SR Powered

Today I took the plunge and drilled and tapped the block for the oil drain on the turbo. As I stated in part one the tools you will need to do this are as follows:

• Drill
• 23/32 drill bit
• 1/2″ NPT tap

It is suggested that you use cutting fluid when tapping the hole. I forgot to purchase the cutting fluid and could not find it locally, so I used motor oil in lieu of the cutting fluid. The motor oil worked well for me, but you need to be particularly careful to ensure that you do not break the tap in the hole.

The following details the process that I used to drill and tap my block.

First, you need to drain the engine oil. After this is done place the drain plug back into the lower pan. This will keep the excess oil in the pan once it is removed, which allows you to carefully dump it without making a mess. Next remove the lower oil pan by removing the 10mm bolts that fasten it to the upper pan. Once the bolts are removed it may be tricky to separate the lower pan from the upper without damaging the fairly soft lower pan. There is a special tool that is designed for this job, but it is also possible to complete the task carefully with a screwdriver and hammer.
Removing the lower pan will reveal the oil pickup and baffle plate. I opted to remove the baffle plate next to get it out of the way. Next comes the removal of the upper oil pan which can be a challenge.

Following the FSMs instructions, you will need to remove two 10mm nuts on the side of the engine that is closest to the transmission. These two nuts are concealed by a plate that needs to be removed (two 10mm bolts). Removal of these nuts is particularly tricky with the engine in the car. I was able to get them out using a short 10mm socket, a universal joint, and an extension. From here you just follow the FSMs instructions for removing the rest of the bolts. Ensure all needed bolts are removed before attempting to remove the upper pan.

Once all of the bolts are removed, the FSM suggests that you use one of the bolts that mate the engine to the transmission (on the engine side) to thread through an open hole in the pan. This will separate the upper pan from the block. This would work great with the engine out of the car, but I did not have the clearance to follow through with these instructions. Luckily there is a small gap between the upper pan and the block where you can use a screw driver to pry. This gap is located on the front part of the block closest to the transmission. Use a beefy screwdriver to pry. Once one side is separated, work your way around the rest of the pan. Once the pan is free, remove it and set it aside.

With the pans out of the way you can start the drilling process. I suggest using a straight edge and a ruler to find the exact center of the boss you are going to drill. I was able to use a regular 19 volt cordless drill since my radiator was not installed. With the radiator installed, space will be tight if you try to use anything but a right angle drill. With the exact center of the boss marked, I used a very small drill bit to start. Pay close attention to the angle of your drill bit. If you have the drill angled too high, the bit will break through the back of the block in a bad spot. This will become a big problem as you step up to larger drill bits. There is no set increment for the drill bit sizes, just increase the size of the bits as you see fit. The last bit you use is the 23/32” bit.

With the hole drilled, it is time to tap the block. Again, the use of cutting fluid is encouraged; however motor oil can be used in a pinch. The process I used seemed to work well. For every full turn of the tap, back it out half a turn. This will slow your progress a bit, but it will help clear some of the shavings out of the threads. Once you reach the end of the hole, back the tap out all the way. After thoroughly cleaning the tap (I used motor oil for this), chase the threads a few more times to clean them up. I then cleaned the newly tapped hole with motor oil again to make sure all of the shavings were removed.

After the hole has been tapped, ensure your fitting threads properly. If it does, replace the pans in reverse order being sure to follow the FSMs instructions, torque specs, and order.

After doing this for the first time, the process is not overly complicated. It does require great care to ensure you do not damage your block. I know some people feel that they can manage the shavings by keeping the upper pan in place and using compressed air. My feeling is that following this process will ensure the job is done correctly. Plus the removal of the upper pan allow you to see exactly where the drill bit is breaking through the back of the block.

Keep in mind that this is just a guide. I take no responsibility for any damage that you may inflict on your block by following this guide. Happy drilling!

