thinking v8 swap, have a few ?s

[Rotary_Rocket_87]

so I am going v8. my motor blew and i dont have the funds to rebuild, so i am dropping a SBC in its place. now for the questions. will the stock t2 rearend hold up well? and can i build motor mounts instead of just buying the v8 conversion subframe? thanks for any info.

[Project10AE]

yes and yes

[djmtsu]

I am not a rotary leg humper, but how is doing an SBC swap cheaper than rebuilding your engine?

And the stock T2 rear end is plenty strong enough to handle an SBC. You can build your own mounts, but there are other issues to contend with. Oil pan, steering rack, etc.

Look at the Granny's kit just to get an idea of what you are going to need to build/buy. It is not nearly as cheap as you think.

[NoDOHC]

I have 750.00 in a TII engine and that includes purchasing it and rebuilding it. (I had $375 in purchasing it and about $375.00 in rebuilding it).

You can reuse all the seals except those that have failed, get an NA housing from eBay for $50.00 and take the diffuser out with a pneumatic chisel, buy a gasket set for $140.00 and you are good to go (apex seals cost me $60.00 each at the Mazda Dealer).

At the same time, I have a friend with a 302 Chevy (old school) in an RX7 and that might as well be a 5.0L rotary (revs like a rotary, has similar power band, makes 350 lb-ft of torque and > 400 Hp). (He has more than $750 in his engine).

[Whizbang]

v8 swaps really never end up "cheap" so dont bite off more than you can chew and end up with a 1/4 done project. Do some research on prices and get a good idea of what all you need so your prepared.

[12arotary]

On rx7club you can find a good running t2 block for less than 500-
just cause you have a sb just chilling doesn't mean its going to be cheaper it usually means you are going to be in the for sale adds in a month with a t2 rolling frame with mounted sb haha

[Max777]

easiest v8 swap into an RX-7:

Carbed automatic.... but then you kind of loose the point of doing it in the first place.

[dudemaaan]

An 87 T2 differential (s4) is extremely strong. A lot of us FD guys (inlcuding myself) swap to them for the clutch style LSD. Rebuildable, quiet and pretty much bulletproof. I'm pushing over 500 HP through mine. (destroyed my stock one)

The series 5 differentials aren't good for drag, and not as strong as the s4.

[Rotary_Rocket_87]

On rx7club you can find a good running t2 block for less than 500-
just cause you have a sb just chilling doesn't mean its going to be cheaper it usually means you are going to be in the for sale adds in a month with a t2 rolling frame with mounted sb haha

if i got as far as to mount the small block i don't think i would sell it. that would be the hardest part of the swap. and i don't think i will have a problem getting a carbed sbc with a t5 tranny to work in the car. i have read many times that the t5 mounts very colse to stock, with the shifter coming up through the original shifter hole.

[Rotary_Rocket_87]

i forgot to mention that i have the engine and tranny already. (my brother is giving me these as he is the one that blew my motor) And i am sorry but if i spend $1000 getting this to work it will be a much better investment than rebuilding as i will have more hp and torque for the same money spent. just makes sense to me. and my brother can build one hell of a v8. he built a 300 hp 283 for a friends mudtruck and it is insane.

[NoDOHC]

Yes, the T5 will go through the stock shifter hole if you can get a straight-up bell housing for the transmission (most bell housings are canted).


And i am sorry but if i spend $1000 getting this to work it will be a much better investment than rebuilding as i will have more hp and torque for the same money spent.


There is no need to be sorry, it is your car, you should make it run like you want it to. I can assure you that I could get more power out of a 350 Chevy than I am getting out of my 4-port rotary. The problem is that I couldn't do it as inexpensively (unless I had a friend/brother who is giving it away, a 270 Hp 350 is going to cost more than $750 installed in an RX7).


just makes sense to me. and my brother can build one hell of a v8. he built a 300 hp 283 for a friends mudtruck and it is insane


If the engine is free, you should have no trouble mounting it in the RX7 for $1000.00. If you are good at fab work, you should have no trouble building your own engine mounts that allow the engine to sit lower and further back. I have a buddy with a 302 Ford in his RX7 that has the stock 50-50 weight distribution and weight (2670 lbs), this is easier with small bock Fords as they have no distributor on the back.

You could get 400 Hp out of a 283 - if you were willing to pay for it. I know several 302 guys that are well over 400 Hp (with only another 1/8" of bore). Of course, they spent more on cylinder heads than I did for my entire rotary engine.

$1000.00 into a 350 will get you 300 Hp pretty easily. If you can find an earlier one (pre-smog) they will make that bone-stock. It is all in what you understand and find the easiest to work on. I have done several v8 swaps into RX7s (because I understood the v8), and then I decided to start working with the rotary engines and found them to be just as much fun, only in a different way.

Rotary engines are simplicity itself, seriously - you should save that engine and rebuild it to put in a dune buggy or something.

If you really don't want it, PM me, I wouldn't mind buying it (Picking it up might prove difficult).

[Rotary_Rocket_87]

Update, we have finally started to gut the car so the smallblock can go in. We decided on a 350hp 350ci that my brother already has built. we are just trying to decide if we want to use a NV3500 inplace of the T5 trans, but that all has to wait till we get all the crap out of the car that it wont need. As we progress I plan on posting pics.