EAB Head Prep

[louisb]

Hi,

For those of you running the EAB heads on a warmed up Flathead what, if any, prep work did you do to them? I am already planning to have them cleaned and magged with the block then milled to .050 clearance. Does the chambers need any other clean up work? Engine is a 276 street engine. I looked around and didn't really find any info on stock heads, just the aftermarket heads.

Thanks,

--louis

[Charlie ny]

louis,
I'm using EAB heads on my 276. I laboriously matched the comb chambers
to the pistons to end up with .040 clearance once the gaskets were installed...metal
to metal with no gasket. On the right bank the pistons contacted the front of the
chambers just opposite on the left. Valve clearance was an issue as well. I used the white lumber crayon and die grinder method....total time for both heads was 14
hours. What else would I be doing.
I hung the heads on the block, using 4 studs, then with gravity and arm pressure holding the head in place turned the motor over leaving a witness mark
where there was interference.
Charlie ny

[louisb]

Hi Charlie,

Thanks for the input. Sounds like a good weekend project.

--louis

[russcc]

I was talking to Ron Holleran today at the Gathering in Rochester MA. He was telling me that the piston to head clearance should ideally be about .005 between the head and the combustion chamber without the gasket. So if you use rolled up aluminum foil, (better than clay), between the head and piston, and turn it over by hand you want to see about .005 clearance when you check the balls. If the gasket is .030 compressed, you are right on the money for .035 to .040 clearance as Charlie NY pointed out. Barney Navarro told me a few years back that the ideal clearance was as close as you could get to .030. Ken Makuch proved that recently in his Bonnevile record holding land speed roadster by running that clearance, and at high RPM the pistons were just barley kissing the head from accumulated "stretch".

[Ol' Ron]

I think this is a slight error. The alum balls won't squish down that small (.005"). Whit I left out waz I use a .050" shim gasket.
Sometimes my tungets tangled up with my eye teeth and I can't see what I'm saying

[Ol' Ron]

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The valve clearance is checked the same way, but I use a mill at 5 degrees to clearance for these, It removes less material. On a 276 65cc chamber gives aprox 8.3 CFR after you take in the piston clearance and valve pockets.

[Charlie ny]

Ron,
I wondered what my comp ratio was with this setup.....the engine runs real
strong but when the ignition is killed it stops instantaneously.
Charlie ny

[louisb]

Thanks again to everyone for their input. When you guys have the heads milled, do you angle mill them and if so any specific angle?

Also, is there any difference between the large letter and the smaller letter EAB heads? Or is this just a a casting thing that changed by year and/or foundry?

Thanks,

--louis

[JWL]

If the engine is in my shop and thus I can control the degree to which accurate clearance measurements are made, I always angle mill the heads. The "angle" depends entirely on the amount of material that can be removed to achieve proper minimum clearances at the outer(exhaust header) side of the piston without crashing elsewhere. If, for example, I can move the head down .030 in the desired outside crown area, I set the machinery to remove .030 on that side of the head and zero at the intake manifold side of the head. This helps preserve transfer area opening and valve clearance while improving the all important CR, turbulence, and residuals reduction.

Refer to my book for more information on the technique including reaming and spotfacing after angle milling.

[louisb]

Thanks JWL, will do. Every time I read through your book I learn something new.

Thanks,

--louis