vmiguel

So to keep thing short..ish, I found a 1980 RX7 in a junkyard, been there for around a month and half, and the guys working there tried to start it with no crank. Turns out the ignition switch was broken, I fixed it with a new one I ordered only hear the fuel pump immediately turn on and dump 20 year old orange stinky Gatorade into the engine bay. Luckily I had already pulled the carburetor to clean/ rebuild and used towels to block the intake so nothing fell in. Removed the fuel tank to inspect if there was rust and finding it completely clean. Great. Here is where I feel like I made a rookie mistake. I finished rebuilding the carburetor, and instead of putting it back in the engine and starting it to check compression or even see if it starts, I had the genius idea of pulling the engine and tyranny that I have been cleaning and making note of everything that needs to be either replaced or cleaned. I thought, this engine is probably good, I have some receipts of oil changes and repairs, there was only one owner as far as I'm aware, when I drain the oil from the engine, tranny, and diff, it came out clean with no glitter, the car is in amazing condition with only surface rust and a roughed up interior, no evidence of mice just a ton of little abandoned wasp? nests. However when I came to just the block (can I call it block?) itself, there was, what appeared to be a nice glob of JB weld or some sort of hardener that I ended up using a hammer and chisel to clean off, thinking not much of it. Mind you I'm still in the process of cleaning the block, its been sitting for 20ish years, the last receipt I found dated back to 1999 of September. Someone had already rebuilt the engine! Under the mysterious glob, there was orange? gasket maker, and when I removed the tranny, the bolts that hold the engine together have been marked.

So, this is where I need your guys advice, or at the very least what would you guys would do next if you were in my shoes.

Should I invest in a rebuild kit, I don't have a whole lot of funds at the moment as I had already ordered other parts (water pump, gaskets, thermostat, both master cylinders, etc. DAMM DO SOME OF THESE PARTS HURT THE POOR WALLET) and I was hoping I would get this rx7 out of here within a month or two since my collage classes are starting in a month and I'll have even less time and less funding.

Or should I trust a rebuilt engine that has been sitting for 20ish years, with a ton of maintenance receipts (which only a few are barely readable) hoping I don't blow up something. Mind you, the oil came out clean, and I doubt those junkyard workers would bother putting fresh oil, much less fresh tranny and diff oil in a 40 year old car. And the miles on the odometer say 87,XXX. It could be just 87,XXX or it could be 187,XXX,

I really don't know what to do next, and I rather not spend more money than I have too at the moment, but at the same time I rather not cheap out. Would you guys trust the engine if you were on a shoe string budget or would you wait and invest in a rebuild kit. I'd hate to see the car in my backyard gather dust as I go to class, but I also would hate if I damaged something just cuz I really want to have the car running. I'm kinda leaning towards just trusting what some other mechanic in the 90s did to it since I do have a backup plan.

There is some private local junkyard that has like 15 rx7s, a mix of SA, FBs, and FCs that I can pull a motor from if it comes to it. But it wont be cheap cuz not only is that a rebuild kit I'd have to buy, but the junkyard motor as well and even more labor. Idk.



before the tear down, my RX7

Toruki

That's a beauty and the 79/80's are especially loved. I bet it would clean up well!

People here will have more practical advice, better ideas, but at this point you're wondering if the engine is any good? First see if you can hand crank it plugs out, see if everything moves smoothly. Next step would be a compression test with the special rotary tester that will read all three faces of each rotor. A rotary shop would have one of those. A quick and dirty test is to use the starter motor to run it with no plugs in the leading spot and listens for "good wooshes".

People use JB Weld sometimes to block off ports when mixing/deleting intake/emissions stuff. I think more pictures would help folks understand what you've got

KansasCityREPU

iTrader: (9)

Depending on where the RTV/JBWeld was, it could have been used to try and fix, futally, an oil or water leak between the irons and housing. My guess is the oil o-ring. Sometimes leaks like these can be minimal.

You can still do a compression test with the engine out of the car and no carb attached. Just put the trans and starter on, connect jumper cables from a battery and a wire that you touch for the starter trigger 12V. Yes the engine will rock but it is doable.

vmiguel

Yeah I knew I should have updated pictures in the first places. Stupid me didn't think, oh these guys need to see it first if they want to help me.


I couldn't find any photos of the glob but it pretty much covers all the gasket maker and half of the M in the Mazda branding.

