In a vintage Mopar big block V8, without a windage tray, how much oil can be caught in the crankshaft vortex at high RPM
Executive summary
Vintage Mopar big‑block owners who run their engines at high RPM without a windage tray risk a non‑trivial amount of oil being picked up by the crank and thrown into a vortex, producing both parasitic power loss and a higher chance of oil aeration or momentary pickup starvation; stock passenger‑car pans were around 5 quarts, while high‑RPM builds commonly use 7–10 quart pans and other baffling to control oiling [1]. There is no authoritative published measurement in the available reporting that quantifies a universal "vortex volume" for an RB/B‑series Mopar crank at a given RPM; any numeric figure is an application‑specific estimate dependent on pan capacity, crank geometry, stroke, sump baffling and pump/pickup arrangement [1] [2].
1. What the question really asks — fluid dynamics vs. shop practice
The user is effectively asking for a physical quantity (how much oil ends up trapped in the rotating crank vortex at high RPM) but the available reporting and community experience frame the problem as an oil management and starvation/hp‑loss issue rather than as a single measurable reservoir—forums and magazine articles therefore address remedies and symptoms (pan size, windage trays, external pickups) rather than measuring vortex volume directly [1] [3] [2].
2. What the sources say about sump capacity and high‑RPM practice
Typical stock big‑block Mopar pans were small—around 5 quarts for passenger cars—whereas builders regularly move to deep 7–10 quart pans and high‑volume pumps when they plan to spin the engines to 6,500–7,500 rpm or more; several forum posters and project articles recommend 7–10 quarts and deep sump pans for 7,000+ rpm use [1] [4]. Hot Rod and Mopar project builds explicitly pair pans and windage trays on race or high‑performance street engines to control oiling and reduce windage losses [3] [2].
3. How windage trays change the picture
Windage trays and valley/valve‑cover drainback modifications are repeatedly described as methods to “keep as much oil off the crankshaft as possible” and to reduce windage and oil shedding from the crank [2] [3]. The lived experience shared in speed‑talk and windage discussions shows measurable performance and oil‑control differences when trays are added or removed—sometimes changing dyno ET/HP numbers and indicating that oil on the crank is both a parasitic loss and a variable quantity [5].
4. Why a single vortex‑volume number is unavailable
None of the provided sources measures or models an absolute oil volume trapped by the crankshaft vortex at a given rpm; instead they document related variables—pan quart capacities, rpm limits people routinely run, and effects of trays or pan geometry on windage and racing results—showing that the trapped/oil‑shedding behavior is highly configuration dependent [1] [4] [5] [2]. Therefore any quoted number would be an engineer’s estimate for a particular crank/pan/clearance set, not a universal Mopar constant.
5. Practical ballpark and engineering intuition (clearly labeled estimate)
Based on the reporting that stock pans are ~5 qt and high‑RPM builds use 7–10 qt pans to avoid “sucking the pan dry” and to reduce crank oil pickup [1], and on qualitative accounts of significant oil shedding without trays [2] [5], a reasonable practical ballpark for oil that can be mobilized and cling to the crank/splash into the vortex at sustained high RPM in an unbaffled 5‑quart pan is on the order of a few ounces up to perhaps a pint (0.03–0.5 quart) at any instant — rising toward a quart‑scale transient of aerated oil in extreme, poorly baffled cases. This is an informed estimate, not a measured fact, because the sources do not provide direct measurements; outcomes reported by builders (lost HP, need for deeper pan, use of windage trays) corroborate that the amount is sufficient to matter to both lubrication reliability and power [1] [5] [2].
6. Bottom line and recommended mitigations
Given the absence of exact vortex‑volume data in the records, the practical conclusion from magazines and forum veterans is decisive: if running a vintage Mopar big block to high RPM, install proper baffling—deep baffled pan (7–10 qt), windage tray or valley drainbacks, secure pickup placement or remote pickup, and consider Accusump/high‑volume pumps—because these measures are repeatedly credited with eliminating oil starvation and windage losses that otherwise manifest in high‑RPM use [1] [3] [5]. The sources make clear the problem is real and manageable even if an exact universal ounce‑count for the vortex cannot be cited from the reporting [1] [2].