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3400 help needed. Whats involved, and will this idea work?? by Jncomutt
Started on: 12-31-2003 02:07 AM
Replies: 16
Last post by: Jncomutt on 01-02-2004 12:23 AM
Jncomutt
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Report this Post12-31-2003 02:07 AM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
I've read up on Fierosounds website about the use of the 3400 block.

It seems by his write up that all you need to do is swap to the fiero heads, intake, and ignition system, and you shuold be able to use this stronger block. The other modification needed is to clearance the lifter 'keeper' things.

Now, due to the fact that the aluminum heads have a smaller combustion chamber, switching to the fiero heads greatly reduces the compression ratio. Wait a minute, this is EXACLY what I want. I was going to rebuild my 2.8 with lower compression for boost. This seems like an easy way to get that lower compression, a better designed block, AND a lower price.

Does this seem right, or am I missing a big step?

Thanks for the help, John.

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Jncomutt
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Report this Post12-31-2003 02:12 AM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post

Jncomutt

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Hmm.. also thinking... I already have an 88 engine, so I can retain the stock flywheel, and this 3.4 has the starter holes already in place, no drilling required.
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Report this Post12-31-2003 10:14 AM Click Here to See the Profile for freedog81Click Here to Email freedog81Send a Private Message to freedog81Direct Link to This Post
Good thinking. I thought about that but then had a 3800 just sitting in the yard. If you do that you will need two sets of the same side pushrods from the 3400 I think from the exhaust because all of the rods on the 2.8 are the same length and the ones on the 3400 are different lengths. Someone emailed me instructions on how to do it i will see if I can dig it up. He said even with the drop in compression it would still put out more than the 2.8. I will see if I can find it. good luck.
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connecticutFIERO
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Report this Post12-31-2003 10:25 AM Click Here to See the Profile for connecticutFIEROSend a Private Message to connecticutFIERODirect Link to This Post
I can't wait to see what comes out of this. Ya know the 3400 SFI is rated at 170 hp. IS there anyway you could keep the 3400 heads? I mean 170 hp with some minor mods and a turbo would be awesome. I wonder how much hp the 2.8 heads would rob from the 3400 if used together?
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Jncomutt
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Report this Post12-31-2003 10:51 AM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
I wouldn't want to keep the 3400 upper end. Using the fiero stuff keeps it stock looking, plus no wiring and that sort of thing. Besides, with the boost, I hope to be well over 170...

Freedog, the info on the pushrods would be appreciated.

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coinball
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Report this Post12-31-2003 02:30 PM Click Here to See the Profile for coinballClick Here to Email coinballSend a Private Message to coinballDirect Link to This Post
the pushrods need to be custom made to 5.850" long (this is shorter than the stock length, which i can't remember right now...)

your compression will be roughly 7.6:1 so daily driving below 1500rpms will suck but above that you should make mad power with a correctly sized turbo...

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Jncomutt
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Report this Post12-31-2003 03:17 PM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
Coinball, thanks for the info.

Anyone know if there is a stock pushrod that size, or a reccomended place to order (I noticed pushrods.net from fierosound, any others?)

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Dough19
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Report this Post12-31-2003 03:19 PM Click Here to See the Profile for Dough19Send a Private Message to Dough19Direct Link to This Post
I'm doing the same swap right now, only it is NA. Should be done in two or three weeks. The motor is sitting in the cradle waiting for a swaybar. I agree with coinball, you will need custom pushrods. Unless they were needed to clear the DOHC pistons that Fierosound used.

I also had some issues with the fiero front timing cover. The water pump has a pressure release hole that empties into the block of the 2.8. My block did not have this hole so I had to make my own release.

If you are using and 88 cradle you will have problems mounting up the 88 front bracket. I had to modify some stuff to get it to work.

Any Q's just let me know


edit: I got pushrods from that site as well. They are the company most known for making custom legnth pushrods. They were about $80 I think. I never got around to looking if there were any stock pushrods that would work. You might want to talk to a machine shop as they would should have a book with all the different pushrod legnths.

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[This message has been edited by Dough19 (edited 12-31-2003).]

