The Stovebolt Site Forums The Shop Area Engine Shop Piston rods for early 235 hi torque engines

I am going to build an early hi-torque 235 for a project I'm working on and had a few questions. Will 216 rods work in a 235 hi-torque engine? I have a set converted to insert bearings. Also, I'm assuming these 235's have dippers and splash oiling. Is it worth it to convert to full pressure oiling? I'll be using aluminum pistons, a NICSON triple, 3/4 to full race cam, etc. I've heard the full pressure isn't completely necessary. I'm not going to be racing the car. Just looking for some advice. Does anyone know approx. how much it would cost to have the crank drilled for a full pressure system? I talked to a well respected machine shop in my town and he said he'd be reluctant to do it. These guys work on everything from race engines, modified A and T engines, early Packards, Jags...everything. Anyone had a crank drilled from one of these engines and who would you recommend? Thanks for any help.

As long as the bearing surface is in good shape and the clearance is right, I don't think the full-pressure oiling is that much of an advantage. Just be sure the tubes that fill the troughs under the rods are aimed properly so they squirt oil directly into the dippers at higher speed. I'm building an original babbit-rod 235 for a 1950 Bel Air/Powerglide restoration, and I'm considering possibly adapting a small block V-8 oil pump to the engine. It would require a bit of imaginative fabrication, but I think it's doable. I'm getting clearances in the 1 1/2 thousandths range by manipulating rod shims after custom-fitting the rod bearings with Prussian Blue and a scraper. The 216 rods I've seen have a slightly different oil groove in the Babbit material of the bearing, but as long as the journal diameter, length, and wrist pin diameter are right, I don't see a reason the 216 and 235 rods shouldn't be interchanged. A good bearing fit, enough oil pressure, and precise clearance is what keeps a lower end together. Full-pressure oiling is a plus, but it's not essential to long engine life.
Jerry

it'd be simpler and most likely more economical to get a later 235 that's already full pressure

you'd have to know the year of the engine, and better yet, the forging number/s of the rods to do a hollander cross reference/ interchangeability check

If you're not going to turn the engine any faster, there's no point in that speed equipment.
At 3,000 RPM it doesn't matter.
Splash stops being reliable when crank speed is high enough that oil isn't supplied reliably to the dippers. Once the supply stops, the rods stop.

That is why Chevy put the sprayers on. They allow the RPM to go beyond the pure splah top RPMs.

and according to one of the old 'hop up' books, with the jet sprayer system, rpm can be pushed to 4-5k, but it gets "hazy" at that point

The reason I'm not using a later 235 with the full pressure oiling system is because I have a full set of speed equip. and from NICSON. So I have a tall alum. pushrod cover I want to use. Not only that I'm building a '27 roadster and I'm trying to keep it period correct in every way around the mid to late 1940's. Thanks for the responses.

Will the later 235 full pressure cranks fit the earlier 235 hi torque motors? Possibly with a little machine work? Like I said I'm not taking the car to bonneville or anything but I might push it a little every now and then for fun. I'm also looking for a Sharp intake and side cover. Thanks everyone.

you need to list some specifics, like the casting number of the crank. hollanders lists a variety, and sometimes they say that you can swap, but the rods have to part of the swap

and if i'm correctly remembering, it isn't just a matter of swaping a later crank, bec there also may be block work to be done. these guys do the whole thing; http://www.inliners.org/becks/index.html

but if you're not doing bonnevile or 4-5k rpm, do you want to go to the extent of your thoughts?

If you are concerned about looks, the only really big difference is the side cover. The older style valve cover would fit a later motor just fine. The oil distributor plate could be glued on, I think, for appearance.

Above 4,000 the inside of the pan looks like a tsunami - the oil is definitely not in the sump and available to the squirters except occasionally, and even this is upset by road conditions and heavy braking.

The sprayers work from the pressure of the oil pump. What you are saying is that above 4000 RPM, there is no oil available to the pump. Would this be because these early engines do not have a tray?

