Engine Identification (Page 1/4)
N1022AR MAY 01, 10:31 AM
Hi! I've been reading this forum ever since I got my 1886 Fiero SE 2.8L 5speed about 5 months ago. I love all the info I've gathered on here.
I am casually working up the courage and funds to do an engine swap. I was looking on Facebook market place and saw a post for a supposed 3800 N/A engine that looks like its already been modified somewhat for a Fiero. The lady that is selling it doesn't know anything about it. I'm hoping that y'all will be able to help me identify this engine. Could it be a 3800? Looks more like a 3.4 to me. Or am I just looking at a regular old 2.8? She lives a couple hours away from me so I'm trying to get some advice before I make the drive. She's asking 1500$ but wants me to make an offer.


P.S. I hope I uploaded these correctly....
1985 Fiero GT MAY 01, 11:41 AM
From what I understand, the 3800, etc. use entirely different parts so the Fiero intake and valve covers cannot bolt on, likely is a 2.8, 3.1 (basically stroked 2.8), 3.4 (basically bored and stroked 2.8 block). Even if it somehow was a 3800, the Fiero intake would restrict that so much it wouldn't be much better then a 3.4.
cvxjet MAY 01, 11:52 AM
A) The 3800 is a 90* V6 based on a Buick V8....The 2.8/3.4 V6 are 60* purpose-built V6s....There is no "Interchange" between the two different families

B) That engine has a Fiero intake, so it is either a 2.8 or a 3.4

C) Not sure exactly where to look but the 2.8 is a distributer-engine, while the 3.4 used a crank-sensor....to make sure which engine block it is, check for that sensor located somewhere low-down on the side of the block.

OK- here is a diagram of where that crank sensor is located....

[This message has been edited by cvxjet (edited 05-01-2024).]

jelly2m8 MAY 01, 12:47 PM
2.8, maybe 3.1 block. No starter holes on the right bellhousing ear where the 3.4 starter would originally have been.
N1022AR MAY 01, 01:21 PM
If that's the case, then this is definitely not a 3.4 because it has a distributer. Most likely a 2.8 then. That being said it does look pretty good, but I'd really like more power than the 2.8 offers.
I will keep looking around. Thanks for the help!
fierofool MAY 01, 05:12 PM
The 3.4 didn't use a distributor when installed in the Camaro or Firebird, but will accept a distributor when installed in the Fiero. I ran a distributor for years when I did the 3.4 swap, then later changed to a coil pack ignition without the distributor. The 2.8, 3.1, and 3.4 are essentially identical blocks.

The 3.4 will have a large "F" cast into each side of the block back near the flywheel. The 2.8 and 3.1 will both have stock bolt holes on the front side of the engine as it's installed in the Fiero. The 3.1 and 3.4 will have a port on the trunk side of the block for a crankshaft sensor. The 2.8 won't have that feature.

Everything from a stock Fiero 2.8 will bolt onto a 3.1 or 3.4 and look identical to the untrained eye. I'm running a 3.1 with distributor in my 86 and a 3.4 without distributor in my 87.

I agree with Jelly2m8 that it's definitely not a 3.4. If it's a 3.1 you will need a neutral balanced flywheel or flexplate from an 88 or later GM 60 degree V6.

[This message has been edited by fierofool (edited 05-01-2024).]

olejoedad MAY 01, 06:29 PM
The 3.4 Camarobird engine also has a cam sensor port above the water pump.
cartercarbaficionado MAY 01, 06:43 PM

quote
Originally posted by N1022AR:

Hi! I've been reading this forum ever since I got my 1886 Fiero SE 2.8L 5speed about 5 months ago. I love all the info I've gathered on here.
I am casually working up the courage and funds to do an engine swap. I was looking on Facebook market place and saw a post for a supposed 3800 N/A engine that looks like its already been modified somewhat for a Fiero. The lady that is selling it doesn't know anything about it. I'm hoping that y'all will be able to help me identify this engine. Could it be a 3800? Looks more like a 3.4 to me. Or am I just looking at a regular old 2.8? She lives a couple hours away from me so I'm trying to get some advice before I make the drive. She's asking 1500$ but wants me to make an offer.


P.S. I hope I uploaded these correctly....


not a 3800. not a 3.4 dohc or standard based on owning 3 of those, might be a 3.1? honestly looks like a late year 2.8l from a formula based on some minor differences, mainly injection stuff
82-T/A [At Work] MAY 01, 07:58 PM
Well... couple of things right off the bat, the throttle body looks like it's been bored (not a stock throttle plate or studs in there)... so that's a huge plus. You also clearly do not have the stock manifolds on there, and they're the pretty rare shorty headers that are no longer available. It's not a 3800 for sure, that's a V6/60, but it could be anything from a 2.8 to a 3.4. $1,500 is a bit high for a used engine... but the headers and throttle body are worth at least $500 bucks. I would show her this thread, and offer her $750. That's kind of the most I'd be willing to pay for something that you don't really know the condition of. For the record, a rebuilt DCC9 3.4 V6/60 that'll essentially drop right in, can be had for $2,000 bucks.
cartercarbaficionado MAY 01, 08:16 PM

quote
Originally posted by 82-T/A [At Work]:

Well... couple of things right off the bat, the throttle body looks like it's been bored (not a stock throttle plate or studs in there)... so that's a huge plus. You also clearly do not have the stock manifolds on there, and they're the pretty rare shorty headers that are no longer available. It's not a 3800 for sure, that's a V6/60, but it could be anything from a 2.8 to a 3.4. $1,500 is a bit high for a used engine... but the headers and throttle body are worth at least $500 bucks. I would show her this thread, and offer her $750. That's kind of the most I'd be willing to pay for something that you don't really know the condition of. For the record, a rebuilt DCC9 3.4 V6/60 that'll essentially drop right in, can be had for $2,000 bucks.


that just looks like the stock formula holley throttle body. at least on mine it's bolted just like that and it was that way from the factory allegedly