Some random thoughts for racers using Ford E-series 4 cylinder engines.


Staff member
You might want to have a "rethink" of how you are designing your engine(s) (or not . . . . . )

The venerable E-series Ford (and its' derivatives) has probably powered more Euro race cars than any other engine family since the late 1950's. The tried and true method to increase performance, as established in the early days of Cosworth Engineering, has been to mill the stock head, as much as possible, to increase the compression ratio. This is done in conjunction with a "flat top" piston and a "thin spec" Coopers head gasket. While this is a relatively reliable method for "modest" static compression ratios, say 11/1 or perhaps 11.5/1, milling further for "high" static compression ratios, can be the cause of head gasket reliability problems.

The problem is that so much material is removed from the deck face of the cylinder head, that structural strength can be "compromised" in certain areas of the cylinder head.

I submit this "evidence" (er . . . . data) for your perusal:

This is a photo of a 116E cylinder head being surfaced after a head gasket failure. This head had been previously surfaced .220", for compression increase.

.003" has been milled off on the first pass. Notice the casting is "distorted" immediately adjacent to one of the water passages, just where the head clamps the fire ring of the head gasket . . . . . . .

If your cylinder head is so "thin" that it is "structurally compromised", well it doesn't matter how much "clamp load" you impose with your fasteners.

Food for thought . . . . . . feed your brain . . . . .

BTW, this issue is relevant for all "heavily" milled E-series cylinder head castings. There are "remedies" and there are "alternate methods" for buildup and repair. Adding material might not be legal for your sanctioning organization. Check your rules ahead of time.

And now back to watching my DVR of Canadian Gran Prix practice and qualifying.

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Crazy about Datsuns
Thanks for sharing! Its always just that little extra that causes problems. lol The head was fine at .210 Ha
I am able to mill .250 off a Datsun head and accomplish the same thing. But am lucky enough to have a good quality aluminium that can handle that.