Andrew89GTU

the title says it: i've got a white '91 N/A RX-7 with a screwed-up motor, and my only option is that i've got a longblock S4 motor out of an '88 N/A with only 20k on a new rebuild. i don't have the time for a rebuild, nor the money, the car's gotta get going this weekend.

what exactly do i have to move/swap over to get the S4 motor to go into the S5 and run....??

i need detailed information on EVERYTHING i've gotta switch over. i'm posting this thread because i know there's people on here who know what they're talking about.. somebody help me out, please :-/..

ASAP, please guys..

thanks,
-Andrew-

Andrew89GTU

somebody help me.... please, i've gotta do this as soon as possible. i don't have a car to get to school or work right now, and i'm running out of people to get rides from....

-Andrew-

staticguitar313

iTrader: (2)

i think you can use everything off the S5 block and just transfer it over to the s4 block, someone else verify this for me, you'd want to use as much from the s5 as possible i think


P.S. i'm probably wrong

Andrew89GTU

i want to try and do that.... but apparently from what i read here somewhere on the forums, is that the S5 LIM won't fit, because the rear S4 iron is too tall - i'd have to grind some of the top of it off....

i heard somewhere that the entire S4 intake manifold and TB can stay on.... is this correct?? because if it is, then this is going to be pretty easy.... meaning i don't have to change any gaskets or seals or anything, just put it in.

and as far as OMP goes, since it's totally mechanical, i am planning on just leaving it in there, and running premix anyways as a fool-proof. i've also gotta take the S5 OMP from the S5 core and plug it into the harness and tie it back somewhere, so the car will stay out of 'limp mode'.

^--- any suggestions?? somebody correct me if i'm wrong....

-Andrew-

C-Murder

Its called a bus pass, haha

Andrew89GTU

..did you read where i was from?? lol - we DEFINITELY don't have a bus system here in the ******* of South Carolina.... nobody would use it anyways..

i've got a few more days, but that's all. i'm driving my dad's truck right now because he's sick.... and even though i like it .... green '91 F-150 5-speed with 198k on original motor, been wrecked 7 times and still going, and it has a badass stereo 8-).... it gets a wonderfully amazing 9 miles to the gallon.... 12 if i baby the **** out of it..

so as you can tell, this is only an option for a few days, at most, me being 17 and barely making enough money to keep gas in ANY car, much less something like the truch....

i'm just trying to get exact answers on what i've gotta do.... because right now the motor is still in the white '91, and the '88 motor is strapped down super-securely in the back of the truck.

but i need to know exactly what HAS to be swapped over, because i'm trying to avoid ordering any parts, which means trying to leave on all the things i can leave on, so i don't have to order seals (which wouldn't come in until early next week, at which point i'm back in school, and working 5-9 every day. i have the weekend to fix the car, pretty much....

-Andrew-

Andrew89GTU

bump.... need some info....


i searched and can't find anything specific enough....

inflatablepets

Ok...where do I begin....I did this swap you speak of. It runs very well too. First of all I had bought an 89 GTU. It had a blown engine, so I bought a 88 GXL which had a low milage mazda reman engine it it. First of all, Pull the S5 motor out. Then bolt in the S4 shortblock. I used the S5 LIM on the S4 block with no fitment issues. I did run ino a few issues though. You will need to buy or make a blockoff plate for the EGR valve. On the S5 LIM you will need to block off the split air port with JB Weld. This port is located under the primary intake ports. (I had to find this out the hard way) You will have to grind a bit of metal off of the rear iron to get the S5 VDI manifold to fit. When you start reassembly, you will see what I mean. You will want to use the S4 clutch and flywheel. You will also need to remove the front cover from the S4 engine and replace it with the S5 one. Be careful of the bearing stack as you take off that front eccentric shaft bolt. in fact, have the flywheel side down when doing this. There also is a couple of small o-rings for an oil passage in the front cover that you will need to know about. Other than that you will want to use as much S5 stuff as possible. Hit me up on AIM if you have any other questions. I might not be around much though.

inflatablepets

You need to be more patient. It takes a couple days to get good info. bumping makes people not want to reply.

