There are a lot of choices when selecting an oil pan for your LT-engine swap, make sure you get the right one!
Regardless of the vehicle, the oil pan is often the most difficult obstacle to overcome in an engine swap. Unlike the LS platform, which has no less than 10 oil pan variations from the factory and countless aftermarket options, the Gen V LT-series engine only has four factory options, none of which are well-suited for swaps, and the aftermarket is just now offering proper solutions. As with anything, a little research and fabrication helps move things along.
From the start, you need to know that modifying an LT oil pan is a nonstarter. Unlike LS pans, the LT’s oil pickup tube is built into the pan itself; it is cast into it. This makes chopping out sections of the pan to clear obstacles not possible like it is on the LS pans. Fortunately, the aftermarket has solutions. Sorting out what works and what doesn’t depends on many variables, including the chassis setup, engine and transmission mounts, intended use for the vehicle, and the engine itself.
FACTORY OIL PANS
There are four factory pans: truck, LT1 wet-sump car, CTS-V/LT4 wet sump, and LT1/LT4 dry sump. Eventually there will be others, but these are the current GM factory options. They are all cast aluminum with integral pickup tubes and oval oil ports to the block. This means that you can’t simply cut and weld the oil pan. The factory oil pans all have a fairly large sump, which is far forward on the pan itself. This means that in most full-frame car applications, the factory pan simply will not fit. Most 2WD trucks will accept the factory car wet-sump oil pans without additional modification, but the truck pan does not fit.
Truck Pan
The truck pan is quite large. Not only is the shallow section of the pan very short, there is a sheet metal extension pan that bolts to the bottom of the main sump. It is very deep, which makes it impractical for use in car swaps. The truck pan will fit 1972-and-older trucks without modification, but 1973-and-newer trucks will require special motor mounts and heavy crossmember modifications. Oil capacity is 8 quarts.
What is certainly the most popular LT-swap engine, the L83 5.3L truck engine has a unique oil pan design, which uses a cast pan with a metal bolt-on sump. Additionally, some L83 and L86 truck engines have an air-to-oil cooler system, as shown here by the aluminum block and lines coming from the pan. It can be used or deleted.
LT1 Car Wet Sump
Found on most LTl-powered cars, the standard wet-sump oil pan is shallow, measuring just 4.75 inches from the bottom of the block. The main sump is 15 inches long and measures 4.75 inches at the back to 4.5 inches deep at the front. The shallow section is 7 inches long and tapers from 2.5 inches deep at the rearmost section to 1.5 inches at the front of the pan (front of engine). This pan will fit most trucks, but most cars will require crossmember modifications because the main sump section is too far forward to clear. Oil capacity is 7 quarts.
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2016–2017 CTS-V/LT4 Wet Sump
This pan is very deep, making it unlikely to be suitable for most swaps. The shallow front section is 11 inches long, so it may clear some stock crossmembers, depending on the engine setback. The shallow section is 1.5 inches deep at the front, tapering to 2.5 inches at the shelf for the main sump. The 7-inch-deep sump is 12 inches long. The main issue with this pan is that it is quite deep, leaving it exposed to road debris and potential destruction. If the vehicle is lowered at all, this pan should not be considered. Oil capacity is 10 quarts.
This is the LT1 wet-sump oil pan with the water-to-oil cooler system installed. The oil cooler does not fit most chassis designs.
The high-powered CTS-V/LT4 wet-sump oil pan is quite large. It may work in some trucks, but the pan is very deep, 7 inches at the deepest section of the sump, so it is not a good option for lowered vehicles.
LT1/4 Dry Sump
Certain vehicles and crate engines come with an optional dry-sump system. The pan for this is similar to the wet-sump car pan, but the shallow section is a little bit shorter than the wet-sump pan, making this a difficult swap for most full-frame vehicles without modifications to the crossmember. This pan has two oil drain plugs. Oil capacity is 9.8 quarts.
Modifying the crossmember to clear a factory oil pan is not complicated, and while it does require good quality fabrication, it is a fairly simple process. The key to this is taking plenty of measurements with several reference points that will not change. This allows you to place the engine without the oil pan installed, make measurements for clearance, and extrapolate the necessary notch required for your application.
AFTERMARKET OIL PANS
It took the aftermarket a few years to get going on LT-swap components, but it has finally come around and there are several LT-swap pans available. Currently, there are four oil pans available for the Gen V LT-series engine: the Holley Retro-fit (standard and drag race versions), the Moroso fabricated pan, and two pans from BRP HotRods—the High Clearance and Extended Sump. All of these pans are designed to add clearance for LT-swaps and should work for most applications. The details set them apart—as does the price. All of these pans are designed for wet-sump oiling systems.
