Mill the head

[RandyLittrell 3,884]

Anyone on here willing and able to mill a few Kohler heads? I won't do business with the guy in Mo. that I had some done before and looking for a new source. 

 

Thanks!!

 

 

 

Randy

[ebinmaine 67,619]

@Greentored.....?

 

Scott..

[305 380]

i'm just curious , not offering .....i have a mill and i could do it , but would probably make some sort of special fixture to hold it. did the other guy have one too?

[pacer 3,173]

25 minutes ago, 305 said:

some sort of special fixture to hold it.

 

Ummmm... that could turn into quite a task. Have to use a fly cutter...yes? I dunno, I'm pretty much self taught, so I've never even thought of trying.

 

Many yrs ago, the guy I used for car/truck engines head facing had a large  (36"??) flat rotating table with - I dont recall if he had sandpaper or an abrasive disk, but he would just run the head back & forth, raising the table til he got what he wanted. Was quick, If he wasnt too busy I'd just wait the some 20-30 min. 

 

Sadly, as is in so many of these old guys, he passed several yrs ago and of course his knowledge - and all the tooling went too.

[Greentored 3,214]

I have done many, but have no way to hold the heads and run a fly cutter across- just using a 1.5" end mill with multiple passes, and touch them up on a marble surface plate with 180 grit. Never had a problem, its just not 'technically' the right way its normally done.

[305 380]

I have a fly cutter , just don’t know how to hold it......thus the need for special tooling.  I imagine one could be made very simply

Edited June 24, 2021 by 305

[Greentored 3,214]

2 hours ago, 305 said:

I have a fly cutter , just don’t know how to hold it......thus the need for special tooling.  I imagine one could be made very simply

same issue haha. I get picked on whenever posting a pic, cutting one with an end mill....but the end result is the same

[305 380]

i'm not familiar with Kohler engines so i stole a couple pictures of a NOS head for a K181...just for an example as it seams to be a very common engine on Wheelhorses

 

if all those machined surfaces for the headbolts are the same height a simple fixture could be made to index off them. clamp through the sparkplug hole with a bolt and washer

 

put it in the mill with a fly cutter and you would be done in minutes

Edited June 24, 2021 by 305

[Mickwhitt 4,642]

Its going to be pretty light cuts so 305 is right in using the stud holes to place jacking pieces under to set the head flat and clamp via the plug hole. 

A table vice could also be used, the kind without a body, just jaws with tee bolts into the slots. 

Decent sized fly cutter would do it all in one pass. 

Its pouring down here so I may set one up as a trial.

Mick 

 

[ranger 1,750]

9 hours ago, 305 said:

i'm not familiar with Kohler engines so i stole a couple pictures of a NOS head for a K181...just for an example as it seams to be a very common engine on Wheelhorses

 

if all those machined surfaces for the headbolts are the same height a simple fixture could be made to index off them. clamp through the sparkplug hole with a bolt and washer

 

put it in the mill with a fly cutter and you would be done in minutes

Be very careful when clamping the head down onto a fixture that uses the head bolt bosses. If they are not at exactly the same height when measured with the head sitting on the gasket face, (due to head warping, etc), and you clamp it down tight, you run the risk after machining, of distortion, (a warp) returning when clamp released. I would personally go for a fixture with “Shoulder” posts for three of the head bolt holes, (to locate the head and resist machining forces), and a spacer under the spark plug hole which can be shimmed to hold the head just clear of the fixture base ( or mill table), to avoid introducing any distortion when clamped. Many years ago, (1970s) I had a Jaguar inlet manifold machined to remove corrosion from the head mounting face. Despite me insisting the manifold be clamped from the sides, the machinist clamped it down onto the the three carburettor mounting flanges. The result, a manifold that looked like a banana and never sealed properly again. 

For the woodworkers amongst us. A couple of layers of MDF with the profile of the head routed out, sit the head into the recess, a wood screw in the plug hole, then run it through the planer/ thicknesser, or belt sander! (Only Joking) 

[Greentored 3,214]

I normally clamp the head 'gasket surface down' first and make a skim cut across the entire surface. Applying that then clamping through the plug hole like @305 mentioned might do the trick and greatly reduce the chances of clamping distortions?

I could see where clamping in only one place MAY allow something to shift, so perhaps clamping a 'bar' along a couple sides of the head might eliminate that chance as well?

Just thinking out loud here. Im self taught and know what the end result has to be, but many of you guys know the CORRECT way to get there.

[Mickwhitt 4,642]

This is a bit down and dirty but I only had a scruffy little cylinder head to play with. 

 

As this head had a series of posts cast into the cooling fins I decided to clamp the head gasket side down and skim the top of the fins to get a flat reference surface.

 

Then I flipped the head over and clamped it through the spark plug hole using thin card as a cushion to help grip.

 

I used an insert face mill to do several passes with just enough cut to remove any warp.

Finished result looks ok. A little hone on a flat surface plate and its good to go. 

If the head can't be milled flat on the top surface then appropriate spacers would have to be made to sit under the stud holes to get it level. 

Mick 

[RandyLittrell 3,884]

Just looking to have .030 or so taken off to wake up a couple of motors. If someone was interested, just milling would be okay and I could sand them smooth on plate glass. 

 

 

 

Thanks, Randy

[Greentored 3,214]

10 hours ago, RandyLittrell said:

Just looking to have .030 or so taken off to wake up a couple of motors. If someone was interested, just milling would be okay and I could sand them smooth on plate glass. 

 

 

 

Thanks, Randy

If you're ok with having them done this way, i'll take em. 

PS- sheet metal scrap under Briggs opposed head- experimental angle milling, and came out within .002 of my goal. It worked!

Edited June 28, 2021 by Greentored

[RandyLittrell 3,884]

14 hours ago, Greentored said:

If you're ok with having them done this way, i'll take em. 

PS- sheet metal scrap under Briggs opposed head- experimental angle milling, and came out within .002 of my goal. It worked!

 

 

I will send a pm for an address. 

 

Thanks

 

 

 

 

Randy