3.4 Question (Page 1/3)
88Fingers MAY 10, 10:59 AM
Hello guys and gals. I would like to know what are the main obstacles to a 2003 Impala style 3.4 V6 with the splayed valve aluminum heads? Would the old style timing chain cover and water-pump transfer to that block? Is it mainly intake and exhaust? Is there a camshaft available with the distributor drive gear or DIS only? Has anyone tried or done this? Thank you for any info you can provide.
Will MAY 10, 11:27 AM
Been done plenty of times. Biggest obstacle is that the FWD alternator mount is high on the rear side of the engine and interferes with the Fiero decklid. Change up to a low mount alternator and rock.

Keep DIS and the engine's original ECM, rewire the donor stock engine harness to work in the Fiero chassis. Exhaust fits, but needs to be custom.

Making it work with a manual transmission may take a little work.

Overall not a hard swap... I don't know why it's not done more often.
88Fingers MAY 10, 12:41 PM
Thanks Will, great info! The intake and other parts transfer okay as in the throttle hookup and such? I noticed the bellhousing bolt pattern is the metric style like the Getrag 5 speed. It seems natural as you get much bigger valves and ports, save some weight and higher compression too (9.6:1). The block has the distributor hole so I thought it could just transfer as well. There must be an oil pump drive jackshaft in there though yes?

[This message has been edited by 88Fingers (edited 05-10-2020).]

Will MAY 10, 02:11 PM
There's a distributor eliminator that carries the gear formerly known as distributor drive gear, now oil pump drive gear.

It's more work to convert the engine to distributor and tune the Fiero ECM than it is to install the original ECM and keep DIS.
88Fingers MAY 10, 06:20 PM
Right on! Thanks Will. This will help my decision!
Will MAY 11, 09:00 AM
Just FYI, as it looks like you're going that direction... Just drop the engine in as-is. Do not install the Fiero intake and accessories.

The Fiero intake does not fit the aluminum heads. The Fiero timing cover and such would fit, but installing it would trade a highly reliable automatically tensioned single belt accessory drive for the less reliable manually tensioned multi-belt drive that Fieros originally came with.
88Fingers MAY 11, 06:03 PM
Agree on the intake Will, I was more referring to the throttle body setup from the Impala engine. I was looking at a full long-block rebuild from Engine Direct and then using a combo of the Fiero parts and ether Dorman or wrecking yard Intake and injection parts. Would be almost like a brand new engine!
lou_dias MAY 12, 09:06 AM
The reason this swap isn't done more often is because of the amount of work involved vs a 3800 or 3800SC and the gains in power. Basically work is the same when you look at you merging the wiring harnesses vs. having to buy 3800 mounts but even with just a 3800 vs a 3400 you make 30-40 more hp out of the box. You can get a 3800SC which isn't any harder and make an even high bang for buck.
There are a couple of people who offer wiring harness conversions already for a 3800[SC] where as for a 3100/3400/3500 you will have to do it all yourself.

You'll still have to modify the front engine mount because of the differences from the Fiero V6.
Still have to make your own exhaust.
Still have to modify the cooling system.

I personally have a 96 Grand Am setup in one of my Fieros which uses the 4T65-E that came with the motor... and coming from a guy who hates automatics ... it does shift smooth and better than most other auto cars[ and setups] I've driven...as far as automatics go...
I also have a 3800SC+auto swap and the stamp I have on the automatic transmission is M6 ... It seems to overpower that transmission and cause it to slip at WOT above 85mph. I'm plannging to convert it to a manual with a SPEC flywheel and clutch.

[This message has been edited by lou_dias (edited 05-12-2020).]

Will MAY 12, 09:48 AM

quote
Originally posted by lou_dias:

You'll still have to modify the front engine mount because of the differences from the Fiero V6.




You don't, actually.

The swap requires a new dogbone, but not a new front engine mount.

[This message has been edited by Will (edited 05-12-2020).]

88Fingers MAY 12, 11:19 AM
Hello Lou, I am just a big fan of the 60 degree V6 and the aluminum heads intrigue me quite a bit. Ultimate horsepower gains don't mean much to my kind of driving and I would just like a more updated engine with some more punch. It is just a personal preference and keeps in line with the original GM design. I hear ya though.