Still getting cleaned.

lots of gaskets have failed and time hasn't been nice to her

tranny is getting a good deep clean, everything shifted perfectly and she was covered in thick dirt and grease

face surgery too, cleaning, inspecting and eventually repainting the rusted spots

vmiguel

Oh shoot your right. A friend of mine mentioned quickly starting the car without the carb when I was rebuilding the damm carb. Guess there isnt much to stop me from doing it now, this might be my solution on what to do next, many thanks!!

Slow_sevens

Was in a similar quandary a year ago. I would test compression and water jacket seals to see if you need to rebuild.
For compression reattach tranny and starter as suggested above. I personally just used a regular compression tester with the none return valve removed and filmed the needle of the tester with my phone whilst cranking the engine. Play back the film in Shlomo and You should get nice even pulses at similar psi per pulse at regularly spaced intervals. If the pulses are uneven eg every third pulse is noticeably lower than the other two then rebuild time There is a good YouTube video on this but for the life of me can’t find it. You will know you have the right one as the commentator sounds like Bob Ross! Anyone got a link. Or…. Maybe you know someone that can loan you a rotary tester.
For the water jacket seal test Pineapple Racing sell a special gauge. A bit expensive, but I can loan you mine for the price of shipping. (I am in California). You do need to block off all the openings and ports to run the test, but it can be done with some plywood and bicycle inner tube as gaskets. Idea is you use the Pineapple Racing device to pressurize the water jacket with air, then let it sit for an hour or two and see if the pressure drops.
worst comes to worse and you find you need to rebuild it is not too hard. Download the rebuild vid from Atkins to get an idea of what you would be in for. As you mention, the cost of the rebuild kit is the hardest part.

t_g_farrell

iTrader: (1)

That glob of JBWeld was probably an attempt to fix the infamous dowel pin oil leak. Can be messy but doesn't mean the engines died yet. As mentioned do a compression and coolant pressure test and see where it stands. It may just run and leak some oil. Typical RX-7. Thats a nice SA, well worth the cost of a rebuild it its needed. Whats the interior like?

vmiguel

Yeah, I'm going have to reattach the starter and the tranny to do a compression test, hopefully its nothing but my gut is telling me a rebuild is coming and I'm going to have to accept the inevitable. The only fix for a leaky dowel pin is a rebuild, right? And thank you for the offer about the gauge, just looked it up, Pineapple racing (didn't know they existed, going to bookmark them along with the other places where i can get rx7 parts) and going to order one for myself as I do plan to get into rotary engines (potential 13b swap in the far future)

Yeah, I have a feeling I'm gonna have to take a bullet and invest in a proper rebuild, after some reading on this "infamous dowel pin leak" the only solution I can find is a rebuild. Fortunately, I've heard that rotary are simple to rebuild. As for your question about the interior. It has seen better days. Mostly sun damage, alot of the trim pieces have faded (trying to find a way to restore the original burgundy color it once had without further damaging the plastic pieces) and I'm going have to reupholster the seats or buy the seat covers from Racing Beat. Oh, someone took the shift **** so either I find another one, which has been a pain, or get an aftermarket one with the weird thread size this car carries. Pictures when I first got it below, right now, it is mostly stripped down, and keeping the carburetor safe

Slow_sevens

My son and I recovered our seats using the Racing Beat covers. Its a great product! Just have to add some common sense to the instructions as they are vague at best. And you will learn such things as what hog rings are... and why you should buy a new set of hog ring pliers rather than the useless ones that come with the covers.
And on the rebuild, my son and I have zero car mechanic experience and rebuilt our 12A using the Atkins Video and rebuild kit, plus a whole pile of help from the experts on this website. The Atkins video missed a couple of things that came back and bit me big time, so let me know if you go ahead and I'll point out the pitfalls that got us. Have also heard there is a better video out there, maybe Mazdatrix or Pineapple?

iowa_hawk1

iTrader: (4)

It's a lot of work to get it right, but SEM Burgandy Colorcoat is probably what you need. https://www.semproducts.com/product/...aerosols/15063. Be sure to watch the video regarding how to apply it successfully.

KansasCityREPU

iTrader: (9)

If that engine is good an does not need a rebuild, replace the pan gasket/sealant while the engine is out. I would save it as one of the last things before the engine goes back in. Also consider switching the pan bolts to studs.