Andrew89GTU

yeah i know.... but i'm starting this today after school/work, and i need to know what i'm doing....


also - is there any way to leave the S4 front cover on?? if not, please explain why i would be swapping it over.... everything should be in the S4 locations as opposed to the S5 locations, since it is a S4 motor.... OMP is being either blocked-off or left on (since it's mechanical, and the S5 OMP will be tied off but left in the harness to leave the car out of limp mode.

and why do i need to swap the LIM from the S5 over?? is there a difference between the S4 and S5 manifolds as far as plugging them into the wiring harness is concerned?? if not, i'm planning on running an S4 LIM and UIM and TB until i can order the proper gaskets to put on the LIM, UIM, and TB from the S5. i'm leaving the stock S4 header on for the moment, until i can order the gaskets to put on my Racing Beat header....

as far as that is concerned, too.... do i leave the header and pre-cat on from the S4?? it doesn't look like the rest of my RB exhaust will bolt up to just the stock header.... so - leave the pre-cat on ??

thanks,
-Andrew-

Andrew89GTU

bump....


hoping one of the moderators will post in here and let me know exactly how to do this.... i'm kinda scared, honestly, guys.... 'cuz if i **** this up - i'm screwed....

-Andrew-

inflatablepets

Still 3 bumps in less than 24 hours is wrong. The MODs themselves will tell you so.

You will be swapping the front covers because you will need the S5 MOP on the car instead of the S4 MOP. The S5 MOP is computer controlled as opposed to the S4 MOP being throttle modulated. There is a way you could run without swapping the front covers, but you have to premix oil into the fuel. if you don't YOU WILL toast the engine. Do the swap. it's not that hard. It was easier than replacing the heater core in the same car.

uRizen

iTrader: (2)

He wants to premix, so he can just skip replacing the front iron. You will need to still keep your S5 OMP connected or else the ECU is going to switch into limp mode. Just plug it in, and wire it up somewhere out of the way.

Oh yeah, I know this has been said before, but make sure you use the flywheel and clutch from the S4, otherwise you're gonna run into a pretty rough engine.

Andrew89GTU

i have to use the flywheel AND clutch plate from the S4?? alright.... will do.

so what i'm planning to do, is that it's a complete S4 motor, so it'll be S4 core, with S4 UIM/LIM/TB, S4 OMP still attached (while running premix at the same time), and the S5 OMP will be still in the harness, but not on the motor (it'll be zip-tied somewhere else in my engine bay). and S5 everything else

will this work??

somebody help me please.... i don't know what i'm doing really, and i'm starting this tomorrow....

-Andrew-

uRizen

iTrader: (2)

I think that might. I'd do a couple of quick searches on the terms s5 to s4 swap and see what comes up. The core irons themselves aren't all that different, just some details.

You don't necessarily have to use the clutch from the S4 car if it's in bad shape, but it's always nice to keep that section of drivetrain together just because it has all worn together and should work smoothly.

Andrew89GTU

the only things i can find on the searches is info on S4 to S5 swaps, but i'm doing the exact opposite.... i don't need to know what i've gotta do to an S5 motor to put it on an S4 car.... i need to know exactly how to put an S4 motor into an S5 car.... and i'm having alot of trouble finding good exact info.... because the search function blocks out the words 'S4' and 'S5' because they're 'too short'

:-( help....

-Andrew-

inflatablepets

http://homepage.mac.com/carldavis/intake.html



I don't understand why you want to use all the S4 intake junk. You will want the VDI system that the S5 engine has. It kicks in at about 5500 and you can feel it pretty well in second and 3rd gear.

Besides that, You will need to keep the S5 injectors on the S4 motor. You will have to pull the intake and all that. You also want to use the S5 fuel rail as it doesn't have the problem with the pulsation dampeners leaking and catching the car on fire!


Trust me it will be easier to convert everything over to s5 if you plan on keeping all of the emissions stuff.

Andrew89GTU

i'm putting the S5 fuel rail and injectors on, but for the moment all the S4 intake **** is staying on there because of a lack of new gaskets, and also - i really don't feel like grinding my rear iron down at the moment. i'm obviously not worried about the performance/speed factor of the car, as i'm doing pretty much a downgrade.... i simply need a reliable, running car, and i'm broke. so yeah, this is what i'm doing 8-)

anyways, thanks for the help you guys.... i'm starting the project here in a few minutes at my boss's shop. wish me luck!!

-Andrew-

Andrew89GTU

update: the motor is in the car.... but not yet running....


does anybody have a vac hose diagram/wiring diagram for the S4 N/A 13B?? it's in an S5 car - '91 N/A....

just need to get everything plugged up....

thanks, guys

-Andrew-

Needa13b

what's an LIM

SpAm@FC

iTrader: (4)

http://www.rotaryresurrection.com/

there are also some infos about this swap...

tech -> Series 5 to Series 4 Engine Swap