Catching up after a three weeks' computer outage, I came across the Oct. 13-14 exchange on distinguishing between B20E and B20F engines. Shayne's identification clincher, the rectangular casting trailing forward from the center right head bolt hole, revealed to me that the E head I acquired to use with carbs on a B20 block is actually an F. I had planned to use the supposed E with the thicker F gasket to get something like a 9.5:1 CR. I know I can have the F head shaved to E specs and get the same results in the same manner, but does anyone have any idea what sort of CR I'd end up with if I used the F head, unshaved, with the thinner E gasket?
Bob

Like Hans mentioned, most shops Always surface grind the head during a removal. So first, measure any heads that you are working with... my Factory Volvo Manual (1974) says that a standard B20F head is 87.0 mm or 3.420" and the B20E head is 84.9mm or 3.340". It says the height is measured from the gasket surface to the cyl. hd. bolt, machined surface. It also says that the Head Gasket is the same for these two engines at, 1.2mm .047" (unloaded) and 1.0mm or .039" (loaded).
Says the B20A is the same 87mm dimension and 1.2mm Hd. Gasket. The B20B head is 86.2mm's(3.390") and uses a .8mm unloaded /.7mm loaded. HTH, Tom

Tom, George & Hans,
You guys are all brilliant. With the information you gave me and the ABE Volume Calculators even this English-major can get to the bottom of his head problem. BTW, the height of this head is 87 mm, which confirms that it is indeed an F and that it has, apparently, never been worked on.
Thanks all,
Bob

Sil, we have all been helped here before, thanks should go to the brickboard moderators.... Tom

Remember your new F head is at least 27 years old, lots of workshops plane the head every time it is off, if its been planed 3 times it will put your calculations way off.
Hans

You can certainly calculate the volume difference between the two thicknesses.
My guess is that it will be maybe one point higher at most (not having done
the calculation).
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma

George,
You flatter me by assuming that I know how to do the calculations. My other handicap was that I could nowhere find a reference to the actual thickness of the two gaskets, but I have now found your dandy table of April 16th on the 120-130 Forum, and, if I read it correctly there is a difference of 0.3mm. ¿De acuerdo? As soon as I find a calculator with a Pi function I'll have at it, but if you are right in your estimate that the E gasket could raise the CR of a B20 with an F head from 8.7/1 to about 9.7/1, it would do the trick for me.
Thanks,
Bob

I did some calculations and found that the difference in volume of the
2 gaskets is about 1.9cc. Calculating backward using 496.8cc per cylinder
(gotten from bore x bore x pi/4 x stroke) gets the following volumes for
standard CRS:
8.7:1 57.1cc
9.3:1 53.4cc
10.5:1 47.3cc

57.1 - 1.9 = 55.2cc
498.6/55.2 = 9.0:1

So you gain a little but not much! (Note that 55.2 is just about halfway
between 57.1 and 53.4)
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma