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Unread 02-12-2008, 10:04 PM   #1
Lupo10
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1995 YJ Wrangler 
 
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Compression Issue. Not good. Is my CJ a goner?

I had to get towed yesterday to my Cousin's shop. I wasn't sure what the heck happened but he ran tests and did a compression test. It turns out the 2nd and 5th valves are in the 50's. So...I'm mulling this one over and figured I'd ask for some opinions on what my options are. I bought it in October for $2800. Its an '85 CJ with a 258. I've since spent around $1000 on it. So selling it as is I'll take a bath. Unless anyone wants an '85 CJ with a blown motor for $3800.

Here's a list I came up with.

1. Sell it. Take the bath and with a new house and 2nd child on the way my chances of convincing wifey that another CJ is a good idea are null and void

2. Get another rebuilt engine (the current engine was a remanufacture with only 15K miles on it!). Take a bath on that one too but get to keep my CJ

3. Upgrade to a 4.0 rebuild and convince wifey that I was going to do this anyway

4. Find a trashed 90's wrangler in a junk yard (no experience here)

5. Trade it for an ATV

6. Lawn Ornament

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Unread 02-12-2008, 10:24 PM   #2
jayhawkclint
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Find an $800 Cherokee XJ with 4.0 HO.
Roll it up next to the CJ.
Buy wife roses.
Swap engine using Cherokee as your rolling parts store.

I wouldn't attempt the swap unless I had the entire Cherokee there right next to the Heep; it's the little stuff that is going to nickel and dime you to death.
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Unread 02-13-2008, 05:57 AM   #3
jeepdaddy2000
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If the valves are bad as you stated, simply pop the head and have them ground. This gives you the option of keeping the CJ running till you can sell it, fix it, upgrade, or heck, drive it for a couple more years. You can go as far as you want as well, from doing just the offending valves to a complete head job. Might call your local machine shop and get some detailed pricing info.
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Unread 02-13-2008, 12:29 PM   #4
starfire340
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Just another idea..I bought my Extremely used 83 CJ7 with supposedly a "bad valve". Turned out to be a bent pushrod..Less than 10 bucks..cost me a head gasket and a gallon of antifreeze....
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Unread 02-13-2008, 04:29 PM   #5
bjf498
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Honestly it sounds like you need to have some one else look at it. unless by "valves" you mean cylinders then your 2nd and 5th cylinders have low compression. I don't see how a motor with only 15k on it since it was rebuilt has that low of compression what are the numbers from the other cylinders?
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Unread 02-13-2008, 05:19 PM   #6
CJhollic
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Quote:
Originally Posted by bjf498 View Post
Honestly it sounds like you need to have some one else look at it. unless by "valves" you mean cylinders then your 2nd and 5th cylinders have low compression. I don't see how a motor with only 15k on it since it was rebuilt has that low of compression what are the numbers from the other cylinders?
x2

Get someone else to look at it. You may have overlooked a few options.
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Unread 02-13-2008, 05:34 PM   #7
Mr.Crowley
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second opinion sounds like the ticket
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Unread 02-13-2008, 05:47 PM   #8
Scrambler82
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Pull all the plugs, I the second and fifth cylinder squirt in a little oil, 30 wt.

Do another compression test; if the compression come up then it is the rings, if the compression doesn't come up then it could be the valves or relates parts.

Your choices have been mentioned above but make sure what is wrong.

Since the engine needs work, after the compression test, pull the head take a look.

Try not to break the head gasket.

Once the head is off don't clean up anything until you look at the area on the block/gasket next to cylinders two and five.

Look for burnt area or wear.

Luck,
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Unread 02-13-2008, 06:01 PM   #9
Chrisfol82
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I agree you need to find out what is causing the low compression. Just to say the engine is blown and no good because it has low compression on two cylnders doesnt make sense. Like was stated above it coudl just a some bad valves.

I ordered a new 4.0 head from clifford performance and when i got it it had at elast two valves that werent sealing causing bad comrpession. Took a while to figure out what the problem was but ended up having to send it back to clifford. So it is possible to get a newly rebuilt engine that just had a bad valve job or somethgn simple like that.

If its the head you may be better off getting a 4.0 head to swap on than you would paying for machine work to fix your 258 head.
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Unread 02-13-2008, 11:00 PM   #10
Lupo10
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Thanks all. I'm not the mechanic of the family thus why my cousin has it at the moment. I don't think he's completely given up plus he's the one getting second opinions. He's a mechanic but since he owns the shop he's having another mechanic, his engine rebuild guy and several others take a look. The compression on the other cylinders was over 100. I don't know 100% what's he's checked but I think he's running all options. Unfortunately this is Waaaaayyy over my head. I'm learning here but unfortunately have to go to work while he looks at my Jeep. I'm trying to remember everything he told me Monday night but he said the plugs were black and wet with fuel and I melted the solonoid I believe by trying to continuously crank it (it died at a very bust intersection and I admittedly got a little panicked). Consequently I ended up killing the battery. Thanks for the advice so far. It gives me hope.

P.S. I heard that if you replace the valves they could be too powerful and blow out the bottom end on the engine. Possible?
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Unread 02-13-2008, 11:49 PM   #11
roundlitefan
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Quote:
P.S. I heard that if you replace the valves they could be too powerful and blow out the bottom end on the engine. Possible?
All the valves do is allow air/fuel mixture into the cylinder and let burned mixture (exhaust) out.
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Unread 02-14-2008, 11:59 AM   #12
sanmiam
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If you want a real high level diagram check this out:

http://auto.howstuffworks.com/engine1.htm

If you read into it further its a pretty good basic understanding of how an engine works.
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Unread 02-14-2008, 01:19 PM   #13
479AZ
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Rebuild it yourself. 258 is a pretty simple engine, you'll learn a lot doing it. Take the individual parts to a local machine shop (ask your cousin who) and do all the assembly yourself. Easier than you think. Are you sure it's only 15K on the motor? something sounds weird, that shouldn't go bad that quick. sounds like a valve train problem. (hopefully not a cracked head or something worse)
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Unread 02-14-2008, 02:20 PM   #14
bjf498
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also get your self a haynes or chiltons book for your jeep and read it like a book every chance you get. I kept mine by the ****er
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Unread 02-15-2008, 10:23 PM   #15
Lupo10
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Thanks again. I am learning and have read and keep re-reading the Chilton's and the Jeep Bible. Great books. I'm also on line alot and ask alot of questions. I don't have a place to rebuild the engine (in a rental house) and can't take up a bay at my cousin's shop as he loses valuable revenue that way. But I'm leaning towards an engine swap for a used 4.0. I have time as I'm not getting kicked out of my cousin's parking lot but its just frustrating. Spring is approaching and I haven't even taken the top off yet. I've been driving it though (20-30 times to work since November) through some of the coldest weather. Time will tell what I end up doing here. Thanks again for all the input and for the link.
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