Repeat headgaskets?

[Matt Saunoras]

Pulled the heads off an 120k 05 F-550 today. I was pretty surprised to find the truck had definitely had headgaskets done atleast once before. The whiz wheel marks told that story.

 

The airtool marks aren't deep and they cleaned up with scotchbrite so I'm not even a little concerned with them. What I'm wondering is why these things failed if they were done atleast once before. The heads are fine as per ford specs but there are recessed spots in the fire ring area that definitely correspond with the failed areas on the gaskets.

 

Obviously the 6.0 has been out a while and everyone has these things figured out. Are you guys putting a lot of stock in what the WSM says is a good head?

 

This truck isn't overboosting and I put coolers in it and cleaned the turbo about 20k miles ago. It just recently started blowing coolant again. Is it common for a loaded down 6.0 to have multiple sets of headgaskets in it's life?

 

Also,has anyone ever had a set of 6.0 heads cut down, just enough to clean up the surface? I'm aware ford states it can't be done and the aftermarket says they should all be machined flat whether they look like they need it or not. It's obvious to me that when you get a reman head from ford it has been machined. Considering the quality of the cores being returned you'd wonder how any heads could possibly be remanufactured.

[Aaron]

Was it studded or did it have stock bolts in it?

 

Only a WIENER would do retail heads and not do studs? (Don't take offense to that, it may have happened before you were a member on here.)

 

That being said, can you measure the depths of the deformities on the head surface?

 

Not having an adjustable valvetrain, I'd be leery about machining that cylinder head, because then you'd be into grinding valve stem tips to make everything right again, etc.

 

If the deformities in the deck surface are bad enough that you're worrying about them, odds are the amount of material that will need to be removed will be well past something even serviceable if you were going to do it on your own truck, in my opinion.

 

There was a guy on one of the aftermarket boards that filled the deformities in the deck surface with something like JB Weld or some such thing, then ground it flat. Was a pretty sharp repair. LOL.

[Jim Warman]

I understand that there is a growing trend towards using an impact on the TTY portions of the head bolt torque sequence - this should be enough to get your spider sense tingling.

 

There are probably many things you can "get away with" - up until you can't get away with them anymore.

[Keith Browning]

Wiener? Guilty. I have never installed studs and at the dealership we simply won't install aftermarket parts that we cannot back. It's genuine Ford or Motorcraft or it ain't going in the truck. Yes, I know the studs offer better clamping force.

 

None of our customers are using tuners and such because they don't tell us that they are nor do they ask us to install studs. Liars.

 

My response to Matt's question is I have only seen one or two repeat head gasket failures in my shop that I know of or recall. Nor do I recall whether we made the original repairs either.

 

Unfortunately most techs use Roloc disks to clean these heads and blocks but if we think about it, given the sheer number of head gasket repairs done using them I would expect to see a much higher repeat failure rate because of the disks going by the warnings about using them. 10 years later and we know that this simply is not the problem we are warned it is but a technician with a new coarse disk can quickly remove a lot of metal instantly and cause low spots in the metal. This is especially true if you are trying to remove the "staining" on the surface or the pitting in the non-sealing areas. The instructions in the WSM and relevant TSB's explicitly tell us not to try to remove those. That MIGHT be important, no?

 

I maintain to this day, that if the cylinder heads and the block are flat, the surfaces are properly prepared and ALL other known problems that cause over boosting are repaired and or verified, head gasket failures are far less common than they used to be. What known problems?

[*]Sticking turbochargers - causing over boost conditions because of mechanical binding and seizing causing no VGT control. Always verify the condition of the turbocharger and ensure that a new treated CRH is installed and that the unison ring control slot is not worn.

