My 1977 REPU Project
Thread Starter
Joined: Jul 2004
Posts: 461
Likes: 0
From: Land o Lakes, FL
My 1977 REPU Project
I picked up a 77 Rotary Pickup about a year and a half ago. Truck was solid and drivable but age and mileage had taken its toll. The truck started needing major overhaul so I decided to bit the bullet and go through the truck. Engine was pulled and found that the irons were not usable, so made the switch to a newer 13B. Custom header, side draft Weber carb and a bunch of other goodies going into it. Hoping to have it be a fun little truck when all is said and done on it.
Joined: Sep 2004
Posts: 3,258
Likes: 9
From: South Florida
Cool project. What do you plan to do with paint? They are fun pick ups. I drive mine at least once or twice a week. It's a blast! Keep us posted on your progress and good luck
Thread Starter
Joined: Jul 2004
Posts: 461
Likes: 0
From: Land o Lakes, FL
i was going to a blue body but decided due to cost to keep it the oem yellow and re-decal it the way it came from mazda.
Trending Topics
If you can take a little constructive criticism, I'll offer my 2 cents on a few things I see that could be changed.
1) You need to build a long primary exhaust. The short collected header won't make nearly as much power. Or should I say TORQUE.
2) You need to upgrade to a direct fire ignition system. Just a simple points to electronic swap isn't really good enough. Not with what we know these days.
3) The way you have the OMP lines routed will blow out the OMP seals and make a big oily mess on the front cover. You need to reroute the lines up into the carb or the very least into the manifold though the stock (long) injectors, and you have to drill them out to the same ID as the stock Nikki/hitachi nipples.
4) Since you have a stock S4 LIM, why not use the aux ports? Get some Atkins sleeves.
If you have questions, do some searches. I can offer some helpful hints.
Some things you did right (I mentioned the bad already, so now I'll mention the good). The stock flywheel is an excellent choice in these trucks. The 24 pound S4 NA flywheel is what I have in both my REPUs. You don't need a street strip pressure plate as stock will do, and the disc can be a modern stock duty Exedy disc in 225mm. You should only upgrade if/when the disc slips. Otherwise you'll fight a short travel heavy pedal forever. Been there, done that.
I was going to run a weber DCOE in mine, but came across a complete S4 NA ECU and harness with injectors etc. I look forward to setting it up for my dad. It is getting a LONG PRIMARY exhaust and will provide far more torque down low and far more high RPM power than any short collected header is capable of. You should look into long primary exhaust systems. By the way, your header is compatible if you chop off the collector and relocate it rearward.
The color scheme is fine as long as the truck is yellow.
Lastly, the radiator is fine if it doesn't leak. It's huge and the oil cooler is huge too. There are no drop in replacements as far as I know.
1) You need to build a long primary exhaust. The short collected header won't make nearly as much power. Or should I say TORQUE.
2) You need to upgrade to a direct fire ignition system. Just a simple points to electronic swap isn't really good enough. Not with what we know these days.
3) The way you have the OMP lines routed will blow out the OMP seals and make a big oily mess on the front cover. You need to reroute the lines up into the carb or the very least into the manifold though the stock (long) injectors, and you have to drill them out to the same ID as the stock Nikki/hitachi nipples.
4) Since you have a stock S4 LIM, why not use the aux ports? Get some Atkins sleeves.
If you have questions, do some searches. I can offer some helpful hints.
Some things you did right (I mentioned the bad already, so now I'll mention the good). The stock flywheel is an excellent choice in these trucks. The 24 pound S4 NA flywheel is what I have in both my REPUs. You don't need a street strip pressure plate as stock will do, and the disc can be a modern stock duty Exedy disc in 225mm. You should only upgrade if/when the disc slips. Otherwise you'll fight a short travel heavy pedal forever. Been there, done that.
I was going to run a weber DCOE in mine, but came across a complete S4 NA ECU and harness with injectors etc. I look forward to setting it up for my dad. It is getting a LONG PRIMARY exhaust and will provide far more torque down low and far more high RPM power than any short collected header is capable of. You should look into long primary exhaust systems. By the way, your header is compatible if you chop off the collector and relocate it rearward.
The color scheme is fine as long as the truck is yellow.
Lastly, the radiator is fine if it doesn't leak. It's huge and the oil cooler is huge too. There are no drop in replacements as far as I know.
Something else occoured to me when I noticed your stock motor mounts. You NEED to get competition mounts for the engine and the trans. You MUST get these. They made my truck feel better than new, or let's just say better than a new modern truck. 
Do you see how narrow the motor mount spread is in these things? Not much leverage against engine torque. Nothing like having an oil pan touch the crossmember and sloppy shifts to ruin your day. And solid mounts are not the answer. Tried in both positions and it sucks. Get hockey pucks for motor mounts at the very least. But you'll like the real competitions more. And don't try the bolt through the trans mount trick, unless you crave the sound of mechanical noises all day.
Here, I'll help you out.
