I blew the motor last friday in my GT. Was on the 410 and it started making this bad knocking/banging sound. I was in an awkward spot and since I have another core at home I drove it a ways to get to a safe place to stop. The motor still ran 'decent", just sounded like a whole lotta stuff was loose inside.
I pulled the cradle Sun and I got the motor apart last nite. I snapped the crank right through one of the counterweights. Strangely my mechanic guessed this was what happened as soon as I said the clutch pedal was pumping a bit when driving the car(after it blew). He said this was common on the 2.8 which I thought was weird since I have never heard anyone mention that here (I've had 2 used engines blow and now this one which I rebuilt 5 years ago-only this one had a bad crank) I think he said it was more common on later 2.8s

Anyone else ever busted a crank shaft in the 2.8? I'm gonna have one bad a$$ paper weight for my desk at work, you know, from my pro-stock Fiero
hehe

I'll try to get pics sometime........

Cheers

Ed Parks of the Fiero Factory has a collection of broken cranks- it's not unheard of.

I had one break once in a S-10 with a 2.8. Broke in the front, just forward of the second main.

I would disagree with the term "common problem" I have owned Fieros for almost 20 years and belonged to many clubs and have only heard of a few crank, piston, rod issues....Paul

He said it was more common on later 2.8's which had larger main journals if I recall. He said in the day when the 2.8 was really popular he had to rebuild a bunch for broken cranks. He only does engine rebuilds so I assume he's seen more than a few...
I was surprised as I had never seen a post here about a broken crank.
Cheers

So what kind of torque can an 18 year old 2.8 crank take?

We have guys doing turbo, others doing carbs, even some nitrous.

So if you build the HP up over 200, is the crank reliable?

I've only heard of one broken crank. And I'm not really too sure about that.
Number 3 & 4 rod bearings, on the other hand...

The crank in my 86 GT broke on Christmas Eve, 2000 on my way home from the grocery store. Sounded like a couple of guys with sledge hammers wailing away inside. When I took the block to the machine shop for clean up the machinist showed me a pile (30+) of broken 2.8 cranks from the previous couple of years. He was not surprised to hear I broke the crank. I used an internally balanced crank from an aluminum head 2.8 as a replacement and it has been fine for 25000+ miles now.

quote Originally posted by Arns85GT: So what kind of torque can an 18 year old 2.8 crank take? We have guys doing turbo, others doing carbs, even some nitrous. So if you build the HP up over 200, is the crank reliable?

I read in a chevy performance book that the stock rods and crank in the 2.8l will handle up to 7200 RPM and 225 HP. The strength of the rods and crank can be increased by putting the rods and crank through a peen shot, slightly sharpening the counterweights to cut through the air better (you will need tobalance the crank after removing material), and use ARP rod bolts. It would be wise to repolished the journals on the crank after the peen shot. The best way to protect the journals on the crank is to get a hold of a set of old rods and cut the actual rod portion off of the crank journal part. Bolt those on your rod journals on the crank and that will protect the crank from damage. You will also need to protect the main journals on the crank too.

IROC

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1986 Pontiac Fiero GT 2.8l
pocket ported, gasket matched complete intake. Still has no nut.

3.4l turbocharged project in process!
- T3/T4 Hybrid Watercooled turbo
- Intercooler with CO2 spray kit
- Dynotuner piggyback computer
- MSD 6al btm

I just got a pic but I can't post it. If someone else wants to I can email it to them. It may need to be resized.

It seems to me that the crank broke starting at the radius of the #3 main journal. I am not sure if thats the common place or not.

I rebuilt this motor myself and have no clue how many km's were on it when I got it. Seems odd that it worked fine for 5 years tho before snapping
<shrugs>

Cheers

The crank on my 87 GT broke last year. Sounded like a bomb going off. Blew the harmonic balancer off, broke the timing cover ... Those parts are on display at the Fiero Factory. Now it has a 3.4l thanks to ED.

The one in mine broke in two... The place we got the part from said the only way it could have happened, was if it had a manufacturing flaw. Not sure how much of that I believe.

One thing that is certain death for Fiero cranks is for a machine shop to weld up a worn journal and regrind to size. This is a common and standard procedure that works well for most cranks, but not for the 2.8 cranks. For whatever reason, if this is done on a 2.8 crank it is guaranteed to break forthwith.

JazzMan

I almost had my crank in my 85 break the machine shop owner was asking how it stayed togher becuse it was starting to crack really bad.

J Sokol

It's not that common. I've only seen 3 and they were 88-91 models.

