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how strong is the 2.8 cast iron block? by joshh44
Started on: 05-31-2011 01:42 AM
Replies: 14
Last post by: TopNotch on 06-01-2011 10:16 AM
joshh44
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Report this Post05-31-2011 01:42 AM Click Here to See the Profile for joshh44Send a Private Message to joshh44Direct Link to This Post
i was just thinking about how strong is the 2.8 block.
im going to guess 250 - 300 is pushing its limits.
say you got the best parts man could buy. custom intake and exhaust with the best turbo. how much would it take to crack the block?
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mattwa
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Report this Post05-31-2011 01:56 AM Click Here to See the Profile for mattwaClick Here to Email mattwaSend a Private Message to mattwaDirect Link to This Post
 
quote
Originally posted by joshh44:

i was just thinking about how strong is the 2.8 block.
im going to guess 250 - 300 is pushing its limits.
say you got the best parts man could buy. custom intake and exhaust with the best turbo. how much would it take to crack the block?


Engine Power never directly cracks a cast iron block. In the case of the 2.8, your going to blow the bottom end way before any torque/HP directly cracks the block. Now a blown rod will break chunks off the block, but that wasn't your question. The way the cranks and main's are set up, its not too strong to take any serious power increase without major machining work. A so-so oil system doesn't help either. It's just not cost effective to use the 2.8 in an attempt to get anything over 200HP.

[This message has been edited by mattwa (edited 05-31-2011).]

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joshh44
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Report this Post05-31-2011 02:22 AM Click Here to See the Profile for joshh44Send a Private Message to joshh44Direct Link to This Post
i was just wondering because i just bought a complete rear drop out. (cradle, tranny, axles, a arms, everything for parts. since its just sitting there. i was thinking of rebuilding and add a small turbo, maybe get 200. i dont think i need anymore then that at the moment. i just finished a project and now im looking for something else to do.
i know people are getting 200hp with out to much trouble. finding a 3.8 or 4.9 even a 3.4 engines are hard to come by here. if you do you rlooking at $1000 for a used engine. even a complete car with the motor are in great shape. so i dont wanna buy a $3000 car just to take the engine form it.

i could order one online but there wouldnt be much of a project/learning aspect for me.
if i do rebuild/. it would be my 2nd rebuild of an engine i ever did.

from what i know. the 2.8 didnt have great oiling system. is there a way to improve that?
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Report this Post05-31-2011 03:29 AM Click Here to See the Profile for jscott1Send a Private Message to jscott1Direct Link to This Post
 
quote
Originally posted by joshh44:
from what i know. the 2.8 didnt have great oiling system. is there a way to improve that?


Use the 3.4 block instead. It has a much better oiling system.
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joshh44
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Report this Post05-31-2011 03:53 AM Click Here to See the Profile for joshh44Send a Private Message to joshh44Direct Link to This Post
in which way is the 3.4 better? does it have a better fuel pump? or are the oil passages bigger in the block?

edit: sorry ment to say oil pump not fuel.

[This message has been edited by joshh44 (edited 05-31-2011).]

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Francis T
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Report this Post05-31-2011 07:09 AM Click Here to See the Profile for Francis TClick Here to visit Francis T's HomePageClick Here to Email Francis TSend a Private Message to Francis TDirect Link to This Post
If yuo're thinking about going above 250HP the block is not your problem but the crank will be. You need a steel crank the sock iron will be iffy at best. But all is not lost. You cant still get a brand new -though now disontinued - steel Egale crank for about $120 which less than half the org price. I put one in the 2.8 I'm building, I think I fund on them on ebey? Last I heard they still maybe 7 left.
I would not go with a stroker crank, they're not steel either and it will just make your engine run like a truck, all bottom end and mid range.

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Dennis LaGrua
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Report this Post05-31-2011 08:23 AM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaDirect Link to This Post
Going back to the 1990's there was a guy by the name of Ron Myers from the Pittsburgh area. Ron built and ran a modified turbocharged 3.1L Fiero with a shot of nitrous. The 3.1L is just a 2.8L block with a crank having a longer stroke. Ron ran many low 12 second 1/4 mile runs and the block and the bottom end held together. IIRC Rons engine used stock internals but with forged 8:1 pistons and stronger bottom end bolts. If you translate a 12 second run to horspower required it would be in the neighborhood of 325HP. This is not to claim that the 2.8L/3.1L block is capable of holding this kind of horsepower long term but 250HP shouldn't be a problem since you only go to peak hp on occasion and only for a few seconds.

