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2.5 to 2.8, what needs changed? by tomanyfieros
Started on: 10-22-2003 10:07 AM
Replies: 8
Last post by: Old Lar on 10-22-2003 09:45 PM
tomanyfieros
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Report this Post10-22-2003 10:07 AM Click Here to See the Profile for tomanyfierosClick Here to Email tomanyfierosSend a Private Message to tomanyfierosDirect Link to This Post
i have an 87 coupe, that has the stock 2.5, and im wanting to drop a V6 2.8 out of my 86 GT, and they are both automatics.. so i was going to drop the K frame out of both cars, and put the V6 in the coupe.. what all other than motor and tranny needs changed, and how hard is it to switch it over to the V6?
Thanks
Jason

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beelizard
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Report this Post10-22-2003 10:39 AM Click Here to See the Profile for beelizardClick Here to Email beelizardSend a Private Message to beelizardDirect Link to This Post
You might be able to just swap the entire engine cradle then just change the air box and swap out the dash gauges. Don't quote me on this, so far all I have done is rebuild the v6 in my 86 and I just started on my 84

[This message has been edited by beelizard (edited 10-22-2003).]

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connecticutFIERO
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Report this Post10-22-2003 11:10 AM Click Here to See the Profile for connecticutFIEROSend a Private Message to connecticutFIERODirect Link to This Post
If they are both 85-87 cars then you can just swap the cradle in addittion to the wiring harness, junction block, vaccuum lines, fuel lines, coolant hoses, and you need to install a V6 fuel pump. You might want to swap in a V6 car's dash cluster to register the right readings. You also have to install a new throttle cable.

I think thats it, I did one awhile ago but it was 87 V6 engine to 88 coupe frame with the ISuzu 5 speed.

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MRJ
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Report this Post10-22-2003 02:30 PM Click Here to See the Profile for MRJClick Here to visit MRJ's HomePageClick Here to Email MRJSend a Private Message to MRJDirect Link to This Post
Hey man well I just put a 3.4 into my 88 coupe. I changed the air box, the wiring of coarse that came on a v6, the fuel pump in the tank, the throttle cable that runs from the pedal on back. I put GT gauges in it and just used the wiring that's already in the 4 cylinders car. The only wiring is the engine wiring harness. Now the coolant lines!? I think that's going a bit far I didn't change mine but it was an 88 one. let us know how it goes!
Matt Jackson

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MRJ
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connecticutFIERO
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Report this Post10-22-2003 03:32 PM Click Here to See the Profile for connecticutFIEROSend a Private Message to connecticutFIERODirect Link to This Post
 
quote
Originally posted by MRJ:

Hey man well I just put a 3.4 into my 88 coupe. I changed the air box, the wiring of coarse that came on a v6, the fuel pump in the tank, the throttle cable that runs from the pedal on back. I put GT gauges in it and just used the wiring that's already in the 4 cylinders car. The only wiring is the engine wiring harness. Now the coolant lines!? I think that's going a bit far I didn't change mine but it was an 88 one. let us know how it goes!
Matt Jackson

I thought I said coolant hoses? In any case the V6 coolant and heater hoses are different than the 2.5 ones. When you put it all in you'll see. I might be wrong but I thought the junction block next to the battery had to be swapped out for the V6. I know I did anyway. Now is a good time for you to put in a CRX intake and scrap the Fiero's. Heck its probably less work anyhow.

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Raydar
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Report this Post10-22-2003 04:00 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarDirect Link to This Post
As the others have mentioned...

Cradle, fuel pump, throttle cable and gauges.
ECM and engine harness. The harness unplugs from the block next to the battery. The V-6 harness plugs in, in its place. You'll need to swap the red wires, too.
The A/C and fuel pump relays are all part of the engine harness.

Your fuel lines already enter from the right side. You just need to connect the hard lines from the fuel rail to the flex lines that come from under the battery tray.

The 86 water pump has a pipe fitting that points toward the trunk. Remove that pipe fitting, and screw a pipe plug in the hole. Do NOT just put a rubber cap over the pipe fitting. It'll blow off. Seen it happen.

The Duke has a water hose that connects to the bottom of the intake manifold. From there it goes to the right side frame rail and down to the heater pipe. Remove it from the car. It needs to be replaced with a pipe/hose assembly that goes up the right side of the firewall and over to the thermostat housing. All 87 and 88 V-6 installations use this hose.

Important! If you're going to retain the A/C, look at the drier canister in the front compartment. Make sure the low pressure switch is installed on the shrader valve. If there isn't one there, you'll need to install one. This requires replacing the heater fan/windshield wiper wiring harness.
Not a big deal to do, but if you *don't* do it your compressor can still kick in, even if there is no refrigerant or oil in the system. Will turn a compressor into a doorstop in very short order. Don't ask me how I know this.

I may have forgotten something, but that's most of it.

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Raydar

88 3.4 coupe. 17s, cut springs 'n all.

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connecticutFIERO
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Report this Post10-22-2003 04:13 PM Click Here to See the Profile for connecticutFIEROSend a Private Message to connecticutFIERODirect Link to This Post
Raydar can you do me a favor and explain exactly what you mean by AC switch and wiring? I did this conversion and my compressor got toasted so now I am going to replace it, but I want to be sure to not blow this one.
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Roylmohr
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Report this Post10-22-2003 09:23 PM Click Here to See the Profile for RoylmohrSend a Private Message to RoylmohrDirect Link to This Post
I just want to say good luck tomanyfieros! Let us know how this ends up.
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Old Lar
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Report this Post10-22-2003 09:45 PM Click Here to See the Profile for Old LarSend a Private Message to Old LarDirect Link to This Post
Won't the fuel pump need to be changed? V6 runs with more fuel than the 2.5L>
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