Chris' 2000 Sentra SE, Turbo Project

Today I unofficially ended the naturally aspirated part of the Sentras life! While working on the oil feed and drain for the turbo, I decided to remove the rest of the Hotshot header. Seven years of salted PA roads took their toll on the exhaust system! If it wasn’t for the electric impact gun, I probably would have resorted to a hammer and chisel! Eventually the cat-back is going to have to come out, but that is going to require that I cut the bolts so for now it just dangles under the car.

After that ordeal, I drained the engine oil and removed the oil filter. With the oil filter removed, I unscrewed the factory oil pressure sender (for the factory dummy light) to make way for the Custom Steel oil distribution block. This block provides two 1/8 NPT ports (one for the oil feed and another for an oil pressure gauge) as well as a 1/8 BPST port for the factory oil pressure sender. In order to relocate the oil pressure sender, I had to extend the wire by a few inches. From there it was just a matter for routing the oil feed line and bolting the oil distribution block to the axle.

The rest of the supplies I needed to drill and tap the block for the oil return arrived earlier this week. I still need a factory exhaust gasket, but that will not hold the process up at this point.

Gauges have been a sore spot for some time now. My initial decision was to go with all 45mm Omori gauges. That was simple enough, until I tried to actually find the gauges! It seems that Omori Japan went out of business, but their North American wing was/is going to take over production. Right now inventory is lagging as they try to play catch-up. Another problem I ran into is the fact that Omori NA has not seen a demand for a water temperature gauge, so they will not be making one of those in the foreseeable future. Currently the only 45mm gauges that are available are boost and EGT.

After measuring my center console, I may have enough room to mount 52mm gauges which would allow me to run at least boost and oil pressure (since I’m not interested in EGT at the moment). So I bit the bullet and ordered 52mm boost and oil pressure gauges from J-Spec Tuning. If they don’t fit in the center console, I will seek to mount them in a clean way on the steering column.

J-Spec Tuning is the only place I could find online that seems to have a decent inventory of Omori gauges. I called them a week ago and the guy I spoke to was extremely helpful and polite. Not to mention he was full of information about what was going on with Omori. He mentioned that in June Omori may be releasing a 45mm oil pressure gauge as well. Another point of interest he brought up was the fact that the new Omori gauges will use different sending units. This means you cannot mix and match the old gauges with the new sending units. Keep that in mind if you find a used set of gauges for sale.

So now I await the arrival of the gauges. It looks like it is going to rain the next few days, so chances are I won’t get to tap the block this week. Once I do that, I will post the process I used as promised.

Chris' 2000 Sentra SE, Turbo Project

One major part of turbo charging an SR20DE is creating an oil return path for the oil that is exiting the turbo. This process can be nerve-racking since many people opt to drill a hole in the block for the oil return. Some people choose to run the return right into the oil pan, but I have heard varying opinions on doing that so I choose to stick with the tried and true method of tapping the block.

The process of tapping the block is not overly complicated, it just requires great care as a mistake here can put you in a bad place!

Drilling and tapping the block requires a few tools:

• Drill
• 23/32 drill bit
• 1/2″ NPT tap

22/32 is the final size the hole will need to be before you can tap it using the 1/2″ NPT tap. It is recommended that you use smaller drill bits to start and progressivly build up to the 22/32 bit. This will reduce the likleyhood that the block will be damaged during the drilling process.

Connecting the oil drain from your turbo to the hole in the block will vary by application. I have an oil return flange on my turbo that gives me a -10 AN threaded outlet. I speced-out the needed fittings from AN Plumbing. In this case I used a -10 AN fitting on the turbo side and a -10 AN to 1/2″ NPT  45* fitting on the block side. Once again I will be using the Koul Tools product to assemble the lines, since they worked very well with my -6 AN lines.

In part two of this series, I will detail the process I used to drill and tap my engine block.

Chris' 2000 Sentra SE, Turbo Project