Assuming one buys an e-shaft and center plate, would it be possible to "piece together" a 20b? I suppose I'm forgetting something... tension bolts perhaps?

I'm thinking about building a special 20b. Only the problem is, with all the new parts (rotors, plates, etc.) that I'm considering, I'd be throwing away most of the original engine. So in this case it might be cheaper to just buy the parts I need individually. I'm not looking to do this on a budget, but rather to do it smartly. As it is, I have to take my time putting the pieces of the whole project together, so I'm not looking to rush it. But if I can save myself the hassle and cost of buying a whole engine when I don't actually need it, then great.

Oh, I should also mention that I was referring to the core of the engine. In other words, I wouldn't need the manifolds or accessories attached to a full engine.

 

good luck finding a center plate.
better to find a blown 20b if you can.
matt

 

i agree....scour ebay for blown motors...and pray to your god that the center plate is still good. people have been price gouging the **** out of them since they went NLA.

 

The center plate is not a problem. If you must know, I was considering the very expensive aluminum plates that Racing Beat sells.

Aside from the center plate though, is there anything else I need to focus on?

By the way, I was running some numbers at work, and a 20B with RB lightened 9.7:1 rotors and aluminum plates should give a weight reduction of about 55 lbs compared to a standard 20B. I am considering attempting to put the engine in a Miata, and thus every bit of weight savings possible would be nice, that is why I'm actually looking into the expensive bits like aluminum plates.

 

You'll need the turbos I have for sale

https://www.rx7club.com/showthread.php?t=545294

 

That would be your best bet, except that racing beat doesnt make the 20B thick intermediate plate sir.

 

Ah, actually I was wondering about that. "We offer a series of Aircraft Grade A356 aluminum alloy side housings to replace many of the heavier, cast iron stock assemblies found on all 1974 and later 12A, 13B, 20B, and 13G engines." I guess I assumed that meant they had all the plates, and just didn't list the thick one on their site.

 

In New Zealand, Precision Engineering manufactures a shorter e-shaft and will modify a 13B center plate to take the extra bearing and gear. That way you could use the alloy side plates that RB sells. The bonus would be an even lighter and shorter engine.
Beware though, I am fairly sure the RB plates have no intake ports; they are meant for PP applications.
Gary

 

Oh and one other thing. If you are not turbo'ing the engine, go with modified RX-8 rotors. You are going to have to have the engine balanced anyways.

 

Correct. I myself am looking for a complete set of aluminum plates and have called Racing Beat about this. As of right now they ONLY make the rear plate. They are currently developing the front plate and will not be done with it till the end of the summer.

Yeah thats not exactly true when it comes to the 20b plates. Since all they have is the rear plate.

The plates are custom made to order. So if you want stock\street\bridge ports they can do it.

 

no. do not use rx8 rotors. they are not meant for use in PP exhaust engines.

 

Counterweights?
That gonna be custom too?
I've seen 20B rotor housings for sale...
I've seen 20B e-shafts for sale...
I've seen 20B side housings for sale...

I've NEVER seen 20B counterweights for sale.


-Ted

 

^ If you buy a "super lightweight rotor assembly" from racingbeat ($3150 for 3 rotor sets) you will get all the counterweights you need.