Purpose of Boring an Engine?
#1
06-27-2007 | 05:09 PM
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Joined: Jun 2007
Posts: 1,283
From: Latrobe, Pennsylvania
Purpose of Boring an Engine?
Why would you want to bore out your cylinders? I am looking at this kit for new forged piston heads, and they are mentioning a .010" overbore
Is getting your cylinders bored out really THAT much of an improvement? I mean, my goal with this kit is to allow to pump more pressure into the chamber to allow hotter compression. So what would a boring do for that?
http://www.intense-racing.com/Mercha...roduct_Count=2
Is getting your cylinders bored out really THAT much of an improvement? I mean, my goal with this kit is to allow to pump more pressure into the chamber to allow hotter compression. So what would a boring do for that?
http://www.intense-racing.com/Mercha...roduct_Count=2
#2
06-27-2007 | 05:31 PM
Monte Of The Month -- February 2008
Joined: Aug 2006
Posts: 4,286
From: Born in East LA
RE: Purpose of Boring an Engine?
As the old saying goes:
There is no replacment for displacement.
The purest way to gain true horsepower and torque is by increasing your displacement and that is what boring does.
There is no replacment for displacement.
The purest way to gain true horsepower and torque is by increasing your displacement and that is what boring does.
#4
06-27-2007 | 05:44 PM
Monte Of The Month -- February 2008
Joined: Aug 2006
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From: Born in East LA
RE: Purpose of Boring an Engine?
ORIGINAL: ExplosiveSoundz
Right, but what does that consist of? is that a professional CNC job that has to be done? Or something I can do?
Right, but what does that consist of? is that a professional CNC job that has to be done? Or something I can do?
I don't know if that technology has changed in the last 20 years but that's how we did it to our small blocks.
#5
06-27-2007 | 05:48 PM
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Joined: Jun 2007
Posts: 1,283
From: Latrobe, Pennsylvania
RE: Purpose of Boring an Engine?
Well, though I will be pulling the engine to do some work on it and install a new torque converter, I can't justify all of that work for that. I guess I will be sticking with stock bore and a higher compression ratio.
Unless someone has seen THAT good of a performance upgrade just in boring it out?
Unless someone has seen THAT good of a performance upgrade just in boring it out?
#6
06-27-2007 | 07:49 PM
Joined: Oct 2006
Posts: 3,986
From: North Fond du Lac, WI
RE: Purpose of Boring an Engine?
Boring does a few different things. First it does increase the displacement, so you will go faster. It's been a long time since I did this, but if I remember the calculations by overboring your 3.8 Liter engine you will be at 4.03 or something like that. Combined with the blower this means more power!
The other big factor is it cleans the cyclinder walls on high milage cars. After time the piston will create a thin lip around the top of the cyclinder, boring will remove this lip and you will have less chance of engine failure.
Finally it doesn't necessarily need to be done on a CNC machine, but a simple milling maching won't cut it either as it will leave chatter marks from the tooling and is a pain to center each cyclinder - too time consuming. It can be done with a mill if they have professional honing tools, but it might cost more.
Bring it to a professional engine reconditioner and you will probably save money.
Unfortunately I don't remember how much this costs, but for the benift it is worth it but you may want to wait till you have over 100,000 miles on it.
#7
06-27-2007 | 07:53 PM
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Joined: Jun 2007
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From: Latrobe, Pennsylvania
RE: Purpose of Boring an Engine?
well then it's settled. I appreciate everyone's response to this! I am gonna let it ride for the time being, and go with a stock, higher compression head, until later down the road, I decide to upgrade even more, then I will get the cylinders bored.
Thanks for that great pic, btw! I guess they use the water to cool it so that it doesnt damage the engine internals
Thanks for that great pic, btw! I guess they use the water to cool it so that it doesnt damage the engine internals
#8
06-27-2007 | 07:59 PM
Joined: Nov 2006
Posts: 520
From: iowa city, ia
RE: Purpose of Boring an Engine?
the overbore would just be to clean them up if there was any wear or scoring.
performance wise, crunched a few mumbers and u'd gain like 1.2 cubic inches on your 231 cubic inch motor. increasing the displacement by about 1/2 a percent. on a 200hp motor this would be worth about 1hp.
if the pistons increased comperssion the hp gains could be considerable depending on how far you go.
performance wise, crunched a few mumbers and u'd gain like 1.2 cubic inches on your 231 cubic inch motor. increasing the displacement by about 1/2 a percent. on a 200hp motor this would be worth about 1hp.
if the pistons increased comperssion the hp gains could be considerable depending on how far you go.
#9
06-27-2007 | 08:00 PM
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Joined: Jun 2007
Posts: 1,283
From: Latrobe, Pennsylvania
RE: Purpose of Boring an Engine?
well, this company recommends that I go from a stock 8.5:1 compression to 9.5:1 compression with stock bore for my m90 eaton that I will soon be upgrading to a gen v
#10
06-28-2007 | 12:21 PM
Monte Of The Month -- February 2008
Joined: Aug 2006
Posts: 4,286
From: Born in East LA
RE: Purpose of Boring an Engine?
ORIGINAL: 04 Intimidator
Boring does a few different things. First it does increase the displacement, so you will go faster. It's been a long time since I did this, but if I remember the calculations by overboring your 3.8 Liter engine you will be at 4.03 or something like that. Combined with the blower this means more power!
The other big factor is it cleans the cyclinder walls on high milage cars. After time the piston will create a thin lip around the top of the cyclinder, boring will remove this lip and you will have less chance of engine failure.
Finally it doesn't necessarily need to be done on a CNC machine, but a simple milling maching won't cut it either as it will leave chatter marks from the tooling and is a pain to center each cyclinder - too time consuming. It can be done with a mill if they have professional honing tools, but it might cost more.
Bring it to a professional engine reconditioner and you will probably save money.
Unfortunately I don't remember how much this costs, but for the benift it is worth it but you may want to wait till you have over 100,000 miles on it.
Boring does a few different things. First it does increase the displacement, so you will go faster. It's been a long time since I did this, but if I remember the calculations by overboring your 3.8 Liter engine you will be at 4.03 or something like that. Combined with the blower this means more power!
The other big factor is it cleans the cyclinder walls on high milage cars. After time the piston will create a thin lip around the top of the cyclinder, boring will remove this lip and you will have less chance of engine failure.
Finally it doesn't necessarily need to be done on a CNC machine, but a simple milling maching won't cut it either as it will leave chatter marks from the tooling and is a pain to center each cyclinder - too time consuming. It can be done with a mill if they have professional honing tools, but it might cost more.
Bring it to a professional engine reconditioner and you will probably save money.
Unfortunately I don't remember how much this costs, but for the benift it is worth it but you may want to wait till you have over 100,000 miles on it.
He'll design in a crank with a longer stroke anda high lift camif necessary, the former will give you even more displacement.
A lot to pay for a 6 cylinder, but it' been done.