Old Henry knew what he was doing - or did he? The V8 is designed desaxe (offset) - the cylinders' centrelines are offset from the crankshaft centreline in the direction of rotation. Advantages of that are reduced piston side thrust, less piston "slap" from cold (quieter), and greater than 180 degrees duration of the intake and power strokes for potential power increase over standard layout (with the penalty of variation in inertia forces). But the offset means that the valve inclination in one bank is different from that in the other bank (7 degrees from cylinder centreline in the left bank, but less than 4.5 degrees in the right bank). And the result of that is that the valve reliefs in the block face are of different volumes. If the cylinder heads combustion chambers are identical, left and right, then the compression ratio is slightly different between the banks (lower in the left bank). With the early pump-in-head engines the heads are handed, left and right, so that the anomaly could be compensated for in the head design. Was it? Later engines had centre dump water outlets and the heads are interchangeable, and identical, so the anomaly is there. Then the 8BA had handed heads again, but was the differnce in compression ratio compensated for in the combustion chamber? Just searching for knowledge. This is the 1932 engine - the angles are the same in the 1939 and later engines.
I read about this years ago in a magazine, don't remember which or when. But the reasons given are the ones you have in your post, reduced piston thrust, etc, and, I am really foggy on this, more inertia from the offset??
I am not trying to start a ******* match, but a lot of Henry's innovations centered around saving Henry's money. It could very well be that it was cheaper to build an offset engine to avoid piston slap than it was to build pistons that didn't "slap"! Another possibility, maybe he was trying to get around someones patents. He really disliked paying license fees!
Isn't one of the high end operation when machining race motors to index the cylinder bore to the CL of the crank? Wonder if its been done to a flathead and what the result was.
Im sure the heads are the same giving slightly less compression on the left bank... You would never really notice that little of a cc difference. also ive seen a flatty run with only one head on, along with personally working on one that was running with 5 stuck valves. its not a very picky engine.
I found a 2009 post from Blown49 - here's an extract: "To keep the combustion chambers (I think he meant compression ratio?), in the pre-1945 heads somewhat similar, the left head and right head combustion chambers were cast different although from the top side of the head they may look the same. The original right heads carried a basic part number **- 6049 and the left head **-6050. Heads were produced in Iron and Aluminum from 1933 thru 1939 for different applications. If these original heads are placed on a later 41A or 59A replacement block, interference between the valves and the combustion chambers may result. These heads would include heads numbered 81A or B, 81T, 99T, 29A." The complete thread is here: www.jalopyjournal.com/forum/showthread.php?t=365715
Auto engineers often did what seems like weird stuff. Some of it can just a result of particular ideology of the manufacturer. Like Ford mastering cast iron so it could be used in place of forgings. Partly cost and partly engineering preference?
I always wondered about the cam timing. The valve inclination was changed and that would change the timing. They should have made cams for early and latr engines to compensate. I had a 1940 engine and the valves were closer to the bores than a 59 series engine. I guess the change was to reduce cracking but it would also reduce compression.
This was a common trick used by all engines. Have seen an adverti*****t from 1913 that listed it as one of the features of the engine design (I forget what make it was). I expect it predated 1913 and may have come from steam engines. Newer engines get the same effect by offsetting the wrist pin in the piston. On those engines, you can get a few more horsepower by putting the pistons in backwards, at the expense of some piston slap.
When the piston is coming up, the rod is pushing it from one side. When the piston goes over center and starts back down, the rod is leaning the other way. As the piston p***es TDC it goes from pressing against one side of the cylinder, and flips to the other side. Since there must be some clearance, the piston will slap when it does this. By offsetting the cylinder (or the piston) this slapping action takes place in a slower gentler way, minimizing noise. Look at the diagram of the engine above and visualize the piston rocking from one side to the other at TDC and you will see it. To put it another way, the piston will stop at TDC and start back down before it shifts from side to side.
This problem of the two sides of the engine being unequal, does not come up with an inline 4, 6, or straight eight. Only in a V type engine. One more reason car makers stuck with the inline type engine so long. Other makers figured out to offset the wrist pin and not the cylinders, in their V8 designs of the fifties.
I don't beleive it was for piston slap..Can't beleive there could be that much with that long of a rod and a whole .168 offset; newer engines with way shorter rods are only around .060 offset in the piston pin...The green bible says 8ba is .0015 feeler with like an 8-12 lbs pull [I had to walk three feet before typing this] , now I don't know what the early engines have for a clearence spec but I would think its pretty close? I think the v8-60 had even more offset, around .250? Oh and the manual said if a .060 overbore didn't clean up the block would have to be replaced, [?] or maybe they were talking on the six...lol...my nickle's worth.........
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