Ok, heres the deal: I'm looking for power, I am NOT gonna swap in no V8, I am NOT gonna swap in a bigger 6pack. Now, I'm looking to run about a 10.5 or 11.0 Compression, Bigger valves (would like some suggestions...), 1.6 Roller rockers, and a good port job. This is just mild stuff, but I would like to know if anyone has bothered to do any of these to your motor. That's pretty much it, if anyone's running these type of mods, post back. If you aren't, but you have a suggestion on vave diam. post back. Thank you for your time.

 

since you don't want a bigger block, six piston or otherwise, look into the supersix motorsport heads. WHy o much compression anyway?

What cam to match heads/compression/**exhaust** upgrades

 

I would stick with the 1.72 1.42 valves. Step up to a custom ground roller cam and order custom pistons with 10:1 compression , put in arp rod bolts and wind it up to 7000 rpm.

 

i would not stick with a 2.8 go atleast 3.1. you can use the same block just get a 3.1 crank to put in it. bore it +.030" would help ya a tad. i am running 10.75:1 compression. i have custom pistons and you don't want anymore compression than that. my motor spark knocks a fair amount and it auto with a set of 4.10 gears in the back, lighten the load on the motor. super six has heads that i think have 1.8 int valves but it'd be SOOO much cheaper to stick with 1.72 int valves. 1.8s would be nice but i know i don't have the money to spend on those heads for an extra .08". do a P&P job yourself. try to find a set of headers or wait til the pacesetters come out. you could get a custom ground cam or just go check out crane cams web site. they've got about 8 available for our motors. any 2.8, 3.1, or 3.4 cam will work. for the rockers, v8 rockers will fit but they run 3/8" studs where we have 10mm; if you get roller tipped rockers, just use your pivot *****, if you want full roller, contact 614streets, i believe that he is running full roller rockers but he may have bought the ones that are made for our v6s, i'm not sure.

 

I was looking in a Speed Pro cataloge, they have 1.6 rollers for our motors, thing is, you have to buy 3/8 studs too (really isn't all that much money). As for stroking the motor...I kinda want to stay away from that sort of thing (but, if I can find a good crank...). The high compression is for the power. I'm not worried about knock, I won't exactly be running regular. Have you tried running 1.6 rockers with a higher lift cam? Thanx

 

i wouldn't exactly call, putting a 3.1 crank in a 2.8 block, stroking it. seeing as how the 3.1 is a production motor also. i have to run 93 octane in my motor all the time and it still sprak knocks; spark knock is not "just there," detonation will crack piston rings or even pistons. then you have a complete rebuild on your hands. i, honestly, wouldn't recomend going higher than 10.5:1. if you don't have to re-thread the heads for the 3/8 studs, go for it. i am running 1.6 roller tip rockers and i have .512 valve lift on the ex side with the 1.6s.

 

I'm not gonna get into a pissing contest over it but I prefer the 2.8 to the 3.1. Good reason why the 3.1 was only used for 3 years.

2.8 or 3.4 are my choices for a build. But still prefer the 2.8 by the bore/stroke numbers.

I would like to drop $400 on a new crate 2.8 but money is tight right now.

 

I thought I should add its kind of like deciding
to build a 377 or a 383, sure more is better but there is million n 1 reason to build one over the other and vise versa.

 

What is your timing set at???? You shouldn't be getting detonation THAT bad, heck there are ways to tune around that compression....I've gotta go with Gumby on this one, I pretty much prefer the 2.8 too, The 3.1's I've driven didn't impress me much (athough, the 3.4 in the firebird I drove was pretty slow too.....?).

 

The 3.1 is low compression, and is the ideal for boost.

Strange that the 2.8 is 135hp, 150tq 9.0:1 comp
While the 3.1 (longer stroke) is 140hp, but 180tq 8.5:1 comp
And the 3.4 (stoked and bored) is 160hp, and 200tq 9.5:1 comp

I know my old s10 2.8 would run circles around this 3.1. Let alone after I dropped that 3.4 in, WOW

I agree, the cost of the super six heads is ALOT. I would do about everything else to the engine before them. I wish I had the cash on hand few weeks ago when their was a set of 1.8/1.5 heads on ebay

 

Doward here...

2.8 vs 3.1? 3.1, no contest. The entire B/S ratio thing is completely moot on a sub 300hp engine, sorry.

Think of this - which would you rather have, a 350 or a 383?

