Maxt

Find someone with a milling machine and real tool if you plan on making a running engine, putting a 500 dollar housing under a 15 dollar hole saw is not a good plan, forget about it....Plus getting a holesaw that exactly matches your tubing, probably isnt going to happen. A hole saw distorts as soon as it hits metal and it would be nearly impossible to get the inner ledge amount right.

I remember Scalliwag was doing it with a hole saw , but was using his lathe as a drill which has much more control that you ever will with a drill press, then he was turning his tubes down to get the best fit possible, either way its a job for machine tools.

If the engine is shelf prop for your garage, go nuts, but any real machinist should be able to whip that off in an hour for a very small fee.

If you can get the tube and hole within .001, you press fit with loctite and it wont ever leak or move, even without devcon filling the cooling passage. The trick is, is to cut your first hole smaller, its cut just just tad smaller than the ID of your pipe, then you cut the outer wall to the Od of the pipe -.001, then cut a ledge recess -.001 on the inner wall for the pipe to fit into without going all the way through the inner liner.. That way you are left about 1/4-3/8 of material to shape the port to the port timing you want with a diegrinder. Cutting that accurate is hard I know, my mill has a DRO to .0001 so with real tools its a pretty easy job, find some(one) with real tools.





And The housings should never be welded either..

shainiac

Here's Scalliwag's p-port build.

http://www.rx7club.com/showthread.php?t=144200

IIRC, he turned the hole saws down in a lathe to get them true. He also replaced the 1/4" bit in the center of the whole saw with a 1/4" steel rod to keep the saw from walking. Seemed to work well for him and the motors he built for Ken Sheepers.

sen2two

thanks! this is just about everything i needed to know!