520 pipefabricator
Member
Just going to satisfy my curiosity urge
here and ask- how much could you safely
deck a ford 8n head?
here and ask- how much could you safely
deck a ford 8n head?
Ultradog MN
Well-known Member
- Location
- Twin Cities
I agree Jmor.
Those heads are very malleable. I've always
thought machine shops that machinine these
flat heads as part of a reman are
borderline dishonest
Those heads are very malleable. I've always
thought machine shops that machinine these
flat heads as part of a reman are
borderline dishonest
I had to get one resurfaced that wouldn't hold the head gasket between #3 and #4 cylinders. Other than corrosion or erosion, there is no reason to resurface the head.
It has been proven many times that just shaving a flat head is not an effective way to increase compression. When increasing compression on a flat head engine, the shape of the combustion chamber is more important than the volume reduction. This is because the flow of gasses is the most important factor.
It has been proven many times that just shaving a flat head is not an effective way to increase compression. When increasing compression on a flat head engine, the shape of the combustion chamber is more important than the volume reduction. This is because the flow of gasses is the most important factor.
HarryVanderpool
Member
- Location
- Salem, Oregon
Never heard of "Decking a Head"
I've heard of "Milling a Head"
I've heard of "Adjusting Deck Height" which has to do with milling the mating surface of the block.
As for assuring a flat mating surface of the head, have we forgot how to correctly use a new, sharp flat file?
Laying the head on the workbench with combustion chamber facing up, I place a NEW, SHARP flat file at a 45deg angle on the face and placing no pressure, I work the face over and over waiting for high, "witness" marks to appear. And THEY WILL appear.
Rotate the file 90deg and gently cover the face, over and over.
Rinse & repeat.
DON'T go all "King Kong" use light to no pressure.
As soon as the entire face of the head displays even the least contact with the file, stop.
Your head is ready to go another 80 years.
I've heard of "Milling a Head"
I've heard of "Adjusting Deck Height" which has to do with milling the mating surface of the block.
As for assuring a flat mating surface of the head, have we forgot how to correctly use a new, sharp flat file?
Laying the head on the workbench with combustion chamber facing up, I place a NEW, SHARP flat file at a 45deg angle on the face and placing no pressure, I work the face over and over waiting for high, "witness" marks to appear. And THEY WILL appear.
Rotate the file 90deg and gently cover the face, over and over.
Rinse & repeat.
DON'T go all "King Kong" use light to no pressure.
As soon as the entire face of the head displays even the least contact with the file, stop.
Your head is ready to go another 80 years.
Ultradog MN
Well-known Member
- Location
- Twin Cities
Good post Harry.
Yes, I also wondered about decking a head
but figured everyone knew what he meant so
didn't 'auto reply'.
As for hand filing a surface you are right
on. But suggesting that folks here do such
an old school technique is a little like
asking a girl under 60 to drive a stick
shift car. They're not likely even to try.
Next you'll be telling us how to pour and
scrape a babbitted bearing - another mostly
lost art from the past.
Yes, I also wondered about decking a head
but figured everyone knew what he meant so
didn't 'auto reply'.
As for hand filing a surface you are right
on. But suggesting that folks here do such
an old school technique is a little like
asking a girl under 60 to drive a stick
shift car. They're not likely even to try.
Next you'll be telling us how to pour and
scrape a babbitted bearing - another mostly
lost art from the past.
TheOldHokie
Well-known Member
- Location
- Myersville, MD 21773
I would agree with some caveats. You can easily pull out twists and bends but not waves created by distortion of the casting. And there are other reasons to deck a head.
Macine milling or decking the head creates a distortion free [[u:5a345c245d]b]flat[/b[/u:5a345c245d]] surface with the proper surface finish needed for securely gripping and sealing a head gasket. Unless you are well trained in hand scraping techniques and possess the proper flatness and surface finish gaging tools and a good supply of machinists dye hand finishing is not a viable DIY option Trying to scrape in a head with a hand file and your eyeballs is a recipe for disaster. You can easily wind up with a surface that looks great but has so many humps a camel would be envious.
Fifteeen or twenty minutes to setup and cut a flathead with a surface mill on a milling machine or or surface grinder will get you a reliable flat surface with a 60 Ra finish just like it came from the factory.
