The crankshaft should fit in the block. But then you'd have an issue with piston dimensions. The 2.8 crankshaft has a shorter throw than the 3.4. So your pistons wouldn't make it to the top of the cylinders. As a result, the compression ratio would be REALLY low.
To fix that, you'd need to have custom pistons made, with the diameter of a 3.4 piston, but the compression height of a 2.8 piston.
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01:35 AM
AL87 Member
Posts: 2578 From: Bradenton, Florida, United States Registered: Mar 2010
The 3.4 is a better engine. The bottom end has better oiling. The block is stronger. It has provisions for DIS. And it has more power potential than the 2.8.
About 6 years ago, I built a moderately tweaked 2.8 V6 for my Fiero... stroker crank, performance cam, increased compression, ported intake, ported heads, Trueleo headers, 7730 ECM, blueprinted and balanced... and it made slightly more power / torque than a stock 3.4 V6. I spent a couple grand on that rebuild, too. If I had it to do all over again, I'd buy the 3.4 crate engine from the get-go, and save the time/money/effort I wasted on the 2.8.
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10:25 AM
Oct 14th, 2012
AL87 Member
Posts: 2578 From: Bradenton, Florida, United States Registered: Mar 2010
where would I find a stronger crank for the 3.4 then?
3500's have forged cranks, and god like heads compared to the 2.8, and they bolt in place of the 2.8 if you swap the timing cover and use fiero accesories....
------------------ there's a Group on 60degreeV6.com for us 660 Fiero owners!
3500's have forged cranks, and god like heads compared to the 2.8, and they bolt in place of the 2.8 if you swap the timing cover and use fiero accesories....
so I'd be able to use that in a 3.4?
what cars had the 3500?
I was thinking of building a 3.4, or just go with what I have in 2.8's
3500's have forged cranks, and god like heads compared to the 2.8, and they bolt in place of the 2.8 if you swap the timing cover and use fiero accesories....
quote
Originally posted by FieroWannaBe:
No. Just use a 3500.
3500 > 3.4
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01:01 PM
AL87 Member
Posts: 2578 From: Bradenton, Florida, United States Registered: Mar 2010
iirc, firstfirebird(on 60v6.com) dropped an LX9 crank into the 3.4 block and found it could work with some clearancing. LX9 cranks have larger rod journals too.
what are your power goals? a '981(iirc) crank is a pretty stout piece to begin with
272cam. with 1.52 or 1.6 (if applicable?) maybe a turbo or centrifugal supercharger. full port and polish. headers. upgraded ignition system.
getrag 5spd transmission?
street-strippin' car.
i dont know what im looking at for power numbers for the 3.4, its funny I know the potental of a 2.8 and 3800s/c more than i do this 3.4...
for all the money you would have in the supercharger, you could have a n/a 3500 putting down the same power. believe it or not, 25 years worth of R&D has it's merits...
------------------ there's a Group on 60degreeV6.com for us 660 Fiero owners!
The 3500 is a late production 60* V6 with dual overhead cam & variable valve timing... Last time I checked, those are a bit complex and expensive to work on because they are newer.
And there is more than just power factoring into this equation... #1 exhaust sound. (throaty and muscular vs hi-reving and exotic) #2 ease of install. (support, and parts availability.) #3 Mechanical complexity. (the simpler it is, the easier to fix and the less expensive it is if anything breaks)
2.8: 140 hp (104 kW) at 5,200 rpm and 170 lb·ft (230 N·m) of torque at 3600 rpm. 3.4: 160 hp (119 kW) at 4,600 rpm and 200 lb·ft (271 N·m) torque at 3600 rpm. I couldnt find a power curve to see what the 3.4's output would be at 5,200rpm, and im pretty sure a stock 2.8 only really makes about 120. The 3.4's max power is at a lower rpm probably because of intake restrictions so Im sure it has more potential than it lets on. And the stock exhaust wouldnt help either. Theres plenty to be freed up without actually upgrading. Simply modifying what I have would be worth it.
The 3500 has anywhere from "196 hp (146 kW) to 201 hp (150 kW), and torque ranges from 213 lb·ft (289 N·m) to 221 lb·ft (300 N·m)"
I see 200hp being achievable with the 3.4; And with that, even more torque... and more so with forced induction*
Although, I could just throw this easy engine swap idea out and get a 300hp S/C3800
[This message has been edited by AL87 (edited 10-17-2012).]