Phil

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87 FIERO GT 2.8 5spd

If you found my advice helpful, please take the time to give me a positive rating. Thanks

Fierochic has one in their basement out of an 85 GT. The car ran fine, but had what sounded like a rod knock. I think it broke between #3 and#4

I believe that the earlier 2.8L's have less efficient oiling on the number 3 & 4 journals which may contribute to breakage of the crank there. I would say that since a fair number of reported 2.8L crank failure storys are on this post, it must be a common problem. However, many Fieros are driven hard by their owners. Driving a well worn old high mileage engine hard, can certainly contribute to catastrophic failure. Prolonged high RPM operation can also heavily stress a crankshaft.
On the other hand there are many 60* V6's that have been heavily modified which hold up fine. My turbo 3.4L has been holding up great for two years to some pretty extreme use but I also never shift above 5600-5800 RPM.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://www.turbochargerpower.com/turbo.htm

quote Originally posted by 85GToronto: I just got a pic but I can't post it. If someone else wants to I can email it to them. It may need to be resized. It seems to me that the crank broke starting at the radius of the #3 main journal. I am not sure if thats the common place or not. I rebuilt this motor myself and have no clue how many km's were on it when I got it. Seems odd that it worked fine for 5 years tho before snapping <shrugs> Cheers

Send me the pic to capt@captfiero.com and I will post it for you.

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85GT 2.9 4spd MSD Everything, Big Cam, No Cat and Nitrous. Nawzz babeee!!!!
http://www.captfiero.com

Someone mentioned in the thread that they had replaced their crankshaft. I was considering replacing mine and upgrading to a performance crankshaft from WCF. Can anyone give me a general understanding of how much work would be involved in that doing it myself. Thanks.

Jason

Well the more I talk to people about this the more I find out. This was/is a problem with the crank of the 2.8. My engine mechanic said he replaced a ton when these motors were common and even in non abused/hihg performance cars like Celebrity's etc. It must be something to do with the way they were cast. Mine broke right beside the thrust bearing cap but I seriously doubt poor oiling would cause a crank to break. Get slightly hotter in that area possibly but cause the break I doubt it.
For anyone to say its not that common I think you only gotta read this thread!
Cheers

Here is the pic

Re-booting server, and running chkdsk pics will be back in a couple of min sorry about the inconvience (sp)

Thanks for posting that Capt.
As you can see it looks like the crack started right on the radius of the thrust bearing journal.
Oh well it makes a cool paperweight <shrugs>
Slaved away all weekend and have the new motor back together and in the cradle. Hope to reinstall and possibly fire it tonight/tomorrow
Cheers

What about the 3.1-3.4 cranks. Has anyone broken one?

Anything is possible, particularly without proper oiling and maintenance. But the design of the 60 degree GM block means that each journal is isolated between two caps. Braking a 2.8/3.1/3.4 crank takes a whole heap of effort. You can destroy a dozen 3.8 cranks for each 2.8 you might brake.

Funny you ask Daniel, my engine guy said the 3.1 wasn't much better. He rebuilt a bunch of both motors when they were common/popular. He did more than a few motors because of broken cranks. The guy he sends his cranks out to said the same, they were bad as well

Cheers

Is it true that the 3.4DOHC motor used a forged crank?

[This message has been edited by DanielKJenkins (edited 12-16-2003).]

When I took my car in for a pre-purchase inspection, my mechanic warned me that the 86 2.8l had a notoriously weak crank shaft. After inspecting it, he gave mine a clean bill of health, but said he'd seen a lot of em with that problem. I really don't care, personally, because I plan to swap in a V8 this summer.

85gtoronto what does he charge my 2.8 spun a bearing and i would like to get a motor for spring.

I had to do somewhat of a budget rebuild due to current cashflow so unless you plan on doing ALOT of work yourself then my price wouldn't be accurate. I assembled the whole motor myself which saves alot. I get my stuff done by Andy at Xtreme Engines in Woodbridge 905-850-2283. I'll be back on the road for under 1K but thats with alot of labour myself. He just basically cleaned the block and got me the parts. He sent the crank out to be cleaned up and redid my heads, which needed to be done anyway. He's done alot of **** for me so I suspect my price is a bit skewed.
Give him a call he's a good guy but he hates working on cars so don't expect him to even quote you on pulling the motor, especially out of a Fiero! The last sorta "stock" V8 I had him totally redo and assemble was about $1300 I think. I think those heads were ok though. I think he said about that same price to rebuild my 4.3 V6 out of my Blazer so I'd guess around there.
PM me if you have more questions, a local forum member messaged me with a running used engine if you're interested
Cheers