Notice the stroke increase between the two - 3.48" to 3.75" That's a .27" increase in stroke, and much more torque. The 2.99" to 3.31" stroke increase (from 2.8 to 3.1) is an increase of .32"! You're actually taking a larger increase in stroke going from a 2.8 to a 3.1, than you would in a 350, going to a 383.

That's why the extra 5hp, but 20 lbs/ft of torque! There are NO changed between the 2.8 and 3.1 mechanically, other than the stroke increase. If you want to pass up a free 20 lbs/ft of torque, that's your call.

As far as the 3.1 only being built for 3 years.... um... what do you think the 3100 motor is?

 

They only used the 3.1 for three years- IN THE F BODY- but continued to use it in everything from Lumina minivans to Cavaliers for a long time afterwords.

Anyway- if you are happy and determined to build a 2.8, build it. But the same induction pieces and machine work applied to a larger displacement engine will gain you more.

Good luck on the build.

Eric

 

[And the pissing contest begins.]

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"They only used the 3.1 for three years- IN THE F BODY- but continued to use it in everything from Lumina minivans to Cavaliers for a long time afterwords. "

Well sure it was use in other cars, other cars that don't matter.
It was dropped form the Fbody like a redheaded step child.

The problem was a car two years old was smacking around the new ones off the lot. They then went 3.4

Match a stock internal 2.8 to a stock internal 3.1 and see why that 20lb of TQ don't matter.

If you are gonna go through all the work of boring and stroking a block the 2.8-3.1-3.4 would be kind of dumb.

Just go 4.3 if a bigger V6 is in order. Or even better the new 3.6 DOHC if it will work. Plenty of stick, auto and 4x4 4.3's out there.
[ make a AWD 4.3 F body]

Or buy a Monte Carlo/s10/s15/jimmy/+ more with a 4.3 for $900, swap engines around and sell it for $700

If you wanted more displacement the 4.3 is the best bang for your buck. That would be well worth it. Then add boost and NO2. It can take it, toss in propane too.

Course you can then go Buick if the 4.3 isnt enough
[bigger is better right]

a turbo 3.8 will rip all of the 60* engines a new one and the 4.3. Turbo 3.8 don't have much competition on the roads. Thats the best of the best v6 GM made.

Until we see what the DOHC 3.6 will do and if it gets boost.
The turbo 3.8 may get shelved.

 

Of course all of them engine options are even easier for us T5 owners.

 

i'm stepping out of this one. if you want to play with the 2.8, the smallest 60* v6 gm ever made, go ahead. my 3.1 will outrun any N/A 60* v6 i've ever seen. if you find one running N/A that you think will beat me, let me know.

 

My 3.1 with just exhaust and half-tuned up slaughtered any 2.8's I ran into. Stock, I'd still whoop up on them...but I only managed about 1 car length then.

They're the same damn motors, except one is stroked. I don't see why you wouldn't want that extra stroke, unless you like to wind the **** out of the motor where it doesn't make any power up there anyways?

I only think they dropped the 3.1 from F-Bodies because they put it into play too late in the game...and by the time Gen 4 rolled around, the F-body was bigger looking and better and the 2.8/3.1 platform was getting tired. Besides, with a new generation of vehicles, it's not at all uncommon to come out with new motors as well. So they dropped the 3.1 and brought in a bigger and better 3.4. Just because the 3.1 HAPPENED to be in the wrong place at the wrong time doesn't mean it was any worse than the 2.8. They did, after all, UPGRADE to the 3.1 for the last 3 years of the Third Gen F-Body.

 

The question wasn't a "which is better" one, PLEASE don't reply to it that way. As far as I'm concerned, I'm working on a TIGHT budget. I have free access to just about any tool you can imagine (and some you prolly cant ), I can make just about anything happen. This is how it's gonna go: I'm gonna pull the motor, Rebuild the bottom end for 10.5 compression (as per some good advice), full port job, 3.1 injectors and 1.6 rollers on the cam I have. And for the 3.1 VS 2.8 thing....I've stomped a few 3.1's, I've had a feww out pull me too. Every motor is different. And for the 350 OR 383 question, I'd rather have a 383 (of course) but I'm poor so I'd have to build a nice 400 horse 350 instead...

 

where do you get a 2.8 crate motor for that price?

 

Same place where I got my new drivetrain from, connections.

 

If you go to ebay motors and search 2.8l under parts and accessories you will find brand new crate 2.8's for $200 bucks.

