I have been reconsidering selling my Fiero and just doing an engine swap. I am looking at either the caddy motor or the 3800 sc.
Doing the www.car-parts.com search for 3800 sc's in tennessee I found several for around 700 dollars. So you may wanna check in TN for a motor

I keep reading on this forum about the all forged internals of the 3.4 DOHC and wonder why mine came with only forged rods. Actually, in my quest I've spoken to quite a few folks from GM (including an engineer) and none of them have ever heard of forged crank or pistons from GM. No one offers an already made forged crank or forged set of pistons for that engine due to production numbers. So if anyone at all on the forum has a forged crank or set of pistons please post the source now or forever hold your peace.

None of it looked forged to me when we had it apart (94 DOHC). The rods are forged? Interesting.

[This message has been edited by terryk (edited 01-24-2002).]

Yes the '96 GM manual states they are forged steel and they certainly don't look cast. According to yhe GM power book, all 60 degree V6 rods are forged steel and ALL cranks are cast nodular iron and are deemed to be quite durable for street performance.

For the 1991 models mated to 5-speed transmissions, there was an "upgrade" due to the torque twisting the cranks. I too, mangled up my bottom end running the car too hard and had the complete bottom end replaced under warranty. According to those records, the new components were of forged steel.

They replaced everything from the main seal to the crank, pistons to the rod bearings. Took them 12 weeks to do!!! Apparently, the parts were long in arriving and they had to send their local tech to a "refreasher course" at the GM factory to work on it.

Anyway, the engine is now in my Fiero with the same 5-speed. Faster than crap! Of course, now that the bottom end is updated, all the extra engine work is no issue. From the factory, 215 HP is good, but a tweaked NA 300 + is better

DKOV -

Hey, DKOV, can you go into more detail on the mods you've done? How's it affect driveability, mileage, reliability, etc? If I can get 280+ HP out of a NA 3.4DOHC, that's definately the way I'm gonna go. Just want a better idea of what I have to do to get it.

Have you checked out www.60degreev6.com ? They currently have a project going on to mass produce some headers for the 3.4DOHC. Now, this is for the W-body chassis, but it should be adaptable to a Fiero. At least it's a start.

Okey Dokey... I'll do what I can

First off, I purchased my 1991 Grand Prix GTP from a friend of mine that works as a Track Official at PIR. He custom ordered the car in '91 with the optional 5-speed Tranny that is so rare and so coveted.

From there, he had a 3-angle valve job done providing another 10 degrees. He also had the heads ported & polished and decked.

He had also added a custom exhaust system that was light wieght and very free. Claimed around 30 HP gain there.

A year or so after I bought the car, I was racing a Mustang GT on the 205 and stupidly tried to use compression to slow myself down soon enough to make my exit. At around 150, I dropped the tranny into 3rd and spun a couple of rod bearings and tweaked the crank.

Luckily, I was smart enough to play stupid and the Warranty covered the damage as well as provided a forged steel upgrade to the bottom end. They did NOT come from a Pontiac, but a Chevy if memory serves. Anyway, 12 weeks later, I got the car back in tip top shape. Forged bottom end and all. While they had it, I swapped a new centerforce clutch and pressure plate and throw out bearing so I would'nt have to replace that at a higher cost. They also changed out the belts and tensioners.

Of course, when my GTP was totalled by a hit-n-run DUI, my first course of action was to swap it into my 88 Fiero GT.

The modified exhaust he had done was useless on my Fiero so even though I was able to reuse hes headers, everything from there back was lost.

While the motor was waiting to get installed, I went ahead and had the upper and lower intake manifolds ported and re-polished. The Intake manifold was ported as well to 56mm. Anything more would have required a custom part and that was to much for me to do at the time.

The K&N cold air charger filter is a given This I ran to the left after removing the restrictor plate from the Fiero intake system. Wow, was that small!!! I then scooped air into toward the K&N for a good rush of cool, clean air.

I also added a Fuel Pressure Riser.

Just before the motor was installed into the Fiero, I broke down and installed and underdrive pulley and pulled the power steering pump and replaced that with a free rolling tensioner for less drag.

Of course, the exhaust needed replacing. For this, I coupled and actual Ferrari 355 muffler to the headers of the TDC. The 355 muffler has TWO intakes. One, which is devided in pairs, for low end, low flow torque settings and the other, single mounted high, for high flow high end HP. We capped the lower two ports and used the high flow inlet. No cats, nothing else but the 355 muffler and its included tips.

