'79 Engine Seized/Carbon Locked
 

Hey guys, I'm in desperate need of some guidance. I picked up a 79 Rx7 from a guy (it was free, so he had no reason to lie to me) who parked it in 92 under a tarp and hasn't touched it since. It was left there because it has electrical issues. I've been following vipernicus42's decarbonizing how-to using atf, but I'm not having any luck spinning it at all, I've sprayed atf into the plug holes, left it for 24 hours (I can try in less time, but it's inconvenient for me). I've done this a couple times, but it's still stiff as all hell. Is diesel a good option? Please help. Sorry if this is in the wrong section.

If you can't turn it by hand you should tear the engine apart

^ yup

how long have you been doing ATF? If its been a couple days, just yank the engine, unlikely you'll get it free'd up, and IF you do, for how much carbon (if thats what it is) is in there, will just destroy the internals. Save the hassle, take motor out, you got it for free, you not out anything

Well damn, thanks for the help. Guess I need to learn to rebuild them anyways, may as well start here

If it has sat since 92, then it's not carbon, it's rust.

The engine will need to be pulled apart.

These videos will help you in the process of rebuild a 13B or 12A engine. While they deal with an older 13B from an RX-5 Cosmo, the engine internals are basically the same for any 12A or 13B. The only real difference is that on engines newer than '85, the coolant O-rings are in the irons instead of the housings as shown in this video.

The first video is engine removal. While it is an RX-5 Cosmo, an car that few will ever see let alone work on, the process will give you the general idea of an engine removal. Steps are similar for most rotary vehicles, it's the details that differ.


The next video is engine disassembly and some cleaning. This is an old carbureted 13B so the accessories bolted to the engine are different than newer engines. However the process of externally disassembling any rotary is about the same. Covered here is also flywheel removal (same for any rotary) and engine parts cleaning.


Cleaning of all engine parts continues in this video. Provided here are examples of how this is accomplished with a minimum of tools and supplies. It's a lot of labor to clean old parts until they are looking new again. At the same time, parts should be inspected.


Finally, here is the engine assembly. This video includes clearancing side seals, assembling all the seals onto the rotor, then assembling all the parts into a 13B short block.