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Old 07-29-2010, 10:42 PM   #1
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Default 2.8-3.1 mod...?

I heard it is possible to make the 2.8 a stroker by using the 3.1 crank and connecting rods. Is there any other mods I would need to make? I have the 2.8 out of a '85 Fiero GT so the journals match the 3.1, but do I need new pistons or will the 2.8 pistons have enough clearance with the 3.1 rods? I'm really hoping I don't have to buy new pistons.
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Old 07-30-2010, 12:12 PM   #2
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your on the right path, ill let someone else chime in, but a 2.8 is a 3.1, Just a different bore IIRC (but dont quote me on that)
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Old 08-02-2010, 03:13 AM   #3
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If you are going to do that you might as well make it a 3.5 liter with parts from the 3500 v6 in the newer malibus. You should join 60degreev6.com
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Old 08-02-2010, 03:15 AM   #4
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Quote:
Originally Posted by 3800_cruiser View Post
If you are going to do that you might as well make it a 3.5 liter with parts from the 3500 v6 in the newer malibus. You should join 60degreev6.com
We generally try not to point people away from here when they come here to ask a question. This question can and will be answered by people who have plenty of knowledge regarding these engines. I'm waiting for Robert Saar to give some insight on this.
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Old 08-02-2010, 03:29 AM   #5
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I'm actually on about 4 different forums right now tryin to figure this out, 60degree is one of them. I've gotten a lot of different answers, and basically what I've heard is screw it just get a 3.1 or a 3.4 and drop it in. I've heard it'* almost a direct swap. I would like to hear from this Robert Saar if he is knowledgeable. It just seems like it would be fun to do it this way though.
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Old 08-02-2010, 06:41 AM   #6
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Is this going in a fiero I take it?

to swap a 3100/3400 an ECM swap to the 7730 or whatever so you can run DIS... other than that it should bolt in and just minor wiring/etc nothing drastic. Maybe some motor mount fab/adjusting.

the 2.8 intake is NOT usable on the new 3400 alum head engines, To retain the Fiero intake and fuel system, Fiero heads are used in place of the aluminium heads a 3400 engine would come with. Because of the larger combustion chambers in the Fiero'* iron heads, you will have change to new pistons.

Thats just about as far as my knowledge goes, sorry.
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Old 08-02-2010, 06:43 AM   #7
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I think I may have answered your question wrong, I wouldn't bother keeping the 2.8 is what I was trying to say, sorry.
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Old 08-02-2010, 10:52 AM   #8
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I can tell you for sure that the 2.8 and the 3.1 have the same bore, but the stroke goes from 76mm to 84mm.
Everybody is right about upgrading to the 3x00 engines though. They are relatively cheap and plentiful. They drop in relatively easily too. You would not be able to run it with your fiero engine harness though since the old 2.8s used distributors. For me that would be a swap killer right there.

I have seen a couple of fiero'* that got the 3.1 turbo swap. If you could get a hold of one of those guys, they could tell you how they did the firewall connector and made the turbo harness work. Honestly, I cant think of anything more fun than a turbo fiero!
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Old 08-02-2010, 10:57 AM   #9
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i can! supercharged... or TWIN CHARGED
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Old 08-02-2010, 02:32 PM   #10
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Could it be possible to use a 3x00 short block with the heads, intake, accessories, oil pan, sensors, and transmission for the fiero 2.8 v6? It seems to me if you could do that, the wiring wouldn't need as much changing, maybe need the ecm retuned a bit. You could retain the original look that way as well. This might be a far-fetched idea though.
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