going...you flip through the pages of a diesel magazine and its filled with advertising that leads you to believe they have the magic fix for your truck, or the 'safe' way to almost double the horsepower a truck was rated at. Fact is, its all nuts and bolts, cold pieces of aluminum, steel and iron that have been running now out there in the world for a decade in the case of early 6.0's. Parts fail, especially when pushed past their intended design limitations. Companies like BPD (not badmouthing them in anyway) aren't magic, they simply provide better quality of materials, or engineer the parts they provide for what people actually use them for. I only pick BPD because they're the first ones that come to mind...but its the advertising (not on their part) that pisses me off. There's plenty of good products out there that help remedy the 6.0's poor design, or poor quality of materials, but all the folk lore around it all makes people think its more magical than it really is. I'm no genius at all, and if I can understand why some of these parts fail, so can everyone else, and make their own educated decision...just as many people on here, jug included have helped me learn a lot too about better and better ways to remedy these problems.

Someone recently mentioned in this thread or another that the 6.0 is kind of a bastard engine, and only had a short production run, and will be doomed for aftermarket support...but one thing that it has in its favor is that they sold a crap load of these trucks with 6.0's in them, and as they get cheaper and cheaper and fall into more peoples hands there are going to be more creative people working to improve on them, and learn from others and teach others. Even the big aftermarket companies are well aware of the market for 6.0 parts. Its a double edged sword...they fail so much, and there's so many of them that there's a huge potential for making them better.
 
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