I got mine for $65 bucks plus 185 shipping. Its legit, I even sold my crank for 100 and the pistons and rings from it for 45. I buzz it to 6k now with the forged slugs. Im satisfied as hell with my engine. :hail:

 

614, you raced your truck yet? if so, what does it run?

 

No , there is snow on the ground, national trail raceway shut down way early this year because of the tracks left lane had a big dip and a few racers crashed because of it. Of that the truck wasnt ready even then. It is sitting in the garage and I am getting it ready for paint. I sold my south side traction bars because the truck rode way to rough on the street with them. No Im moving to florida around late april and saving money for a new driver , school and other expenses.

If I end up making decent money before then Id need money for caltracs traction bars. I got the new pro software upgrade from Doug Flynn at holley and have to set it up. It still isnt fully tuned but I managed to put about 1200 miles on it before the weather got bad. Its running a bit too rich at idle 11.0 af-10.5af , the pro firmware should help since all I have to do is tie my wideband 02 set up to it and I can run full closed loop at any a/f I want it to.

The truck also had a small fire inside (welding ext cab patch) so the interior is gutted. Its about 90% finished, might try to debut it at the 2004 world of wheels show. Money is really tight because of my decision to go to school....

 

i do paint too... and its not snowy or anything here (imagine that) just a little cold...nice dense air.

 

Yeah I was in Orlando 2 weeks ago was not bad at all.

I really got a kick out the weather guy I watched at the rooney in southbeach. He was explaining a cold front approaching , I was in the ocean the next day

 

edelbrock ( i know im spellin it wrong i forget how to right now ) has a manifold,cam,and lifters on their site for the 2.8. i wonder what kind of numbers as far as tq and hp theyd get you. Anyone know?

 

lol...i hear ya! we did have a little ice on the cars and grass and stuff this, Sunday, morning. i wanna see your truck man! bring it as soon as you can, alright?

 

Will do. Got to bring it down when I cant keep it stored securely.

 

cool, yea i know what you mean about storing it too! my car got broken into right in front of my house one night....we normally don't have any trouble around our house. i think it was one of the neighbor kids...took my stereo

 

userid=surplusautoparts


$199 + $185 shipping = $400 round abouts

 

what you need to do is look for a GM Performance book that has a build up of the 2.8 and small blocks in it. I can't remember the name off the top of my head but I do remember some things that it said to do.

Find a set of aluminum heads...I heard these came stock on some cars but not sure (can get a 1 set for 100 bucks)

Shave the heads so it will raise the compression **BUT** use SMC 350 rods in it to handle the compression. The only thing that has to be done to the rods is to shave the offest off of them that is around the crank journal (make it even on both sides) These will bolt in.

I'll see if I can get ahold of the name of the book but it's very popular with people who build Chevy hi performance motors

edit: The GM Power Book if I remember right

 

thanx gumby , the cheapest i seen one so far was 400 for a rebuilt short block with a 175 core charge and no warr.

 

Gumby, thanks for that link. I sent them an email to see if they can get new, gm 3.4 short blocks

Aluminum heads would be nice, reduce front weight, but I have heard many storys that aluminum heads on steal blocks blow gaskets fast

 

Doward again... lol

You guys do realize that's the '82-'85 2.8, right? With the smaller mains, weaker oilling system, etc...

As far as the 350 vs 383 - what if you could build the 383 cheaper than the 350? I got my 3.1 crank kit from Carquest and IT WAS CHEAPER than the 2.8 crank kit.

Why? How long did GM build 2.8s (please remember - two seperate cranks, and two seperate blocks for those 2.8's!)? How long did they build 3.1s (all using the same basic crank mold)? Exactly.

The 3.1 is more powerful than teh 2.8, point blank. Mod them both the same (same cam/compression/etc) and the 3.1 will always make more power.

Overall, though, it is your call. I got a lot of beef about turboing a 2.8, instead of dropping a 350 in it - it's your car, you have to drive it, so you have to be happy with it.

 

The reason it list as "'82-'85 2.8" is for emission laws. It would be illegal to put it in anything newer or list it for anything newer.
I seriously doubt GM went through all the trouble to build a new 2.8 block but when they went to make up crates, they said lets use the older flawed design and dug out the older molds???


Same reason you will see new crate motors in catalogs say for 72 and older cars or not for fuel injection. Doesn't mean it was build at 72 specs. by law they can not list it for anything newer or list it to fit a certain car unles it 50 state smog legal.

We are just lucky they did a carbed version first or we may not even be able to get a whole crate. Its only cause they used a carb in 82-85 are they allowed to sell a crate like that. Other wise I bet the 2.8 crate would be racing only or you would have to build it piece by piece off the shelf.