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Fiero84Freak
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Report this Post05-31-2011 10:39 AM Click Here to See the Profile for Fiero84FreakClick Here to Email Fiero84FreakSend a Private Message to Fiero84FreakDirect Link to This Post
 
quote
Originally posted by joshh44:
in which way is the 3.4 better? does it have a better fuel pump? or are the oil passages bigger in the block?

edit: sorry ment to say oil pump not fuel.


It's the oil valleys, which are somewhat inadequate compared to what they could be. It's a casting issue, and not something that can be readily remedied without significant work (i.e., money).

As mentioned, your best bet if you're overly concerned is probably to upgrade to the 3.4L block.

[This message has been edited by Fiero84Freak (edited 05-31-2011).]

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rpro
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Report this Post05-31-2011 02:34 PM Click Here to See the Profile for rproClick Here to Email rproSend a Private Message to rproDirect Link to This Post
After owning Fiero's for the better part of twenty years, I have come to the conclusion that 2.8 is a door stop at best.
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TopNotch
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Report this Post05-31-2011 02:37 PM Click Here to See the Profile for TopNotchClick Here to visit TopNotch's HomePageSend a Private Message to TopNotchDirect Link to This Post
The GM 60 Degree V6 Power Manual says that you can improve lubrication by replacing the cam bearings with those from a small block chevy (they're wider), and by cross-drilling the two middle main journals on the crank shaft, which will improve lubrication to the rods.
This book was written before the 3.4, so it may already have those mods.
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IROCTAFIERO
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Report this Post05-31-2011 04:55 PM Click Here to See the Profile for IROCTAFIEROSend a Private Message to IROCTAFIERODirect Link to This Post
If I remember correctly it is about 5 strong points.
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Francis T
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Report this Post05-31-2011 11:14 PM Click Here to See the Profile for Francis TClick Here to visit Francis T's HomePageClick Here to Email Francis TSend a Private Message to Francis TDirect Link to This Post
I should have added, if your changing intake manifolds for power above 4.5k or going with boost or NOS to get to or beyond 250HP you're also going to need forged pistons.
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joshh44
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Report this Post06-01-2011 01:41 AM Click Here to See the Profile for joshh44Send a Private Message to joshh44Direct Link to This Post
thanks for the info guys.
my 2.8 in my car now has some blow by. enough for it to come out from the oil cap a little bit. i know i need a new oil cap. but i can feel air pumping out threw the oil fill in opening. and it burns alittle oil on start up. (valve seals). im just asking questions and doing searches before i drive to far into it.
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02greens10
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Report this Post06-01-2011 07:46 AM Click Here to See the Profile for 02greens10Click Here to Email 02greens10Send a Private Message to 02greens10Direct Link to This Post
 
quote
Originally posted by joshh44:

thanks for the info guys.
my 2.8 in my car now has some blow by. enough for it to come out from the oil cap a little bit. i know i need a new oil cap. but i can feel air pumping out threw the oil fill in opening. and it burns alittle oil on start up. (valve seals). im just asking questions and doing searches before i drive to far into it.


Air is supposed to come out of there, the PCV system deals with it....unless it's not working or plugged up.
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TopNotch
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Report this Post06-01-2011 10:16 AM Click Here to See the Profile for TopNotchClick Here to visit TopNotch's HomePageSend a Private Message to TopNotchDirect Link to This Post
 
quote
Originally posted by 02greens10:

Air is supposed to come out of there, the PCV system deals with it....unless it's not working or plugged up.


Actually, on a tight, properly running engine with no blow-by, air will be sucked into the oil fill hole if you remove it with the engine running. On the 2.8, for example, there's a line that goes straight from the firewall valve cover to the air intake tube. Air being sucked in by that will cause the vacuum you feel at the oil fill hole.

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