thought it was a 2.8, its a 3.4!

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   howdy all, awsome site/forum here. well i'm a new fiero owner, just picked up a 86 gt for next to nothing as it had a bad engine knock/tick, which turned out to be a rod bearing. interesting part is that as i tore this engine apart and started measuring things to order parts, i found out its not a 2.8, but a 3.4. had the red 'fiero' upper intake plunum and everything so i never even asked. anyways my question is when a 3.4 has been put in place of a 2.8, where does the 2.8 end and the 3.4 begin? i know every conversion can be done differently, but typically speaking, would the computer and harness be fom the 2.8 still? what would need to be changed to put a 3.4 in place of the 2.8....would the intake have to be changed (ths one had the red 2.8 upper part at least)... would injectors ahve been changed, or would the 2.8 ones work? the cam had 4 failed lobed and that metal debris got into all bearings. luckily crank and pistons still in good shape, so i'm putting in all new bearings, a hone with new rings, new cam and lifters. i've ordered all that based on 3.4 an by size so thats all fine, but what led me down this question is the oil pressure sensor was broken off, so that got me asking wether i'd order the stock 2.8 fiero oil pressure sensor or order one from a 3.4? (or they might be the same). my guess would be the block, crank, pistons and rods, and heads would all be 3.4, then intake and everything else 2.8....i'm a heavy duty mechanic by trade so automotive/gas type intake systems not really my field of expertise. anybody who's savy with that stuff or has done a 3.4 conversion, i'd really appreciate a little advice or whatver insight anybody could throw at me. thanks to all and cheers for now.

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dgsmooth Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 30 September 2013 Location: Canada Status: Offline Points: 1	Post Options Post Reply Quote dgsmooth Report Post Quote Reply Topic: thought it was a 2.8, its a 3.4! Posted: 08 October 2013 at 7:48pm
	howdy all, awsome site/forum here. well i'm a new fiero owner, just picked up a 86 gt for next to nothing as it had a bad engine knock/tick, which turned out to be a rod bearing. interesting part is that as i tore this engine apart and started measuring things to order parts, i found out its not a 2.8, but a 3.4. had the red 'fiero' upper intake plunum and everything so i never even asked. anyways my question is when a 3.4 has been put in place of a 2.8, where does the 2.8 end and the 3.4 begin? i know every conversion can be done differently, but typically speaking, would the computer and harness be fom the 2.8 still? what would need to be changed to put a 3.4 in place of the 2.8....would the intake have to be changed (ths one had the red 2.8 upper part at least)... would injectors ahve been changed, or would the 2.8 ones work? the cam had 4 failed lobed and that metal debris got into all bearings. luckily crank and pistons still in good shape, so i'm putting in all new bearings, a hone with new rings, new cam and lifters. i've ordered all that based on 3.4 an by size so thats all fine, but what led me down this question is the oil pressure sensor was broken off, so that got me asking wether i'd order the stock 2.8 fiero oil pressure sensor or order one from a 3.4? (or they might be the same). my guess would be the block, crank, pistons and rods, and heads would all be 3.4, then intake and everything else 2.8....i'm a heavy duty mechanic by trade so automotive/gas type intake systems not really my field of expertise. anybody who's savy with that stuff or has done a 3.4 conversion, i'd really appreciate a little advice or whatver insight anybody could throw at me. thanks to all and cheers for now.

DannyCanuck Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 04 July 2011 Location: Canada Status: Offline Points: 106	Post Options Post Reply Quote DannyCanuck Report Post Quote Reply Posted: 09 October 2013 at 11:32pm
	I'm no expert on the 2.8 and 3.4 but think that the computer and harness are the same between the two. ive been told anyway that you can pull a 2.8 and slot in a 3.4 without changing anything. I run a 2.5 so dont hold me to that, if anyone with actual experience could chime in that would be nice.
	88 duke, bog standard

bcampbell Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 14 November 2011 Location: Canada Status: Offline Points: 160	Post Options Post Reply Quote bcampbell Report Post Quote Reply Posted: 16 October 2013 at 12:08pm
	To be sure about the oil pressure sender, I would bring the old one into the parts store and check it with the new one. The old senders have a different wiring connector but the signals are still compatible between new and old style. If it's the typical 3.4 installation, chances are it's using the Fiero timing cover/accessory drive, intake(s), 3.4 injectors, distributor/coil, and stock wiring harness. There may be a couple sensors unused from the 3.4.
	'86 2m6 F23 5-speed, LSD, 3.5L LX9 '89 Firebird 3500T, T56

Capt Fiero Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039	Post Options Post Reply Quote Capt Fiero Report Post Quote Reply Posted: 17 October 2013 at 10:39pm
	Basically its a 3.4 "Engine" 3.4 rods, pistons, block and crank. Heads are the same on both motors. Everything bolted onto the motor, ECM, Timing Cover, waterpump, intake and exhaust will be 2.8. Make sure the exhaust manifolds are ported. Flywheel will probably be 88 Fiero. Side note, in most cases, they use the 87/88 Fiero Timing cover and oil pan.
	Capt Fiero 88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd.