Below is a quick run-down of the upgrades, restoration, and renovation of the 2.8 V6/60 in my Pontiac Fiero. Many of these improvements were done nearly a decade ago. For the benefit of documentation, I'll list those here as well as the more recent renovation. List of repairs, in no particular order:

  - Engine Rebuild, 2.8 to 3.2

  - Bored Throttle Body, 54mm to 57mm

  - Port Matching the Intake Runners


Back in August of 2000, I overheated my engine due to a failed waterpump impellar. The engine didn't seize, but it destroyed the main bearings. When making the decision to fix or replace my engine, I ultimately decided on a stroker kit. This allowed me to keep my existing engine block, and didn't require me to buy anything more than what I would have had to in order to rebuild the engine in the first place. The kit came from ARI Performance Racing Engines. At the time, the kit was roughly in the neighborhood of $700. The kit is a bit more expensive when you factor in 10+ years of inflation. The kit that I purchased came with the following:

•2.8-3.1L Basic Stroker Kit (Crankshaft, Main Bearings, Rod Bearings, and Connecting Rods)
•Hypereutectic Pistons (from "Sealed Power")
•Phase 2 Camshaft & Lifter Kit (Known as the "Fireball 2 Camshaft")
•Clevite Cam Bearings
•Brass Freeze Plugs
•Fel-Pro Complete Gasket Set
•Double-Roller Timing Set (Cloyes "Tru-Roller")
•Stock Oil Pump
•Head Bolts
•Stock Pushrod Set
•Timing Chain Dampner

The rebuild worked well for a few months, but unfortunately I've experienced other issues with the engine including a rattle. The new issue does not appear to be the engine itself as it isn't consistent with RPM and is intermittent. I suspect it could be a loose torque converter bolt (see video below). I'm able to mostly confirm this since the rattle appears to be very similar to the sound in this other video I found: click here. Since I am in the process of swapping to a manual transmission, I'm not overly concerned. When I get to the point where I am ready to check the condition of the engine, I'll probably replace several parts again anyway, including swapping the camshaft to an H272 Crane Cam that I purchased several years ago. The Fiero hasn't really been driven in over 7 years.


The Fiero's stock throttle body, made by Holley, has an interior throttle body diameter of 54mm. This is more than sufficient for the 2.8, and realistically for anything up to 245 horsepower. In an effort to improve airflow to the throttle body and provide more volume to the engine intake Darrell Morse, a Fiero enthusiast and member of the Minnesota Fieros Club, offered a series of upgrades for the Fiero's V6. The improvements offered was a machine / boring package for the Fiero's stock throttle body. This upgrade increased the size of the stock throttle body by 3mm, to a total of 57mm. Other services offered including matching the new bore of the throttle body to the intake. The original prices from the Fiero Club were as follows:

•Stock # 1517 Complete Refinishing of your unit sent in......$218.90
•Shipping and handling.........................................................$  38.50
•Core charge if you cannot supply a unit..............................$137.50

I opted to have the throttle body bored and port-matched to the intake plenum. The improvement was nominal of course since the engine was still mostly stock at the time, but I did notice a slight improvement in throttle response, though it could be a plecebo effect. At the very least, it should provide more volume to the intake when the engine's camshaft and head porting is able to take more advantage of it. Below is the comparison between the stock and bored size, as well as a picture of what the throttle body looked like when it arrived from Darrell Morse.


In addition to the throttle body, I also port-matched and gasket-matched the intake components. The Fiero's intake is made up primarily of three components: the intake plenum, the intake runners, and the intake manifold. Matching between the plenum and the runners is actually pretty good and all that it really needs is gasket-matching. Gasket-matching is the grinding of material on the intake so that it reaches the limits of the interior area of the exposed intake. This is to ensure optimal flow from one component to the next where it will not be impeded by imperfections. Port-matching on the other hand, is the process of grinding away material from the intake components to ensure proper alignment between the exit and entrance ports. This is where the Fiero picks up some considerable improvement in the mid-to-upper rpm range. The alignment of the ports between the intake runners and the intake manifold are horrendous. The ports on any one side are off by as much as a third of an inch. When you consider that there is misalignment on both sides of the intake, this can result in 1/2 to 3/4ths of an inch restriction between the components. As shown in the image below, it is necessary to grind away where the ports do not properly meet. Because the Fiero has an exhaust gas recirculation (EGR) system, the parts of the intake exposed to the internal process should be heavily stained. This will work in your favor as it will provide you with the appropriate template for grinding. Make sure that the components you are port-matching came together. Port matching differs from Fiero to Fiero, so it's important to ensure the runners and intake manifold came together at the factory if you intend to use this method. Grind away at the stained areas of the intake ensuring that you do not go beyond the clean metal that was originally protected by the gasket material. You will want to grind away the metal on both sides (intake runners and intake manifold). Use a sanding wheel to smooth out the insides if you have time, this will optimize the effort.


More coming...


For any questions or comments, click here!
Copyright - PontiacPerformance.Net