To rebuild or not to rebuild - JeepForum.com
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post #1 of 10 Old 08-09-2020, 01:52 PM Thread Starter
82/84 CJ7
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To rebuild or not to rebuild

Hello everyone I need your help really quick. This is a very condensed overview but basically my jeeps been running on 4 cylinders and low oil pressure pulled the valve cover saw two pushrods one for cylinder 4 and one for cylinder 5 just laying down not touching the rockers. Pushrods are not bent and rockers look fine. Here’s the kicker though there is metal in the oil. It is non magnetic I took a big stick magnet didn’t attract a single piece so in my opinion that would mean lifter and bearing material in the oil which would explain my lack of oil pressure (around 10-15 pounds at rpm). The engine also has some pretty solid ring ridge at the top of the pistons my finger will catch on the ridge. So at this point what do I do. I’m thinking pull the whole engine out and rebuild at home using a rebuild kit online or I can just replace the cam but then I would think that all the metal left in the motor and the low oil pressure would just screw more stuff up down the road. And is there anyway to do this stuff in the car?
Thanks
Jarod

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84 CJ7 with 258 and T5 On 30x9.50x15 general grabber ATX
She ain’t fast but she’s fun.
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post #2 of 10 Old 08-09-2020, 05:23 PM
pedal2themetai
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HI,
Yes motor would have to come out to do a rebuild.. You would need several tools.. Torque wrench Ft. Lbs. , Ball hone, piston ring compressor, Piston ring pliers, ridge reamer tool, sent the block to a machine shop and have it hot tanked to clean it up and have them install new soft plugs, cam barrens, it may need bored depending on how bad the cylinders are. If you going to send it to a shop wait to order parts until you get it back as it might need bored and you would need oversized rings.. ONLY bore it enough to clean it up .30 max. going to much can cause overheating problems. If they have to go more than 30 you may need new oversized pistons as well... + what ever head work you need or want done..

It might be cheaper to find a newly rebuilt short block, cost might be the same.. depending on your abilities.
Just a look at what is needed to rebuild.
good luck
tim
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post #3 of 10 Old 08-09-2020, 08:12 PM
ACAMS
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Looks pretty nasty ... get somebody that knows what they are doing look at it.
If you end up doing the job yourself I will give you one word of warning ... when you put the new engine back in be VERY,VERY sure you burped it real good filling it with water ... I own a machine shop and have seen time and time when that was not double checked and a new engine got too hot. I am pretty sure you will have an air bleed somewhere ... probably on or by the thermostat housing!
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post #4 of 10 Old 08-09-2020, 09:42 PM
BagusJeep
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Quote:
Originally Posted by 82/84 CJ7 View Post
Here’s the kicker though there is metal in the oil. .... I’m thinking pull the whole engine out and rebuild at home using a rebuild kit online or I can just replace the cam but then I would think that all the metal left in the motor and the low oil pressure would just screw more stuff up down the road. And is there anyway to do this stuff in the car?
Thanks
Jarod
You need to pull it out. Apart from needing a crane, it will not take long and it will make working on it sooooooo much easier. Theoretically you could do this work with the engine inside the Jeep but you will have to remove the front clip to get access and then be working underneath doing vital tasks. To take out the rear cam bearing the rear freeze plug needs to come out, which is going to be mighty tricky in Jeep. And to add to it all, a good build needs absolute cleanliness, hot tanking the block and building it on a clean workbench (better a stand) will make it so much easier.

Metal in the oil means something has worn and has exited the oil galleries, it does not mean that metal is circulating in the engine. The strainer and the oil filter will keep them out.

My money is on the camshaft bearings and maybe the cam lobes. Worn cam bearings will drop your pressure low. You really need a machine shop to replace these bearings. It is possible to do at home but you will be beating them in with a special tool rather than easing them in with a press, and no way to check the alignment is spot on. Also when putting the cam back in, you must avoid nicking the bearings, it is much easier if the engine is stood on its rear and you can lower it in.

when you get the mains and big ends off, you may find the crank needs a grind. When in there you may as well redo the crank seals. With no main bearings and big ends, with the new cam bearings, you may find the oil pressure shoots up.

And whilst it is all apart you may want to check timing gear and bores, maybe new pistons and a rebore even.

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1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
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post #5 of 10 Old 08-09-2020, 10:43 PM Thread Starter
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Thanks everyone for the reply’s. I agree on pulling the engine out. I got the engine pulled out tonight and it’s going on the stand tomorrow after noon after I get off work and by the hardware to mount it to the stand. I’m doing a complete tear down. Looks like the motor has definitely seen some miles though. Should I be concerned it’s not the original engine being it’s a 1981 engine block in a 1984 model year jeep? Thanks
Jarod
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84 CJ7 with 258 and T5 On 30x9.50x15 general grabber ATX
She ain’t fast but she’s fun.
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post #6 of 10 Old 08-10-2020, 03:39 AM
BagusJeep
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Nope, the only difference that mattered was the manifolds. There was also a host of emissions equipment on top in 1984. Does your State allow an older block or for emissions equipment to be stripped?

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1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
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post #7 of 10 Old 08-10-2020, 10:57 AM Thread Starter
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Originally Posted by BagusJeep View Post
Nope, the only difference that mattered was the manifolds. There was also a host of emissions equipment on top in 1984. Does your State allow an older block or for emissions equipment to be stripped?
In my state it doesn’t matter the set up as long as it passes the emissions standards of that model year (1984). Although I don’t have to deal with emissions as I have it under classic car insurance and therefore it is exempt from testing.

84 CJ7 with 258 and T5 On 30x9.50x15 general grabber ATX
She ain’t fast but she’s fun.
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post #8 of 10 Old 08-10-2020, 11:42 AM
pedal2themetai
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HI i don't think its the insurance that makes it exempt its how you register it..you have to register it as a classic as well. and with that is has limitation on how much you can drive it..
good luck
tim
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post #9 of 10 Old 08-10-2020, 12:32 PM Thread Starter
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Originally Posted by pedal2themetai View Post
HI i don't think its the insurance that makes it exempt its how you register it..you have to register it as a classic as well. and with that is has limitation on how much you can drive it..
good luck
tim
Yes you’re right on that I kind of simplified my explanation. I have it registered as a historic vehicle as well but in my state (Arizona) the state doesn’t enforce a mileage limit it’s my insurer and they put a 15,000 mile a year limit. More then enough for me.
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84 CJ7 with 258 and T5 On 30x9.50x15 general grabber ATX
She ain’t fast but she’s fun.
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post #10 of 10 Old 08-10-2020, 02:13 PM
pedal2themetai
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Hi good to know.. I just shipped my 1961 Comet to my daughter in Phoenix so it can get used some.. good to know she's most likely not limited on miles.. thats more than she'll drive it.
good luck
tim
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