RX7 1975-1985: Engine - External: Competition Transmission Mount - 79-85 RX-7 -
RX7 1975-1985: Engine - External: Competition Engine Mount - 79-85 RX-7 -
Do you see how narrow the motor mount spread is in these things? Not much leverage against engine torque. Nothing like having an oil pan touch the crossmember and sloppy shifts to ruin your day. And solid mounts are not the answer. Tried in both positions and it sucks. Get hockey pucks for motor mounts at the very least. But you'll like the real competitions more. And don't try the bolt through the trans mount trick, unless you crave the sound of mechanical noises all day.
Here, I'll help you out.
RX7 1975-1985: Engine - External: Competition Transmission Mount - 79-85 RX-7 -
RX7 1975-1985: Engine - External: Competition Engine Mount - 79-85 RX-7 -
Thread Starter
Joined: Jul 2004
Posts: 461
Likes: 0
From: Land o Lakes, FL
If you can take a little constructive criticism, I'll offer my 2 cents on a few things I see that could be changed.
1) You need to build a long primary exhaust. The short collected header won't make nearly as much power. Or should I say TORQUE.
2) You need to upgrade to a direct fire ignition system. Just a simple points to electronic swap isn't really good enough. Not with what we know these days.
3) The way you have the OMP lines routed will blow out the OMP seals and make a big oily mess on the front cover. You need to reroute the lines up into the carb or the very least into the manifold though the stock (long) injectors, and you have to drill them out to the same ID as the stock Nikki/hitachi nipples.
4) Since you have a stock S4 LIM, why not use the aux ports? Get some Atkins sleeves.
If you have questions, do some searches. I can offer some helpful hints.
Some things you did right (I mentioned the bad already, so now I'll mention the good). The stock flywheel is an excellent choice in these trucks. The 24 pound S4 NA flywheel is what I have in both my REPUs. You don't need a street strip pressure plate as stock will do, and the disc can be a modern stock duty Exedy disc in 225mm. You should only upgrade if/when the disc slips. Otherwise you'll fight a short travel heavy pedal forever. Been there, done that.
I was going to run a weber DCOE in mine, but came across a complete S4 NA ECU and harness with injectors etc. I look forward to setting it up for my dad. It is getting a LONG PRIMARY exhaust and will provide far more torque down low and far more high RPM power than any short collected header is capable of. You should look into long primary exhaust systems. By the way, your header is compatible if you chop off the collector and relocate it rearward.
The color scheme is fine as long as the truck is yellow.
Lastly, the radiator is fine if it doesn't leak. It's huge and the oil cooler is huge too. There are no drop in replacements as far as I know.
1) You need to build a long primary exhaust. The short collected header won't make nearly as much power. Or should I say TORQUE.
2) You need to upgrade to a direct fire ignition system. Just a simple points to electronic swap isn't really good enough. Not with what we know these days.
3) The way you have the OMP lines routed will blow out the OMP seals and make a big oily mess on the front cover. You need to reroute the lines up into the carb or the very least into the manifold though the stock (long) injectors, and you have to drill them out to the same ID as the stock Nikki/hitachi nipples.
4) Since you have a stock S4 LIM, why not use the aux ports? Get some Atkins sleeves.
If you have questions, do some searches. I can offer some helpful hints.
Some things you did right (I mentioned the bad already, so now I'll mention the good). The stock flywheel is an excellent choice in these trucks. The 24 pound S4 NA flywheel is what I have in both my REPUs. You don't need a street strip pressure plate as stock will do, and the disc can be a modern stock duty Exedy disc in 225mm. You should only upgrade if/when the disc slips. Otherwise you'll fight a short travel heavy pedal forever. Been there, done that.
I was going to run a weber DCOE in mine, but came across a complete S4 NA ECU and harness with injectors etc. I look forward to setting it up for my dad. It is getting a LONG PRIMARY exhaust and will provide far more torque down low and far more high RPM power than any short collected header is capable of. You should look into long primary exhaust systems. By the way, your header is compatible if you chop off the collector and relocate it rearward.
The color scheme is fine as long as the truck is yellow.
Lastly, the radiator is fine if it doesn't leak. It's huge and the oil cooler is huge too. There are no drop in replacements as far as I know.
I ended up getting a refund from the seller and sending my stock radiator to a local radiator shop to get rodded out. Had a custom shroud made for it and put a Volvo electric fan on it. (Same as the famous Taurus fan, but mounts flat) That fan/radiator combo pulls the engine water outlet temp down by about 13 degrees F in ~40 seconds of fan run-time.
Thread Starter
Joined: Jul 2004
Posts: 461
Likes: 0
From: Land o Lakes, FL
truck is back in my possession. a few things were (or weren't) done which haven't left me 100% satisfied. details aside, there is some work i need to do on my end to make the truck right. the tune on it is what i would consider very basic, and the truck is fairly sluggish to drive. any advice on proper jetting or timing for this setup - even if its somewhat vague - is welcome if anybody has any pointers.
Full Member
Joined: Sep 2013
Posts: 57
Likes: 1
From: Wisconsin
77's are cool, and if your interested to see where this truck is at now you can follow it here https://www.rx7club.com/old-school-o...1064634/page2/
Thread
Thread Starter
Forum
Replies
Last Post
