Has anyone else tried shoehorning one of these 36X ABC sets into any of the earlier Fox combat engines? In theory anyway they should practically drop-in, but I haven't really tested the theory as I don't usually have more than one engine disassembled at a time.
I have a Series III with soft compression, so my spare 36X ABC set came out of the drawer and I did a bit of poking around to see if it'd work in the Series III. The Series III has the picture window intake port in the liner, but otherwise the timing looks the same as the 36X ABC set, and the liner drops in the Series III case easily. The piston is a bit of a different story, the 36X ABC pistons have the top of the piston curving into the baffle vs the stock Series III and for that matter the stock 36X with it's straight inverted T baffle, more on this later. Also the wrist pin is beefed up a bit on the 36X ABC, it's larger than stock and larger than the Series III. Where I hit a stumbling block is that the bottom end of the 36X ABC rod is a bit tight on this Series III's crankshaft pin. I'm inclined to blame the snug fit on tolerance stacking, and Fox more than the ABC set. Fox rods are so sloppy that the stock rods both fit the Series III crank pin and neither is remotely tight. I think the ABC set's rod could be lapped to fit the Series III crack pin easily enough, but not sure I want to do that just yet. Just from a quick comparison, the Series III rod is a symmetrical design, with only the backplate wear pattern and the chamfer to differentiate front from back, while the 36X rod is offset a bit. Also I want to say the Series III has a longer crank pin, and the bottom bearing of the rod is a bit longer to match. Also the 36X rod looks just a hair longer, which shouldn't be a problem since the 36X liner is taller to raise the head. The reason I haven't gone ahead and lapped the ABC's rod to fit the Series III is that I'm not sure the top of the ABC piston will pair up with the Series III head. I don't want to modify the rod to fit the engine and then run into an issue with the head. I would imagine that a 36X head would probably bolt right on the Series III case, but I don't have an extra 36X head... The swap would work with stock Fox parts by just using the Series III rod with the 36X piston and pin, but due to the larger wrist pin in the ABC that's a no-go. So I weenie'd out and put the mostly worn out piston/liner back in the Series III and tucked it back in the engine locker.
I'll probably end up putting the spare 36X ABC setup in one of my better 36X engines, then use the stock take off 36X piston/cylinder in the Series III. I'm curious if anyone else has tried the 36X ABC set in anything other than a 36X. I would expect it'd drop right in a 35X or Blue Ribbon 35 since they're both closely related, but I haven't tried it. Spares for all the early Fox combat engines are virtually impossible to come by, so it'd be nice if these reproduction parts would retrofit. It's probably not worth the trouble to make ABC sets specific to the earlier engines since they have other inherent issues that the piston/liner/rod wouldn't address.