What did you do to your XJ/MJ today? - Page 2336 - JeepForum.com
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post #35026 of 91572 Old 04-11-2012, 03:56 PM
Oregon187
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Originally Posted by No4x4Yet View Post
So just a stock rebuild? You should really bump the compression up at the very least.
Since the subject came up, how do you increase the compression ratio? I'm just looking for a general idea so I know how to tailor my research. I'm hoping to rebuild an engine this summer.


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post #35027 of 91572 Old 04-11-2012, 04:03 PM
nateyz2000
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Originally Posted by Deacon
Good lord, man, your feelings really bruise that easily, like a ripe peach? Were you emotionally abused as a child, leading to being so easily wounded and quick to take offense as an adult?

He was offering a suggestion that costs you little or nothing extra since you have your engine completely torn apart and being rebuilt anyway.
Who said anything about feelings? I believe that was more of a "i am excited to have my engine back and new parts to put in it" parade... I don't have emotional problems, but since you bring it up, are YOU ok? It was a sarcastic comment... Why you gotta be so serious? Lol this is not a thread for your ******* comments... Just saying...

Edit: and clearly it says the word "trying" insinuating he was unsuccessful... If I wanted to raise my compression I would have bought the pistons for it... Obviously I didn't want to... For what I use it for, what I have is better than perfect.

Keep on Keep'in on

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post #35028 of 91572 Old 04-11-2012, 04:14 PM
ChiliPepperXJ
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Originally Posted by Oregon187 View Post
Since the subject came up, how do you increase the compression ratio? I'm just looking for a general idea so I know how to tailor my research. I'm hoping to rebuild an engine this summer.
From what I understand, in order to increase the compression ratio, it can be done by two ways or both; either increase the bore in your cylinders and/or increase the stroke length. The compression ratio is cr=v2/v1 where v2 is the volume of the cylinder plus clearance volume (total volume above piston at bottom of stroke) and v1 is clearance volume above piston at top dead center (end of compression stroke). Learned all of this this morning in my Thermodynamics class For a little more reading, check this out as far as the discussion on octane and engine pinging http://en.wikipedia.org/wiki/Compression_ratio


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post #35029 of 91572 Old 04-11-2012, 04:20 PM
ninjakid
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Quote:
Originally Posted by Oregon187

Since the subject came up, how do you increase the compression ratio? I'm just looking for a general idea so I know how to tailor my research. I'm hoping to rebuild an engine this summer.
I've got a popular mechanics book from 55 that talks about a lot of stuff that can be done to make the engine run better and increase performance.
One of them was welding in metal rods in the head to bump up compression.
Don't really recommend doing that nowadays with unleaded gas though (nor would I recommend it anyways)
Of course they also talked about how nuclear powered cars would be available in the next 15-20 years.
Still waiting for my nuclear jeep...

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post #35030 of 91572 Old 04-11-2012, 04:23 PM
N8N
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tons of ways to increase compression... shaving the head being the most common, or using pistons with a "dome" to them (not sure if there any available for the 4.0)
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post #35031 of 91572 Old 04-11-2012, 05:15 PM
PhilipJ
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Originally Posted by GregB_00XJ View Post
Removed side flair extensions....
Here come the cops!

Messed around with the brakes and front end, looking for the cause of my slight driver's side pull...or is it the Lock-Right that does it? It's not really noticeable except at highway speeds, and I've ruled out every other possibility.
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post #35032 of 91572 Old 04-11-2012, 05:15 PM
ChiliPepperXJ
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Originally Posted by ninjakid View Post
Of course they also talked about how nuclear powered cars would be available in the next 15-20 years.
Still waiting for my nuclear jeep...
I'm with you on nuclear powered vehicles. I am a strong proponent of nuclear power and believe it could solve the majority of our energy crisis and relieve our reliance on diminishing foreign fossil fuels, but that argument is for another day. Nuclear powered Jeep would be AWESOME!


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post #35033 of 91572 Old 04-11-2012, 05:18 PM
Oregon187
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Originally Posted by ChiliPepperXJ View Post
From what I understand, in order to increase the compression ratio, it can be done by two ways or both; either increase the bore in your cylinders and/or increase the stroke length. The compression ratio is cr=v2/v1 where v2 is the volume of the cylinder plus clearance volume (total volume above piston at bottom of stroke) and v1 is clearance volume above piston at top dead center (end of compression stroke). Learned all of this this morning in my Thermodynamics class For a little more reading, check this out as far as the discussion on octane and engine pinging http://en.wikipedia.org/wiki/Compression_ratio
I love the scientific answer! And as a part time college instructor I appreciate that you pay attention in class

This helps me understand how specially shaped pistons and shaving the head would effect the compression ratio.

