I bought an RX-7 a couple years ago with this problem but never researched on what it took to repair so I ended up scrapping the project.

Now I bought another RX-7, this one in a little better shape body wise, but same problem...popped water jacket.

The previous owner told me the car hadn't been run long that way, but just for kicks lets say it was ran that way for a while.

What will it take to repair? What kind of issues am I looking at in the future if I were to keep this motor? Is this even salvageable?

Help for a Honda head plz plz :-D

 

If the engine has, in fact, a failed "water jacket", meaning I presume a failed coolant seal or seal channel, you likely will be rebuilding or replacing the engine. If you rebuild, you may need to replace one or more of the housings and/or rotors, plus the usual wear components such as seals and "O" rings. If you do the work yourself, you're probably looking at $1K-$2K, assuming the housings and rotors can be reused.

In addition, if the engine has been sitting idle for a long time with the coolant in the "combustion chambers", there could be considerable damage from rust in which case you might consider just buying a remanufactured engine from Mazda.

Only way to know the extent of the damage is to disassemble the engine and have a look and to make sure the internal components are within the factory specification. To get an idea of what a rebuild entails, get one of the several DVDs that walk you through the entire process. Here's a link to one of them:
http://www.rotaryaviation.com/custom_mazda_engines.html

 

^ what he said.

You need a rebuild. You'll probably be able to re-use most of the parts but there is no way to know until it's all apart. "Coolant seals", "Water gaskets", etc mean the same thing - o-rings that seal between the layers of the engine block. Only a rebuild can fix that. (Block seal is a cheap temporary option but ends up damaging other things)

It's possible to do your own rebuild, and there is plenty of documentation out there. But it's not a simple task - small details can mean quite a lot. First rebuilds don't always go too well, so if you do try to rebuild it yourself seriously bone up on information and don't skimp.

Dave

 

It would be better to go to an expert if you want 100% success.

 

Read this thread, might be an option for you...

https://www.rx7club.com/1st-gen-archive-71/engine-coolant-seal-repair-maybe-750774/



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Sounds like how my motor went down. Started to run really rough when cold. Was told the water was leaking into the motor and would take several minutes to burn up.