Making a crate motor they gotta follow some strict rules / laws in the listing of what it will fit. Now selling parts piece by piece, they could and can do anything.

 

The only reason it says 82-85 is because of the crankshaft being external balance , it is the big main version. It also comes with the h.o. pistons. I ran my used internal balance crankshaft with mine , but the external unit is plenty strong. Here are some pictures of mine from a year or so ago.

http://614streets.com/2.8cratemotor2.jpg

 

i've got a few sets of aluminum heads but you do have to run the FWD intake manifold. ours will not work. and, the compression will jump just going to aluminum heads because of the smaller combustion chamber on the aluminum heads. if i remember correctly, the aluminum heads are 28cc where the iron ones are 54cc(??).

 

Use a fiero 2.8 the best one GM ever made. 145hp (85-86)

 

fiero 2.8 is the same as ours.

They just benifit from better air intake, and exhaust, and better programing.

 

It is NOT the same.The fiero version has the high output heads and has the most hp of any stock 2.8 ever 145hp.The f-bod 2.8 makes a great boat anchor.

 

Aluminum heads WARP, heat makes them warp. They only blow headgskts when you run them too hot. THATS why the cadillac Northstar V8 is a piece of Crap, Aluminum heads AND block...If you blow a head in one of those puppies...Might as well buy a new car. Anyhow, as for more power always being better...True, usually. I've driven plenty of vehicles with"power" that were slow. I raced a 97 Firebird after work and stuck my 3rd gens **** in his face (he was pretty pissed he lost...). I'm pretty sure his 3.4 or whatever had more power too...I just want a really quick 2.8L General Motors Engine....I'm fully aware that there is more power to be had elsewhere (obviously). I don't really care either, I like my 2.8, Takes a lickin and keeps on tickin! I'll be seeing plenty of "more powerful" cars at the light, "Sometimes you get spanked, SOMETIMES you're the domanatrix..." Have a nice day, and go kill a Honda...Thin the herd.

 

Zapper, the heads are EXCATLY the same as our fuel injected heads.

Gm's part number is the same
any aftermarket company the part is the same.

The power is made thru a more efficent intake, better exhaust, and better ECM programing.

This has been gone over, betten to death, and part numbers are the same, valve size is the same. 1.72 and 1.42

 

Al heads only warp if you run them way too hot. Like, 240+ degrees hot. I don't know about you guys, but if my temp gauge hits 220, I hit that fan, and if it doesn't come down, the engine gets shut off - there's obviously a problem.

Dale beat me to it - better intake/exhaust is the reason the Fiero has 10 extra hp.

Yeah, you're right tho. A lightweight, DOHC V8 IS a huge POS.

If you want real performance, you're going to have to take better care of your car than just changing the oil every couple thousand miles. The more power you squeeze out of a smaller package, the closer you have to watch things, so they don't go all catastrophic on you.

 

Just thought I'd add...

The big 'problem' with Aluminum heads in conjunction with an iron block, is that they eat head gaskets.

It's actually the different heat expansion rates of Iron vs Aluminum. You HAVE to retorque those heads after 500 miles, and keep checking every 5000-10000 miles or so. As long as you keep check on your coolant temps (don't overheat the engine) you'll be fine.

 

Another person not to listen too!

 

Does anyone listen to Fiero owners???

Just kidding as I'm about to be co-owner of an 87 Fiero Go-Kart.
No title , no chance, gonna chop it into a rail and re-titled it as a custom build.

Anyone want to buy a highway legal Go-Kart????

 

Doward...ya do?? I got aluminums on cast iron and never touched the bolts since they were installed. And the car has seen 6500 rpms on more than one occasion.

 

Come on now you know he was generally speaking about the 60* cars.

The ford doesn't matter That have use Alum for a while.

I'm sure we could hear from some import guys too but it don't matter much if a Toyota can go 50,000 miles with finger tight head bolts.

 

ALL MPFI 2.8's came with the "High Output" heads.

The only difference the Fiero engine has is the Valve covers, Injectors and Exhuast manifolds.

 

Yeah but I figured the premise would still be the same. They're both the same kinds of metals so why should the expansion properties, etc. be different?

 

aluminum heads don't need to be retorqued unless copper gaskets are used. GM does not have all the new 60 degree motors come in at 500 miles to be retorqued. yes aluminum does have a different expansion rate then iron. this is why a different head gasket that allows the head to expand across the deck without ruining it is used.