On the recomendation of Ranger et al I bought the TC Motorsports baffle for installation prior to the next race. On removal of the oil pan I found that the stock oil pan already has a somewhat serviceable baffle and along with the inexpensive TC baffle and a couple bucks worth of HW can be made to simulate some of the pricier baffles.
The TC baffle is nothing more than plate aluminum with clearance holes for the pump, dipstick, and OP switch. If you’re sufficiently inspired you could duplicate this part on your own for less than $10.
Removing the stock baffle is just a matter of drilling the stud in the front passenger side corner of the oil pan where the stud has been swaged over the mounting hole in the baffle and sliding the baffle off of the stud and out of the rubber isolated holes in the side of the pan. Try not to drill the stud any more than absolutely necessary as you’ll use it later to refasten everything.
Once the stock baffle was out I used bimetal hole drills to add some holes to the lower baffle area where it leads into the sump on the driver’s side of the engine. NOTE: Measure the clearance of the holes laterally to the oil pump pickup with the oil pump in the pan. If the holes are drilled too far towards the rear of the pan, the oil pump pickup WILL INTERFERE with the door. (Ask me how I know.)
Next comes a flap door made from some 0.063 sheet steel I had around from another project. This was kind of flimsy and if I were to do it again, I’d probably opt for something thicker or some aluminum plate. I added a couple of hinges from the local Ace Hardware and connected it all with my favorite fastener for the welding impaired. A 3 or 4 mm buttonhead would have worked a little better but you have to be careful how much thickness you add to the back of the door as this impacts its ability to seal the newly added holes in the factory baffle. If you’re careful, you can dimple the factory baffle where the fasteners are to make this a more flush fit, but I’m too lazy to eliminate the last 1 mm gap. You also need to make sure that the hinge mounting allows for free movement of the door. This may involve either replacing the hinge pins with something thinner, ala the VAC wired hinge, or maybe a thin shim under the hinge body where it attaches to the factory baffle. I just lightly pried up on the hinges to make sure that they moved freely.
Next I attached the TC piece, again with pop rivets.
Finally I drilled and tapped the original mounting stud for a 4 mm large head screw and refastened the newly enhanced factory baffle back in place with threadlocker red to make sure it stays there.
Hopefully this will help limit the oil starvation problem M20’s seem to have and eliminate the need for any more bottom end work for a while.