I thought I'd drop my spare 250 crank into my 230 block to see what clearances I have for possibly rigging up piston oil squirters (to cool the pistons when I put boost to it) when I ran into an unexpected hiccup... The counter weights tag the oil baffle mounting tabs, d'oh! In the 250 block the two mounting tabs have been replaced with a single one in the center to clear the counter weights. So I ground the rivet head off, punched out the remainder and removed the baffle and ground down the tabs to clear. I'll make new baffles and make new mounting points, likely to the side of the block.
That's not supposed to hit...
Or there....
When I turbo the engine, because of the cast iron head and the relatively poor chamber design (by modern standards) I want to try and use every trick in the book to keep detonation at bay. I've already started with reverse flow cooling so the head get's the cool radiator water first, and I've separated the exhaust manifold from the intake to keep heat transfer down, and I'll be using an intercooler and possibly a water/meth injection system, but one other trick is to spray the underside of the piston with oil to help cool the piston and prevent it from being a hot spot in the chamber. It's common in many modern high compression and boosted engines. My thought was to tee off the external lash adjuster galley line and run it to an internal oil rail that would have squirters at the bottom of the cylinder bore. Now that I've re-mocked up the crank in the block, I'm not so sure I can fit a system in there.... =/
Those Pontiac engineers packed every thing in there pretty tightly! I don't think I could get even an 1/8th inch line between the block and counter weights and I think I'd need at least a 3/16th line to have a meaningful impact. That bulge next to the drain back hole (running parallel to the block) is the oil feed line for the mains.
Going to the other side may be possible by drilling a hole to the exterior of the block right at the base of the bore and running a line from the outside to each cylinder. I need to mock up with a connecting rod in place to really see how much room would be available. I'd also have to contend with the exhaust heat as the line would be between the block and exhaust manifold/header and running an oil line to the other side of the engine where even with the turbo I'm going to try and keep all the oil lines on the passenger side. I'm becoming less inclined to try it, at least at this stage.
The other thing I noticed was how poor the oil drain back set up is. The size of the drain back holes are more than adequate, but their location is right above a counter weight that is in it's upwards throw, so it would seem to me that a fair amount of excess oil is getting flung around as crank windage. Not sure what I want to do about that yet. Again it's a room issue, but if I can find a way to extend the drain backs past the crank, I think that would be best. An extreme measure would be to tap and plug the drain backs at the bottom then tap the drain backs from the outside of the block and run a line to the oil pan or even the block's oil filler cavity. This would maximize oil control below. Alternatively would be to build a baffle that carries the oil up against the side of the block, shielding it from the crank windage.
This picture again. Like grind out the hole to flow towards the block wall, then put a baffle between the hole and crank. Even if it covers most the hole, if it's been opened towards the block side it should still flow back reasonably well. Securing the baffle in place I think would be the real challenge.
The 4 vertical ribs going down the side of the block are the oil drains. I would only need to tap into cylinder 3 and 6 and make them drain back to the oil filler cavity, one already drains to the oil fill cavity and I think #5 could be drilled to connect internally to the oil fill cavity. Only really needing to mess with two make this option sound more appealing.
