So I know what you're all thinking, why would I waste my time rebuilding a rotary engine. The short answer to that is, I got sick of oil dripping on my hot exhaust making the car smoke at stop lights and being a huge fire hazard. Despite my engine hemorrhaging oil out from between the front iron and front rotor housing, the car still ran like a champ. I just considered it a constant oil change. The failure was an internal oil ring on a oil passageway that had become hard and cracked, more or less a $3 o-ring around the dowel pin oil passage was failing. I knew of this leak before I bought the car, which is why I managed to pick up a virtually rust free, virtually mint rx7 for a mere $500.
After some budgeting and some thinking to myself, I decided it would be silly of me to go through all the work of pulling out my engine and disassembling it without just throwing down the $800 for the full rebuild kit. The gasket kit needed for the replacement ring would have been $100 anyways. So I decided to borrow the cash from my pops so I could just go through with a full rebuild. Heres what I got for my $800:
And so the process begins. First things first, had to borrow an engine hoist from a high school friend of mine. With that checked off the list, it was on to phase one. Clearing out the garage. My parents kindly let me kick both of their cars out of the garage so I could take it over for a while to fix my car. I thank them greatly for this. Unfortunately it was very much after dark when I decided to start the process, so all I accomplished was draining the oil and coolant out of the engine. The next day the fun began. The process started with removal of the clutch fan, and then the radiator and radiator shroud from the front of the engine bay to free up some much needed work room. Next on the list is removal of the belts. The most fun one was of course the air conditioning compressor that could not be taken out of the car or disconnected since it has the precious freon inside of it. Therefore, I decided to chain and bungee cord the compressor to the garage wall to support it and keep it out of the way
After the AC is out of the way, its time to pull out the carburetor. This is a HUGE pain because the 4 nuts holding it to the engine are buried underneath all the vacuum lines and emissions bullshit, so it takes some good flat wrenches and a little patience. Once the carburettor was out of the way, it was on to the wiring harness. Starting on the drivers side of the engine, I disconnected all the electrical plugs from the engine carefully. With the wiring out of the way, it was simply a matter of disconnecting hoses. Pulling out some of the coolant lines and whatnot, the engine was almost free. Last thing to do was to disconnect the torque converter from the drive plate. This was fun, theres a tiny little plate that gives you access to do this at the joint for the bell housing and engine block underneath the car. It was good fun.
After a quick check to make sure everything was out of the way, its time for the trickiest part of the whole process. I had to support the back of the engine, the front of the transmission, and pull the engine out, all at the same time. Thank god for jack stands. After some fun wriggling and wrestling the engine out of the car, victory, out she came and oh my was it ever dirty.
The tear down was the easiest of all. Basically I just pulled off the oil cooler and filter assembly, the intake, emissions (rats nest), oil pan, and the exhaust and all thats left is the bare block. All thats left after that is to remove the front cover, remove the oil pump assembly from the front of the block, and take out the 18 bolts from the back of the engine. Then the engine simply pulls apart from the back to the front.
After pulling everything apart, it was time for a little cleaning. My housings were in remarkably good condition for an engine with 117k miles on it. Hardly any chrome flaking, no horizontal lines, no real damage to speak of or worry about. This was good news because this meant nothing would have to be replaced and it was all re-usable. Heres what resulted!
After the cleaning was all over, it was time to rebuild the rotors. After removing all the parts of the rotors, it was a simple process of replacing all the hard seals on them. First its easiest to replace the oil rings and springs. Then its on to side seals and springs, and corner seals and springs.
After all the seals other than the apex seals are in place, Its time for reassembly. First things first, I needed to insert the water seal jackets into the housings and seal them in with some Hylomar. There are also some areas on each housing and plate that I put some black sealant on because they tend to be a common leak spot with time. The rebuild process is fairly simple from there on out. Its a matter of, front iron plate, drop the housing onto the front plate, guided by the dowel pins After the front housing is in place, its time to drop in the first rotor. You simply drop the rotor into place, roughly where you think it belongs, then set the eccentric shaft in place, putting the rotor exactly where it belongs. With the corners of the rotors up against the housing, you slide the apex seals into their grooves, followed by the apex seal springs, which go with the ends facing outward as I found out the hard way the first time I rebuilt my engine, and then the tiny last piece of the apex seal.
This is the part where having a friend nearby is nice. To get the center plate back into place, you have to lift the eccentric shaft an inch or two while sliding the plate downward, working it around the lobs on the shaft. I found it best to have your buddy push the shaft upwards from underneath the engine while watching the the rotor to make sure no seals get jostled loose and having the other person lower the center plate onto the front housing.
The process for the rear rotor is exactly the same as the front rotor. After the rear rotor is in place, you simply lower the rear plate into place, being careful not to jostle and seals loose or smash the eccentric shaft into the rear main seal in the rear iron. Then its a simple matter of replacing, the 18 bolts back into the engine, reattaching the oil pan, drive plate, exhaust, intake, oil cooler, and emissions nest, and getting ready to drop it back into the car. The re-installation of the engine block are basically the exact opposite of taking the engine out. Once you have the engine dropped onto the mounts at the front of the bay and bolted back up to the transmission, the hard work is done. Just reconnect everything, add oil and coolant, and its time to start the beast.
Whenever getting ready to restart a rebuilt engine, it is important to crank the engine for 30 seconds without plugs to build up oil pressure and get any air locks out of the fuel lines. After you crank it, replace the plugs, turn the key, and pray. It took me two rebuilds to get everything working correctly, so seriously, cross your fingers!
