Need to surface heads .008... safe? - Ford Powerstroke Diesel Forum
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Old 10-15-2012, 05:37 PM
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Need to surface heads .008... safe?

I have been going back and forth over this a bit trying to decide. The machine shop is saying you shouldn't resurface per Ford spec. They can still do it but are a bit awry over the whole thing which obviously bothers me a bit.

If I do have them surface .008 off any special considerations besides valve recession I need to worry about?
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Old 10-16-2012, 01:02 PM
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IMHO if they are nervous.... dont let them do it!

Talk to some other shops in town and tell them you need to shave .008 off the heads. Ask them what is needed and if they are confident in doing the work?
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Old 10-16-2012, 02:11 PM
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Ford's position is the heads can not be resurfaced. If they are out of spec replace them.

That being said any GOOD machinist can machine them. .008 is generally considered the max that can be shaved without recessing the valves and trimming the valve stems.

Personally, I'd find a machine shop that is more familiar with 6.0 heads or doing high performance work. This isn't that unusual.
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Old 10-16-2012, 04:41 PM
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Agreed, my heads were shaved .008 and also had a valve job done. My machine shop told me abou the ford spec only because he felt obligated in doing so. Take them to someone confident. Or just spend the money on new heads.
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Old 10-16-2012, 07:16 PM
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Everything is related. If you mill the heads, you decrease valve recession, if you recess the valves more (cut the valve face, or valve seat = valve job) you increase the "valve height", which then must be compensated for as 6.0's don't have adjustable rocker arms. So, you then must clip the tips of the valves down (where the bridges go) to achieve proper valve height. Without this, the pushrods would provide too much lifter preload. Also, but "sinking" the valves into the head, you're decreasing valve spring pressure, which can be an issue at high rpm, and high boost.

Do yourself a favor while it's apart, and have a valve job done (by a shop very familiar with these heads...if the one you're using isn't familiar that is). Trust me...I've seen it way too many times. Factory valve recession specs are .013-.027"...you can't be anywhere near .013"...I promise. You need to be at least .020...at the bear minimum, but most of these engines from the factory were set at .016-.020 so if you cut .008 off, you're at the limit. How bad would it suck to get it all back together and fire it up and then all the sudden loose compression on one or two cylinders because the valves hit the pistons. I've seen other machine shops that are good machine shops, if you have a small block chevy, or small block ford...just never messsed with this stuff before...it's finicky. Valve jobs on 32 valve motors aren't cheap, but neither is taking it all back appart and starting over. They can safely take .003-.004" off *most* heads, IMO, and that is (not to brag) but a very experianced decision. As long as your valve recession stays above .018-.020 or so, you'll probably be ok. If milling them .008 or more will put you closer to the .013 end, you need to "sink" the valves into the heads. You don't necessarily have to cut the valve seats, and the face of the actual valves, you could save money and relatively safely just do "half" a valve job... and just take .005 or so off the face (seat area of the actual valve, not to be confused with the seat in the head), and then readjust the valve height...which is another story. Valve height, measured from the spring seat pad (without the valve stem seal) is 2.220-2.225". I do so damned many of these I remember all these useless figures like this, but can't remember anniversary's and birthdays...lol. Anyway, if your heads have a valve height of 2.222, and you cut .005 off the face of the valve, and .005 off the valve seat in the head, you're effectively "sunk" the valve .010"...which needs to be clipped (ground) off the tip so as not to effect the rocker geometry. Now, that will change too as you mill tons off a head and/or block you have to compensate for that in valve height...it's all related, but that's way more in depth. Hope some of that made sense...

Check out the thread in my sig. Lots of pictures. You didn't get into the cracked issue, and the need for seats either...I bet they're cracked too. Can't accurately magnaflux (magnetic particle inspection that "finds" cracks") with the heads assembled. Anyway, Good luck, let me know if you have any questions. If you get me the measurements of your heads (valve recession before being milled, valve height, how much needs to be milled) I can help more. Sorry for rambling so long...I just really want people to understand this stuff...and it's one area I can actually really help people in. We build more than 200 of these a year (that's 400 heads, and 6400 valves, lol) we're busy.
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Old 10-16-2012, 08:00 PM
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Nice post Gearhead!
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Old 10-16-2012, 10:12 PM
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Originally Posted by bismic View Post
Nice post Gearhead!
I agree, lol Gearhead I almost figured you for a after reading your custom tune equals cams for gassers thread. You nailed this one dead on you really know your stuff!!
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Old 10-17-2012, 12:31 AM
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Originally Posted by Gearhead2012 View Post
Everything is related. If you mill the heads, you decrease valve recession, if you recess the valves more (cut the valve face, or valve seat = valve job) you increase the "valve height", which then must be compensated for as 6.0's don't have adjustable rocker arms. So, you then must clip the tips of the valves down (where the bridges go) to achieve proper valve height. Without this, the pushrods would provide too much lifter preload. Also, but "sinking" the valves into the head, you're decreasing valve spring pressure, which can be an issue at high rpm, and high boost.

