12a engines

re japi · March 17, 2011, 05:12:39 AM

I didnt find any info about differences in 12a engines. Are there any differences in 1st, 2nd and 3rd series engines? Can i swap parts between them?

Lets say that i have -84 engine. It blows up. I find -82 "scrapyard" engine. Wicth parts i can use?

Thanks

David Nock (RIP) · March 17, 2011, 12:56:27 PM

I think the main difference is the oil cooling. Your \'84 S3 will have a beehive oil cooler on the engine, your \'82 S2 will have the cooler under the radiator. The S2 radiator is therefore shorter than the S3 so that the cooler will fit under.

The S2 clutch is smaller diameter than the S3. The S3 is 225mm.

I think the S1 engine is similar to S2 but might have points ignition. At sometime there was a power increase, but don\'t know which engine that came with. Possibly with the S2 but the increased clutch definitely came with the S3.

The engine builders on here might have better information.

Hope that helps

Steve-A · March 17, 2011, 01:46:56 PM

The only bit of use I can add is that I believe the power increase was from S1 to S2.

rei99 · March 17, 2011, 03:15:05 PM

Interesting topic. Signed!

captainbizzaro · March 17, 2011, 08:46:59 PM

http://www.rx7club.com/showthread.php?t=938481&highlight=differences+12A

David Nock (RIP) · March 18, 2011, 12:11:40 PM

Ahhhh....need to be specific here then.

I\'m referring to UK 1st Generation 12A engines, all of which were thermal reactor / carburettor types from the factory. That\'s right isn\'t it?

Weren\'t the US engines fuel injection in the later 1st Gen 12A\'s?; the link says no thermal reactor on the later engines.

Ian65 · March 18, 2011, 12:24:28 PM

Quote from: David Nock;749780Ahhhh....need to be specific here then.

I\'m referring to UK 1st Generation 12A engines, all of which were thermal reactor / carburettor types from the factory. That\'s right isn\'t it?

Weren\'t the US engines fuel injection in the later 1st Gen 12A\'s?; the link says no thermal reactor on the later engines.

as far as I\'m aware, all 1st gen 12a\'s were carb\'d with the exception of the 12a savanna turbo which was JDM only. The US fuel injected cars ( GSL-SE) were all 13b\'s.

A7RXY · March 18, 2011, 12:48:07 PM

I think you are right Ian, as I\'ve never read any different.

re japi · March 18, 2011, 02:19:28 PM

Ok, thanks for the info

vin likes diesel · March 18, 2011, 07:30:23 PM

can you run them without the thermal reactor and just have a normal manifold?

myatt1972 · March 18, 2011, 07:45:37 PM

Quote from: vin likes diesel;749886can you run them without the thermal reactor and just have a normal manifold?

Its a must !

captainbizzaro · March 18, 2011, 07:58:22 PM

Yeah deffo, ditch all that crap.

vin likes diesel · March 18, 2011, 08:25:15 PM

See! i told you i knew nothing about these engines.lol.

Ian65 · March 18, 2011, 08:31:03 PM

yeah, chuck that emission crap in the bin and free up those horses! Best bang for your buck is to put headers on it and a decent exhaust.

re japi · March 19, 2011, 05:30:54 AM

Ya, thats a 1st step. And you get save lots of weight when you lose that original exhaust.

2nd step is rebuild carburator. And port and clean manifold, so it will flow nicely. Line up carb to manifold and manifold to engine. Me and my brother noticed that they do not line up well. Its easy to do and you get few extra horses. (i would imagine) I dont know how far you can go with original manifold and carb. But if engine is stock, those modifications should help engine to breathe better.