Hello there,


My name is Neal and I own my second FD since 2004. Ever since i got into rotaries, the 20B has been a dream but I never got past the 13B unit.

I'm in Europe, so even if 20B's are rare in the US, they are even more rare over here.

Having researched quite a bit over the past years, i found out that a lot of parts of the 20B engine are interchangeable with 13B engines.
Basically, you could build a 3 rotor with only the 20B exc shaft and thick center(rear) plate. All the rest could be sourced elsewhere.Even with a few advantages (like bigger exh ports on 13B's)

Now... I would like to know what you would need from the 13B engines (FC or FD) to build a 3 rotor. possibly with advantages or disadvantages.
Maybe it may be a guideline for others as well.

I'll start of.... Feel free to copy the list and adjust with your comments/additions

20B parts:

- excentric shaft
- center rear plate
- short tension bolts for rear section


13B

- Housings ?
->how about those exhaust port size compared to 20B's?)
->what about water jackets?

- Stationary gears?

- front cover? FD should work? what about timing pick up?

- Plates/Irons? front should work, center as well, rear can be either from manual or auto acc to what gearbox you want to run and available adaptor plates for them (T56, FD gearbox, etc)
-> how do the intake ports compare of the different 13B plates compared to the 20B thick center plate?

You see, the base is the short block, anything else from there can be custom build or taken from the 20B as desired.

Thanks


PS: Iw ould like to add that, unlike this looks like a cheap *** story to build a 3 rotor, we have very strict regulations when it comes to engine swaps...it's forbidden. The fact that rotaries are very rare over here and the "13B marking" would be on the engine, would help me get through tech inspection.

 

It is far easier and typically less expensive to just source a 20B long block. On the used market the thick iron and e-shaft add up to the average 20B long block cost.

You have forgotten about the intake mainfolds, oil pan, pick-up tube, fuel rails, etc.

None of the FC irons can be used, and the FD irons will need a lot of porting to get the runners to the size of the 20B. Any FD iron would also need to be machined to accept the larger diameter bolts, the front iron would need holes drilled through it for the front bolts.

There are bolts that run the full length of the engine as well as short front section bolts.

Rotors and rotor housings can be used. Rotor housings also need to be drilled to accept the larger diameter bolts.

 

Thanks, that's duly noted.. and i completely get your point.. but having followed the 20B engine prices go up from 2000$ upto 4500$ (that's without shipping to Europe), the cost balance is changing over here.

I have some friends who are metal fabricators and such, so if needed, some of the mechanical work could be done cheap.

An additonal question.


Currently I have big streetport 13B with Gt40R (4088) turbo on it.

Would that turbo be useable on a 20B/3 rotor? Not looking for big numbers here, about 550 hp in the 'most reliable rotary' way. We have small roads so it's all about low end power, there is no need to go 300km'h on the freeway...

A 13B can do this but the sound of a 3 rotor is just beyond that

 

Might as well build a 4 rotor and run it N/A.

 

You would need a Cosmo Re block and then all of the 20B specific parts..

Can it be done this way? The answer is yes.. Is it worth it to do it this way? The answer is No. Will it cost you alot more money to do it this way? The answer is Yes. Will you have a serious hardtime finding the 20B specific parts? Hell YES!

Are you the 1st person to ever consider sourcing the parts this way? The answer is NO..

Threads like this pop up about once every 3 or 4 months..



Buy a longblock= Getting all the parts all at once..

If buying a longblock is out of your price range, then you should stay REW...

 

the 20B long blocks aren't that rare, we've got more of those than good 13BT parts....

anyways, the rotors and rotor housings interchange between the 13B/20B.

you must use the cosmo front iron, the 13B iron needs to have the front tension bolt holes milled out.

thin center the cosmo part should be used again, again 13B or 20B, a couple holes need to be milled for the big 20B tension bolts.

rear cosmo iron. same as the other two.

you need the thick center plate, and the Eshaft, and the tension bolts. the cosmo oil pan isn't available new anymore, so you get to make that or try an find a used one.

and then you need intake manifolds.

