Log modification / removal

Invectivus

Well-known member
Subscriber
Gold Supporter
I have a mess of heads floating around, and a big old mill. I want to start with a 2v conversion, then work my way up to milling off the log (leaving the exhaust), boring the intake nubs, and pressing in new intake runners like the South Americans. I’m also super ignorant, though I have a buddy who was a machinist.

Before I bug him, I thought I’d check and see if anyone had advice as to which end mill to use? I’m leaning toward carbide just from random research, but I don’t know what kind of cast iron our heads are:
Gray cast iron (GCI)
Nodular cast iron (NCI)
Malleable cast iron (MCI)
Compacted graphite iron (CGI)
Austempered ductile iron (ADI)
Reading https://www.sandvik.coromant.com/en-us/ ... rials.aspx they mention CGI as common in engine blocks and heads. They suggest dry cutting, carbide with thick coatings. I have a pic I’ll try to post, with along straight shank end mill.
 
So when I did this, i milled it straight level with the table and used a 3/8" 4 flute carbide end mill. I ran it at 500 RPM. Apparently the machinist guy with me said I'm super lucky. I didn't have any chatter whatsoever. And at one point i did something stupid and chipped off one of the flutes, fricker still cut with no chatter.

A lot of it is gonna be by feel. If its chattering play with the RPM till it doesn't. Don't over push the mill, just go by feel. Go slow, take your time. I got beautiful results.

It won't let me post pictures here, if you want pics PM me.

The adapter plate is another story. If you want to hear about that just ask.
 
This may have been done ona a vertical end mill (Bridgeport is what we call'em).
The table can B set-up automatic (speeds'n feeds). On a head like this there's no need for cutting fluid.
I've seen it done ona surface grinder (same, auto table). The table & pieces are walled off w/plexi glass as cutting fluid is
used & would B a mess otherwise. Better finish, slower process, all automatic tho.
A shaper would be another way (I love that machine) but cast does not turn out so good there.

Just like a ratchet, adjustab;e or ele impact ona nut or bolt - theres alot of choices to B made (sequence of operations, machine, process, speeds'n feeds, etc). :nod:
 
Yeah, I have a huge ancient manual vertical mill, looking forward to having fun and mangling iron.
 
ours still has the Dept of the Navy tag on 'em from the WWII effort.
The the "vertical mill, boar, drill, broach" has 30 ft ways, 10 ft sq table
and the tool post can start at the celling 40 ft up it appears.

Pretty awesome stuff, no?
 
I'm interested in seeing what you did for an adapter plate. I have a C8 head with the log milled off. Looking into creating a CAD drawing to make a plate to mount to the head with the goal of using a commercially available intake. I'm looking at how difficult it might be to mate up an intake from an L28 or similar.
 
cr_bobcat":1sh49dkh said:
I'm interested in seeing what you did for an adapter plate. I have a C8 head with the log milled off. Looking into creating a CAD drawing to make a plate to mount to the head with the goal of using a commercially available intake. I'm looking at how difficult it might be to mate up an intake from an L28 or similar.
Here's my thread, the good stuff is on page 2.

viewtopic.php?f=1&t=79809&start=50

I cut the log flat on the table. I cut the angle into the adapter plate. It woulda cut more on one side or thr other had I angled the head when I cut.
The adapter plate was all cut based on tracing a gasket lol. I used an end mill to get the rough shape, then i eyeballed the bolt holes from the gasket, drilled and tapped, then faced the top. I cut the angle on the bottom of it by using s protractor on a piece of paper. I put the paper in the vise, lined up my horizontal line with the top of the vise, then placed the plate in and lined it up with the angled line. Then I cut and faced. It took forever and I had to go in steps starting by cutting off the high side until i got it where I needed. I then drilled the holes to mount it to the head and left on the short side maybe just less than an 1/8" piece of meat under the cap screw.

You shoulda seen my cutting those holes in the plate. I drilled into the head first, so lining everything up was time consuming. But it all worked out. Hopefully it actually works when its on lol.

I do need a 1" spacer on top of my angled plate, otherwise the carb linkage that actuates the butterflys hit the log. Or you can just use a much larger plate.

Ryan
 
Back
Top