TOH
TheOldHokie
Well-known Member
- Location
- Myersville, MD 21773
In fact check deck height of all components. I am guessing a .015/.030 skim off the L-head ain't going to be an issue but I have never actually tested that theory :roll:
TOH
Ultradog MN
Well-known Member
- Location
- Twin Cities
A couple of thoughts.
When milling a head it is much easier to
clamp to the sides of the head - if
possible.
If you clamp it Down to the table you need
to shim it on 4 corners so you can mill the
bow or warpage out of it. Shimming/clamping
can take a long time to do.
My engine machinist has an interesting
machine. A head resurfacer - built by
Winona Tool
It is a simple flat table with a spinning
grinding wheel about 12? in diameter in the
center of it. Grinds on the face of the
wheel. Turn it on and manually slide the
head back and forth. Adjust the depth of
cut by raising the wheel. Not for heavy
.010+ removal of metal but for a quick
flattening or refinishing it does a great
job rather quickly. When I replaced the
flanged sleeves in a block the flanges were
proud by about 3 to 5 thou. We turned the
block upside down and ground the flanges
till the wheel just kissed the deck. Block
was heavy so I helped slide it back and
forth. Would be the cat's meow on a flat
head that is light weight.
I think you dismiss the use of a file too
quickly. Harry V and I were not talking
about removing metal with the leading edge
like you would on the ways of a machine. A
good, sharp 12 in. mill file will actually
remove a fair amount of material by hand by
draw filing. A new framing square with a
bright light behind it is a pretty good
home brew indiactor of flatness or warpage.
I have never heard of someone decking a
head. Only the block. Have only heard of
someone milling or resurfacing a head. But
maybe...
When milling a head it is much easier to
clamp to the sides of the head - if
possible.
If you clamp it Down to the table you need
to shim it on 4 corners so you can mill the
bow or warpage out of it. Shimming/clamping
can take a long time to do.
My engine machinist has an interesting
machine. A head resurfacer - built by
Winona Tool
It is a simple flat table with a spinning
grinding wheel about 12? in diameter in the
center of it. Grinds on the face of the
wheel. Turn it on and manually slide the
head back and forth. Adjust the depth of
cut by raising the wheel. Not for heavy
.010+ removal of metal but for a quick
flattening or refinishing it does a great
job rather quickly. When I replaced the
flanged sleeves in a block the flanges were
proud by about 3 to 5 thou. We turned the
block upside down and ground the flanges
till the wheel just kissed the deck. Block
was heavy so I helped slide it back and
forth. Would be the cat's meow on a flat
head that is light weight.
I think you dismiss the use of a file too
quickly. Harry V and I were not talking
about removing metal with the leading edge
like you would on the ways of a machine. A
good, sharp 12 in. mill file will actually
remove a fair amount of material by hand by
draw filing. A new framing square with a
bright light behind it is a pretty good
home brew indiactor of flatness or warpage.
I have never heard of someone decking a
head. Only the block. Have only heard of
someone milling or resurfacing a head. But
maybe...
TheOldHokie
Well-known Member
- Location
- Myersville, MD 21773
The rotary grinding process you are describing is called Blanchard grinding. A 12" machine is a runt a good size machines are 50" and up.
Shops doing head work don't clamp to the table with shims. They hold the work with an adjustable purpose built fixture and jack screws that make head setup very quick and easy. Here is a picture of an L-head fixtured for resurfacing. Its a very simple setup compared to a modern head. Take 2/3 skimming (<.010) passes with the face mill / fly cutter to find and remove just the imperfections snd high spots. Flat with a well controlled surface finish in a matter of minutes.
TOH
Ultradog MN
Well-known Member
- Location
- Twin Cities
Toh,
A blanchard grinder with a big rotary
table and the grinding wheel above is not
at all what I described in my other post.
I resurfaced a few heads myself - once upon
a time though not with a purpose built
machine.
My first ship was a submarine tender. It
was a repair ship. Had a big machine shop.
We had both a 36 shaper and a 3'x6'
planer. I enjoyed running them and usually
asked for those jobs. Every ship always has
its own small boats. Liberty boats for the
crew and the captain's gig.
When I was aboard all those boats were
still running Detroit diesels. I planed a
couple of heads for our own boats. Once we
pulled into Naples Italy for about a week.
