Max Allowance for Head Milling?
Posting Guru
Joined: Jul 2006
Posts: 1,181
Likes: 1
From: Fairfield, CA
I'm wondering if the flatness issue is over rated, at least for folks running with head studs.
Has anyone ever torqued heads down with plastigauge and say .002" shim washers instead of a head gasket to see what reality looks like.
I would be more concerned with the surface quality roughness average, which I understand is rather poor on original 6.0 heads.
I also noticed a key term missing from this thread "valve Recession".
Has anyone ever torqued heads down with plastigauge and say .002" shim washers instead of a head gasket to see what reality looks like.
I would be more concerned with the surface quality roughness average, which I understand is rather poor on original 6.0 heads.
I also noticed a key term missing from this thread "valve Recession".
Elder User
Joined: Apr 2012
Posts: 904
Likes: 1
Most shops would touch the heads on a belt sander at that point to clean the surface.
That being said .002" should pull back into flatness when torqued.
The surface should be fine with .002" warp as long as it has not been hit with a wire wheel or gouged in any way.
That being said .002" should pull back into flatness when torqued.
The surface should be fine with .002" warp as long as it has not been hit with a wire wheel or gouged in any way.
to my way of thinking, the minimum amount removed to restore
flatness and leave a cleaned up surface is the correct amount, and
i'm surprised nobody free grit laps the heads..... it isn't gonna get
any flatter, and sure not any smoother, and you can put the head
on the lap, and let it run till it cleans up, and you are done.
there aren't that many people that do it. here is someone who does.
Cylinder head resurfacing
when they make gauge blocks, they do it with a lap. that should answer
any doubts.
Thread Starter
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Junior User
Joined: Sep 2011
Posts: 65
Likes: 0
I miss stated microns it should have been micro when referring to finish.. I understand that as I work in a machine shop that manufactures safety devices for the nuclear industry. The variation in measuring devices is a moot point in my opinion being a machinist for 20 years. A machinist will know the variation and will be able to take into account. If I measure something 10 times and get the same measurement 8 of the 10 times and it is verified by someone else, I would say the variation is moot. If you are worried about a micrometer/measuring variation on a head resurfacing on a stock engine then...well....I think your over thinking it. As long as the head is flat and has a correct finish and still is above the minimum thickness called out in the shop manual, then that is all that matters. .
The only shops I know that use CMMs on engine work are shops that the average JOE can not afford. Also CMMs are only as good as the people using them. My current employer bought one a few years ago. The guy that was hired to bring their QA up to speed didn't understand how to set it up and failed every single part for 3 weeks.
I'm a metrologist, not a meteorologist. Sounds & looks similar but very different. See http://en.wikipedia.org/wiki/Metrologist
Hotshot
Joined: May 2005
Posts: 13,484
Likes: 42
From: Stevens Point, WI
The flatness issue is over rated some. If you take a strait edge, perfectly flat +/- .0001 and you just put your hand on the back side of it for a few seconds it will go out of flat and have a bow to it because of the heat from your hand.
I can set up a dial indicator on my lathe on some sort of stock in the chuck. Just by simply pushing on the headstock or tailstock or push down slightly in the middle of the bed will make the dial indicator move.
If you clamp one end of a 6.0 head onto a table and stick a dial indicator on the other end, simply placing a coffee mug on the end will make the head flex some.
All metal flexes with surprisingly little effort.
When bolting the heads down with 240ft/lbs of torque flatness over all isn't an issue. What can be an issue is a cupped head that has a dip between a couple cylinders or the like. That part doesn't get flattened out when bolted down and can cause a problem. The most important thing for any seal is surface finish. Some like rough, some like smooth, all depends on the gasket used and the application of the part.
One big fail of the 6.0 is the head studs pass threw 3 different types of metal... That is simply stupid engineering. The guy that thought that up should be slapped and demoted to McDonalds or be a walmart greeter. Then I bet the same guy said lets only use 4 studs per cylinder. Someone HAD to of brought crack to the office that day! I also bet it was the same day they designed the crank and cam setup.
So in recap, head flatness all has to do with the weather, temperature, what kind of table the head is laying on when measured, gravitational pull, high tide, and how much you had to drink that day.
I can set up a dial indicator on my lathe on some sort of stock in the chuck. Just by simply pushing on the headstock or tailstock or push down slightly in the middle of the bed will make the dial indicator move.
If you clamp one end of a 6.0 head onto a table and stick a dial indicator on the other end, simply placing a coffee mug on the end will make the head flex some.