Quote:
Originally Posted by N8N View Post
tons of ways to increase compression... shaving the head being the most common, or using pistons with a "dome" to them (not sure if there any available for the 4.0)
Thanks!!

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post #35034 of 91572 Old 04-11-2012, 05:23 PM
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Originally Posted by ChiliPepperXJ View Post
I'm with you on nuclear powered vehicles. I am a strong proponent of nuclear power and believe it could solve the majority of our energy crisis and relieve our reliance on diminishing foreign fossil fuels, but that argument is for another day. Nuclear powered Jeep would be AWESOME!
Jeep could change their slogan to "Get Nuked".

I took my spare back down off the top. Got to looking at that roof rack vs. no roof rack thread and now Im debating on not doing a roof rack altogether. Ill just keep my 3 crossbars and leave it at that I believe. Thinking about buying a kayak anyway and that would be handy to have the stock rack freed up.

Also been driving with my sway discoed for the past couple days around town. My leafs are still so new that it really doesnt allow much sway anyway, I can hardly detect much difference, other than turning off the main road up into a parking lot is a MUCH smoother transition at an angle haha.

Would like to see little smoother ride out back though. I am considering removing one of my leafs and running a lift shackle instead to get a little more performance/better ride out of my setup. Its not YJ rough (haha) but its stiffer than an XJ should be for sure. Any thoughts on this?

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post #35035 of 91572 Old 04-11-2012, 05:36 PM
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Originally Posted by VegasGT View Post
Jeep could change their slogan to "Get Nuked".

I took my spare back down off the top. Got to looking at that roof rack vs. no roof rack thread and now Im debating on not doing a roof rack altogether. Ill just keep my 3 crossbars and leave it at that I believe. Thinking about buying a kayak anyway and that would be handy to have the stock rack freed up.

Also been driving with my sway discoed for the past couple days around town. My leafs are still so new that it really doesnt allow much sway anyway, I can hardly detect much difference, other than turning off the main road up into a parking lot is a MUCH smoother transition at an angle haha.

Would like to see little smoother ride out back though. I am considering removing one of my leafs and running a lift shackle instead to get a little more performance/better ride out of my setup. Its not YJ rough (haha) but its stiffer than an XJ should be for sure. Any thoughts on this?

i order my lift kit from rough country through jeff at rough country and i have the 3" leafspring packs and extended shackles for my 4.5" xseries kit. it is in the shop right now due because rough country sent me fricken full size jeep springs instead the 3" leafsprings for xjs. what a fricken head ach to get the springs i needed i had to have a 4x4 shop mechanic call and tell them they gave me the wrong springs. the extended shackles should work well for flexs and should ride pretty nice.

4.5" Rough Country x series lift kit/ lifted xj 31x10.50 15x8 4"backspacing cragar rims/ trimmed front rear fenders/custom swaybar quick disconnects/custom winch bumper w/ warn winch/custom roof rack/ lights mounted.
my build thread https://www.jeepforum.com/forum/f22/my-jeep-build-xj-1156115/index3.html
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post #35036 of 91572 Old 04-11-2012, 05:38 PM
ChiliPepperXJ
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Originally Posted by Oregon187 View Post
I love the scientific answer! And as a part time college instructor I appreciate that you pay attention in class

This helps me understand how specially shaped pistons and shaving the head would effect the compression ratio.
No problem I'm studying Civil Engineering so the thermodynamics stuff didn't interest me until the prof began talking about engine efficiencies and someone asked how the engine worked and off he went on a tangent. Needless to say, it was an interesting lecture!

Quote:
Originally Posted by VegasGT View Post
Jeep could change their slogan to "Get Nuked".
Exactly!! Wouldn't that be sweet! However, a nuclear powered Jeep would get rid of the classic red jerry can look on a sparetire carrier/roof rack in the fact it could go for virtually forever


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post #35037 of 91572 Old 04-11-2012, 06:25 PM
customizer1000
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Quote:
Originally Posted by scottd16
picked this up today!
8.25?
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post #35038 of 91572 Old 04-11-2012, 06:37 PM
jeeplesjeeper
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8.25?
no 8.8 i think

-Jake
- Big Blue-'98 XJ 6.5inch w/ 33's -R.I.P
-Current- Eep A Green'98 XJ 4.5inch w/ 33s
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post #35039 of 91572 Old 04-11-2012, 06:40 PM
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8.8 for sure.


havent been posting much....saving money for the next phase in my jeeps life.
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post #35040 of 91572 Old 04-11-2012, 06:45 PM
jeeplesjeeper
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good idea lol

-Jake
- Big Blue-'98 XJ 6.5inch w/ 33's -R.I.P
-Current- Eep A Green'98 XJ 4.5inch w/ 33s
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