When the fleet found out we had a planer
and could resurface a 671 head guess who
got real busy for a while.
Bet I did at least a dozen of them.
I would dial in and shim the 4 corners. If
they are warped you have to level them the
best you can - split the difference, etc.
An old X71 Detroit head you can clamp them
from the sides so that's how we did it.
Was not complicated at all.
Yes, you could do the job on even a small
mill though maybe not on an inline 6.
A blanchard grinder with a big rotary
table and the grinding wheel above is not
at all what I described in my other post.
I resurfaced a few heads myself - once upon
a time though not with a purpose built
machine.
My first ship was a submarine tender. It
was a repair ship. Had a big machine shop.
We had both a 36 shaper and a 3'x6'
planer. I enjoyed running them and usually
asked for those jobs. Every ship always has
its own small boats. Liberty boats for the
crew and the captain's gig.
When I was aboard all those boats were
still running Detroit diesels. I planed a
couple of heads for our own boats. Once we
pulled into Naples Italy for about a week.
When the fleet found out we had a planer
and could resurface a 671 head guess who
got real busy for a while.
Bet I did at least a dozen of them.
I would dial in and shim the 4 corners. If
they are warped you have to level them the
best you can - split the difference, etc.
An old X71 Detroit head you can clamp them
from the sides so that's how we did it.
Was not complicated at all.
Yes, you could do the job on even a small
mill though maybe not on an inline 6.
TheOldHokie
Well-known Member
- Location
- Myersville, MD 21773
All good but its not what you will get in a modern machine shop. Here is a good video of a flathead being resurfaced on a modern machine. This machine is very rigid and he dispenses with the jack screws shown in my earlier picture.The setup process isnt shown but its just dialing in the surface using a depth gauge mounted on the fly cutter. The head is bolted to the fixture through the spark plug holes and its squared up using the independent adjusting slots in the fixture so its not being torqued by the clampung. Should not take much more than 5 minutes to do the setup. I lost count but it was 6-8 skim cuts with something like .003 DOC and what looks like 30+ IPM feed. Final pass was done with a fresh cutter to get the proper "mirror" (40-60Ra) surface finish. Total DOC was .016 and video is 8 minutes long which with the editing and added narration is probably close to what the actual machining time would have been. If you are building an engine, including a flathead, this is money well spent.
https://www.youtube.com/watch?v=MEBiIl3ShXg
TOH
PS> I could probably get a "small" inline 6 on my "small" 12 x 56 Cincinnati.
This post was edited by TheOldHokie on 08/18/2021 at 07:24 am.
HarryVanderpool
Member
- Location
- Salem, Oregon
Well, I really don't want to beat a dead horse into the ground, but...
There are (thank heavens) many solutions to the myriad problems that can arise.
For a massively warped head, there are good solutions for repair as have been illustrated here.
I want to share what I have seen with flathead heads, once removed.
Usually, the area around the bolt holes down the middle of the head, after many decades of heating and cooling cycles has stress relieved, and deformed an area about 1'' around the hole.
When the head is removed and found to be flat within tolerance, the only issue remaining is to return the area around the bolt holes to surface height.
In this case, heavy duty precision machine equipment is major overkill. The head is flat. It does not need milled.
A new, sharp flat file used at fingertip pressure at 45 and 90 degree angles makes quick work of this common problem.
I'm the first one to encourage folks to do things right the first time.
But "Porting and polishing, balancing and blueprinting" when the problem is a fouled spark plug is not good economy.
Just trying to save folks from wasting their hard earned dollars.
There are (thank heavens) many solutions to the myriad problems that can arise.
For a massively warped head, there are good solutions for repair as have been illustrated here.
I want to share what I have seen with flathead heads, once removed.
Usually, the area around the bolt holes down the middle of the head, after many decades of heating and cooling cycles has stress relieved, and deformed an area about 1'' around the hole.
When the head is removed and found to be flat within tolerance, the only issue remaining is to return the area around the bolt holes to surface height.
In this case, heavy duty precision machine equipment is major overkill. The head is flat. It does not need milled.
A new, sharp flat file used at fingertip pressure at 45 and 90 degree angles makes quick work of this common problem.
I'm the first one to encourage folks to do things right the first time.
