NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   12a Exhaust Port Question (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/12a-exhaust-port-question-52571/)

diabolical1 09-06-2005 07:53 PM

Hi All,



I'm still working on my streetport 12A project (shown in the link). I haven't had the time, money or tools to dedicate to this thing as I would like to, but it's coming along.



Anyway, I finally got some tools to cut the exhaust ports and I've started, but I have a question. What do you guys use to fill in the gaps and holes in and around the sleeves? This is a streetport, so I didn't think it was necessary to remove them. Any insight or advice from those with experience is welcome.



In all honesty, I was advised to leave them alone because flow would not be impeded as long as I filled in the air injection holes and that's fine with me. I just wanted to get as many opinions as possible.



Thanks,

1

diabolical1 09-06-2005 07:56 PM

Also ... I wanted link you to the original thread because I have links to 2 other threads of interest. One is on the www.rx7club.com site and the other to a Paul Yaw writeup.

diabolical1 09-09-2005 12:53 PM

okay, i realize that this crowd is most 13B, so what do you guys use on 13B engines when you port the exhausts?

scathcart 09-09-2005 06:26 PM

[quote name='diabolical1' date='Sep 9 2005, 09:53 AM']okay, i realize that this crowd is most 13B, so what do you guys use on 13B engines when you port the exhausts?

[snapback]756869[/snapback]

[/quote]



I press in an aluminum plug into the exhaust port (zero tolerance, heat the housings, freeze the plugs) and then port smooth. I usually add a dab of green loctite to the plug, but with the exhaust temps, doubt it does much, and then dimple the edges of the plug with punch.

I cut the plugs from just plain old aluminum round and machine to fit.



I TIG in SS into the exhaust sleeves and use a carbide burr followed by sanding drums to get them back into spec, if I am keeping the stock sleeves.



I don't know what the 12A's look like for the exhaust port; I never deal with first gens.

diabolical1 09-11-2005 11:50 PM

thanks for the reply. https://www.nopistons.com/forums/pub...IR#>/smile.png do you have any links or pics of your work or process?



honestly, it sounds a bit more than i am capable of doing because i don't know how to weld and even if i did, i don't have access to a TIG.

diabolical1 09-11-2005 11:54 PM

1 Attachment(s)
here's a shot of one of the ports:



Attachment 21430

diabolical1 09-11-2005 11:56 PM

1 Attachment(s)
here's another:



Attachment 21429

scathcart 09-12-2005 06:20 PM

[quote name='diabolical1' date='Sep 11 2005, 08:50 PM']thanks for the reply. https://www.nopistons.com/forums/pub...IR#>/smile.png do you have any links or pics of your work or process?



honestly, it sounds a bit more than i am capable of doing because i don't know how to weld and even if i did, i don't have access to a TIG.

[snapback]757559[/snapback]

[/quote]





God, everyone always asks for pictures.

I'm one of those people that gets working building something and gets completely absorbed into it. I never remember to take pictures.

That being said... I'll try to find a few of them. If I can't, I'll take some of some I built recently.



You'll have to remove the sleeves to weld in the SS inserts... so if you have them out, you could just take them to someone. Shouldn't be much of a charge.



Without a mill or a lathe... I dunno how you would make the plugs and get them to fit right.





Keep in mind: Most people do nothing with the holes. That's why there are not many replies.

diabolical1 09-14-2005 04:53 PM

well i definitely appreciate your input thus far. i've been waiting for over a year to get this thing together and i'm sure i'll be waiting a few more months before i'll have the time to do much else, so i may decide to remove the sleeves and have them welded in the manner you mentioned or i'll just take the advice given to me on the other board and leave them alone.



thanks, scathcart https://www.nopistons.com/forums/pub...IR#>/smile.png



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