Hi all,

The weather is warming up, which means it is time again to struggle with the FD. Last year I spent some time working on the FD but it developed a fuel leak from the AN fuel lines, directly over the engine. It was difficult to figure out where it was coming from, because it would only leak with the engine actually running, not when the fuel pump was just turned on via the diagnostic jumper, even if I turned the fuel regulator all the way up (~60psi). So, anyway, I ended up replacing all the lines and I think the leak is stopped, Not sure though because now I can't get it to start. I finally went and picked up a compression tester. =( The front rotor bounces evenly to around 70psi and the rear bounces evenly to around 90psi. So it looks like I have damage on at least two seals in the front rotor. Very sad.

So, questions for the experts out there.
- Would one damaged rotor with the above compression be enough to prevent it from starting, or is there likely another issue as well?
- How complicated is a rebuild? I have previous experience replacing head gaskets, valves, piston, rings, rods, and rod bearings, also normal front and rear main seals. Obviously rebuilding and replacing the seals in a rotary engine is not exactly the same as these things, but is it significantly more difficult?
- With the above pressure, would you expect i can replace seals only, and not have to get housing machined/replaced? Or is there no way of really knowing until I disassemble the motor?
- What would you expect to spend on parts for a rebuild? Should I plan to replace all the seals including the ones on the rear rotor and replace bearings as well?
- Is this something I should try on my own? How much time should I expect it to take as a first timer, discounting time to remove and replace the engine?
- Anybody want to buy an RX-7, lol?

I had a previous post that has other information about my car. Only real updates, are that I now have a datalogit, and it doesn't run at all anymore.

Thanks for any advice or comments.

 

Rebuilding a rotary is easier since you don't have to have any machining done and there are far fewer moving parts.

That said, I would bite the bullet and have a professional do it, having pulled a rotary engine apart twice myself (and doing it wrong the second time). Meaning a rotary specialist, not a Mazda mechanic (very very few Mazda mechanics are actually qualified to build rotary engines).

 

To clarify the compression test results, on the front rotor I saw even bouncing to ~70psi with the schrader valve removed from my compression tester. With the schrader valve installed I got 85psi on the front rotor. For the rear rotor, I observed uniform bouncing up to ~90psi with the schrader valve removed and ~108psi with it installed. This was in both cases on the leading plug and with a cold motor. Based on what I have read on this and other sites particularly the write up on racingbeat, this pressure of 85 should enable me to start the car without a huge amount of trouble. If you agree and think there is something else I should check, please comment with your recommendations.

Thanks!

 

A 20 PSI difference between the rotors alone probably warrants a rebuild, even if the engine isn't "blown." You might be able to reuse all the original rotors and housing if you are lucky.

Take it and get it checked with a proper rotary compression checker (sold online for about $300 I think) if you want to know for sure.

 

Thanks for the info Valkyrie, mind sharing what went wrong specifically in your second build and the result? How much was your budget for the rebuild the two times you did it?

I understand about having a person who knows how to do it. Unfortunately, my money is kind of tight on this project. If I can't get the car back running for a reasonable amount (couple grand and some sweat), I may have to sell it. I bought the car years ago when I was young (and dumb) and payed someone else to do everything. Now that I am old, (and still dumb) married, and have kids, it seems I don't have the money to pay anyone else to do anything, and can rarely find the time to do anything myself. I can commit the time to this project now, but that doesn't mean I want to make a bigger mess of it than it started by throwing a bunch of time and money at it and still having a broken car.

Anybody know any capable rotary mechanics in the SC or Charlotte areas?

Thanks

 

It's a tough car to have on a tight budget. I've been there when my daughter was in college about 10 years ago. I second the professional if that's a viable option at all. If you can R & R the engine yourself and transport it a reasonable distance a shop it will probably save you quite a bit.
Do you have a copy of the Factory Service Manual? If not, download a copy and take an evening to read thru the engine section. It will give you a better idea of what's involved in the rebuild. There are also tutorial videos available from (IIRC) Pineapple Racing and some others that go thru the process, including pulling the engine. That said, the BEST is someone that's experienced, has a few of the needed specialty tools like an engine stand adaptor, micrometers etc., and someone EXPERIENCED that can hold your hand thru the rebuild...AND reliable enough that he's not going to leave you stranded half-way thru. You also need a relatively clean, well-lit area that you can close off from those kids and all the basic tools. Air or cordless tools a plus and a utility sink or some big storage tubs that you clean/rinse parts in. I'd figure about 2k for parts minimum. If you're housings aren't reusable that goes up considerably, but your earlier post said it was a remain without a lot of miles, likewise bearings.

 

LS swap

 

Shut yo mouth

 

 

I didn't do a proper rebuild, I tore it apart to fix some blown water seals.

 

Realistically you are probably going to be looking at 2-5K+ depending on what you find after opening the motor up. Here is the rebuild kit prices from atkins to give you a good Idea. Shopping around might save some, I dont know for sure. 93-95 Turbo Rebuild Kits
If it just needs soft parts great, but if you need new housing, Irons, or rotors thats when the prices is going to climb. Then its all the small stuff that will nickel and dime you, like new bolts/nuts, hoses, anything thats broken when stripping the long block.
As for local places, RotorSports Racing is over in Kannapolis, Addicted Performance unlimited just over in TN, and Rotary Resurrection again just over the line in TN are the place's I know off the top of my head thats within 3-4 hours of Charlotte.

 

If you want to start your rx7 try a push start or have a buddy tow you with a long strap. I have done this many times you will be amazed at how easy it will fire up. I have a slopping driveway and have started my rx7 many times this way. Oh if you have automatic your screwed!😣

 

If you have an automatic, youre screwed anyways.