walshy

Hi guys

Im Kris and im writing this from across the pond in the UK

I am currently looking at building a bridgeported motor on stock twin turbos to reach 400BHP+ now i have spoken with other people in the uk that have done it and it is do able

Now im looking at porting the motor myself and am struggling to find any information about it, i have seen threads with alot of post but not many pictures or videos, now i am happpy to read all the threads but im after pictures of Half bridge and full bridge ports to study and compare my future work to

Also videos showing the porting being done would be the most benifitial right now as i havent ported before but i have a few sets of dead irons to practice on

Please could you post where i can find videos on the porting itself and pictures of your work and any tips that i might find usefull,

Thanks for reading

Kris

Trots*88TII-AE*

iTrader: (11)

Welcome to the board Kris.

First off, make sure you understand what porting is accomplishing, specifically bridgeporting. It seems simple, but I didn't understand it when I first started. If you are already familiar with all this, disregard it. http://www.rotaryengineillustrated.c...ts-intake.html Now that said, I'm not sure that a bridgeport is the best way to go with stock twins, but if you are already set on it, that is your choice. Just remember that bridging (opening the port earlier) and at the same time closing the intake port later (and thus creating considerably more duration) will shift your powerband up in RPM, and the twins were not made to handle the large volume of air your engine will want at higher RPM. You may end up with a much less useable powerband vs. say a streetport. Food for thought.

Next, you would be best to either buy a known good template for the bridgeport (Racing Beat, Mazdatrix, etc.) to be able to repeat it identically on all irons, or make a blank template yourself, and draw out on to the template the leading and trailing tracks of the side seals. This is important because if you open the bridge too low or the main port too high, you can have the leading edge of the side seal dropping in the port, contacting the closing edge of the port, and eventually ruining the seal. Check out what Barry Bordes has to say about it, he says it best: https://www.rx7club.com/showpost.php...2&postcount=10 If you have a spare rotor, I would highly recommend cutting it out so you can see the backside of the cornerseal/sideseal area, and properly trace it out as Barry has shown. Plus it's fun.

Now, if you search on youtube for BDC (nevermind, here it is: http://www.youtube.com/user/bdc196?feature=watch) he has some videos showing porting, even some half-bridging I believe. He does very nice work on ports, so it is a good reference. He also has a website with many galleries of porting pictures that you are after.

Make sure you have the proper tools for porting, namely:

-Different sized carbide burrs, some round and/or tapered with a fairly large diameter for smoothing the main port bowl, and some cylindrical or similar, small enough in diameter to work inside the bridge without messing stuff up.

-Flap wheels of different grits to smooth the runners, as well as help smooth imperfections in the bowl.

-some finer porting stones of different shapes

-a mandrel and many different sizes/grits of sandpaper roll-ups (can't remember what they are actually called)

If you search on this site, and spend some time in the "Rotary Engine Building and Porting" section on the NoPistons . com Forum : http://www.nopistons.com/forums/foru...g-and-porting/ you will get MANY helpful tips. Things like ducktaping around the ports before starting, putting a proper bevel on the closing edges, etc. Especially useful is the FAQ section on building and porting

When it comes down to it, pictures may or may not really help you in the long-run, it's going to come down to practice and experience. I would definitely recommend spending as much time as you can on junk irons until you feel comfortable enough to do them on the good ones.

Good luck