Thursday, January 20, 2011

1993 Mazda Rx7 - Rotary Engine Rebuild - Final

Intro - Part 1 - Part 2 - Part 3 - Part 4 - Parts List - Final

As promised here are a few final photos of the engine bay as well as a couple videos of the car running. There is a short clip of the interior where you can see the aftermarket gauges/gauge pod as well.

Engine start-up, interior layout, slight engine revving videos

Hope you find the information on these posts useful. If you have any questions, feel free to contact me and I would be glad to assist.


Tuesday, January 11, 2011

1993 Mazda Rx7 - Rotary Engine Rebuild - Parts List

Intro - Part 1 - Part 2 - Part 3 - Part 4 - Parts List - Final

Below I have listed practically every part I had ordered for the rebuild of my 13B engine as well as any additional parts that were upgraded/replaced as well. All of the "xxxx-xx-xxx" part numbers towards the top are Mazda specific part numbers which can of course be found at your local dealership or online if you take the time to look. Minus the extras listed at the bottom (transmission, radiator, vacuum line, motor mounts, oil pan brace, etc.), the engine rebuild alone cost around $2,000. Since I did the job myself and saved on labor costs, I was able to put that savings back into the car with reliability mods/upgrades as well as replace additional items like brittle coolant/air hoses, gaskets, oil injector lines, etc. These items are typically overlooked when doing just a core rebuild however I can be certain that if a part was bad or had potential for failure, then it was replaced.

Qty Description Part #
2 (2 needed) 13B Rotor Bearing (pre-93) Note: same as 93+ /cheaper 1011-11-111
2 (2 needed) Main Bearing (93+) NF01-10-E26
1 Pilot Bearing N326-11-D03
1 Pilot Bearing Seal 1881-11-404A
1 93-95 Front Side Housing N3F1-10-C00
1 Oil Injector line 93-95 Front Housing N3A1-14-670
1 Oil Injector line 93-95 Rear Housing N3A1-14-660
1 93-95 Water Pump Housing Gasket N3A1-15-116
1 86-95 Water Pump Housing to Block Gasket N386-15-162
4 (4 needed) 93-95 Turbo Drain Gasket N3A1-14-293
1 (1 needed) 93-95 Turbo Oil Drain Gasket N3A2-14-293
4 (4 needed per car) 93-95 Turbo Oil Line Gasket N3A1-13-712
1 OEM 93-95 FD Lower Intake Manifold Gasket N3A1-13-111C
1 Upper intake Manifold Gasket N3A1-13-112
1 93-95 Hose End at Left Rear of Engine B455-61-240A
1 Front Main Seal (pre-93) Note: same as 93+ /cheaper 0820-10-605
1 Rear Main Seal (all, except RENESIS) 1668-10-556A
2 Side Oil Seal Spring -95 Front - Inner N225-11-351
2 Side Oil Seal Spring -95 Front - Outer 1011-11-353A
2 Side Oil Seal Spring -95 Rear - Inner N225-11-361
2 Side Oil Seal Spring -95 Rear - Outer 1011-11-363A
4 Rotor Side Oil Seal -95 Small O-ring - Inner 0820-11-341
4 Rotor Side Oil Seal -95 Large O-ring - Outer 1202-11-343
12 (12 needed) FD-Style Corner Seal Springs (74-95) NF01-11-C24
12 (12 needed) Corner Seal w/Plug (86-95) N326-11-C20A
12 (12 needed) 0.7mm Side Seal (86-95) N3Y1-11-C11
12 (12 needed) 0.7mm Side Seal Springs(86-95) NF01-11-C17
6 (6 needed) Mazda 2mm 13B Apex Seal N351-11-C00C
6 (6 needed) Mazda 2mm 13B Apex Seal Spring (Long) N326-11-C06C
6 (6 needed) Mazda 2mm 13B Apex Seal Spring (Short) N326-11-C04A
1 Front housing gasket N3A1-10-502
1 Oil Metering Pump O-Ring N350-14-604
1 Oil pump lock washer 9997-91-200
1 Oil pickup tube gasket 0810-14-171B
18 (18 needed) Tension bolt seal/washer 0839-10-455
2 (2 needed) Oil filter tower o-ring 9954-10-1601
2 Oil injector N3G1-14-631
2 93-95 Primary Fuel Injector Diffuser N3A2-13-C61
2 Primary Fuel Injector Diffuser Seal N3A1-13-257
4 oil metering line washers/seals (4 needed) 9956-21-000
1 coolant hose N3A1-13-536
1 coolant hose N3A1-13-54X
1 coolant hose N3A1-13-691A
1 coolant hose N3A1-13-681A
1 coolant hose N3A1-13-692A
1 air hose N3A1-13-766
1 air hose N3A1-13-765
1 clutch fork assembly (trans. bell housing) N315-16-520B
1 shifter dust boot (shifter) M513-17-480A
1 nylon shifter bushing bottom (shifter) 0398-17-462A
1 upper bushing (shifter) M508-17-481A
1 lower bushing (shifter) M501-17-481
1 groove bushing (shifter) M501-17-515
1 Koyo Radiator with N-FLO R1443N
1 OBX Silicone Radiator Hose Kit RH10381
1 Fan blade x 2 - ebay $ 80 for whole assembly N3A1-15-140
0 Fan motor x 2- ebay $ 80 for whole assembly N3A1-15-150
1 HD Water Seal kit FD/REW/S5/RE
0 Dowel Pin O-ring set (incl. w/ HD water seal kit) N3A1-10-B73
0 72-02 Rear Stationary Gear O-Ring (incl. w/ HD water seal kit) 0813-10-555A
0 74-95 Front Cover O-Ring (incl. w/ HD water seal kit) N231-10-174
0 Front Cover Teflon O-Ring (incl. w/ HD water seal kit) N326-10-C15
1 2 Poly. Motor Mounts - Street/Race RX-7 93-00
Himni Racing
14 Copper Clad Exhaust Lock Nut - (10mil) Himni Racing
1 Himni SS Oil Pan Nut & Bolt Kit, 93-99 Rx7 Himni Racing
1 Red silicone vacuum hose kit HoseTechniques
1 Mazda Genuine Thermostat 89-95 EN650155
1 Thermostat gasket (o-ring) 89-95 Rx7 EN650153
1 AST Aluminum air separator tank - FD EN650140
1 used -94 Rx7 Manual 5 Speed Transmission

