I'm in the process of building up a couple of early Chevy spray-oilers, a 216 and a 235, with a pressurized crankshaft and connecting rods for a later model 235. It's necessary to tinker with the thrust surfaces on the #3 main bearing since the spray-oiler crankshaft has a wider thrust. Either widen the flanges on the crankshaft or narrow the main bearing web in the block- - - -either way works. The 216 can be bored 60 over to accept standard bore 325 pistons, making the "216" a 235, or it can be run with the original cast iron pistons to become a "224" with 292 Chevy connecting rods. None of the above is a bolt-in swap, but no exotic high dollar parts are needed.
There's even a way to increase the stroke on the 216 and make it a 258 cubic inch engine that looks "bone stock" from the outside. That involves using H-beam connecting rods for a Nisssan 4 cylinder, and aluminum pistons for a Buick/Olds 215 V8. Similar mods to a 235 turn it into a 270, and a 261 with the stroker crank approaches 300 cubic inches. "All of the above" can be done without altering the stock appearance of those engines. Jerry
Here's another view of the roller rocker arm cylinder head I'm working on. It will have oversize intake valves and oversize stainless steel exhausts for a small block V8. That engine will also have H beam connecting rods, aluminum pistons, a roller cam, and main bearings for a Chevy small block 400 V8- - - -1948-53 216 main bearings are almost impossible to find, and cost over $200.00 a set when they're available. SBC 400 mains are usually less than $50.00. That conversion requires some pretty serious whittling on the block and the crankshaft- - - -it's not a drop-in fit!
Like Hank Williams Jr. says, "It's a family tradition!" In the very early 1950's my father was doing similar stuff to flathead Ford V8s- - - -moving the cylinder centerlines apart on the two in the middle of the block to avoid a thin spot in the casting around the exhaust passageways and boring the block 1/4" oversize, and stroking a 49-53 Mercury crankshaft to 4 1/8" to get almost 300 cubic inches from a 239 engine. Connecting rods for an 85 HP flathead. Then he raised the compression ratio to 11.5:1 and ran methanol and Hydrogen Peroxide for fuel on a lot of southeast dirt tracks. He was outrunning most of the grandfathers of current NASCAR drivers with engines he built in a little shop in Nashville Tennessee.
The rods I'm using in my stroker engines fit a Nissan 2.4L 4 cylinder. They are available in an H beam type, rated for 1K horsepower or more, depending on the rod bolts used. That's far above any power a stovebolt could ever make, no matter how it's modified. Smaller rod journals, lightweight aluminum pistons, and a few other sneaky tricks should let the guys who want to outrun their friends with a stock appearing rig with a 258 cubic inch "216" wear a big grin, though!
Back then it was truly amazing what was going on in little machine shops all over this country. Almost every gas station had a shop and most of them had at least a lathe. Many parts houses had full machine shops. There were thousands of WWII vets that had grown up on farms where things were fixed and had become machinist during the war. Many women had done intricate work during the war and had vast skills. Much rubbed off on their children. My dad was a machinist at Douglas. He built a bench lathe from a brake lathe & a piece of railroad rail for his shop at a grain elevator near Happy Texas. It was good enough for most repairs until he made parts runs to Amarillo where he had access to better machines. That man could literally fix anything. There were many like him who looked for a challenge. Sounds like your folks were some of them. I'm very interested in your work here and your mind set. I wish I had payed more attention and had more time with my dad. He died when I was 21 just as my experience was showing me that most other men did not know what he did. Sorry for the rant.
One of my other "one of these days" projects is a dual overhead cam cylinder head for a MOPAR 4 cylinder (PT Cruiser)- - - - -adapted to a Ford Model A block. It will have a belt cam drive and an electronic ignition distributor driven off the end of one of the camshafts. That one should be an attention-getter at a car show sitting on a run stand with my Go-Power water brake dyno attached to it.
As parts sources dry up, and the skill set involved in fitting Babbit bearings on the old inlines also becomes a lost art, we're either faced with scrapping the old stuff, or finding a work-around. The old stovebolts were way over-engineered for the amount of power they produced, so it's possible to dramatically increase the performance and reliability without going to some modern "belly button " (everybody's got one) small block V8.
For those engine builders who are interested in less radical modifications to the spray-oiler sixes, it's possible to machine Babbit connecting rods for an insert bearing for a Perkins Diesel engine, and regrind the crankshaft to fit the new bearings. That takes the Babbit rods out of the equation. Jerry
I just happen to have a couple of Atlas 4.2 engines on hand, and one spare head. Sometime soon I'll dig out a stovebolt head gasket and compare cylinder spacing, width, and coolant passages to see how closely they would compare. I have an idea a solid plate bolted to the top of the block could be drilled and tapped for studs, and coolant flow could be routed from the back of the block up to the head, then forward again. It also looks like the cam drive could be converted to a dry belt instead of a chain.
A quick and dirty tape measure comparison between a stovebolt head and the Atlas looks like it's doable. I'll need to make an adapter plate to bolt to the top of the stovebolt block with flat head Allen bolts, and drill and tap the plate for studs to secure the Atlas head. Longer connecting rods and a stroker crankshaft will put the piston tops and some pressed-in sleeves a little above the top of the stovebolt block, so the compression won't suffer much. There will also be almost 10 cubic inches more per cylinder (300 VS 250) and a MUCH smaller combustion chamber, so the compression should be more than adequate. I'll also be converting the cam drive to a dry belt and eliminating the chain cam drive and the variable exhaust cam timing.
12 port crossflow head- - - -24 valves, and dual overhead cams- - - -what's not to like?
