Due to a time crunch with this years drift season opening on my birthday(04/03) i am trying to get my Half bridgeport motor back together after a catastrophic failure. The motor is originally "poorly" done half bridge with 9.4 compression rotors in it, pfc, and 1680 secondaries, garret 60-1 t4BB. Well one rotor had the bearing chewed to bits when the rear dow land cracked and i lost oil pressure without realizing it, while the other has a side seal STUCK in the rotor. So i have 2 s5 9.7 rotors laying and have replaced and reported the irons and am currently attempting housings porting (since they are wasted as well)

the basic question is will the 9.7 cr rotors cause a huge problem compared to the 9.4. Obviously some retuning will need to happen, but are there certain things i should look out for, or do?

Sorry this is my first rotary rebuild and i am trying to do things as best as i can with what i have available to me so please go easy. also i will be posting pictures of porting work and what not as i go along so maybe some pointers if you all dont mind?

 

Other than tuning, you'll need S5 front and rear counterweights.

 

covered! keep going

 

Measure everything. Then clean it and measure again. If you think it's out of spec try to replace it. May be common sense, but I can see people skipping things just because they don't have the right tool. Good luck buddy, i'm sure you'll do fine.

 

Yeah tomorrow is double check all my readings for sure. I find all of this fascinating because as a vw tech at a dealer it pretty cut and dry. Your motor blows we put you in a new one. So this tedious rebuild is fun but a new area for me and i just wanna make doubly sure i am not missing something

 

alright so here some internal pictures and i have some questions after looking at some more bridge ports. heres the one that was in it to begin with


it looks rough obviously, but the real question is should the port be longer and wider? most ports i have seen are longer like almost to the top of the main port

heres a look at mine and i have obviously over ported into the water jacket. I have a experiment i am going to run with some PRK-99 by goodson. Its rated to 500 degrees and drys like a rock. I seriously have some in a old jar that wont scratch with a scribe tool. But again a question of to put it on front and back or just one side?




should i leave the small casting ripple alone in this picture? As i understand it it could act as a swirl and help to atomize fuel? maybe BDC will chime in...

 

I wouldn't use that iron anymore, especially if you are going to be using it for competition drifting, I'm going to bet that your PRK-99 will give out.

 

+1 I'm not sure what prk-99 is, but repairing that scares me. I would not want to build the keg and wonder each day "how long will it last?!"

 

well we will wait and see on that one, if it doesnt hold then oh well spend a couple hours repairing and 250 bucks on a new iron oh well experiment failed.

anyways more concerned with the length of the cut for the eyebrow. If you ever saw the rebuild video with bruce he uses some stuff that like 150 degree rated or something to smooth out the secondarys on an n/a.

 

replace it, don't be foolish... your going to ruin your rotors and housings and irons when that thing comes apart again... this is why rotarys get a bad wrap. Half ***-ed work.

 

That housing is junk. not bad if you want to convert it to some decoration or something. Someone will probably buy it off 10-20 bux.

get a new one.