All metal flexes with surprisingly little effort.
When bolting the heads down with 240ft/lbs of torque flatness over all isn't an issue. What can be an issue is a cupped head that has a dip between a couple cylinders or the like. That part doesn't get flattened out when bolted down and can cause a problem. The most important thing for any seal is surface finish. Some like rough, some like smooth, all depends on the gasket used and the application of the part.
One big fail of the 6.0 is the head studs pass threw 3 different types of metal... That is simply stupid engineering. The guy that thought that up should be slapped and demoted to McDonalds or be a walmart greeter. Then I bet the same guy said lets only use 4 studs per cylinder. Someone HAD to of brought crack to the office that day! I also bet it was the same day they designed the crank and cam setup.
So in recap, head flatness all has to do with the weather, temperature, what kind of table the head is laying on when measured, gravitational pull, high tide, and how much you had to drink that day.
Lead Driver
Joined: Oct 2010
Posts: 5,420
Likes: 16
From: Ouray, CO
One big fail of the 6.0 is the head studs pass threw 3 different types of metal... That is simply stupid engineering. The guy that thought that up should be slapped and demoted to McDonalds or be a walmart greeter. Then I bet the same guy said lets only use 4 studs per cylinder. Someone HAD to of brought crack to the office that day! I also bet it was the same day they designed the crank and cam setup.
Fleet Owner
Joined: Apr 2012
Posts: 27,307
Likes: 549
From: Spanaway
The flatness issue is over rated some. If you take a strait edge, perfectly flat +/- .0001 and you just put your hand on the back side of it for a few seconds it will go out of flat and have a bow to it because of the heat from your hand.
I can set up a dial indicator on my lathe on some sort of stock in the chuck. Just by simply pushing on the headstock or tailstock or push down slightly in the middle of the bed will make the dial indicator move.
If you clamp one end of a 6.0 head onto a table and stick a dial indicator on the other end, simply placing a coffee mug on the end will make the head flex some.
All metal flexes with surprisingly little effort.
When bolting the heads down with 240ft/lbs of torque flatness over all isn't an issue. What can be an issue is a cupped head that has a dip between a couple cylinders or the like. That part doesn't get flattened out when bolted down and can cause a problem. The most important thing for any seal is surface finish. Some like rough, some like smooth, all depends on the gasket used and the application of the part.
One big fail of the 6.0 is the head studs pass threw 3 different types of metal... That is simply stupid engineering. The guy that thought that up should be slapped and demoted to McDonalds or be a walmart greeter. Then I bet the same guy said lets only use 4 studs per cylinder. Someone HAD to of brought crack to the office that day! I also bet it was the same day they designed the crank and cam setup.
So in recap, head flatness all has to do with the weather, temperature, what kind of table the head is laying on when measured, gravitational pull, high tide, and how much you had to drink that day.
I can set up a dial indicator on my lathe on some sort of stock in the chuck. Just by simply pushing on the headstock or tailstock or push down slightly in the middle of the bed will make the dial indicator move.
If you clamp one end of a 6.0 head onto a table and stick a dial indicator on the other end, simply placing a coffee mug on the end will make the head flex some.
All metal flexes with surprisingly little effort.
When bolting the heads down with 240ft/lbs of torque flatness over all isn't an issue. What can be an issue is a cupped head that has a dip between a couple cylinders or the like. That part doesn't get flattened out when bolted down and can cause a problem. The most important thing for any seal is surface finish. Some like rough, some like smooth, all depends on the gasket used and the application of the part.
One big fail of the 6.0 is the head studs pass threw 3 different types of metal... That is simply stupid engineering. The guy that thought that up should be slapped and demoted to McDonalds or be a walmart greeter. Then I bet the same guy said lets only use 4 studs per cylinder. Someone HAD to of brought crack to the office that day! I also bet it was the same day they designed the crank and cam setup.
So in recap, head flatness all has to do with the weather, temperature, what kind of table the head is laying on when measured, gravitational pull, high tide, and how much you had to drink that day.
You all wrong it was not a young Engineer/Manager it was an Old Accountant .
Sean
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Hotshot
Joined: May 2005
Posts: 13,484
Likes: 42
From: Stevens Point, WI
Because all the old navistar engineers only knew how to build 7.3's? lol "6.what? Who are you? and it has to have emissions? Yeah we got someone that knows what they are doing."
Fleet Owner
Joined: Apr 2012
Posts: 27,307
Likes: 549
From: Spanaway
And then you will have there theme song.
Sean
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