Do yourself a favor while it's apart, and have a valve job done (by a shop very familiar with these heads...if the one you're using isn't familiar that is). Trust me...I've seen it way too many times. Factory valve recession specs are .013-.027"...you can't be anywhere near .013"...I promise. You need to be at least .020...at the bear minimum, but most of these engines from the factory were set at .016-.020 so if you cut .008 off, you're at the limit. How bad would it suck to get it all back together and fire it up and then all the sudden loose compression on one or two cylinders because the valves hit the pistons. I've seen other machine shops that are good machine shops, if you have a small block chevy, or small block ford...just never messsed with this stuff before...it's finicky. Valve jobs on 32 valve motors aren't cheap, but neither is taking it all back appart and starting over. They can safely take .003-.004" off *most* heads, IMO, and that is (not to brag) but a very experianced decision. As long as your valve recession stays above .018-.020 or so, you'll probably be ok. If milling them .008 or more will put you closer to the .013 end, you need to "sink" the valves into the heads. You don't necessarily have to cut the valve seats, and the face of the actual valves, you could save money and relatively safely just do "half" a valve job... and just take .005 or so off the face (seat area of the actual valve, not to be confused with the seat in the head), and then readjust the valve height...which is another story. Valve height, measured from the spring seat pad (without the valve stem seal) is 2.220-2.225". I do so damned many of these I remember all these useless figures like this, but can't remember anniversary's and birthdays...lol. Anyway, if your heads have a valve height of 2.222, and you cut .005 off the face of the valve, and .005 off the valve seat in the head, you're effectively "sunk" the valve .010"...which needs to be clipped (ground) off the tip so as not to effect the rocker geometry. Now, that will change too as you mill tons off a head and/or block you have to compensate for that in valve height...it's all related, but that's way more in depth. Hope some of that made sense...

Check out the thread in my sig. Lots of pictures. You didn't get into the cracked issue, and the need for seats either...I bet they're cracked too. Can't accurately magnaflux (magnetic particle inspection that "finds" cracks") with the heads assembled. Anyway, Good luck, let me know if you have any questions. If you get me the measurements of your heads (valve recession before being milled, valve height, how much needs to be milled) I can help more. Sorry for rambling so long...I just really want people to understand this stuff...and it's one area I can actually really help people in. We build more than 200 of these a year (that's 400 heads, and 6400 valves, lol) we're busy.
Gearhead, you are the man! What is your profesion? / why so much experience on the matter?
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Old 10-17-2012, 11:50 AM
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Quote:
Originally Posted by Tuscany View Post
I agree, lol Gearhead I almost figured you for a after reading your custom tune equals cams for gassers thread. You nailed this one dead on you really know your stuff!!
Man, I wish i knew half as much then as I do now when I wrote that a couple weeks ago. I'll still say that a good custom cam, from a knowledgeable experianced cam grinder/engine builder is a lot like the custom tune analogy. Unfortunately a couple local shops around here dilouted my initiial perception of the word 'custom'...before I knew about the Vivians, the Matt's, the Eric's, and the Bills out there. I'm still learning and reading more about what parameters they're changing and the software that allows them to do so, very interesting stuff...everybit as complex as weighing all the aspects of camshaft profile for gassers, and how it effects literally everything.

Quote:
Originally Posted by BIG Laing View Post
Gearhead, you are the man! What is your profesion? / why so much experience on the matter?
I started several years ago at Tidewater Machine, a general machine shop that did everything from machining king pins for big trucks, to running engines (mostly big Detroit's...no 6.0's) on our dyno, to drilling out a bolt on a lawn mower and of course building engines. We also had a contract with UPS and sold them reman engines for their trucks on the east coast...Chevy 4.3's...hundreds of them. Around the time i started we began selling engines online via our first very crude website and shipping engines all over the country (mostly 12v Cummins and marine 350 and 454 engines) and that took off like wildfire. We bagan selling 7.3's and 24v Cummins, followed by the 6.0 and 6.6 duramax, and in the last year or so the 6.4. The diesel stuff paid better and really took off so the gasoline stuff kinda went to the wayside. Then we moved to a much bigger building, almost 10,000 square feet, and in a year have out grown it...we've actually grown about 80% the last 3-4 years as a business. We changed the name to Blackwater Engines a couple years ago due to website domain conflicts. (blackwater is an area of chesapeake/virginia beach). I've been doing all the cylinder head work for a little more than 3 years now...also mill the blocks and sometimes machine the rods, and cranks, occasionally help out with assembly when theyre busy. not a sales pitch at all, I'm always on here on my own time, I don't get paid for it.
Just some back ground info, perhaps to qualify my ramblings.
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Old 10-17-2012, 11:58 AM
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Nice.
Glad it is working out for you
Always good to have knowledgable people on here!
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