Results of milling iron heads.
 

After consulting Ol' Ron's and JWL's books, I measured my combustion chambers with the tin foil balls. I had 50thou taken off the heads, and realised that the dome shape in the chamber no longer matches the top of the piston. Some judicious use of a flap wheel produced a shape fairly close to that of the piston top, with a 45thou clearance. A pair of new Best gaskets and torque 'er down. Woah! they are right. This is the best bang for the buck to be done to a flattie. With an otherwise stock C59A engine, the result is amazing. The torque rocks the car considerably when the throttle is blipped, and out on the road the little AV8 goes like a raped ape. It actually goes much better than when I had the Weiand heads on it. Just thought this result may be of interest to anyone contemplating some basic mods.

Re: Results of milling iron heads.
 

Damn good stuff right there. Always good to here actual seat of the pants results.
Increased flow as we know helps up top, and cutting heads drops the breathing ability, again we know that. But cutting heads also ups the compression ratio, which helps down the bottom, and this is where you feel it in real world driving on the road.
Like what you did with the flap wheel, it removes a sort of sharp edge left over from the cutting.
Are the heads also C59A? Are these already slightly higher compression ratio than the US 59A heads? I don't have my head chart with me. Did you CC the heads pre and post cut? Be good to know the numbers ( for me )
last thing the Weiand heads, I think these were actually quite low compression when compared to Offy 400's and down, and Edelbrock heads. I've heard reports in the past from folk who put them on stock size engines and we're disappointed with the result, replaced them with offy 400's and loved them. To clarify I'm talking stock size street driven flatheads with stock or mild cam, two carbs and No porting. Not high winding large cube silly cam race engines.
"raped ape" I like that a lot, sounds fast.
Martin.

Re: Results of milling iron heads.
 

The heads are C7RA-A which seem to be what comes on the Canadian 59As. I did not cc them first unfortunately. The edge of the chamber after cutting was about 5/16" in from the gasket line, and when I tried them like that, the edge kissed the piston, so I shaped the dome back out to the gasket line.

Re: Results of milling iron heads.
 

A while back there was a lot of talk about "great results"grooving heads of other than Ford Flatheads. Has anybody had experience grooving Ford heads?

Re: Results of milling iron heads.
 

I am also a big believer in the C7RA heads. The combustion chamber seems to be much better shaped than the aftermarket hi-compression stuff available.
Just my opinion

Re: Results of milling iron heads.
 

Charlie Yapp had an article in Secrets of Speed about a year and a half ago about a guy in India who was grooving head combustion chambers with supposedly positive results. These were later model overhead valve heads but as I remember some of the feedback was that a lot of guys were itchy to try it on their early Fords, both bangers and V8's. Maybe a call to Charlie would be worthwhile to see where that whole thing went.

Re: Results of milling iron heads.
 

Good to hear. I suppose it would be the same for my little 37 21 stud? chamber size similar?

Re: Results of milling iron heads.
 

>050" is quite a bit, I just took .040" off a set of EAB heads and had to do the sane thing with the edge. I really don't think it raises the CR all that muck, mabe 1/2 point at most. What it does is create a very high turbulent AF mixture slamed right into the spark plug at just the right time. This will also improve fuel economy in cruise. Now get you AF right, and timing right and you'll understand what John, Richard and I have been talking about for the past few years. It's called Tuning.

Re: Results of milling iron heads.
 

Yep! Cutting heads a decent amount (.040-.050 or as much as you dare) will give you higher compression ratio and a tighter combustion chamber, all good.
Just make sure nothing touches.
Martin.

Re: Results of milling iron heads.
 

I do know that if you mill .100 off '49-'53 Merc heads and run them on an 8BA with a '52-'53 Ford cam you will have to use two gaskets on each spark plug to keep it running :). But, that engine would also run 60 mph easy in a '47 COE with a 16' bed and a two speed axle. I don't really know if milling the heads made much difference other than causing the valves to mash the spark plugs closed, but the engine did run good. I modified the late model cam so I could use a '42 crab distributor. The engine was bored .040 but otherwise stock. I always felt the cam probably helped as much as anything.
Mark

Re: Results of milling iron heads.
 

The 52-53 EAB cam is a good cam.

Re: Results of milling iron heads.
 

Thanks Scooder. Is it wise to work off the chamber size? Meaning can it be taken that if it CC's at what a stock head should be it would then be safe to mill OR can there be other variables?

Re: Results of milling iron heads.
 

I arrived at the 50thou by using the tinfoil ball system. The tinfoil spec'd out at 95thou. Ol Ron and JWL recommended a 45thou quench space, so there's the 50thou. There was heaps of space above the valve heads, so that did not enter into the equation.

Re: Results of milling iron heads.
 

I don't fully understand your question. But I feel you may be over thinking this. Stock engine with stock heads, a 0.050" cut won't get you in to trouble. Just make sure of your clearances. I feel an more than 0.055"-0.060" the head sealing face may be gettin to thin, if you look at them the castings arnt very thick.
I would be cool if you did cc them before and after, and let us know the figures and type of head. I do like good reference numbers.
Martin.

Re: Results of milling iron heads.
 

It was over fifty years ago the last time that the 59 AB engine in my '36 was rebuilt. We discarded the Offy heads that had been on the engine since '54 because they were badly eroded. The machinist that did the work was very heavy into building engines for the stock car racer's, therefore he wanted longevity..
I don't recall how much the 59AB heads were shaved, I do recall that the heads were modified, being "domed and flycut".. I do know that the object was to get the compression ratio up to about 9. to 1.. The engine is over-bored .060, four ring pistons, Weber F-1 cam. The carbs are two 97's on a Offy Super manifold..
The engine runs very nicely on 89 octane fuel..

Re: Results of milling iron heads.
 

Still going strong after fifty years, I'd say he got the longevity right. Sounds like a nice little engine.
Martin.

Re: Results of milling iron heads.
 

don't think you can get any where near 9:1 CR with stock 59 a heads with that small an engine. The transfer area is much too big. The best heads for that engine would be the 81A heads, but 8;1 would still be difficult. However, a tight piston to heaad clearance can do wonders.

Re: Results of milling iron heads.
 

Glad I saw this thread!..I was just thinking about doing this to the 21 stud motor in my car rather than buying a set of repop Eddie Myer heads..After discussing it with my machinist we decided to start with a 35 thou cut but I'll try the tin foil measurement first to see what clearance I have..CCing the chamber too!

Re: Results of milling iron heads.
 

Is yours using flat top pistons or dome? Got an early 50's hotrod yearbook here with an article on cutting heads in this it states, for dome top 0.050" cut. With no need to dome or flycut for valve clearance, but on flat top type you can cut 0.080-0.090" and get 8:1. I can double check if you want.
Martin.

Re: Results of milling iron heads.
 

34s4ever, Those repop Eddie Meyers perform far better than any stock Ford head; cast iron or aluminum. They have a different shaped combustion chamber and relocated spark plugs.