RX-17

I need help finding somewhere to machine my 13b-rew rotors to 3mm. does anyone have any suggestions?

13btnos

iTrader: (1)

http://www.rx7.com/store/rx7/fdengine_internals.html $175 each rotor or CLR Motorsports (305) 235 3696 search his user name GT1-20b his name is Carlos very knowledgeable that's my choice of who to send your rotors to.

banzaitoyota

I recommend Carlos at CLR Racing.

Maxthe7man

Yes... Don't do it and save your money..... ....Many seal slots end up worse after the cut, than they were before the cut...Not only that the hardening layer of the rotor is removed during the cut..
While I happen to have it open right now, read page 44 of the RB catalog..

Project84

Usually, apex seal grooves are only machined to 3mm when the original seal is damaged or worn beyond limits. Increasing it to 3mm is cheaper than buying a new rotor. There isn't a performance gain to be had here. 2mm seals are quite capable of handling high horsepower applications.

13btnos

iTrader: (1)

https://www.rx7club.com/general-rotary-tech-support-11/counterweight-rotor-machining-443361/ His other thread states that his rotors are out of spec. So getting them machined to 3mm is the most cost effective method.

Maxthe7man

Cost effective in the sense of getting the motor back together, but the least cost effective in terms of engine performance or life...Max

RX-17

Maxthe7man: Can you give me a reasonable explanation as to why you are so incredibly against 3mm apex seals?

13btnos: thnx a lot for the help i think i will be contacting Carlos very soon.

Maxthe7man

Yes, its impossible to get them milled correctly, I dont care who is doing it. Yes its possible to get the apex seal slot to the correct width, however all the rotors I have seen milled end up with hour glass shaped slots. On top of that its more than just the right width, its getting in the right place on the rotor, so the corner seal relationship is right, and doesnt bind the apex seal up.
. As posted previously, you are removing the hardened edge of the seal slot, the tolerances are not guaranteed to be there after milling, and with the seal slot soft, will quickly wear to past tolerance again.... Then comes the fact that 3mm seals will float and chatter alot earlier than 2mm seals... In the end it doesnt have any safety benefits, the damage just shows up somewhere else, doesnt it make more sense to spend the time tuning out of the damage zone rather just shifting the damage around to the next place.. From my experience 3mm dont survive any better than 2mm anyway when it comes to detonation.. All the motors I have seen with broken apex seals were all 3mm motors..
3mm seal will retain more heat than a 2mm seal and is more likely to show greater effect from thermal stress than a 2mm, that is one of the key reasons mazda moved to the 2mm on the high output turbo motors.
Spend the money on tuning..
On my last Japan tour, I asked every shop I spent time at the same question
Knightsports=2mm
I-feelin=2mm
KKM=2mm
RE amemiya=2mm
Revolution=2mm
Arena=2mm
Irs=2mm
RS pantera=2mm
Anniversary racing factory=2mm

I could not find one shop that would back the retrofitting of 3mm seals, they all responded with generally the same answers which I gave you above along with "tune it properly"... Which I did, 20 psi on pump gas grocery getter with 2mm seals...

The 3mm seal thing is a hack fix, when someone detonates a piston motor, do you get the ring lands machined for bigger heavier rings, nope..You learn not to detonate the motor, same applies to the rotary, heavier rings/apex seals hurts seal and performance, so you end up pushing things further to try and regain power that is lost through added weight and inferior sealing..
I've had 3mm motors, 2mm aftermarket seals and 2mm stocks seals, nothing seals as good or makes as much power as stock 2mm seals...Max

RX-17

wow i really appreciate that explanation. there are some very good reasons in there and now im gunna stick with 2mm seals. Honestly, thank you for taking all that time to respond like that. I am trying my hardest to rebuild this engine right the first time. I dont know u are willing to and/or someone else explain the good/bad between 1,2, and 3 peice 2mm apex seals like maxthe7man did on 2mm vs. 3mm? i havent found enough about that to base a descision on. thanks a lot!
addtition:Also, the good/bad between the different materials of apex seals. theres no way i can afford ceramic so i dont need to know about that. i havent seen anything from any manufacturers about the difference between steel or carbon. is there any other material other than steel, carbon, or ceramic?

1sgen

iTrader: (1)

i do agree with max and his explanations if we where living in a perfect world , with mechanicals or electricals there is no such thing ,all it take is a faulty fuel pump relay or a bad connection or a sticky solinoid on a boost controller which is beyond anybody's control and your engine is toast. i do agree that if you tune the engine right there is no reason for 3 mm seals but you or any tuner make one mistake bad enough and puffff there goes you engine , we are human and we all make mistakes, but what i totaly dont agree with is that the 3 piece 2mm is the best. no my friend they are actually the weakest . they might seal better but they are the weakest and if you have them in a test they will break first when pushed . i have built engines with 1 piece, 2 piece and 3 piece and my pick if you where to stay with 2mm is 2 piece unless you are planning to get into it again.
my 2 cents
thanks

Maxthe7man

In the end it doesnt matter perfect world or not, detonation breaks motor parts, 2mm or 3mm...

1sgen

iTrader: (1)

it will take alot more detonation to brake a 3mm than a 2mm ,tried and proven

RX-17

the good of 2mm definitely outweigh the good for 3mm. theres just a little tiny bit more room for error with 3mm possibly. But detonation can create pressures of 150,000 psi so i do not belive that 1mm is going to matter. plus why would u want bad sealing and compression at low rpm and chattering at high rpms. personally with all the facts in front of me im going with 2mm. thnx though

1sgen

iTrader: (1)

i had a hks ebc3 go bad on me while running a 1/8 mile my boost hit 18 psi my engine was tuned to handle 10 and my 3mm seals survived , my end plate did not :-)