[*]Faulty EBP sensors and wiring providing inaccurate back pressure data to the PCM required for proper VGT operation

[*]Out of date engine calibrations that do not contain more aggressive over boost protection: fuel rate and timing adjustments and use of EGR to dump exhaust backpressure intended to slow the turbocharger

[*]Inoperative EGR valves which includes deletes *important for the above calibration. Verify that the EGR cooler is not leaking and causing the EGR valve or the turbocharger to stick

[*]Aftermarket intake and exhaust systems that can modify the airflow across the MAF sensor which can affect EGR and VGT operation

[*]Aftermarket performance tuners - there are good and bad one's but we all know the results of going too far and the result of excessive boost and cylinder/exhaust temperatures can be downright devastating

These are all things that I have learned or come to understand can contribute to head gasket failure either directly or in part as sometimes any combination of these items can be found on any vehicle. If anyone disagrees with any of those items fee free to bring it up. My theorem on this is always evolving.

 

So, if you have a repeat head gasket failure then either something was missed, the workmanship was lacking somewhere or there is something the customer is not telling you.

[Aaron]

(Keith - it was just a reference to Jim calling Ralph a wiener on the Canadian dealer boards, which got him a lifetime ban.)

[Keith Browning]

(Keith - it was just a reference to Jim calling Ralph a wiener on the Canadian dealer boards, which got him a lifetime ban.)

I know.

[Bruce Amacker]

I've had many techs tell me in my classes nationwide that they routinely mill a few thou off the heads with no negative results. If presented with the situation, I am sure I would too.

 

[Matt Saunoras]

The deformation on the head is .003 deep. It's like a veritcal ridge where the fire ring seals.

 

I've cleaned up quite a few 6.0 heads and never once thought one looked bad enough not to go back on the truck. These ones are different though, I just don't feel right about them.

 

 

I've been reading up on the subject a little bit and it seems the general consensus is .008" is max. Anything less than .006" is going to be fine. After that you start getting into valve recession problems. The seats would need ground deeper and the stems shortened up.

 

I'm going to call the machine shop on monday. Don't know if they'll touch diesel heads but it's worth a shot.

[Keith Browning]

Considering the cost of new heads machining is still the best option if you have it. You are right about valves having to be machined as you need to be mindful of clearances. I think most of what I have read also confirms that is what most guys are doing.

[Aaron]

FWIW, there is a minimum thickness spec for the head casting on these.

[Matt Saunoras]

I don't make practice of offering customers headstuds unless they request it. The problem becomes parts availability. You tell the customer about head studs and from that point on they're usually a week away.

 

I suppose I could keep some in stock but honestly I don't like having money tied up in parts when I am not a parts department. You wouldn't believe the stuff I've aquired over the years that I keep "in stock" because parts won't keep it around.

[DieselD]

I understand that there is a growing trend towards using an impact on the TTY portions of the head bolt torque sequence - this should be enough to get your spider sense tingling.

 

There are probably many things you can "get away with" - up until you can't get away with them anymore.

Yep I have argued with guys on why this is a bad idea....

 

I might be putting money on this being your repeat repair cause. I have come across repeat HG failures and have found loose bolts during tear down

[Jim Warman]

Matt, that seems to be a curious way to regard a source of profits. Way back when I used to sign the FRONT of the cheques, profit on parts was the next best thing to free money. Aim for your GPM (do not confuse this with mark-up) to average out at 30ish percent and, with enough stock turns in a fiscal period, you are a LOT further ahead that you ever would be by trying to save money. Head studs are a popular and sensible upgrade and are a lot more honest than any wallet flushing bullshit some guys resort to.

 

Bottom line, if you aren't selling parts that are proven to be beneficial (even in just an "insurance" respect), you are doing yourself and your wallet a disservice.

 

Dustin - It isn't just loose bolts. There are also missing bolts as well as fasteners that are grossly overtightened. I think impacts are fine for disassembly, but we desperately need to rethink some (if not all) of our reassembly techniques.

 

Impact wrenches are taboo in aeronautical disciplines and for good reason. Even the fasteners are designed differently. But there is good news - it only takes a few minutes of practice with a speeder handle and/or a T handles to be veryearly as quick as blasting through stuff with nearly twice the air pressure your gun recommends - and who here is going to tell me their compressor isn't set for more than 1,000 kpa?

[lmorris]

I was told if there is a ridge by the firering that catches your finger nail, you need to replace the head.

[Matt Saunoras]

now that you guys mention it I do recall a few bolts that didn't feel too tight. Not loose, but perhaps not as tight as the others. Standing in the engine bay with a 3/4" breaker bar may not be an accurate way to determine tightness but whatever.

