TomP or others "in the know"
Thread Starter
Supreme Member
Joined: Mar 2000
Posts: 1,777
Likes: 0
From: First one out of liberty city, burn it to the ground
TomP or others "in the know"
ok...im going to keep the 2.8, but swap cranks from a 3.4 Now the 3.4 is a Bored and Stroked 2.8, so if i went and bored the 2.8 .060 and with the stroker crank would i technically be having a 3.4? Now...Anyone know if forged aluminum pistons are available for no2 use?
------------------
88 Firebird 2.8
MODS (either coming or on):
Flowmaster Cat Back, Random Technologies Cat, 3" intermediate pipe, 10.4 Taylor Race Wires, MSD Coil, MSD Ignition Module, B&M Shifter, Transgo Shift Kit, Cold Air Induction..Then peeling and cracking paint..
2"cowl hood
3.4 engine -new-
s/c'r then im done, maybe some no2...
------------------
88 Firebird 2.8
MODS (either coming or on):
Flowmaster Cat Back, Random Technologies Cat, 3" intermediate pipe, 10.4 Taylor Race Wires, MSD Coil, MSD Ignition Module, B&M Shifter, Transgo Shift Kit, Cold Air Induction..Then peeling and cracking paint..
2"cowl hood
3.4 engine -new-
s/c'r then im done, maybe some no2...
Supreme Member
Joined: Mar 2000
Posts: 13,414
Likes: 6
From: Central NJ, USA
Car: 1986 Firebird
Engine: 2.8 V6
Transmission: 700R4
I don't think you can bore the 2.8 out enough to become a 3.4... there's not enough metal between the cylinders.
The 3.1 is a stroked 2.8, so the 3.4 crank might be the same as a 3.1 crank. That is, unless the main journal sizes changed for the 3.4.
------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
The 3.1 is a stroked 2.8, so the 3.4 crank might be the same as a 3.1 crank. That is, unless the main journal sizes changed for the 3.4.
------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
Junior Member
Joined: Sep 2000
Posts: 20
Likes: 0
From: TX
The way it was explained and the info i have is:
3.1 is a STROKED 2.8, bore is the same.
3.4 is a BORED 3.1 stroke is the same as a 3.1.
There should be a way to use the crank, for a destroked 3.4 for high rev but whats the point on a engine that small. There is no way to overbore a 3.1 to a 3.4, actually safely it would be a 3.2. So there should be even less of a chance to bore a 2.8 to a 3.4 being stroke is not the same.
To answer the piston question, yes, companys do make pistons for the 2.8, however you HAVE to watch the valve clearance. The iron head and aluminum head pistons are way different. Has something to being to "dome" or not to "dome" the pistons. My advice is this, just have a custom set made for your car OR search the fiero sites for aftermarket pistons. I do know for the 3.1 guys we can use pre 68 chevy rods and have them sized down and have the custom pistons fitted. Its expensive BUT will hold to more HP then all but the stoutest 3.1's will ever make. Do some research to see if the 2.8 can accept the same. I looked at the aluminum heads as well so i could bump my compression upto 10.0:1, but found out and was told by engine builders the iron heads are best in the 3.1 hope that helps.
David
------------------
David
91 Firebird
3.1L MPFI
Dynomax exhaust, cold air, 8mm wires, splitfires, shift kit, B&M Shifter.
On the table waiting to go in:
Ported/polished iron heads, 1.6:1 rockers, Lightly ported/Gasket matched Intake. Ported/Polished TB, Compucam 2030, 5" tach, duel pod w/oil temp, tranny temp gauges. Hood pod w/Fuel pressure, NOS pressure.
Coming Soon:
FastChip, 275 rears, 235 fronts, Ram air hood, suspension mods.
3.1 is a STROKED 2.8, bore is the same.
3.4 is a BORED 3.1 stroke is the same as a 3.1.
There should be a way to use the crank, for a destroked 3.4 for high rev but whats the point on a engine that small. There is no way to overbore a 3.1 to a 3.4, actually safely it would be a 3.2. So there should be even less of a chance to bore a 2.8 to a 3.4 being stroke is not the same.
To answer the piston question, yes, companys do make pistons for the 2.8, however you HAVE to watch the valve clearance. The iron head and aluminum head pistons are way different. Has something to being to "dome" or not to "dome" the pistons. My advice is this, just have a custom set made for your car OR search the fiero sites for aftermarket pistons. I do know for the 3.1 guys we can use pre 68 chevy rods and have them sized down and have the custom pistons fitted. Its expensive BUT will hold to more HP then all but the stoutest 3.1's will ever make. Do some research to see if the 2.8 can accept the same. I looked at the aluminum heads as well so i could bump my compression upto 10.0:1, but found out and was told by engine builders the iron heads are best in the 3.1 hope that helps.
David
Originally posted by TomP:
I don't think you can bore the 2.8 out enough to become a 3.4... there's not enough metal between the cylinders.
The 3.1 is a stroked 2.8, so the 3.4 crank might be the same as a 3.1 crank. That is, unless the main journal sizes changed for the 3.4.
I don't think you can bore the 2.8 out enough to become a 3.4... there's not enough metal between the cylinders.
The 3.1 is a stroked 2.8, so the 3.4 crank might be the same as a 3.1 crank. That is, unless the main journal sizes changed for the 3.4.
------------------
David
91 Firebird
3.1L MPFI
Dynomax exhaust, cold air, 8mm wires, splitfires, shift kit, B&M Shifter.
On the table waiting to go in:
Ported/polished iron heads, 1.6:1 rockers, Lightly ported/Gasket matched Intake. Ported/Polished TB, Compucam 2030, 5" tach, duel pod w/oil temp, tranny temp gauges. Hood pod w/Fuel pressure, NOS pressure.
Coming Soon:
FastChip, 275 rears, 235 fronts, Ram air hood, suspension mods.
Thread
Thread Starter
Forum
Replies
Last Post