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07:12 AM
renderareason Member
Posts: 49 From: Wakefield, MA, USA Registered: Feb 2006
Originally posted by AL87: The 3500 is a late production 60* V6 with dual overhead cam & variable valve timing... Last time I checked, those are a bit complex and expensive to work on because they are newer.
A 3500 is a OHV engine jsut like the 2.8,3.4,3.1 engines.
Its heads are the best 60 degree heads made, 3.4/2.,8 have 2nd to worse its intake is the best 60 degree intake made, 2.8l has the worst It is used in many late model cars, these cars are more plentiful than v6 camarobirds. Its cost is low, it is not seen as a high performance engine unlike a now rarer camaro engine. It makes more power stock than a cammed 3.4 will. A modded 3.4L needs computer work. A modded 3500 needs computer work.
3500 wins, all the mods to equal performance of the stock 3500 would cost more than just swapping a 3500. Trans and engine mounts will be fiero units, any performance upgrade needs better than stock rubber (even a hopped 3.4) Accessories will be stock fiero. No starter to be redrilled, no jig to buy.
I dont see why you think a 3.4l is going to be better or easier than a 3500.
not in a fiero but a stock LX9 3500, with the exception of a cam and valvesprings. otherwise this engine is uncracked, 250 bucks from the boneyard. 11.1 et @ 130 mph.
The 3500 is a late production 60* V6 with dual overhead cam & variable valve timing... Last time I checked, those are a bit complex and expensive to work on because they are newer.
And there is more than just power factoring into this equation... #1 exhaust sound. (throaty and muscular vs hi-reving and exotic) #2 ease of install. (support, and parts availability.) #3 Mechanical complexity. (the simpler it is, the easier to fix and the less expensive it is if anything breaks)
2.8: 140 hp (104 kW) at 5,200 rpm and 170 lb·ft (230 N·m) of torque at 3600 rpm. 3.4: 160 hp (119 kW) at 4,600 rpm and 200 lb·ft (271 N·m) torque at 3600 rpm. I couldnt find a power curve to see what the 3.4's output would be at 5,200rpm, and im pretty sure a stock 2.8 only really makes about 120. The 3.4's max power is at a lower rpm probably because of intake restrictions so Im sure it has more potential than it lets on. And the stock exhaust wouldnt help either. Theres plenty to be freed up without actually upgrading. Simply modifying what I have would be worth it.
The 3500 has anywhere from "196 hp (146 kW) to 201 hp (150 kW), and torque ranges from 213 lb·ft (289 N·m) to 221 lb·ft (300 N·m)"
I see 200hp being achievable with the 3.4; And with that, even more torque... and more so with forced induction*
Although, I could just throw this easy engine swap idea out and get a 300hp S/C3800
yes, the 3.4 has potential, especially when you swap 3500 heads onto it, but then again, you could just start with the 3500, and get a roller cam, roller rockers, better oil distribution, and oh yeah, the heads flow 230 CFM on the intakes STOCK! you CANNOT make 3.4 heads do that. it isn't possible. the 3500 BOLTS in place of the 2.8, all you need to do is swap the timing cover, and accessory drive.
200 hp stock? or 200 hp with a wild cam, poor fuel economy, horrible reliability, and a torque curve that nosedives....
in the words of John Ligenfelter "The worlds's best cam combined with a poor set of heads will produce an engine that's a dog. But bolt on a set of great heads even with a poor cam and that engine will still make great power."
heads are where your car will make power, stock 3500 heads will outflow max effort 3.4 heads all day long.
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05:43 PM
ericjon262 Member
Posts: 3136 From: everywhere. Registered: Jan 2010
ah crap, really? I was probably looking at something else... (went to search... AH... *I missed something*) ((Aside from the LX9)) XD "My bad"
The High Value engine family from General Motors is a group of Cam in Block or "Overhead valve" V6 engines. They use the same 60° vee bank as the 60° V6 family they are based on, but the new 99 mm (3.9 in) bore required offsetting the bores by 1.5 mm (0.1 in) away from the engine centerline. These engines (aside from the LX9) are the first cam in block engines to implement Variable Valve Timing, and won the 2006 Breakthrough Award from Popular Mechanics for this innovation. For the 2007 model year, the 3900 engine features optional displacement on demand or "Active Fuel Management" which deactivates a bank of cylinders under light load to increase highway fuel economy. It was rumored GM would produce a 3-valve design, but that never came to be. These engines are produced primarily at the GM UAW factory in Tonawanda, New York. The assembly line for this engine was manufactured by Hirata Corporation at their powertrain facility in Kumamoto, Japan.
so its like a 3.4 pr. just a smidge different?
and this a direct bolt in, that plugs up to everything stock?
