ok so ,i might build a hybrid 4-port.

can i use the 1985 GSLSE rotor housings with the 12A side plates?

if i can, can i use series 5 n/a rotors and counterweights?

and will a racing beat weber manifold for a 13b 4-port fit this hybrid engine?

 

You can mix 12A and SE housings.
You shouldnt use 2nd gen rotors in SE housings because of changes to the shape of the housings and rotors.Racing Beat and other builders recommend against doing it,but there are people who say they've done it and not had any problems(for how many miles though, I dont know)
It should fit up,although youll likely have to do some port matching.
(easy grinding/smoothing)

 

yes ... what Steve said.

 

Connected to your other thread

 

How is the shape of the housings any different from the later or earlier 13b's?

 

i thought they all used the same epitrochoid pattern?

 

http://mazdatrix.com/eng13bsp.htm

 

Well,I cant provide an online link, but this is pulled directly from Racing Beat's tech manual.Engine internal section,page 48, paragraph 2 under rotor housing tips....

"Another significant,but not obvious difference is the actual shape of the peritrochoid chamber in 1986 and later engines as compared to 1974-1985 13B engines.While differing only in a few thousandths of an inch,the difference is enough that we do not recommend mixing rotors or housings from 1985 and earlier 13B engines with 1986 and later engines."

 

final: im buying a rebuildable series 5 6-port n/a , a turbo II engine with trans. and a series 4 13b front cover (probably get the Mazda factory racing dry sump front cover) so i can run a distributor, and the weber 51 adi carbs

final result :

hybrid 13b 4-port (bridgeported) on weber carbs,9.7:1 compression rotors and turbo II tranny shooting for 240rwhp


thanx for the help

 

it's easier said than done my friend

 

I am in the process of a hybrid 4 port 13B, I was planning on using GSLSE housings with S5 rotors. This is the first time I have ever heard of it being a bad idea to mix newer rotors with older housings. Anyone done this with no ill effects?

Edit: Although I am far from a rotary expert, given the small size difference, I don't see how it would have any noticable problems. The Eshaft lobe governs the motion of the rotor. The only possible problem I see is sealing. However, the apex seals are spring loaded, allowing them to move up and down in their grooves. If the housings were slightly smaller, it would only mean that the apex seals are a little more recessed. This would compress the springs more and give slightly better low RPM sealing. If the housings are slightly larger, the low RPM sealing would be slightly less, but I can't image this causing any damage or much power loss.

 

I have a good friend who just built an engine. 13B - GSL-SE engine.

SE Plates, SE Housings AND Complete S5 rotating assembly. Built by a builder with over 15 years experience. Used in a Supercharger application which I must say runs very smoothly.

 

I've seen the 85 housings with 89 rotors - but it was on a PP engine..

I don't know if that really helped or not..

 

That gave me some more confidence, I'm going to build it how I originally planned - SE Housings with S5 Rotors and 12A Plates.

 

I got old school 13B plates/-se housings and a S5 N/A rotating assy in my SA.. runs nice.. also a holley on it..

 

Yes, yes, and yes.

It's not a "hybrid" engine. '74-78 13B's used the same side housings as 12As. You'd just be making a '74-78 style 13B. Nothin' fancy.

 

damn! freaking chip.. everywere I look..

!!!yes you can use the 'se rotors and houseing with the 12a irons...

but what freaking gasket set and apex seals am i going to freaking buy!!!

 

74-78 seals and gaskets i belive.

 

really.. humm.. i thought it would have been some combination of 12A and 13B seals and gaskets. Can anyone confirm this?

 

The difference in the gasket kits is the width of the apex seals, 12A/13B, and the engine accessories that bolt on, i.e. intake. Side seals and the rest of the internal seals are the same, otherwise you couldn't mix and match the housings and irons.

You are basically building an old style 13B 4port, the 74-78 kit should provide you with most everything you need.