How far can you deck the head?

[Flash_G]

It has been an interesting day, I got the 8n running and the more it ran the worse it ran. After some investigating I found that the head bolt between 3 and 4 was not tight against the head and it was loosing compression out of the bolt hole. I have removed the head to find that the gasket was blown and the head is warped due to the bolt being loose for who knows how long. My question is how far can I cut the head before it hits the valves or the pistons? Or do I need to find a new one? And if I need a new one where do I get one?

 

[TheOldHokie]

(quoted from post at 20:02:30 01/01/23) It has been an interesting day, I got the 8n running and the more it ran the worse it ran. After some investigating I found that the head bolt between 3 and 4 was not tight against the head and it was loosing compression out of the bolt hole. I have removed the head to find that the gasket was blown and the head is warped due to the bolt being loose for who knows how long. My question is how far can I cut the head before it hits the valves or the pistons? Or do I need to find a new one? And if I need a new one where do I get one?

New cylinder heads are readily available. John Smith was of the opinion that warped heads would easily pull flat and did not need to be milled.

https://www.yesterdaystractors.com/Ford-8N_Cylinder-Head_8N6050A.html

TOH

 

[504]

I don t disagree with anything poster below. The old
hot rod way to check for clearance is a hand full of
PlayDough. Put it over the valves and bolt the head
back on turn the motor over and take the head off and
measure the thickness of the clay.

 

[Bruce(OR)]

Then take into account increased comp ratio, higher octane gas, spacing for valve float and ignition timing just for the fun of it.
Bounce it up high enough is the radiator sufficient? Pistons are cast or forged? Chamber temp is how much?
I will stop for now. This is getting to be too much fun.
Untitled URL Link

 

[Den N Ms]

Flash_G , I would check the head for being flat with a straight edge and a feeler gauge,under straight edge in the lowest spot.If it is more than.005 it should be planed flat.After being planed lay the head on the block,with out any head gasket under it with a couple bolts left loose(just started on each end.)
Then roll the engine by hand with crank or by turning over with the fan blade two full revolutions,while watching for movement of the head. If no movement you are good to put on head gasket and bolt and torque it down.
I would use a Fel Pro head gasket NAPA# NGA-1950 best gasket you can use.
If the head moves when turning the engine over ,there is piston interference and the head will need to be clearance by grinding the pocket on the head .It should not take much. Post back if you need more help.

 

[Ultradog MN]

I tend to agree with John Smith.
Those flat heads are a relatively thin,
malleable piece of cast iron and there are
enough head bolts to pull them down flat.
It would be an interesting experiment to
take an empty block and a known warped
head.
Use some spot blueing and torque to specs.
See what you get.

 

[Tim PloughNman Daley RIP]

I concur with the others. No need to mill the head. It would have to be severely warped and that is hard to do. Many fellas don't understand
matching and think a head needs to be re-milled whenver it is removed. Flatness /__ /is checked in a free state and should be within .005.
That's how it is spec'd on the blueprint. Also, if the head needs a fly cut, if you dont let a qualified machuie shop do it, you can muck it
up. The part must be trammed in first and you ain't gonna do that on your workbench. DEN has the method in his post. Best to take the head
with you with the stripped block when you get it to your trusty local machine shop. He will boil the parts clean, then inspect with MagnFlux
for any cracks, and then proceed from there.

Tim Daley(MI)

 

[JMOR]

(quoted from post at 06:41:44 01/02/23) I concur with the others. No need to mill the head. It would have to be severely warped and that is hard to do. Many fellas don't understand
matching and think a head needs to be re-milled whenver it is removed. Flatness /__ /is checked in a free state and should be within .005.
That's how it is spec'd on the blueprint. Also, if the head needs a fly cut, if you dont let a qualified machuie shop do it, you can muck it
up. The part must be trammed in first and you ain't gonna do that on your workbench. DEN has the method in his post. Best to take the head
with you with the stripped block when you get it to your trusty local machine shop. He will boil the parts clean, then inspect with MagnFlux
for any cracks, and then proceed from there.

Tim Daley(MI)

, too, go along with John Smith.. Also, of you do surface the head, it will not be the valves (just under 0.3" valve lift) hitting the head, rather , it will be the piston hitting the head on opposite side of cylinder from the valves (the shinny area in the picture).

.

 

[Ultradog MN]

Speaking of John Smith,
has anyone heard from him lately?
I haven't seen him around in a while.

 

[JMOR]

Retired from the Ford tractor scene a few years ago & turned over much of his material to Ford Fordson Collectors Association.

 

[Flash_G]

Well I put the head back on after some cleaning and torqued to 70ftlbs. It runs better but I think I have carb issues. Then I stuck the bendix against the flywheel which locked the motor. After disassembly of the starter and beating it until it came free from the flywheel, I have now rebuilt the starter and set it in the floor beside the tractor and I'm headed inside to find an adult apple juice and contemplate my life choices! Lol

Thanks again for the info, I'm sure Ill have more questions that aren't answered by books.

 

[lha]

Not exactly the same,but when my Toyota truck blew the head gasket,I took it to an old school machine shop in a tiny town. He told
me that the head [overhead cam,like I said not exactly the same] was close to it's minimum thickness. He checked it and marked the
areas that needed a few thousandths taken off to bring it to specs. That worked well with a copper spacer and a head gasket. Five
years later,the truck runs great with 350,000 miles.

 

[HarryVanderpool]

The term "Warped" often is off the mark for flat head service.
Usually, after years of normal service, barring some terrible event, the head is very flat.
However, what you will find is that the area around the bolt holes "stress relieved" over time after all of the heating cycles and pulled toward the deck against the gasket elasticity.
Looking at the picture above, generally a slight high 1" circle around each bolt hole.
For this, I lay a new, sharp file on the surface, and with my fingertips , gently move the file in an X pattern over the entire face and these high spots appear.
I AM NOT SAYING TO GRAB A FILE AND GO ALL KING KONG, FILING AWAY ON YOUR HEAD!!!.
With your fingertips, gently move the file over the entire face and the high areas will witness.
At this point the majority of the deformation can be reduced with a minimal amount of materal removed.
In fact zero material removed on 90% of the head.
O.K. I'm ready for my whipping.

 

[Flash_G]

@HarryVanderpool I count that as "cleaning"! Lol