EXE-UK

After trying to find up to date info on this topic, I've given up and decided to post a thread. I can only seem to find very old threads. Maybe I'm doing something wrong?

I have an engine completely stripped, rear bearing went so just needs new eshaft and bearing (+ rebuild bits).

I have a budget of around £10,000 to spend on the car over a year, but I will be doing as much as possible myself.

The housings and rotors look fine to me, however is it worth having them examined professionally?

Next step is porting. Ive looked at the templates, heard about taking it too far and too early... I'm trying to find a clear answer/blueprint as to the optimal porting sizes and shapes for bridge porting, or as close to this as possible. At present it is 100% stock, the end product will be F.I, from what I see, porting specs vary depending on N/A and F.I?

The exhaust ports are a huge concern and I can't seem to find and modern conversation on this subject. I'd imagine there have been some advances in the last few years, but I can't seem to find any info. (maybe I'm not looking in the right places?)

Aside from blowing my budget on lightweight housings and rotors, is there anything else that can/should be done while I'm at this initial stage.
Looking at oil jets, balancing, better seals.

Thanks.

EXE-UK

Found porting resource, so.don't worry.

http://www.jascoautomotive.com/forum/viewtopic.php?t=37

And a good YouTube video that I'm trying to find again

Mysterion

For a video on rebuild and porting, try searching YouTube for 76 Mazda Cosmo uploaded by aaroncake. He does a fully detailed rebuild of a 13B engine complete with porting on video(s) and would seem to be well-versed in same as he built his own 500 HP RX7 plus other rotaries.

niteshade247

Rx7 13b is not the same as a rx8 13b so watching a 13b out of a 7 will not help with a 13b rx8 rebuild.

Mysterion

Firstly, I mentioned his RX7 just to reassure readers that Aaron knows his stuff. Secondly, the process is the same for any rotary from a 12A to a 13B NA, 13B Turbo, 13B-REW or any other variant of the 13B. The basics he shows clearancing, installing apex seals etc, apply to all 13B engines making this a good video for all potential rebuilders to watch just to get an idea what they are in for.

Williard

iTrader: (18)

The process is not the same actually, you are incorrect.

The RX8 and RX7 are two similar engines, but NOT the same. This video will get you in the ballpark, but not to the whole show.

And just as an addition, just because someone know's RX7's does not mean they know RX8's.

That is told to every single new member that comes in and says "o but i owned 3 RX7's"

Some of the information is similar. I.E. for oil changes, and general care of the engine.

But BUILDING an RX7 engine is NOT the same as building an RX8

If you think I am wrong call any reputable builder, Pettit, BHR anyone and the same information will be told to you.

Hope everyone is having a good day

Travis

niteshade247

And porting is very different in 7s and 8s critically so.

MolsonB

I'm trying to think of some differences in my head....

o-ring on dowel pins?

niteshade247

Port locations is one big difference. How the roter moves is another. In porting the cooling area is so close to the exhaust port one slip and your done new housing time. Point is yes it a rotary but it has critical differences from the rx7.

MolsonB

Ah I meant in assembly. Yes it's not step by step the same putting the housings back together but *I think* if you can comfortably assemble a 13b, I don't see a big show stopper difference in 13b-msp assembly. If you had the Workshop manual for reference ofcourse. Again this is just 'me thinking'...

niteshade247

The basics are the same as far as I know. If you can put a 7 engine together I would think you could do an 8. But the changes come in when moding the engine there are huge differences.

EXE-UK

Went for a half bridge port, just waiting for new eshaft and clearanced rotors.