That's about it. The power difference is very evident and only pulls harder the closer to 7500 RPMs you get. Torque hasn't seemed to suffer any and it is VERY drivable as a daily.

I have never claimed anything but MATH on the HP, but as it is, it adds up to 340 HP although my G-tech says 322. In the spring, I will Dyno it and get the exact number for you all.

Side notes are massive weight loss to the car as well as huge 13 inch brakes, 17 inch wheels and complete poly race kit and Koni adj/Eibach 300# springs.

I hope I remembered it all. This project has been long and continual. It is NEVER finished

I hope that helps...

DKOV -

No cam timing changes, huh? Sounds like the head work probably gave you the biggest increase. I'd love to see pics of that exhaust system, if you're ever inclined!

I'm thinking, take a 96 DOHC, underdrive pulley, ported throttle body and upper intake from Ram Air Tech, fuel pressure riser (maybe). Maybe extrude hone the intakes. Of course, the K&N intake (water diverter is already gone ) and no power steering pump (yea!).

For an exhaust, I'd stick with as close to stock as possible, for now, feeding into the factory Fiero exhaust system. That to be replaced down the road with custom headers and a 2.5" or 3" exhaust system routed like OEM, and a SpinTech muffler from WCF. How's that Ferrari muffler sound? Do you get a big improvement from it? Was it worth the bucks? (I'm sure any Ferrari part will be expensive)

I'll be running the Getrag 282 from my Formula, with Archie's Centerforce clutch. So far the suspension is stock, with KYB's, but it'll be getting poly, and 17 or 18 inch wheels and uber-tires during the conversion.

I'll probably hold off on head work, unless I'm rebuilding the engine. Hopefully that won't be necessary, and if I get a later model engine, I'm hoping it will already have the forged internals. Does this sound like a solid plan to you? Hopefully that would put me in the 250HP range. That would be a great place to start.

bump - cuz I love hearing about these engines.

DKOV, buddy, I know you've got sound clips to taunt us with?

PS: email me about 355 stuff. ;D)

Best!
Ben

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

Yeah! Does that 355 muffler change the tone that much? No wonder that sucker sounds like a Ferrari; Ferrari muffler, 7000 rpm, about the same displacement as a 355, only with 2 fewer cylinders. Not bad.

I'd love to hear it, or see pics of the setup.

Hey, Ben, when are you gonna get that N* done? What shows to you plan on taking it to this year? You do plan on showing it, don't you?

The 355 Muffler is a bit of a unique bird when it comes to using it on the Fiero... not because it was hooked to the 3.4 or anything like that though...

You see, the 355 muffler is a TWO PART system. There are 3 inlets to the muffler and 4 exhaust outlets.

During the low RPM, torque phase, the exhaust is routed through the lower two inlets then out the outter two outlets. When the RPM come up, butterfly valves change the exhaust through the system to the top set of pipes and combine the flow into the single upper inlet, which then exit the 2 inner outlets.

Kinda strange but the net result is we are using the one inlet and have capped off the lower two inlets. So, looking from the rear, only two of the four exhaust outlets are functional. BUT... the path we ARE using is the HIGH FLOW path

Pretty sweet setup too

Posting Sound... good idea!!!

DKOV -

Looking forward to hearing that!

I'm also crossing my fingers that the Tax Man will be kind to me this year. If I get a decent return (or at least don't OWE) I may be able to get an engine this Spring for a Spring/Summer project! [fingers crossed]

Hey bud, send me a file (email attachment or such) and I'll post it if you like I wanna hear this!

Best!
Ben.

quote Originally posted by DKOV: As soon as I learn HOW to get the sound recorded and up here, I will Maybe I'll look into that now DKOV -

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

So far, for me, Maintenance has not been an issue. Yes the forward plugs are very hard to get to. But, they were just as hard in the Grang Prix the motor came out of!

As for everything else, it is MUCH easier to get to the Alternator and everything else than it EVER was in the GTP. Just pulling the wheel give you most of the access you need.

We have made a couple of little "mods" to help with the access issues...

We cut a little door that hides behind the center console. When opened, you can easily access the dip stick for checking the oil. Silly, stupid, functional!

Also, I added a "flap" that is attached to the underside front of the rear decklid. That way, when it is raised, I'm not dumping water into the spark plug valley!

I pulled the stock decklid springs entirely and added Rodney's twin decklid struts to work things. That provided more room and needed access as well.

