Difference 12A to 13B?
02-21-03 | 02:39 AM
#1
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Joined: Jan 2002
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From: Port Orchard, Washington
Difference 12A to 13B?
I've got two cars with 13Bs in them, so I haven't really looked at the 12A. A friend asked me if the bell housings were the same and I didn't know. I know that manifolds don't interchange without adapters,but what about bolt patterns on the bell houseing and being able to bolt a 13b to a 12a trans. Are the flywheels/clutch different? He wants to bolt a rotary into his kit car, he bought an adapter off of ebay and wants to know if it will fit the 12A and 13B. Also, what about the '93-95 rotary engine is it just a 13B or is there a difference? What is interchangable between the 12A &13B, if anything.
02-25-03 | 06:59 AM
#3
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Joined: Mar 2001
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From: -
Here's two websites your friend should know about:
http://shoptalkforums.com/bbs/cgi-bi...ne=&LastLogin=
http://shoptalkforums.com/bbs/cgi-bi...ne=&LastLogin=
The first one is about engine conversions (lots of rotaries there!), and the second one is about kit cars. Lots of good reading material.
http://shoptalkforums.com/bbs/cgi-bi...ne=&LastLogin=
http://shoptalkforums.com/bbs/cgi-bi...ne=&LastLogin=
The first one is about engine conversions (lots of rotaries there!), and the second one is about kit cars. Lots of good reading material.
02-26-03 | 10:14 AM
#4
Old [Sch|F]ool
Joined: May 2001
Posts: 12,637
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From: Cleveland, Ohio, USA
All '74-02 rotaries have the same bellhousing pattern. I do not know about the new side port engine at this time.
A '74-78 13B and '74-up 12A are practically identical. The 13B just has 10mm wider rotors, and everything related to engine length is stretched accordingly. Side housings and front covers interchange directly, as do all the internal engine seals not related to rotor width.
The GSL-SE engine is essentially a '74-78 13B with 6-port end housings and injector bungs in the center housing. You could mix and match to make a 6-port 12A (if you can find an intake manifold for it... 6-port carb 12A's were sold in the home market) or you could make a 4 port 13B, and the GSL-SE center housing can be used in any of them to make fuel injection more painless.
The '86-up engines have different intake manifold bolt patterns, thinner 3-piece apex seals, and the water seals were relocated to the side housings. There were other minor changes but the basic blocks can be swapped provided you are aware of the intake bolt pattern issue. A 85-earlier front cover can be swapped straight on to allow the engine to be fitted easily to a '85-earlier chassis.
A '74-78 13B and '74-up 12A are practically identical. The 13B just has 10mm wider rotors, and everything related to engine length is stretched accordingly. Side housings and front covers interchange directly, as do all the internal engine seals not related to rotor width.
The GSL-SE engine is essentially a '74-78 13B with 6-port end housings and injector bungs in the center housing. You could mix and match to make a 6-port 12A (if you can find an intake manifold for it... 6-port carb 12A's were sold in the home market) or you could make a 4 port 13B, and the GSL-SE center housing can be used in any of them to make fuel injection more painless.
The '86-up engines have different intake manifold bolt patterns, thinner 3-piece apex seals, and the water seals were relocated to the side housings. There were other minor changes but the basic blocks can be swapped provided you are aware of the intake bolt pattern issue. A 85-earlier front cover can be swapped straight on to allow the engine to be fitted easily to a '85-earlier chassis.
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