The MGA Twin Cam engine originally uses a cast alloy sump for extra capacity and improved oil cooling. You may notice that the dipstick goes directly into the sump rather than through the side of the engine block. After the first 500 Twin Cam cars were produced, field service feedback compelled the factory to add five large holes in the front suspension cross member for easier access to the front bolts of the sump.

You can see from the first illustration that the alloy sump is wider, which requires some more difficult fiddling with the bolts for installation (or removal), especially if you want to R&R the sump with the engine in situ.

Photos below show the bolt pattern and interior of the original Twin Cam alloy sump. Notice the dip stick port at the left rear corner of the sump. (Photos compliments of Ian Renshaw)..


More photos from Christopher Cox who adds the following note:
Please do not to be brutal with the seized sump plug (having watched with horror some well known TV shows where brute force and ignorance caused catastrophic damage to hens teeth castings; where my screams at the TV ''Don't do that'' made no difference! Too late....



At right is an original MGA Twin Cam alloy sump with hand fitted steel oil surge baffle. Photo compliment s of Chris Champion. The trick here is the lip attached around the oil pickup hole.

Below is an example of an aftermarket alloy sump for MGB 5-main bearing engine. This is narrower at the main body, allowing easier access to the side bolts similar to the steel pan on pushrod engines. Mind you it has a different bolt pattern and will not fit directly on the Twin Cam engine, which has the bolt pattern for a 3-main bearing engine (unless you have converted your Twin Cam to a 5-main bearing engine block). But a similar aftermarket alloy sump for 3-main bearing engine may be available. Any of these parts would need modification to add the dipstick tube for the Twin Cam engine.

While the alloy sump is a hallmark of the Twin Cam engine, and perhaps a nice bit of eye candy, you can make service life easier by installing an oil cooler and using a mostly standard steel sump from a pushrod engine. See next page for that modification.