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Discussion Starter · #1 ·
Good day, everybody!
I'm new to the group, although I keep bumping into it online while searching for info. Figured it was time to join. 馃槀 I own a first gen 1990 trooper LS. It's my forever truck and I'm currently making the 2.8L all it can be. Pulled the motor to just replace the leaky main seal but found a bunch of items needing TLC. Now I'm upgrading the camshaft, match ported the heads, previously added a 4.3 tbi, 1.6/1 rockers, K&N filter etc. It's slow going because I work two jobs, but it's gonna get there eventually. Got a full gasket kit and I'm gonna start reassembling the engine soon! Wish me luck!

Matt
 

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Discussion Starter · #3 ·
HI, Matt, welcome to the Planet! If you're not too far along in your reassembly, here's a tip that will greatly enhance the performance of your GM 60-degree Little V6 That Could:

Get a 3.1/3400 crankshaft kit with matching main and rod bearings. The 3.1 has the same bore as the 2.8, just a longer stroke. The 3.4 has a redesigned block with larger yet bore, and the same stroke as the 3.1. Cranks are physically interchangeable across the board, with exceptions noted below.

Pick up a set of new pistons for a 1991 Camaro 3.1, or a '91 Isuzu Pickup or Rodeo. The 3.1 has the same bore as the 2.8, just the crankshaft is stroked. So you can turn your engine into a 3.1 with those components.

I'd recommend Sealed Power H562CP "Coated" pistons, the anti-friction coatings on the skirts prevents scuffing and they run quieter. Assuming your block is Standard and not worn out, a set of Std pistons should work nicely. Install the new pistons on your good 2.8 rods.

Here's a standard set on eBay for $115 shipped: Sealed Power Piston Set #H562CP Standard - 3.1L Chevy (6 PCS) | eBay

One caveat: Check your bore sizes so there will be no surprises. Standard bore size for 2.8 and 3.1 is 89mm.

You should be able to get a crankshaft kit from your local auto parts store. They'll probably be happy to take your 2.8 crankshaft as a core, since good 2.8 cranks are getting scarce. Plenty of FWD 3.1/3100/3.4/3400 crankshafts out there. Doesn't matter if the crank has a reluctor wheel or not; later FWD models and the Camaro 3400 have crank sensors for the distributor-less ign, and that requires a wheel on the crank. Since we're using an old-school distributor, the reluctor wheel is moot.

Regardless of displacement, your V6 will benefit from improved exhaust. You can do a 2-1/4" cat-back, and if you really feel Sporty, you can chop out the exhaust Wye and use an upgraded cat for a HUGE improvement in performance. The wye is very restrictive and getting rid of it is a definite improvement.

Use a cat with dual 2" inlets. The V6 downpipes are run right into the cat. Lucky for us they happen to also be 2" pipes!

These cats usually have an O2 sensor bung right on the cat body, this runs the sensor hotter than sitting in the wye, which means faster warmups into Closed Loop, and better operation down the road.


For a 2.8 or 3.1, you'll have to use a reducer on the 2-1/2" inlet, down to 2-1/4". You don't need any larger pipe than that. I have 2-1/2" on my 3.4, but even it probably doesn't need that big of pipe. You'll have better low-end with smaller diameter. But starting from 1-7/8" stock exhaust, the performance difference is remarkable.

I used a Dynomax Super Turbo muffler and it sounds great. Doesn't drone at hiway speeds, either. You can tuck it up into the frame a bit more for better clearance and a straighter run. Don't know why ZuZu made the piping going to the stock muffler so convoluted.

2-1/4" size Dynomax: Dynomax Performance 17747 Dynomax Super Turbo Mufflers | Summit Racing You might find a cheaper one on eBay with free shipping, or better availability.

Back in 2006 I build a "2.8 Stroker" '89 Trooper for my folks. I was really surprised at the good low-end torque the 3.1 had, way better than my old 2.8. It got pretty good mpg, too. I used a Delta Cams (Tacoma, WA) "torque" regrind but otherwise it was stock. My Stepdad passed away in 2011 and my Mom gave the Trooper to my Nephew and he's still enjoying it to this day.

Anyway, hope there's something in there that you'll find useful.

Good luck with the project and post some pics when you get a chance...........ed
Thanks for all the advise Ed! As much as I would like to stroke the 2.8, the bottom end is super healthy. No gouging or scuffs on any cylinders, no slop in the bearings, so I opted not to break it down that far. I am replacing the timing chain/gears though, and I'm installing the comp cams 206/206 high energy cam lifter kit. With my higher ratio rockers, this should end up a touch bigger than the 212/212 cam they offer. Hopefully it's not too lopey, if it is I'll just swap back to stock rockers and it should be fine. I have match ported the heads and did a lot of blending on those. Polished and lapped the valves, new water pump, smog pump and maybe EGR delete, electric fan conversion, and I just ordered the Heddman 69370 headers which I'm hoping to fit with minor cutting/welding/rearranging. I'll be sure to check your numbers when I get to the exhaust, since I'll probly have a muffler shop build it from scratch. Maybe MSD Ignition? I've heard of awesome results using those. I know I could squeeze a V8 into my Trooper for less than what all this will cost, but I just want to see what that 2.8 is capable of I guess. lol
 

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Discussion Starter · #9 ·
Hey sorry so late just getting to see how this site works. I have my 3.2 done and in , all is doing well but other day going hang gliding in mountains i got a 43 code . It is so much more top end than the 2.8 i am installing 2 1/4 from Y back today. Ill send pics . Thank you for all the advice [email protected]
Are you gonna use a Y to a single exhaust outlet like stock? I'm still messing with my 2.8L. Finished head porting, and have the engine on a stand. I'm replacing the pan gasket and then I'll start building it back better. :DGot most of the parts just waiting to go in. I bought the hooker headers which I'm sure I'll have to modify at least on the driver's side but I was toying with the idea of dual exhaust, or even sidepipes. Thoughts?
 

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Discussion Starter · #10 ·
Are you gonna use a Y to a single exhaust outlet like stock? I'm still messing with my 2.8L. Finished head porting, and have the engine on a stand. I'm replacing the pan gasket and then I'll start building it back better. :DGot most of the parts just waiting to go in. I bought the hooker headers which I'm sure I'll have to modify at least on the driver's side but I was toying with the idea of dual exhaust, or even sidepipes. Thoughts?
I meant HEDDMAN HEADERS, NOT HOOKER HEADERS. I forgot already.
 
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