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avengador1
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Report this Post12-31-2003 03:31 PM Click Here to See the Profile for avengador1Click Here to Email avengador1Send a Private Message to avengador1Direct Link to This Post
The rental car Im driving here in Arizona is a Oldsmobile Alero with the 3.4 engine. This is a midsize car and is probably a lot heavier than a Fiero. The point Im trying to make is that it really can accelerate with me and the family onboard, even with the auto tranny, and I could make it do a burn out just by pressing the gas pedal. I wasn't sure what engine was in there till I popped the hood. It looks like the Vortec engine because of the intake. I thought the car might have even had a 3.8 by how quick it could get going. The other good thing was that I got 28 miles per gallon, even driving at 80-85 MPH, the speed limit on some of the highways here was 75 MPH but in some stretches, where you could literally see for about 20 miles ahead, Im sure you could open it up even higher without fear of a speeding ticket. Im thinking of this engine as a possible future transplant some years down the road.
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Report this Post12-31-2003 03:37 PM Click Here to See the Profile for connecticutFIEROSend a Private Message to connecticutFIERODirect Link to This Post
 
quote
Originally posted by avengador1:

The rental car Im driving here in Arizona is a Oldsmobile Alero with the 3.4 engine. This is a midsize car and is probably a lot heavier than a Fiero. The point Im trying to make is that it really can accelerate with me and the family onboard, even with the auto tranny, and I could make it do a burn out just by pressing the gas pedal. I wasn't sure what engine was in there till I popped the hood. It looks like the Vortec engine because of the intake. I thought the car might have even had a 3.8 by how quick it could get going. The other good thing was that I got 28 miles per gallon, even driving at 80-85 MPH, the speed limit on some of the highways here was 75 MPH but in some stretches, where you could literally see for about 20 miles ahead, Im sure you could open it up even higher without fear of a speeding ticket. Im thinking of this engine as a possible future transplant some years down the road.


I've had to have the intake manifold gasket replaced twice now on mine. Its a great engine, but some problems do exist. Supposedly the new gasket I got this time is a new design.

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Jncomutt
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Report this Post12-31-2003 05:26 PM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
I guess the stock designed used a plastic gasket which was only spec'd to like 10lbs when u torqued it down. I plan on using the fiero setup anyways.

Dough, can u give me the info you used when ordering? I read the length is 5.850, and they're 3/8th, but what do I order for tips, stock spring pres, etc that the site asks for??

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Report this Post12-31-2003 05:47 PM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
Stock pushrod... (EDIT 3100SFI)

"Intake valve push rods are painted with two yellow stripes and measure 144.18 mm (5.68 inches) long."
"Exhaust valve push rods are painted with two green stripes and measure 152.51 mm (6.0 inches) long."

Yep.. too long, too short.


And oh yea, wish me luck, just picked up a 3400 from a 2000 Impala.

[This message has been edited by Jncomutt (edited 12-31-2003).]

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Report this Post12-31-2003 11:05 PM Click Here to See the Profile for Formula88Send a Private Message to Formula88Direct Link to This Post
You have to change the pistons, and possibly the pushrods to use the Fiero heads/intake on a 3400SFI. You would use 3.4DOHC pistons, I believe. Considering the Fiero 2.8 is rated at 135-140HP and the 3400SFI is rated at 170-185HP, you will probably see somewhere in the neighborhood of 155-165HP with the Fiero intake. (just a guess) The GenIII aluminum heads are VASTLY superior to the iron Fiero heads (GenI). But it can be done.

The 3400SFI has also been swapped in complete and is a good running swap.

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Report this Post12-31-2003 11:17 PM Click Here to See the Profile for The_RavenClick Here to visit The_Raven's HomePageClick Here to Email The_RavenSend a Private Message to The_RavenDirect Link to This Post
I would swap the complete 3400 in, I agree the genIII top end, well the complete engine is a much better design then the genI design. It's lighter and has a higher HP potential, where can you go wrong.

Alos if you use the genI heads with the stock 3400 pistons, you will have a very low static compression ratio, somwhere in teh neighbourhood of 7:1.

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Jncomutt
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Report this Post01-01-2004 03:15 PM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
Low compression is exactly what I want. I was going to rebuild my 2.8 with 8:1 compression pistons. This lower compression will be better still. Given the low end power will suck, I'll be able to run some damn good boost.

I don't want to do the top end, cause I don't want to worry about the electronics and the DIS etc. My whole plan is to put the fiero heads on the 3.4, shave the lifter holders, get new pushrods/shorten mine, put the fiero intake on, get my 2.8 turbo chip further tuned to properly run with more displacement, and then go whoop on some rustang butt...


Do I buy headgaskets for the iron head 2.8, or do I get them for the 3400???

[This message has been edited by Jncomutt (edited 01-01-2004).]

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Report this Post01-01-2004 07:11 PM Click Here to See the Profile for freedog81Click Here to Email freedog81Send a Private Message to freedog81Direct Link to This Post
I looked at the email the guy sent and he said the intake pushrods from the engine would work. If you say they are too short to work then I don't know who is right. I will try to look at it again and forward the whole thing to you as soon as I get a chance.
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Jncomutt
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Report this Post01-02-2004 12:23 AM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
Awesome, that would be apreciated!

Do you happened to know about the headgaskets (is it stated?)

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