The pickup is probably uncovered pretty easily - they didn't understand windage, and the spray to the rod itself is as accurate as [censored] in a hurricane. The oil forms a rope that wraps around the crankshaft like taffy.
The oil supply to the rod (by pressure, scoop and dip, spray) is only refreshing the actual local pressure produced by crankshaft rotation, and is many times higher than nominal (gauge) pressure.
It's a function of RPM, bearing circumference (~ as journal diameter) and viscosity. If it "pumps dry" (refresh rate is slower than the leaks) the rod goes BANG.

Yes, a pressure system can uncover the pickup at speed as well - but there are fewer variables, and the remedies are well known (deep pan, baffles, windage tray).

Don't tell the oldtime round track racers that a splash engine can't live at high RPM! I grew up watching high-revving Chevy and GMC 6-cylinders try (and fail) to catch Dad's flathead Fords around a lot of 1/4 mile dirt tracks in middle Tennessee, and road conditions and braking don't get much worse than a dirt track! The military-surplus GMC 270 was the favorite of the 6-cylinder guys, and it is a full-pressure engine, but there were a lot of babbit-rod Chevvies out there, too.

Alcohol, Nitromethane, and Hydrogen Peroxide in the right proportions puts a lot more stress on rod bearings than gasoline ever has, and some of those engines were surviving at 11:1 compression or more!
Jerry

oil not in the sump?
so, the galleries/system etc would have a gallon of oil in it?

How is this done: exactly as I said - enough pan depth and control devices to keep the pickup covered.
That's all it takes.
Sometimes this was "discovered" by accident:
They kept losing motors until they added enough oil that the crank itself was splashing through it - yes, it increases oil temperature and reduces power but the rods always got enough.

oil not in the sump?
so, the galleries/system etc would have a gallon of oil in it?

Ever open the top of a blender when it's making a milkshake?
Did the milk stay in the bottom, where you put it? Or did it try to get as far away from the blades as possible, including out the top and on your face?
That's what the oil does.

One of the first lessons a serious high performance builder learns is to buy, or build a windage tray. Shaping one around the dipper troughs on a splash engine would be an interesting process, but by no means impossible. When I'm custom fabricating a tray for an engine that doesn't have one available from a speed equipment supplier, I usually use lightweight expanded metal or heavy hardware cloth with appropriate bracing to help it retain its shape. The horsepower gains are measureable on the dyno when the oil is prevented from wrapping itself around the crank. If we're building a circle track engine (the only REAL racing), we also build swinging-door baffles around the pump pickup to prevent oil from flowing away from the pickup screen in a left turn.
Jerry

the blender analogy doesn't equate bec it's functioning as a propeler, dual in a blender, should, by moving a medium for inline propulsion. and now it makes me wonder if there's a look-see oil pan demo

I think a see-through oil pan would be interesting, but once it got covered with splash from inside the engine, I doubt if many details would be visible. I was involved with a road-racing Datsun 240Z inline six in the early 1970's. Every time the driver would brake hard for a turn, then accelerate away, the exhaust would generate clouds of blue smoke. After a very few laps, the #1 and #2 spark plugs would oil-foul and the engine would show at least a quart low in the sump. The oil pan was very close to the crankshaft under cylinders 1 and 2 for crossmember clearance, and we theorized that the crank was picking up oil and stuffing those cylinders full. This was happening at 6,000+ RPM. We designed and built a windage tray to try to keep the crankshaft from sucking up oil in that area, and installed some anti-splash baffles, and the problem went away. I doubt if a stovebolt engine at considerably lower crankshaft speeds would need a tray, but it couldn't hurt.
Jerry

h rod - yeah, with a see through, you'd always need new/very clean oil and an internal light source

and exactly. under those conditions, it'd be a necessity. street - i doubt a problem

Right - it's only emptying the pan on one side, and throwing it up against the wall on the other side.