[This message has been edited by AL87 (edited 10-19-2012).]
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01:31 AM
AL87 Member
Posts: 2578 From: Bradenton, Florida, United States Registered: Mar 2010
475 WHP is the most ive seen out of an iron head 3.1 with the "981" crank. worked over heads, solid roller cam, 60-1 turbo, fully polished crank, and was wound up to 8K rpms. the guy who built the engine/car found he had a heart condition and sold the car and later the engine. used to have a website iirc turboz24.com
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03:42 PM
ericjon262 Member
Posts: 3136 From: everywhere. Registered: Jan 2010
475 WHP is the most ive seen out of an iron head 3.1 with the "981" crank. worked over heads, solid roller cam, 60-1 turbo, fully polished crank, and was wound up to 8K rpms. the guy who built the engine/car found he had a heart condition and sold the car and later the engine. used to have a website iirc turboz24.com
same boost level on a 3500 would probably be close to 600 whp or better. Again, 25 years of research and devlopment is worth alot of power and reliability, cylinder heads matter, there's a reason 3500's make more than 3.4's.
------------------ there's a Group on 60degreeV6.com for us 660 Fiero owners!
not in a fiero but a stock LX9 3500, with the exception of a cam and valvesprings. otherwise this engine is uncracked, 250 bucks from the boneyard. 11.1 et @ 130 mph.
another member has an N/A LX9 with 275 WHP
I think it needs to be restated that Mars and superdave have these motors putting down some awesome numbers, superdave's camaro is sub 14 second with a ported heads and a meaty cam.
not in a fiero but a stock LX9 3500, with the exception of a cam and valvesprings. otherwise this engine is uncracked, 250 bucks from the boneyard. 11.1 et @ 130 mph.
another member has an N/A LX9 with 275 WHP
running 15psi boost I would not call that "a stock engine"
For the original question..... Stock 3.4L cranks do not break. No need to go anything else. The only way it would break if other broken parts mess it up. It is NOT the weak point of the engine.
running 15psi boost I would not call that "a stock engine"
For the original question..... Stock 3.4L cranks do not break. No need to go anything else. The only way it would break if other broken parts mess it up. It is NOT the weak point of the engine.
Okay thanks for the answer!
What is the weak part of the 3.4 then?
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04:50 AM
ericjon262 Member
Posts: 3136 From: everywhere. Registered: Jan 2010
the heads, the flat tappet cam, the choked up intake...
they are the same heads that are on the 2.8, and I think they are better suited to the 2.8 as well...
hydraulic flat vs. hydraulic roller: flat is better for low end, roller is better for top end. (to me the bigger the displacement, the more low end you want)
and its obvious (even more so on the 3.4) that the intake (top, bottom and manifold) are all pretty restrictive, and dont give much room for porting in any way.
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01:15 AM
ericjon262 Member
Posts: 3136 From: everywhere. Registered: Jan 2010
Gentlemen, there is no hope for this one, move on, nothing to see here.
So, I read this whole thread because it caught my interest about the 3.5 engine. I just finished a 3.4 swap in my '86 GT (late run with Getag) and wish I'd have known about the 3.5. So, I guess one can take the 3.5 out of a Pontiac G6, say with the G6 six-speed and bolt it to the cradle of a Fiero...as is, and go? What am I missing, or misunderstanding here?
Also I went to the trouble of filling out the registry on the 60*V-6 site you referenced, tried every acronym I could think of on the random question, none were right, so they wouldn't let me register. The fact that they make registration contingent on some random question that makes no sense is crazy! :-/
[This message has been edited by hypo327 (edited 10-21-2012).]
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03:35 PM
ericjon262 Member
Posts: 3136 From: everywhere. Registered: Jan 2010
the acronym for 60*v6 should be "Wide open throttle"
The engine will bolt to the fiero transmissions no problem, the G6 6 speed will take a bit of work though. also, the 3.5 and 6 speed were not offered together, just the 3.9 which is a whole different beast... also, the 3.5 can be run on a 7730 with DIS. the engine will physically bolt in with the fiero timing cover and accessories, but wiil require a bit of wiring to interface it with the fiero.
Look for RPO LX9, don't get the VVT 3500 unless you are willing to go through the extra steps to make it work!
------------------ there's a Group on 60degreeV6.com for us 660 Fiero owners!
