Recut domes in EAB heads

[cadillac512]

I have a pair of EAB heads that have been milled at some point, and were too close to the pistons in my 260" Merc. I've been running a nice pair of lightly milled 8CM heads that have .035-.040 piston clearance (block is decked). I wanted to try the EAB's so after researching on the Barn I made a cutter like Ol' Ron did (Thank you!) from a file and an extra mag wheel lug nut. Made a drill press jig to radius it at 6" and sharpened it carefully by hand/eye on a bench grinder.

I took it to work this morning and mounted the heads on the Bridgeport Mill and set the speed to 60 rpm...slow as it goes. Wants to chatter a bit and everything needs to be VERY tight but it went well and did the job. The domes are now back to original diameter and depth is approx .040" deeper than when I started. Should put the clearance right back to where it is with the 8CM heads.

Many thanks to everyone who has done this and posted the info for us to learn from, with special thanks to Ron Holleran for the pics and info he posted.

In a week or so I'll see how this deal pans out!


P.S. I will sand out the grooves and dress down the center bump...just wanted to post this now.



Terry

[Ol' Ron]

Yes, smokey was my hero. Never had much money, so I had to make most everything. As I got older, I discovered that making things was more fun, especialy when it didn't work, and you had to figger out why????? Nice work, glad to help.
Gramps

[cadillac512]

Smoothed and ready to test fit.

[cas3]

Nice job !

[Bored&Stroked]

Cool tool! I'll have to make one and see how well it does on aluminum. My problem is that my cheap mill won't go slow enough - so I may need to go to my friend's show and try his out. How did you cut the radius?

[cadillac512]

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Originally Posted by Bored&Stroked

Cool tool! I'll have to make one and see how well it does on aluminum. My problem is that my cheap mill won't go slow enough - so I may need to go to my friend's show and try his out. How did you cut the radius?

Thanks guys. To cut the radius I scribed a line with a compass set at 6" and hand ground the file roughly on the bench grinder. Then I used a 90 degree rig made of two 1/2" bolts welded head to head at a 90 degree angle with one leg screwed into the lug nut part of the cutter and set at 6" length. The other end of the bolt rig I chucked up in the drill press so it would swing around on a 6" radius. Used my drill press vise to vertically mount a die grinder with a 1" diameter stone so the cutter would swing past the stone and slowly clean up at the radius. Then I carefully sharpened the tool by hand.

Like an idiot I didn't take pics! However, wouldn't take much to throw the simple rig back together and get a few shots. Here's a link to Ol' Ron's rig...pretty much same as mine but a lathe instead of drill press.



I'll bet it'd cut aluminum great with some WD40 for cutting lube.



https://www.fordbarn.com/forum/attac...7&d=1329249637


Terry

[38 coupe]

Thank you for posting this. Please add pictures of the grinding setup if it isn't too much work.

[cadillac512]

Here's a pic of Ol' Ron's setup for grinding the cutter radius...mine is the same but I used a drill press rather than a lathe. We both just swept the cutter over the stone back and forth by hand. Credit to Ron for this pic.

[Ol' Ron]

Holding was a series of pipe fitting se t at the redius I wated the radius of the cutter. This was set for the Ross pistons which I think is 7" , but I'm not sure now. However the fixture is adjustable.
Gramos
PS that pic was taken over 20 years ago. I have allot of them on different projects. Ran out of Grand kids so it's hard for me to post pics and videos..
G

[Pete]

Two things that will help get rid of chatter. Take about 2 degrees of rake off the tool or get a speed controller for the motor so you can slow the spindle down.

[Brian]

Also, increase the feed rate....

[mfirth]

Way to go Terry, nice job! Hope "my" cam & those heads work well together.

[cadillac512]

Originally Posted by mfirth

Way to go Terry, nice job! Hope "my" cam & those heads work well together.

Thanks,Mike. The 8CM cam has been perfect for this engine and I'm sure it will be with the head swap too. Lots of time spent at low rpm on gravel and dirt backroads and seldom above 3000 rpm on the pavement (3.54 gears/29" tires). I've put about 15,000 very enjoyable miles on it in the last two years.


Terry

[Ol' Ron]

This cutter works best on Aluminum heads. My Mill will not slow down enough to do cast iron heads. I have a friens that has an old CNC Bridgport and wrote a program for this. Works very well. The beauty of the Foed Barn and the flathead movement amazes me, how people figger out hoe to accomplish the impossible, with nothing. I think if we put our minds together, we could save the place????

[cadillac512]

I installed the re-domed EAB heads on my 260" Merc ( 8BA/8CM type) this morning. Without gaskets the pistons were lightly kissing the heads...about .005"-.010", so on went the .050" Graphtite gaskets. I spent about 3 1/2 hrs doing the job on the '41 Merc. The previous gaskets (same brand) lightly stuck half to the head and half to the block but were easily removed with a single edge razor blade and a small shop vac.

It fired up instantly and runs beautifully (as it did before with the 8CM heads and .040" clearance) but now has a bit more growl under throttle and cruises with a bit less throttle opening to maintain the same speed. Acceleration is crisp and strong and will pull from 10 mph in high gear.

It's a nice improvement...not huge, but a step up from an already sweet running flathead. I'll be interested to see if any fuel mileage improvement is noticeable.

By the way, for those interested in such things: I checked cranking compression pressure when I returned from a drive just a bit ago. Previously checked at 120# with the 8CM heads--now checks at just under 150#. Nice.

Terry

[chap52]

Sweet... Wish I would of had access to those tools years ago. While working on the truck under the nearby shade tree we just doubled the head gaskets putting a bit of bearing grease between them. Poor folks, poor ways.
Sometimes my flash-backs are ingenious for a 16 year old. I am amazed at how much wisdom I have lost after all these years...LOL
Great post... Chap

[cadillac512]

Thanks, chap. I know what you mean! When we didn't know any better we tried all kinds of oddball interesting stuff, and sometimes it worked amazingly well. Our supposed knowledge limits us sometimes! Now, the energy I've lost....we don't want to think about that.


Terry

[TomT/Williamsburg]

Nice work!

[cadillac512]

A followup to the recut dome EAB head installation on my 260" Merc. I've run a few tanks of gas through it now, and where it previously delivered 16.5-17 mpg I am now seeing 18-18.7 mpg. The extra torque from the compression increase really has made a difference.



Terry

[Zeke3]

Terry, thanks for the update.