|Home > RX-7 > My RX-7 > Project Tina > Project Tina, April 30th, 2010: TII Oil Pump and Transmission Installation, Catch Can, MOP Removal, Intercooler Improvements|
It's time for another update in my ongoing bridgeported turbo-NA project. Last time, I mainly covered installing a boost controller, fabricating a new fuel tank and prepping for a TII transmission install. This update is a bit more scattered as I had a whole bunch of random stuff to accomplish, some small and simple while some things more involved. A sample of what is covered here is; TII transmission installation, MOP removal, TII oil pump upgrade, oil catch can, intercooler un-suckifying and a rear suspension rebuild.
The last thread ended with the newly rebuilt TII transmission painted to match the rest of the engine bay.
To use the TII transmission, I needed to swap the NA flywheel for the TII flywheel. As a general rule, everything behind the rear iron must match the transmission. I picked up this TII flywheel at the same time I purchased the TII transmission and then had the flywheel turned at a local auto parts store. Whenever I bring them a rotary flywheel they always think it is from a VW Beetle, no idea why as I've never seen a VW Beetle flywheel.
I ran a copper puck clutch before which worked fine but it did wear out quickly in daily driver duty. After speaking with the clutch guy, he recommended a Kevlar clutch for my power level and use, so that's what I ended up with.
A modified stock pressure plate came with the clutch and is spec'ed to have a 30% clamping power increase. That was installed along with a new pilot bearing and seal. One day I will buy a pilot bearing puller because I am so seriously sick of grinding those things out with a Dremel. Not a big deal to do when an engine is on a stand, but not so much fun when the engine is in the car.
That that point, the transmission slid right on with a little wiggling. Since I was ordering some stuff from Mazdatrix, I also picked up a TII transmission mount. However the NA mount can be used easily by just elongating the mounting holes. In fact, it appears that both mounts are exactly the same, with oval shaped holes. Mazda just welds on a plate to close off part of the hole depending on whether they are producing NA or TII mounts.
With the rear of the engine supported again by the transmission it was time to solve a problem that has been bothering me since I first started the car. For whatever reason, the front hub leaked oil past the hub bolt. This could have been caused by improper installation of the o-ring on the bottom of the bolt or the copper crush washer that seals the face of it. Either way, it ended up leaking a drop or so of oil ever 10 minutes which kept making a mess of the engine bay. Due to the location of the e-fan and rad I had been putting off fixing this but since I also wanted to upgrade the oil pump (more on that below), the front cover (and thus the hub bolt) was coming off anyway.
When I built this engine I performed the Weber jet eccentric shaft oil jet mod. The mod increases cooling oil flow to the interior of the rotors, which is especially important in a high compression turbo engine. But the downside is that with the NA oil pump, this will drastically lower idle and low RPM oil pressure. The NA pump just doesn't have the volume at these low speeds to keep the pressure up with so much oil being sprayed on the interior of the rotors. Consequently, I had around 5 PSI of oil pressure at idle and 20 PSI at 3000 RPM. As you can see in the image below, the TII oil pump on the left has much larger rotors then the NA oil pump on the right, and thus moves a lot more oil. Installation of this pump will correct the low RPM oil pressure problem.
For a little while I considered converting to a full dry sump system and began making a list of parts required and pricing out pumps. However, it took only a little longer before I realized going to dry sump would be rather stupid on a street car. The belt driven dry sump pump would be far less reliable then the stock oil pump unless I spent a lot of effort modifying the front cover for a fully enclosed chain drive or spent a tonne of money on the Mazdacomp dry sump front cover.
The TII oil pump is a direct bolt on upgrade to all 2nd gen NA blocks. Note that it won't fit earlier 13B or 12A blocks, the mounting holes are different.
With the drive sprockets and chain reinstalled, the front hub can be snugged down to prevent potential disasters involving the spacer and torrington bearings.
Shown here is the underside of the front cover, exposing the metering oil pump drive gear. While the front cover was off I decided that I would remove all this stuff and convert to premix. Now, I find premix to be a big pain in the ass. But a larger pain in the ass was trying to interface the 80MM Mustang throttle body I have on my custom intake to the metering oil pump. After trying 4 different methods involving cables and rods I had just given up and started premixing. Additionally, my rebuilt metering oil lines were leaking again and while I have a new set of Mazda lines on hand, I just didn't feel like messing with it anymore. Ultimately I will be making an automatic premixing system which automatically adds the appropriate amount of premix every time the car is refuelled.
The drive gear and shaft comes out quite easily once the two snap rings are removed.
Once the MOP drive shaft is removed, the passage that feeds the shaft with oil must be plugged. If it is left open then all that oil will just spray uselessly under the front cover and likely cause a fairly severe low RPM drop in oil pressure. The stock size of this hole is sized perfectly to be tapped for 1/4" course threads. A grub screw can then be installed.
After the hole is tapped, the grub screw threads right in and sits below the surface.
I did the same thing to the feed hole on the metering oil pump flange.
Finally, the big metering oil pump shaft hole was filled with JB Weld. This, in addition to the standard block off plate, will virtually eliminate the possibility of a leak.
I should mention that this was my second choice in how to accomplish this. On my original front cover I ground off all of the metering oil pump related castings and then shaved down the area by welding in sheet metal. A little grinding and some more welding and it looked as if the front cover was cast that way at the factory. The problem is that during the welding process, the cover became distorted and would no longer fit the engine. It was only off by about 0.5MM, but that was enough to stop it from fitting over the dowels on the front iron. Clearancing it to fit was not an option since that may shift the position of the eccentric shaft hole and CAS area.
The other end of the oil passage was also filled with JB Weld after the grub screw was installed. This is so the gasket will have more area to seal against.
With all the work on the front cover complete, it was repainted and reinstalled on the engine. Note my custom made front hub holder tool. It's made of the little ring inside the stock pulleys and a spare length of square 1" tubing. Also notice that I installed studs on the bottom of the front cover. This makes it a hell of a lot easier to install the oil pan (and oil baffle plate) from underneath the car as you can hook the front on the studs after sticking the gasket in place with sealant.
Another area of the engine that bothered me was the Push Lock tubing I used to feed coolant to the turbo. The only reason I used it originally was because I didn't think of removing the stock water nipples and tap them for AN fittings. It was a silly oversight on my part. Since the water pump housing was removed for the front cover job it was a perfect time to fix this. I yanked the stock metal nipple out of the back of the water pump housing with a big set of Vice Grips, and then drilled and tapped it for 1/4" NPT.
Testing the new hole with a spare brass 1/4" NPT fitting.
After the water pump housing was tapped, it was repainted and then all of the front engine stuff was reinstalled.
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