1 OES Genuine Fuel Filter RX-7|Base W0133-1612591
1 FR Seiken FD01-41-990B Clutch Master Cyl. FD3S 41-990B-FD01
1 FR Seiken FD01-41-920 Clutch Slave Cyl. FD3s
1 Stainless Braided Slave Cylinder Hose 4926
1 A-Pillar Gauge pod triple ATM-22675
1 Autometer 2-1/16" water temp gauge 100-250 sweep
1 FD3s Oil Pan Brace FD-OPB

My next post will include some final pictures of the car and engine back together, and possibly a video or two.

Rebuild was completed on 9/19/2010
Car had 93,850 miles on it at the time of rebuild.

Tuesday, January 4, 2011

1993 Mazda Rx7 - Rotary Engine Rebuild - Part 4

Intro - Part 1 - Part 2 - Part 3 - Part 4 - Parts List - Final

It has been a while since my last post due to a touch of procrastination...then the holidays ended up creeping in on us. In this posting I am going to go over some engine rebuild notes as well as some of the reliability mods I had installed in hopes to prevent the issue which prompted this rebuild in the first place.

First off, a lot of the links I had provided in my previous rebuild postings are to websites/videos that really helped me so I suggest you check those out. Below I am also including additional links to specific videos/procedures which I had used during my rebuild.

1. Installing heavy duty water seals
A lot of people use gasket sealant around the outside of the motor housing water jacket. I however, opted not to gum up the entire motor with sealant as it is completely unnecessary. If you take your time cleaning your housings and verifying that they are within spec, you can simply follow the process in the instructional video above and you will be good to go.

2. Eccentric shaft thermal bypass valve modification
This simple mod bypasses the eccentric shaft thermal valve so it allows more oil to reach the rotors sooner rather than waiting for the engine to heat up. At the same time, if this valve fails it will prevent your rotors from being cooled properly and can lead to seal failure. Definitely a mod worth doing while you have the engine apart.

3. How to set end clearance on rotor side seals

4. Installing rotor bearings (similar to main bearings)

On to the parts! Below I am going to review the main components I had selected for the rebuild along with the upgrades/reliability mods I had installed as well. I am going to skip over all of the typical gaskets/seals I had replaced however I will be posting a complete list of parts with part numbers soon.

Heavy Duty Water seals:
My choice for replacement water seals were from Pineapple Racing - - They claim that the seals are reusable and that they have been building race engines with these seals for quite some time without any issues. Check the site out for more info as they provide a few other key rebuild seals within the kit also. Note: I just realized that my kit did NOT come with the 18 tension bolt washers as stated in the description so make sure to double check your parts if you order this kit!

Thermostat w/ gasket:
Good time to replace this guy! Can be found at - I am glad I remembered to crack the thermostat housing open because my thermostat was completely warped and the gasket was falling apart.

Apex seals:
I purchased from Mazda dealership but they can be found at - The apex seals that I had removed from the motor after 90k miles still would have been usable if they had not been rusted into the rotors. Because of this, I ordered the stock replacement Mazda 2mm 13B steel apex seals (2 piece) to ensure I had the same quality and best compression for my motor.