The Driver's side of the motor is very open despite the Cruise Control and new Intake. Access is good there, but to what? There's not much on that side

Moving the Battery to the front of the car provided some more room on the front passanger side of the motor too. Enought to reach in there a bit.

From underneath, alot is very accessible. The motor sits right down on the cradle and provides good access to most of the front side with use of a lift or ramps.

In short, good if you ask me

DKOV -

(Edited for spelling )

[This message has been edited by DKOV (edited 01-29-2002).]

quote Originally posted by DKOV: We cut a little door that hides behind the center console. When opened, you can easily access the dip stick for checking the oil. Silly, stupid, functional!

Oh you've GOT to be kidding! Is this the best way to check the oil? I never thought of that problem.

Heh, I'm doing something similar on the N* car. (though I'm relocating the oil FILL to the other valve cover via some welding. At least I think I am so far.)

Hey, it'll probally work. ;0)

(and it's not as bad as it sounds. Just keep Mobil 1 in there every 3,000 and you'll do fine.)

Best!
Ben.

quote Originally posted by Formula88: Oh you've GOT to be kidding! Is this the best way to check the oil? I never thought of that problem.

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

All kidding aside... Once you tuck the 3.4 DOHC up into that bay, the dip stick is right up against the firewall. If you were lucky enough to not bend it in half while installing the thing, you'll immediately see that unless you replaced it with a highly flexible stick, it's there to stay!

And people say the sparkplugs are hard to get to!!!

Just pull your 3.4 L DOHC Fiero into a Jiffy Lube and walk away for a good laugh!!!

DKOV -

quote Originally posted by DKOV: Just pull your 3.4 L DOHC Fiero into a Jiffy Lube and walk away for a good laugh!!! DKOV -

Count on it!
Is there any way to move the dipstick to the other side? It's a hole in the block, right? Not real feasible to move, I would imagine. Can you post some pics of your "oil door" ? Is it on one side, or in the middle? If it's on the side, putting an access panel behind the seat wouldn't be a big deal. Heck, it might even help with other maintenance back there!

i think when my duke goes im going to be saying hello to the 3.4 DOHC! seems like the easiest way to get more bang

oil door thats a good idea could use that for the front plugs too

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see my toys click here

Unfortunately, the dip stick outlet is nearly dead center. The access hole will actually provide a good reach to the center spark plug as well. It hides necely behind the center console. I don't think it could be moved other than a few inches from sie to side.

In order to access the other two plugs this way, two more holes would have to be cut. That's getting a little messy.

What has worked is a nice big crow bar and a strong "persuasive" movement of the engine block! It was easier with the rubber bushings but now everthing is Poly. Haven't tried it since the Poly swap.

As most of you know, this car is mechanically being prepped for a 355 swap. When the new Interior is installed and completed, it will be much eaiser to hide access holes to those points. For now, in Fiero attire, just the one is all I felt I could get away with.

DKOV -

Ooh. That doesn't sound good. You have to remove the center console and ECM just to check the oil?!?! I don't like that at all. There's got to be another way around that.

No, just flip open the storage compartment there

The Fiero ECM goes away (bye bye!) and the 3.4DOHC's should go in teh trunk for easy access or such.

You just cut a hole, it's not as scary as it sounds.

PS: for the spark plugs? use double-plattinum tipped. (OE on the Northstar) change every OTHER time you do a clutch

Best!
Ben.

quote Originally posted by Formula88: Ooh. That doesn't sound good. You have to remove the center console and ECM just to check the oil?!?! I don't like that at all. There's got to be another way around that.

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

If I remember correctly, we ended up using the stock 2.8 dipstick and just slightly bent it. Its accessable pretty much in the same manner it was on the 2.8 on my 3.4. Perhaps a little lower (due to the heads being so tall) but still accessable.

88-DOHC:

Do you get proper readings with the 2.8 stick? Had I know that, I may not have cut a hole!

DKOV -

I believe so. I would have to ask Mike Smith the previous owner for complete verification (he knows WAY more about the car then me).

Remember the 2.8 and 3.4 blocks are very, very similar, so I think that is where Mike got the original idea of just using the 2.8 dipstick. Even if it is slightly inaccurate I don't think its enough to matter.

Well, for anyone doing the swap, while the engine is out of the car, it would be easy enough to fill it with oil and install each dipstick to check. You can then make any marking changes required to the 2.8 dipstick. That sounds a lot better than cutting a hole in the firewall. That kinda blows away the OEM believability I'd want to strive for.

Yup - just HAD to bump this post up again. Even though I OWE taxes this year and won't be able to do mine for a while.