 

I was told if there is a ridge by the firering that catches your finger nail, you need to replace the head.

That's exactly what I have. The ridge is .003" deep, way more than enough to catch a nail on.

 

Jim, should I reconsider keeping studs around? Now lets say I do have studs, would I only offer these to my customers or lets say our other guy gets a headgaskets job should I offer them up for him to sell also? Would it be unfair if I didn't? Currently I'm the only one whos ever installed studs and I'm not sure if the topic would come up.

[Matt Saunoras]

Also, I did send the heads out this morning and I'll be getting them back tomorrow in the AM. They wacked .007" off the deck. I'm pretty excited to see how they turn out. The machine shop is confident everything will work out fine, in the end everything was still in spec.

 

If they look good I'll post pics

[Jim Warman]

Matt, it does seem a bit odd that your parts mongers are leaving something like this up to an individual in the shop or what-have-you (though I could be misreading your situation). Any time you sell a part, you NEED to make an expected profit margin - this is called "doing business".

 

As long as you are doing an adequate number of stock "turns" and you are making your deserves mark-up, why not? You aren't there to compete with your store.

 

Back in the day, I had several instances where an abject stranger would ask to borrow a 9/16 wrench. Since a truck driver that can't adjust his brakes isn't much of a truck driver, I would offer a wrench on a blister pack at a fair mark up.

[Matt Saunoras]

These heads look amazing (I would marry them if I could). Milled, cleaned, pressure checked all for $165

 

 

I hope it all works out in the end. There's always a what if when you do something the WSM tells you not to. If it does though you can bet it wont be the last set of 6.0 heads that get sent down.

 

I'm going to get a set of studs to keep around.

[Bruce Amacker]

Did they do them with the valves in or out?

 

[lmorris]

We have sent 1 set of heads out for the instalation of fire rings and they machined them, but I am not sure how much. There has been no complaints thus far. Been over 3 years. I beleive the WSM states that local machine shops don't have the required machines to be able to match the fineness of the machining. I don't think it has to do with deck height. More-so the quality of the final product.

[mrbudge]

We have sent 1 set of heads out for the instalation of fire rings and they machined them, but I am not sure how much. There has been no complaints thus far. Been over 3 years. I beleive the WSM states that local machine shops don't have the required machines to be able to match the fineness of the machining. I don't think it has to do with deck height. More-so the quality of the final product.

I have seen new heads that look like they were machined by a chainsaw, the machine shops we use do much better than that. There used to be a spec somewhere got the distance between the head gasget surface and rocker carrier surface, but I haven't seen it lately. We send our heads out for pressure testing and re-surfacing every time, no problems yet with valves not closing or repeat failures. In also have seen guys say up to .005 surface warpage is ok. I would not put on a head that I can slide my .0015 feeler guage under the straight edge, gas or diesel. And if I see roloc disc marks on a gasget surface, as far as I am concerned the head is ruined.

[Matt Saunoras]

This machine shop has never done us wrong BUT they also don't do a lot of diesel heads.

 

Bruce I honestly don't know if they machined them valves in or out. I didn't know it was possible to do it with the valves in.

 

From what I've read the single most critical measurement after milling 6.0 heads is valve recession. The spec is .013" to .027" if my memory serves correct(not listed in the WSM). If the valves aren't recessed enough there will be piston to valve contact and you're not exactly safe on the shallow side of the spec. .020" is good for a diesel head.

 

Got everything back together and the truck started this afternoon. I had one hell of a time getting it to fire even with good ICP. I can only figure it wasn't getting fuel in the heads because once it started everything was fine

[Aaron]

These heads look amazing (I would marry them if I could). Milled, cleaned, pressure checked all for $165

 

Dude, you need to get out a little more.

[lmorris]

Originally Posted By: Matt_Saunoras

These heads look amazing (I would marry them if I could). Milled, cleaned, pressure checked all for $165

Dude, you need to get out a little more.

He needs a little more of something else I think, and not the kind that costs $165.

[jimmy57]

I thought the idea was to NOT marry any part of a customer vehicle you repair!