Greetings,

 

One of the things that's always bothered me about making a PP housing is leakage.  I've heard very experienced folks say that eventually, any PP housing you make will leak, and it's easy for me to imagine that happening.  I don't think I've heard the same thing about factory housings though.  How are the ports installed in the factory PP housing? 

 

The other problem with a conversion is the side ports.  I know people fill these with their favorite epoxy, but I'd worry about that coming loose, and getting into the rotor.  How much would it hurt the PP operation if you just sealed the ports on the outside of the side housings with a plate where the intake would have been?  

 

Cheers,

Rusty

 

Hi Rusty;
I have heard of several leaks with homemade PPport housings.  Factory housings are cast.

I have read of several instances where epoxy filled sideports have debonded and fallen into the engine ruining someone's day.
It only takes a few hours to make custom fit plugs.  I grabbed some scrap 1"? aluminum tube, bent to shape with a vice, cut and ground/sanded to fit.
Not perfect, but they will not fall into the engine.

If you are really concerned about leaks you can fill the irons as Lynn suggested.
You could also add another leak barrier layer of rubber or silicon with different thermal expansion properties than the JB weld in the water passage.

BTW - JB Weld does not create the best surface bond to Aluminum without some surface prep - try some on alclad.  Etching works.  You could also sand the aluminum with epoxy on the surface to prevent the oxide surface from forming.  Another form of mechanical backup to prevent the tube insert from falling in/out of the engine is probably not a bad idea - Welding, brazing, threads, bolts, step, press fit...

The hardest part is getting up the nerve to cut into a perfectly good housing...practice on a junk housing first.
There are several threads at  rx7club.com and nopistons.com

Have fun!
Cary