Question : what parts do i nead to bild a 3.1 fiero engine

[bigbird62]

hi guys i am trying to strock my fiero 2.8 v6 to a 3.1. Any one help me with what parts i nead, as I am in Scotland i have a Complete, Generation 2, 3.1 V6 Beretta engine and have bean told it has all the bits i nead but wat bits ???? any hlep would be great, thanks lee

[mongo]

If you are using the original 2.8 as a base and just stealing parts from the 3.1 I believe you only need the crankshaft, harmonic balancer and the flywheel/flexplate.

The 85 and 86 2.8 Fiero motors were externally balanced using the flywheel and harmonic balancer. The 87 and 88 2.8 Fiero motors are internally balanced at the crankshaft and use a neutral flywheel and balancer. I think your 3.1 is internally balanced.

The crank alone should increase your stroke to 3.1 with your only worries being balance and possibly tuning/timing.

Someone else here should be able to verify this for you or expose me as a fraud! A lot depends on the year of your 2.8....

[robertisaar]

if you're going through that trouble, why not just swap the whole 3.1 in? lack of equipment?

[55trucker]

We can try to give you as much useful information as possible....you might want to check out (and join) the Pennocks Fiero Forum. You might even get a hold of Cliff (Pennock) himself, he's in the Netherlands, no tooooo far away from where you are. There's a world of info there on everything involving the Fiero and what can be done with it. If you're trying to keep the engine looking original, why not put the iron heads, 2.8 camshaft (if you choose to) and top end onto the 3.1 block (there's your *stroked* engine) http://www.fiero.nl/cgi-bin/fiero/Ul...i?action=intro

[Superdave]

We can try to give you as much useful information as possible....you might want to check out (and join) the Pennocks Fiero Forum. You might even get a hold of Cliff (Pennock) himself, he's in the Netherlands, no tooooo far away from where you are. There's a world of info there on everything involving the Fiero and what can be done with it. If you're trying to keep the engine looking original, why not put the iron heads, 2.8 camshaft (if you choose to) and top end onto the 3.1 block (there's your *stroked* engine) http://www.fiero.nl/cgi-bin/fiero/Ul...i?action=intro

7:1 compression would suck..

He'd need the flat top 3.1 pistons to get it back up to normal...

[55trucker]

7:1 compression would suck..

He'd need the flat top 3.1 pistons to get it back up to normal...

Sorry 'bout that...I was thinking for a moment along the lines of the 3.1 iron head engines that were used in the trucks.

[geoffinbc]

You need the 3.1L crank and IRON HEAD 3.1L pistons. The aluminum head pistons wont work. You will also need to verify your Fiero is internally balanced. If it is not you will need to have the flywheel machined and neutral balanced or just buy a new one that is.

But you cannot just throw the crank and pistons into your block. Your going to need to remove the whole engine and have a shop bore and hone the cylinders to accept the new pistons (a .040" overbore will make you a 3.2L). You will then want to check all your bearing clearance and tolerance to be sure everything will last.

So beware that "Just Stroking" you motor actually means a rebuild.

[carbon]

ONLY the 1988 Fiero 2.8 V6 is internally balanced.

And as far as just swapping in the Gen 2 3.1 MPFI, it has the same 140HP and a whopping ~20 more torque...

You need a 3.1 or 3.4 crank, which will all be internally balanced and 3.1 pistons and rods from a Camaro or Firebird, yes the rods on the 3.1 are different length, it's not just the stroke that changed. The aluminum head motors had pistons that had way to much dish to make worthwhile compression as mentioned above.