VS just buying a used long block, or someones unfinished project

 

Neal

For your inspection , you could always use 13B rotor housings and try to convince somebody that engine is still 13B, but 3 ROTOR sign on manifold is bit more obvious

And from my point of view, there are 3 ways doing it - buying 20B, building your own engine (like Teqheim is doing on 4 rotor) or your way.......and yours is seriously last resort. If you cant make your own eshaft and other stuff, its simply not worth trying.

You can always get 20B or whole Cosmo from UK or Japan and at current exchange rate its not that expensive. There is a lot more to it what will become expensive, than the block itself.

Regarding turbo for 20B, yours should do no problem, i am using smaller (GT35R) and it works good, spools about 1000 rpm sooner than on 13B

 

Thanks Higgi, we'll talk about that on FB or MSN :-)

I guess that says it all :-) and a 20B short/long block is the only sensible way to go.

@ Japan2LA.... thanks fo your reply... but looking at your prices for parts and 20B's in particular (even if they are so called 'low mileage' or perfect compression) is one of the reasons people start looking for other ways to do this.

I have never seen one of your 20B longblocks go for less than 4000$ in the past 2 years.

 

Sounds like you are dreaming out loud to me.. and that this swap is well outside your budget and know how.

If you cant afford to start with solid foundation ( a real 20B longblock) regardless of who or where you buy it from...then you most likely cant afford the balance of parts required to make it complete boosted or NA.

And if you want it for the sound and only 550 HP, that really makes no sense..

You can make 550 on your REW for much cheaper...

Just being real here

 

^ And this is why they are rare.

 

Don't be mistaken, I really know what this conversion would cost... considering subframe, ECu, bumpsteer correction, and other custom work...

I'm well aware that a 20B turbo configuration is capabale off putting down much bigger numbers than 550hp.

Thruth is, I want my car to work when I want it to drive it. And not take it to the very limit of it's possibilitiies to find it either not working, broken down or just too much of a handfull to drive it in a good way.

Again, I live in Belgium, Europe. Streets and traffic are nowhere like the US and overpowering is no blessing in any way.

On the other hand I like to work on projects and then drive them. Just not at all cost...

Japan2LA... reading my post again, I understand you might be offended allthough that was not my intention. I just wanted to point out that 20B engine prices have gone up fast and I'm looking for a cost effective alternative.

 

Find importers in your country (or neighboring) and start talking to them. That will cut down on a lot of the shipping cost right there. However keep in mind that $4k-ish for the long block engine is really a small portion of the complete conversion cost

 

'cost-effective' and '20B' don't really belong in the same sentence IMO

Lots of good advice here, but will you take it? That is the question

 

not to sound argumentative but after reading this thread i still have no idea why you are considering a 20b? if you want to build your 13b to 550hp, that would work fine. 550hp is still a way from the limits of the engine, and as long as it is properly build and tuned then its still a reliable car. 20b's are great but if your looking to save money then it not the rout to take. but to help out with possible engine buying try looking at www.jspecauto.com this site sells 3rotor twin turbo 20b for $3795.00 so theres your under $4000.00 20b

 

There's someone who sells 20b's here but they cost about 4000euros, if you're interested.

 

some good information on here....dznutz, who do you know on the site that sells the longblocks?

 

and did you mean sells longblocks here as 'in Europe' or as in 'rx7club' lol

 

I guess you're not really getting my point here :-). I know that the whole project will cost quite a bit of money and that is not keeping me away from it.

On the other hand, I can not see why I would want a 4000 dollare engine if I'm going to tear it down anyway to rebuild it and start from scratch.
I guess someone who would just like to buy the subframe and all other parts and drop in a stock 20B (maybe even with stock turbo's) would do just fine with a good compression engine.

I'm not...
and as for 'keep to the 13B' comments... you are right, it works... but then again... what did those guys inspire out here to build a 20B NA engine making less power than the OEm FD engine? Maybe just to have a project going and doing something different.
I'm one of those.

Once again, I'm not in the US, I don't care if the engine makes max output. I can't use it here anyway and the nearest drag strip is probably across the pond in the UK....

 

4,000.00 EUR = 5,861.50 USD

That's $1361.50 USD more than what I offer the "BETTER" C and D code longblocks for..

Good to know, maybe I should raise my prices for the overseas buyers?