Rotor bearings/ Main bearings:
I purchased from Mazda dealership but they can be found at

Front side iron housing:
Needed because the original iron housing was cracked which caused my coolant loss and water seal blow out as seen in "Part 3" of my Rx-7 rebuild posts.

Koyo Radiator with N-FLO & OBX Silicone Radiator Hose Kit:
Ordered from - All aluminum aftermarket radiator which I believe is twice as thick as the stock radiator and installs perfectly in the stock position without any modifications. I must say I am very happy with this purchase.
Below is a photo of the stock radiator.
As you can see, one of the fan blades broke off of the electric fan motor and flattened many of the fins on the radiator, preventing proper airflow. I am guessing this probably is one of the factors to the initial overheating issue.

Below is the new Koyo radiator with repaired stock electric fan assembly and new silicone hoses. I found a great deal on a used stock radiator fan assembly on ebay for $80 which included 2 good motors. Now I have a spare for backup!
Note: After the car reached normal operating temps, I had driven around on multiple occasions under medium-heavy boost (Apex-i is dialed in @ 13PSI) and I am seeing steady 179F-180F temps while driving on my aftermarket temp gauge. (installed next to the thermostat housing)

Aftermarket motor mounts:
Ordered the" 2 Himni Polyurethane Motor Mounts - STREET/RACE Mazda RX-7 93-00" from - The installation required some modification to the stock brackets however the install was very easy. The price is not bad either when compared to stock replacements. Note: Once you get a majority of the old rubber off of your brackets, I recommend using a bench grinder with a 6" wire wheel to remove any excess rubber. The wire wheel makes this a breeze.

Silicone Vacuum hose kit:
Ordered from - I purchased this kit to replace ALL of the vacuum lines on the car since most of them were getting brittle due to heat. The kit is nice but it includes much more than what you really need to replace all of your vacuum lines. You probably can save some cash by purchasing solely what you need.
Before and after photos ...
If anyone out there has the motor apart and is unsure whether or not to replace these vacuum lines, do it! It is well worth it to get all of those brittle lines removed and it is extremely simple to do. Just take your time and replace the hoses one at a time and you will have the peace of mind that any small vacuum leaks will have been fixed. My only caution is to be careful when removing the lines from the vacuum solenoids, I actually cracked a nipple off one of them because I was in a hurry. Luckily, I was able to epoxy it back on without an issue.

Aftermarket Aluminum Air Separation Tank (AST):
Ordered from - Bolts into stock location perfectly and the aluminum design resolves issue with the stock, plastic AST cracking due to excessive heat.

Oil pan brace:
Ordered from - I used to have a seemingly non-stop drip of oil coming from the bottom of my motor around the oil pan, which is typical for this car (especially with 93K miles). Some people have reported success with this type of oil pan brace which allows you to tighten everything down uniformly so the pan does not twist/bend. Accompanied with "Permatex's Ultra Black Maximum Oil Resistance RTV Silicone gasket maker", I have not seen any drips yet. **Crossing fingers**

This oil pan brace kit comes with all required hardware (studs/nuts) however I purchased the "Himni SS Oil Pan Nut & Bolt Kit" from since it includes stainless steel bolts.

Here is an image of the oil pan w/ brace bolted onto the motor using the Himni stainless bolt kit. You will also notice the Himni poly motor mounts installed as well.

Here are a few other things I had done while the engine was apart and out of the car.

Polished intake manifold:
Hand sanded and polished upper intake manifold to improve overall appearance of engine bay. Below are a couple photos after the hand sanding and polishing.
Note: You will need a dust mask for this and I recommend some latex-type gloves as well, you do not want to be breathing this stuff in. I started off with a heavy-medium grit sandpaper to remove any large imperfections, then repeated the process with medium, fine, very fine, then lastly I wet sanded the surface as smooth as possible. The more scratches, dimples and chips you are able to sand out of the surface, the better it will look after polishing. Then I used some white aluminum oxide compound with a buffing attachment on my air die grinder and buffed the entire surface to get ready for final polishing. Lastly, I put on a new buffing pad with some red rouge and polished the surface to a high gloss finish.

Exhaust manifold cleanup:
I cleaned up the exhaust manifold with my bench grinder, retapped one of the turbocharger bolt holes due to a broken stud and replaced the nuts with new copper nuts to make disassembly easier in the future.

Painted shortblock housing:
Decided to take some time and paint the shortblock housing. This will give it a clean finish and assist in keeping oil and dirt from sticking to the surface.

That just about completes the main rebuild part overview. My next posting will include my complete list of parts ordered for my rebuild as well as some info on trouble I ran into after the car was back together. If you have any questions regarding the rebuild process or are looking for recommendations, please feel free to contact me and I will reply as soon as I am able.