Building an engine from the ground up is an opportunity to make it better and address issues that every motor has. I previously never had an RB engine, but I would here about oil issues. Australian builders really took the RB engines to the next level with heavy research and amazing builds.
Whenever I start going over an engine, I take the preventative maint. approach. One issue I really wanted to address with the RB25 was the head drain. I know it is an issue with having an upgraded pump (in my case, an N1 pump), during high/long driving races, the oil gets trapped in the head and starves the bottom, causing rod bearings to fail.
Even though I don’t plan on heavy driving/drifting or anything like that, it still doesn’t hurt to have a head drain.
Initially, Marco said the head drain wasn’t necessary, but it couldn’t hurt either. I know that all the Skyline guys in Australia immediately put on head drains religiously. I decided to go that route.
It is also easier to put on since the engine is out and that was my whole point. Do everything while the engine is out.
My timing was lucky in getting a completed kit. Someone was selling a Franklin Performance head drain, a hose and a new oil pan that already had the bung welded in!
Since the car was a drift missile and slammed, the original oil pan took a major beating and I needed to replace anyway.
So it all worked out!
Since I got this kit used, I decided to get everything needed from Franklin Performance.
I bought their drill and tap kit.
I also needed an O-ring for the head drain, so I reached out to them and they told me the diameter and even sent me a link to one on Ebay.