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2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

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Old Jun 16, 2008 | 09:55 PM
  #1  
pgtr's Avatar
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Car: 84 Firebird: F41, Pwr, Instr Pkg
Engine: LC1 (V6 2.8L, 280k mi)
Transmission: MD8 (700R4)
Axle/Gears: GU5 (3.23)
2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

I've got an '84 2.8L V6 w/ 175k miles and (knock on wood) it seems to be running quite well... It's dependably driven daily - more hwy than city. It gets 26-29mpg. Change oil (10W30) about every 6-7k.

I'm wondering what I should keep an eye out for as far as wear/age related/mechanical issues as it goes beyond 25 years and 200k miles hopefully...?

Timing chain? Other?

I appreciate any input so I might do some preventative maintenance or have an idea what to be on the look out for in the future.

Thanks!
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Old Jun 16, 2008 | 10:36 PM
  #2  
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Re: 2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

The 2.8 V6 had a tendency to suddenly break a rod and throw it though the side of the block at @60,000 miles or so. If your has made 175,000, I think you are on borrowed time. The fix is to replace the 2.8 rods with rods from a 3.1 or 3.4. I suspect that your timing set includes the fiber gear that GM used for so many years. I may be mistaken about the fiber gear; but with 175,000 miles, I think I would plan on a new timing gear set regardless.
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Old Jun 16, 2008 | 10:41 PM
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

the rods in the 3.4 and 3.1 are exactly the same , the carbed 2.8's had smaller crank/rod journals, which were weaker, if the motors got 175k on it just keep up with the reg maint and replace the timming chain and chain guide.
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Old Jun 16, 2008 | 11:21 PM
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Car: '85 maro
Engine: In the works...
Transmission: TH700 R4
Axle/Gears: 3.73 posi
Re: 2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

Furthermore all 60* rods are forged from the factory. Rods aren't an issue.

Consider yourself lucky, though. Usually the early carbureted versions are loaded with problems when they reach your mileage. Timing chain strech is common, and if yours hasn't been replaced yet do so. Mileage tends to drop drastically if basic maintenance and tuning aren't kept up with. Like project89 said the pre-'85 blocks have smaller main bearings and can be problematic.
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Old Jun 17, 2008 | 09:13 AM
  #5  
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From: Pennsylvania
Car: 1984 firebird
Engine: 2.8 v6
Transmission: T5
Axle/Gears: soon: A working car.
Re: 2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

Can i use a timing chain? or have to use a new belt?
I think mine is the same engine, 134,000 or 34,000 as all the papers and odometer say. my only problem is cold stalling. so far.
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Old Jun 18, 2008 | 01:08 AM
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Car: '85 maro
Engine: In the works...
Transmission: TH700 R4
Axle/Gears: 3.73 posi
Re: 2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

Wouldn't hurt.
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Old Sep 30, 2023 | 09:15 PM
  #7  
Brian Ott's Avatar
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Re: 2.8L V6: Hi-Mileage Life Expectancy and 'Weaknesses'

Originally Posted by pgtr
I've got an '84 2.8L V6 w/ 175k miles and (knock on wood) it seems to be running quite well... It's dependably driven daily - more hwy than city. It gets 26-29mpg. Change oil (10W30) about every 6-7k.

I'm wondering what I should keep an eye out for as far as wear/age related/mechanical issues as it goes beyond 25 years and 200k miles hopefully...?

Timing chain? Other?

I appreciate any input so I might do some preventative maintenance or have an idea what to be on the look out for in the future.

Thanks!
I've got the 2.8 v6 in my 91 s10 and the odometer and dash gauges stopped working at 480,000 miles and I still rag on mine daily, ive had it for a couple years since the gauges stopped working. I think its safe to say you got a few miles before you should worry😂
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