2.8L Fiero looking for suggestion on Engine rebuild

[Scott205]

building it up some

Thanks, I am planning on pulling off the heads and redoing the gaskets.. thanks for the tip on the 0.4s i will look for those. Already looking into moly rings (would sealed work well also?) Being a DOHC guy (started with 2.8 Firebird, then 3.1L Lumina, now 2 3.4L cars) yes, they did make some 3.4L DOHCs with manual tranmissions.... boy are they hard to find though, only the z34s, pace cars, and internationals had those as an option, otherwise you had to order them special from the factory. I think around 10-12% of the DOHCs had a manual, of that, the W bodys only had about 10-15% of them with the DOHC.. so a fairly small number, tough to find a wrecked one that some junkyard did cut the harness on. If i could find one in decent shape i would steal the 5 speed tranny too!! but most of those fetch much higher dinero than i want to spend, lol. There is a guy near me in Louisiana with a Northstar and an ECM already for a fiero, but with the amount of sand and dirt on the engine, i question whether it didn't get flooded. But I am thinking a solid 3.4 DOHC with the manual tranny and the lighter fiero body ought to flat fly. I guess i need to tag Ben and see if his chip can solve my issue or if he has a different ecm suggestion.

[85maro]

DOHC would be the way to go because from what I've heard it's easier to get decent airflow out of them than the older pushrods. Sealed rings are worth the improvement in vaacum and compression (because they have superior blowby prevention) if you have the $ for them, but a good set of moly rings will cost 1/3 of sealed rings. I'd avoid cruddy engines coming out of Louisiana, chances are it was a flood victim. You don't need to grab a manual that came with a DOHC to make it run, just about any manual with the starter on the correct side will bolt up to it, your main problem will be getting the ecm to work with it. If you have the tranny functions deleted from an auto ecm you could run an older (non-computerized) manual with it just fine, but if you want to keep the tranny functions with a newer one it gets a bit hairy. Late model ecm's use input from the tranny to improve fuel economy and correct engine functions under load (going up hill, wide open throttle, ect.) It'll probably be easier to use an auto ecm with the trans functions deleted if you have your heart set on a manual, otherwise go with an auto. Glad to help!

[Canyonero]

If you have the tranny functions deleted from an auto ecm you could run an older (non-computerized) manual with it just fine, but if you want to keep the tranny functions with a newer one it gets a bit hairy.

Where could a person (me) have this done?

[85maro]

Most performance part shops should be able to do it for you, but the cheaper route would be to buy the equipment to burn your own prom chips and do it yourself.

[Canyonero]

Most performance part shops should be able to do it for you, but the cheaper route would be to buy the equipment to burn your own prom chips and do it yourself.

Either way, I need to have it done. I'm trying not to double post, but I started a thread with that question a couple weeks back with no responses. http://60degreev6.com/showthread.php?t=34428

[85maro]

I'm not trying to be rude, but don't expect someone to explain chip tuning to you because it's pretty involved. If you do a quick search on thirdgen.org you can find tons of tuning info for the older obd1 computers, but seeing as your computer's a '94 it could be an obd1 or 2. Probably obd2. Try looking for obd2 tuning info on a late-model pontiac board or a 4th gen camaro board. If you haven't tried it before it's probably best to let someone else do it. Good luck!

[Canyonero]

I'd love to have someone else do it - if someone would offer to help for a reasonable price. But I'll probably end up buying a whole new ECU.

[85maro]

Yep, it's pretty ridiculous. Some companies charge $250 or more just to burn a "starter" prom chip for you, then you have to datalog it in your car and send it back so they can charge you another $50 for a properly programmed one! That's why so many guys do their own tuning. There was a guy that advertised on thirdgen.org that did prom tuning pretty cheap, but I think he went out of buisness. If you just need the tranny functions swiped it should be cheaper than tuning it, so avoid anyone that wants full price to do it.

[Canyonero]

$50 for used ECU from a manual equiped Firebird. Yeah, I think I'll just do that. I wouldn't mind doing my own tuning someday, but my priority is to get this engine installed and running.

Right now the engine is bone stock internally, with the exception of a K&N intake and 2.5" high-flow exhaust (and the fact that it's bolted to a 2-ton 4x4 instead of a Firebird). Should I even think to bother with tuning?

Next year I tentatively plan to install 1.6 roller rockers and port'n'polish the intake. Tune it then?

Somewhat back on the Fiero rebuild topic: I have a decently running 2.8L TBI engine coming out of a Trooper, and a mess of extra parts from a 3.4L SFI. Would it be just crazy of me to make an engine with the 2.8L long block using the 3.4L SFI injection system for installation in an '86 Fiero GT? I have the engine, and an old friend/coworker has the engineless Fiero at his parent's place that he will give me a deal on (cheap as free I hope). So it's stuff I have, and I'd like it to be cheap considering how much money I've blown on this Trooper project already. I like hacking stuff together like this, but guess what I'm asking is - is this such a stupid idea that I should stop thinking about it right now (e.g. it simply WON'T or CAN'T work)?

[85maro]

Don't worry about tuning the trooper right now, it'll run just fine the way it is. Later on you might want to consider using a cam designed to give you more torq along with the 1.6 rockers and porting the intake, then tune it. A hulkey vehicle like a trooper will benefit more from low-end torq to get it going from a stop.

A 2.8 with 3400 uppers would be a pretty stout little engine, it's definately worth the effort. You're going to need some level of engine-building skill though, because you'll have to set up the valvetrain to run correctly and have the pistons modified to lower the compression and clear a 3400's canted-valve design. 3400 heads on a 2.8 long block will give you 12.5/1 compression which is way too high for pump gas. If you have 10cc dishes milled into the pistons and use .06" head gaskets your compression will drop to 10/1 which is safe for pump gas, but you may also need valve reliefs cut into the pistons to clear the valves. You'll also need custom pushrods made to give it the correct valvetrain geometry so it doesn't get damaged. The easiest way to find out what length pushrods you'll need is by using adjustable pushrod checkers to test the valvetrain geometry throughout it's cycle. You might be able to get away with the stock 3400 ecm's programming if you keep the stock 3400 valvetrain (except pushrods), but it's best to reflash it to make sure.

Never skimp on a rebuild, down the road you'll regret it. Have the block hot tanked and honed, new cam bearings and freeze plugs installed, replace every gasket, use new bearings and piston rings and reassemble it with plenty of moly-grease. You could do a good rebuild for less than $500 and run it for years without a problem.

[bszopi]

He isn't talking about using a 3400 top end. He is talking about using a 3.4L Camaro setup...

[85maro]

Oops... I should read things more carefully. Ditch the camaro setup, it won't give you much of a gain (if anything) over stock.

[FallenZ24]

Does anyone have any opinions about just putting a mild turbo setup on the gen1 2.8L?

I'm getting a 87SE soon and was thinking about it until I put my 3100 in it.

-Joseph

[85maro]

Go for it, the 1st gen 2.8 is perfect for turbocharging. With it's low c/r you could manage 6-7 psi of boost without a problem, just make sure to tune it well. With intercooling you could get 100hp over stock.