SkyF41

whats the largest i can get my 2.8 bored out to safely and what else should i get done to it to improve preformance.it is carburated if that matters.

PhantomBanshee

I'd really like to know that too. I have a 2.8L '89 RS....and it kinda sux how my friend is continually beating me with his '93 3.1 OLDSmobile.
...but yeah. I am curious too. And sure getting a V8 is an easy power up, but I'd rather buy an older Camaro w/ V8 in it, than spend money on one for my lil crusier. I am looking at at a Turbo, and have doing lots of research and I think that I have a plan. But any help would be nice.

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SUPER-SPORT-CHEVY

.30 over is what most people do but im sure you can go.40
SSC

Brian K

.60 over I have heard of it, but the compression was raised and it was a racin engine..

SkyF41

so what would .40 make it in terms of liters?

Camaro_hunter_d

the safest level is actually 70 over. however getting the corrected piston size is a Biatch so go 60. after 90 the walls are too thin. as far as displacement is just under 3.1 think its close to 3.08 or something like that. This is off 2.8 numbers.

SkyF41

so can i get my 2.8 bored out to a 3.1? i would probably have to adjust my carb right? sorry for all the questions but i am new to making cars faster and since my 2.8 has only 107hp i think i am going to bore it out since i can't do alot of the mods the newer cars can do.what would i have to change on my car if i bore it out.

85f-bird

if you're aiming for say a 3.1L, you'll probably have to bore, and stroke it. Stroking the motor involves changing the crank, which will make the pistons move farther in each individual stroke, which means it gives your engine more displacement. My motor is bored .40 over, but that was standard, when i got the new engine installed. it puts me at 177.2 ci. which is a 2.9L, nothing special, but that's all.

Camaro_hunter_d

well if you go 60 over you get almost to 3.1. Keep the original crank and all. It won't harm anything. As I posted before it is like 3.08 or something like that.

3.1 firebird

I think you have to use a 3.1 crank and new pistons (3.1)to get the 2.8 stroked to a 3.1, both engines share the same rods. Then you would need to get it all balanced. ITs probably better to just find a junker 3.1. You can safely bore it over .030 I believe, which should make a 3.1 turn into a 3.2, and a .030 should jump a 2.8 to a 2.9. Better yet find a 3.4 and have it overbored to make a 3.5.

BC86TPI-Z51

GM sells 3.4 litre blocks complete...maybe they can work for ya?

x55Cam

Sky,

I recently had my block bored .020 over from what was originally .020 over making a toltal of .040. I asked my machinest if I could squeeze out another .20 over and he felt that I could but if I had to do further work to the block down the road it would probably have to be sleeved. It all depends on what your're looking to do. There are a number of choices:

1. Just bore the block to .060 over
2. By a bore and stroke kit for the 2.8
3. By a 3.4 block from the junkyard for
about $300 which contains the crank and
do a rebuild to the short block and scrap
the 2.8 (wise move! )

Here's a small chart of what a bored 2.8 comes out to compared to a 3.4

Block(CI) ----------Bore----------Stroke
========================================
2.8(173ci) ----------3.50-----------2.99
2.8(175.5) ----------3.53-----------2.99
2.8(176.5) ----------3.54-----------2.99
2.8(177.5) ----------3.55-----------2.99
2.8(178.5) ----------3.56-----------2.99
2.8(197.6) ----------3.56-----------3.31
3.4(207)-------------3.62-----------3.31
3.4(209)-------------3.66-----------3.31

If your gonna rip the motor out,IMO, go for the 3.4L and save yourself the hassel. You'll gain alot more in performance even if it costs you a few dollars more. Seach 3rd gen for topics on doing the swap.

SkyF41

well theres a wrecked 90' 350 down the street so i might buy it from him and do a motor swap, but i don't want to leave the v6 board, its great here.