But "Porting and polishing, balancing and blueprinting" when the problem is a fouled spark plug is not good economy.
Just trying to save folks from wasting their hard earned dollars.
Tim PloughNman Daley
Well-known Member
Decking is a machinist's term used in machine shops. First of all why do you think you need to mill your head? Do you know and understand what flatness, concave, convex, profile of a surface, and micro-finish is? Milling/machining anything requires the know-how of using such equipment. Any machining requires that the workpiece be of the most rigid and secure setup. Any movement when the cutting tool is applied will result in catastrophe. You don't need a Blanchard grinder. The head would have to be trammed in using a precision InterRapid Indicator with .001 or finer increments. A 1/32 or a 1/16 cut is way too much to consider milling. You would want to take a fly-cut of say no more than .010 just to dust the surface. You'd apply a layout die (DYKEM typical) to observe the cleanup. Your best bet, if you need a decking at all would be to take it to a trusty local machine shop who has the experience and equipment to do the job right. He probably already has a special fixture made for the job.
Tim Daley(MI)
Tim Daley(MI)
Hobo,NC
Well-known Member
- Location
- Sanford, NC
That cost me a hour are so of my time thanks for posting the link...
I can use one of these well two of them most any time I want to. A exhaust manifold are a small part BOOM its great "sometimes".
https://www.youtube.com/watch?v=mMqHf2leFlc
I have decked my own N block and a head along with quite a bit of stuff on them. Its one ell of a nasty job and I don't like getting dirty : ( I had rather pay for a precision job. I can pass the labor on a customer pay job I had to try the belt sander tho : ) It worked out OK but I was the one that ate it if it went bad...
I did the file thing on a Farmall engine its working out OK but I would not recommend it to others no no no... Cheap is not always best the next guy may not be as impressed.
It comes down to how well it may taste if it goes bad...
Smokeonthewater
Member
I recently went through this dilemma on the aluminum head for my 2.5L inline 6 bmw.. not overheated and very little distortion after 200,000 miles... agonized over what diy method I would use to prep it for a week... In the end my machine shop guy took off .007 and left me w a perfect finish for a whopping $60..... yeah that's not free but peace of mind that I won't be buying another $250 worth of gaskets and head bolts plus $50 in fluids and doing another 2 days of wrenchingis priceless....
Granted everything about our old tractors is simpler, cheaper, and easier so the risk of loss is so much less but still the same principal.
This post was edited by Smokeonthewater on 08/19/2021 at 07:58 pm.
Granted everything about our old tractors is simpler, cheaper, and easier so the risk of loss is so much less but still the same principal.
This post was edited by Smokeonthewater on 08/19/2021 at 07:58 pm.
Smokeonthewater
Member
Calm down Goofball.... the experience of which I speak relates to the previous post's mention of doing something right vs trying to save a couple bucks and do it by hand w files or sandpaper...
You really need to ask your psychologist for some Prozac or something similar...
Smokeonthewater
Member
Why jmor over reacts to these things I can't say, but I think the root of his confusion stems from the classic/ modern view differences...
When I'm replying in modern view I see all replies in chronological order and it's plainly obvious that I'm responding to the line of discussion in hobo's and tim's prior posts...
In classic view it's a mystery as you can't see the other posts unless you click on each one.... A person could easily go back and reread prior posts to understand why I mentioned my totally different engine but that same person could also choose to slobber out some insulting blurb and then exclaim something about large water fowl lol
When I'm replying in modern view I see all replies in chronological order and it's plainly obvious that I'm responding to the line of discussion in hobo's and tim's prior posts...
In classic view it's a mystery as you can't see the other posts unless you click on each one.... A person could easily go back and reread prior posts to understand why I mentioned my totally different engine but that same person could also choose to slobber out some insulting blurb and then exclaim something about large water fowl lol
HarryVanderpool
Member
- Location
- Salem, Oregon
Next time you are at the welding store, buy a couple of high quality files.
I can't think of many flat gasket surfaces that I don't check with a 12" mill file before assembly . Keep it cleaned and lightly oiled rolled up in an old bath towel . Keep a steel straight edge rolled up in another towel . I remember paying about $20 but I see they are 2 - 3 times that now (Straight Edge ) .
This post was edited by Ken(Ark) on 08/20/2021 at 08:18 pm.
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