dnlloran

Hello, It is me again, with another newbie guestion.
Will a 12a engine from a 1980 RX-7 fit in a 1984 RX-7 that had a 12a engine in it?
D.

vipernicus42

iTrader: (4)

Short answer: yes

Long answer: *might* need a different flywheel, and some other small mods, but the engine itself is a drop-in. Or at least should be.

Anyone else wanna chime in?

Jon

dnlloran

Thanks Jon,
I found a used 12a engine out of a 1980 RX-7, and was wanting to put that in my Rex while I rebuilt the one that is sitting in it now.
D.

pratch

Actually the flywheel is balanced to the counterweight in the engine. So if you switch the engine, you'll take the flywheel and starter with it.

Or rather bring the starter to the new car. Didn't mean to give the impression that the starter was somehow attached directly to the engine in any way

dnlloran

The person that is selling the engine says that he bought the vehicle for the (racingbeat) flywheel and carb., and that he does have a stock flywheel for the engine he is putting the (racingbeat)fly wheel on. is this going to create problems with either engine or my tranny?
D.

pratch

Here's (how I understand at least) how it could effect things.

A) Different year engines had different teeth ratios on their flywheels - hence why different starters have different teeth patterns and must be used to match.

B) Depending on the flywheels' weight and the counterweight installed, if those two don't match properly you will have some rotational instabliity on the engine in addition to putting unbalanced loads on the eccentric shaft.


I could be misinformed, but as far as I know, that's the reason behind the always-match-your-flywheel-counterweights-and-starter rule

nipper

I've done the swap. Yiu don't have to worry about flywheel/starters, However the intake and exhaust and emissions from the newer[1984] will have to be put on the 1980 block. Yes, carb and emissions too.

Jeff20B

iTrader: (13)

An '86 or later NA starter fits a '74 REPU heavy stock flywheel just fine. It also fits any 12A with a stock or RB aftermarket flywheel, as long as it's NA.

dnlloran

let me see if I have got this right, it would be better for me to have the original flywheel and starter, but not neccary as long as I use the 84 carb, intake and exhaust on the 80 12a. emissions are not a concern in my area as of yet.
D.