Holley Retro-Fit Street and Drag
Holley has been at the forefront of the LS swap game for quite some time, and things are no different when it comes to the LT-series engines. Like its LS pans, the LT Retro-fit Street pan (part number 302–20) is cast aluminum, has a built-in oil filter port that matches the factory placement, and has all the other fittings seen on a factory pan.
The pan reduces the rear sump length by 5 inches, providing plenty of clearance for full-frame vehicles, and is only 1 inch deeper than the factory sump, so there is good ground clearance for lowered vehicles.
This pan fits just about any application where an SBC or LS would clear. The shallow front section is just 1/4 inch deeper at the front than the factory wet-sump car LT pan.
This Holley swap pan fits like a dream and has all the same features as the factory pans, but this one actually fits most chassis designs. The Holley pan is the most affordable of all the currently available options at around $400.
The Drag model (part number 302–22) is the exact same oil pan, only with an added set of baffles that bolt into the pan for controlling oil slosh in extreme G situations. This is specifically designed for drag race applications. This keeps the oil in the sump surrounding the pickup where it needs to be.
At approximately $400, the Holley Retro-fit models are the cheapest solutions to the factory pan. Unless you really want to modify your frame, you can’t get a pan for less. It comes with the Holley quality that you would expect, and it looks good. It is cast aluminum, which can be polished if you are looking for a fancy oil pan, painted, powder coated, or left raw. This is a simple solution for a difficult problem.
The only potential issue with this pan is that it is cast aluminum. The only real drawback is that if it is hit hard enough, it can crack, leaving the engine without oil. Is this likely? No. Not even a little. But it could happen. The factory pan is cast aluminum as well, so this really isn’t much of a drawback. Because it is cast aluminum, adding additional fittings to the pan is more difficult.
Moroso Wet Sump
This Moroso fabricated pan (part number 20155) is made from sheet aluminum, which means that the pan is flat and square. There are no little bumps or raised sections in the middle of the flats that can cause clearance issues. This pan features a billet aluminum O-ring rail to match up to the block and a removable pickup tube. It uses Moroso’s billet oil filter adapter, so the stock location can be used for the filter; no remote filter is required like most sheet metal pans use.
The front shallow section is 1⁷∕₈ inches deep and 14½ inches long. The rear sump measures 5⁷∕₈ inches deep and 8½ inches long, so there is plenty of clearance for most crossmembers. Included with the pan is a trap door baffle and windage tray for better oil control.
The sheet metal construction makes it lightweight, and adding other fittings to the pan (such as an oil return for turbos) is easy. Because it is not cast, road debris is less likely to crack or split the pan because the sheet metal aluminum will dent rather than crack like cast aluminum.
The disadvantage is that the Moroso pan is nearly double the price of the Holley pan, so that is a big drawback. It might make up for it if a return fitting for turbo system needs to be added, but that can be done on both.
BRP HotRods High Clearance Sump
The High Clearance pan (part number 000-6490-00) is designed specifically to work with BRP’s MuscleRods swap kits. It is a fabricated sheet metal pan like the Moroso. It features the correct O-ring placement and pickup tube. It is a very good-looking oil pan, and the aluminum is easily polished. The high-clearance version is for applications that require maximum clearance, such as Tri-Five Chevys.
This is the BRP HotRods LT swap oil pan, which is a fabricated pan (welded sheet aluminum instead of cast), which is quite nice. It fits the block, has all the right ports, and is designed to work with the BRP LT swap system.
BRP HotRods Extended Sump
If you have a front steer-style steering system, the extended sump pan (part number 000-6451-00) is suggested by BRP to gain the clearance without losing the 5-quart capacity. It has the advantage of sheet metal construction for less weight, and it fits BRP swap kits. However, these pans are very expensive to build, and that is reflected in the price, which is similar to the Moroso pan.
Regardless of which pan is chosen for a swap, it will likely need to be removed at some point. This is a bit different from every other GM engine that came before it. There is no oil pan gasket, instead General Motors used gray RTV silicone. Gray silicone is specifically used for high-torque applications where sensors and oil are present. It is important to use the gray silicone on the oil pan because it is the only defense against leaks.
Another potentially catastrophic issue with the oil pan install/removal is the oiling fitting O-rings. There are three: one on the pickup tube to the block and two on the oil filter ports that run to the external cooler or bypass cover. These have a habit of sticking to the engine block when removing the pan, so the pan will come off with these missing, and if you miss it during the process, you can lose them, which would mean a massive internal oil leak and no oil pressure. If you are replacing the pan or putting on a new O-ring but the old one is still on the block, you will have a really tough time getting it all to go back together.
Written by Jefferson Bryant and republished with permission by CarTech Inc.
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