I have the option to buy this engine from a friend. My question is can i make it fit in my 85 gs? I have a spare single dizzy front cover but will it bolt on? and will my trans and everything else bolt up?

The reason I want this engine is first off, my first teardown and rebuild, I want to make my owne EFI intake and use the megasquirt ECU I have had so much luck with and tune it for a dailly driver. My current 12a in the 85 runs strong and i dont want to open it up, this way if the engine pops that i rebuilt i wont feel so bad.

 

answers to ur ?'s is yes and yes.

 

A better answer would be yes but why bother? Twin dizzy engines with 6mm carbon seals are vastly inferior to later model engines.

 

The FB tranny bellhousing won't bolt to the rear iron of a twin dizzy engine. I wouldn't bother trying anyway. For daily street use, the old twin dizzy engines just aren't nearly as good as the 74 and later engines.

 

it's true about '73 won't bolt to a '74+ trans.

 

True in terms of sealing, but those 6 mil carbon seals are quite friendly to the housings.
Id take a set of unknown condition early housings vs. later ones any day.


Something about the old twin dizzy motors is just so cool as well. They just look oldschool, and if you tear one down its wild to see the mammoth seals on the rotors.
Theres just something oddly compelling about those ol beasts..They may not be the birth of the rotary engine, but they are definately a piece of its history!

 

I have one. I haven't felt a great need to rebuild it.

 

so 73 and older use the 6mm apex seals and twin side seals?
are these also the top mount starter, thats why the bell housings wont match?

 

What are you smoking? Early engines are notorious for apex seal chatter on the rotor housings.

 

Perhaps, but Ive seen a couple "junk" engines with low compression torn down that had perfect housings so I cant fully agree.

 

Yes, the 73 and earlier engines used 6mm wide carbon apex seals and twin side seals. There were two different bellhousings for the 73 and earlier engines with a manual tranny. The early engines had a top mount starter but sometime in 73 Mazda changed to a bottom mount starter but neither type of these bellhousings will bolt to a 74 or later engine.

 

They are a piece of history and it's true that the 6mm seals never ate the chrome out of the housings. The old twin dizzy engines were tough as nails...but after they had about 30k miles on them they would start hot for anything. Having one as a daily driver during the 70's, I became an expert at finding a hill to park on if I wanted to re-start it while the engine was still warm.

 

That's why that RX-2 engine in the MG had so much trouble starting. Well, one potential reason anyway. I'm glad I did the research and took the time to swap in a 13B now.

 

Yes, the early carbon seal 10a's and 12a's are really a pain to get started hot once they have a little wear. You are definitely better off with the 13b in the MG.