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iTrader: (20)

I just found out that my motor had been ported before and had 3mm apex seals in it. My concern is that whoever did the porting did not port the intake side at all and ported the exhaust ports up. Which I heard was a bad thing. Do I need to get new housings or will they be ok? I am having my motor Race Ported down at BNR and he said it should be ok, but I want a very reliable motor so if that is a really bad thing then I want to get some new rotor housings for it. What do you guys think? Thanks, Scott

trickRX7

Ah ha!

So the guy actually had the engine done over by Pettit?

Good to know I guess.

What caused it to come apart?

Later,
Wes

Rotortuner

#1. please start by telling us what kind of car and motor you have. The difference in the port between what a 12 would use and a 13b turbo are quite a bit different. I looked at your profile and it said you have a 93 R1 so i take it you have a 13b turbo. Twins? single?
#2. There are many different techniques out there and some people say you have to leave the exhaust port closeing timing alone other move it way up and have had very good results. Depends quite a bit on which turbo your using etc. So what if they did go up are you really willing to spend another $950 on another set to turn around and pay another 200 to have them ported? If so then you have more money than any one i know on here.
#3. If BNR said it OK then i hope you trust their word because they are the ones building your motor or at least porting it. So you shouls be OK.

CJG

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iTrader: (20)

I just wanted to make sure that it will be ok. When he said it was a big no-no to port like that it makes me wonder if I should just replace the housings and have it done right the first time instead of covering up someone elses mistake. I agree with you that I shoud trust BNR and I do. He said it "should" be ok, that means it is a questionable part. So if anyone else has had any problems with this type of thing then I would like to see if they cared to share there own knowledge with me.

About Pettit doing it.... I am doubting that they did it but I am not posotive. That is who I was told did it and that is where all the bills came from but that was only like 10,000 miles ago. So I am having a hard time beleiving that a world famous rotary builder would sell a motor that was done wrong and only ported on one side. Seems kind of odd that my water seals went out so soon if it was true. But I honestly don't know. Scott

RICE RACING

Well if it makes any difference to you, I have mine ported up as far as the housing will allow before leaking water into the combustion chamber

They are very very large, I have not had a problem with this style, the extra overlap gives the engine a fatter flatter torque band and lifts the peak power speed.

I use a large exhaust housing and proper race designed header to take advantage of the extreme exhaust porting. I have had no relibility issues at all. If the engine is tuned right then you should experience no problems.

voodooracing

i have mine ported upwards also. there is no actual proof that is a NO-NO to port it upwards.
Porting the exhaust port helps letting out more exhaust gas. By enlarging it upwards not touching the bottom, will allow the same duration of combustion. But the bad thing is it induces slightly more overlap.
Porting exhaust port downwards will allow more exhaust gas to be released after combustion. But since the port is opening sooner. The combustion will end sooner. It might take away slight power at low-mid powerband, but will reduce the chance of preignition since the combustion is not long.
It depends on what kind of driving you need the engine to perform under, and how the engine builder like to make power. Like creating a personality for that particular motor.