Like the RB series motors, the CA18 also has issues with oil pooling at the back of the heads, especially when drifting. This means less oil makes it’s way back down to the sump. Which means the motor can suffer oil starvation and you can end up with spun bearings. One of the easier ways to combat this is by installing drains at the back of the head which prevent oil pooling by moving it back down to the sump.

There are a few kits on the market that include everything you need, but I decided to put my own together using fittings from Nick Murray in Australia. Instead of having to weld AN10 bungs to the back of the head, Nick’s fittings just press into the welch plug holes. They’re reasonably priced and shipping from Australia is affordable since the package is small. You can find him on Facebook here.

The only big downside to doing these is the fact that you have to do it with the motor out of the car. You could press the fittings in while the motor is in, but getting the welch plugs out would be just about impossible.

The smart way to put these in is to stick them in the freezer for a few hours so they contract a bit and press in easy. Of course, I didn’t do that and just whacked them in with a mallet. Once they’re fully seated you don’t have to worry about them blowing out.

In addition to the head fittings, I needed a pair of AN10 steel bungs for the return to the oil pan. I got a pair of them for $10 off of Amazon. They were easy enough to install. I just drilled a couple holes in the pain, popped the fittings in and welded them out. Then I grabbed some Rustoleum and re-sprayed the pan. I was very careful in the placement of the fittings and made sure there was enough space between them to be able to get the hose-ends threaded on.

I used a variety of fittings to get the lines to stay tight against the block. Off the head I used two tight 90s from Vibrant. Off of those I went with a 45 degree hose-end on the left and a straight hose-end on the right.

After some fiddling I got the lines to bend the way I wanted. Because these run under the exhaust manifold I went ahead and slid some DEI heat sleeve on both lines.

On the pan side I used some regular 90 degree hose-ends I had laying around. I think these are either Jegs or Summit brand. The AN12 bung you see to the left was already on the pan when I bought the motor and will be used for the turbo oil drain later.

After some adjustment I managed to get the lines to clear the Trust manifold without actually touching it. This shot was taken before I put the heat sleeve on. I’ll be running a Trust TD05-16G, which is only oil cooled so I don’t have to worry about routing water lines through as well, which would have made this harder to do.

I was concerned with how much space I would have between the head and the firewall, and if the drains would get in the way at all. Later, when I had the motor back in the car it turned out there was a ton of room. Especially since I used tight 90s off the press-in fittings.

In the end, this was a cheap and easy mod to make and will hopefully keep oil moving down to the sump efficiently. I already had half of what I needed to get this done, but if I was buying everything at once I’d say this could be done for about $100.