Obviously this write-up is NOT a step by step on how to rebuild a rotary engine. If you every want to do a rebuild, please feel free to contact me, I'll be more than willing to help. Hope you all learned something by reading this!
Here are some more pictures of the rebuild process:
And the final result:
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After some budgeting and some thinking to myself, I decided it would be silly of me to go through all the work of pulling out my engine and disassembling it without just throwing down the $800 for the full rebuild kit. The gasket kit needed for the replacement ring would have been $100 anyways. So I decided to borrow the cash from my pops so I could just go through with a full rebuild. Heres what I got for my $800:
And so the process begins. First things first, had to borrow an engine hoist from a high school friend of mine. With that checked off the list, it was on to phase one. Clearing out the garage. My parents kindly let me kick both of their cars out of the garage so I could take it over for a while to fix my car. I thank them greatly for this. Unfortunately it was very much after dark when I decided to start the process, so all I accomplished was draining the oil and coolant out of the engine. The next day the fun began. The process started with removal of the clutch fan, and then the radiator and radiator shroud from the front of the engine bay to free up some much needed work room. Next on the list is removal of the belts. The most fun one was of course the air conditioning compressor that could not be taken out of the car or disconnected since it has the precious freon inside of it. Therefore, I decided to chain and bungee cord the compressor to the garage wall to support it and keep it out of the way
After the AC is out of the way, its time to pull out the carburetor. This is a HUGE pain because the 4 nuts holding it to the engine are buried underneath all the vacuum lines and emissions bullshit, so it takes some good flat wrenches and a little patience. Once the carburettor was out of the way, it was on to the wiring harness. Starting on the drivers side of the engine, I disconnected all the electrical plugs from the engine carefully. With the wiring out of the way, it was simply a matter of disconnecting hoses. Pulling out some of the coolant lines and whatnot, the engine was almost free. Last thing to do was to disconnect the torque converter from the drive plate. This was fun, theres a tiny little plate that gives you access to do this at the joint for the bell housing and engine block underneath the car. It was good fun.
After a quick check to make sure everything was out of the way, its time for the trickiest part of the whole process. I had to support the back of the engine, the front of the transmission, and pull the engine out, all at the same time. Thank god for jack stands. After some fun wriggling and wrestling the engine out of the car, victory, out she came and oh my was it ever dirty.
The tear down was the easiest of all. Basically I just pulled off the oil cooler and filter assembly, the intake, emissions (rats nest), oil pan, and the exhaust and all thats left is the bare block. All thats left after that is to remove the front cover, remove the oil pump assembly from the front of the block, and take out the 18 bolts from the back of the engine. Then the engine simply pulls apart from the back to the front.
After pulling everything apart, it was time for a little cleaning. My housings were in remarkably good condition for an engine with 117k miles on it. Hardly any chrome flaking, no horizontal lines, no real damage to speak of or worry about. This was good news because this meant nothing would have to be replaced and it was all re-usable. Heres what resulted!
After the cleaning was all over, it was time to rebuild the rotors. After removing all the parts of the rotors, it was a simple process of replacing all the hard seals on them. First its easiest to replace the oil rings and springs. Then its on to side seals and springs, and corner seals and springs.
After all the seals other than the apex seals are in place, Its time for reassembly. First things first, I needed to insert the water seal jackets into the housings and seal them in with some Hylomar. There are also some areas on each housing and plate that I put some black sealant on because they tend to be a common leak spot with time. The rebuild process is fairly simple from there on out. Its a matter of, front iron plate, drop the housing onto the front plate, guided by the dowel pins After the front housing is in place, its time to drop in the first rotor. You simply drop the rotor into place, roughly where you think it belongs, then set the eccentric shaft in place, putting the rotor exactly where it belongs. With the corners of the rotors up against the housing, you slide the apex seals into their grooves, followed by the apex seal springs, which go with the ends facing outward as I found out the hard way the first time I rebuilt my engine, and then the tiny last piece of the apex seal.
This is the part where having a friend nearby is nice. To get the center plate back into place, you have to lift the eccentric shaft an inch or two while sliding the plate downward, working it around the lobs on the shaft. I found it best to have your buddy push the shaft upwards from underneath the engine while watching the the rotor to make sure no seals get jostled loose and having the other person lower the center plate onto the front housing.
The process for the rear rotor is exactly the same as the front rotor. After the rear rotor is in place, you simply lower the rear plate into place, being careful not to jostle and seals loose or smash the eccentric shaft into the rear main seal in the rear iron. Then its a simple matter of replacing, the 18 bolts back into the engine, reattaching the oil pan, drive plate, exhaust, intake, oil cooler, and emissions nest, and getting ready to drop it back into the car. The re-installation of the engine block are basically the exact opposite of taking the engine out. Once you have the engine dropped onto the mounts at the front of the bay and bolted back up to the transmission, the hard work is done. Just reconnect everything, add oil and coolant, and its time to start the beast.
Whenever getting ready to restart a rebuilt engine, it is important to crank the engine for 30 seconds without plugs to build up oil pressure and get any air locks out of the fuel lines. After you crank it, replace the plugs, turn the key, and pray. It took me two rebuilds to get everything working correctly, so seriously, cross your fingers!
Obviously this write-up is NOT a step by step on how to rebuild a rotary engine. If you every want to do a rebuild, please feel free to contact me, I'll be more than willing to help. Hope you all learned something by reading this!
Here are some more pictures of the rebuild process:
And the final result:
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