Need advice on my 258

[85laredo]

Hello everyone, happy to b a part of a Jeep family! I have owned several Cj's and each one i have sold i wished i had it back>>Well about a year and a half ago i hesitantly sold my beloved 85 CJ7 stock Laredo . It had about 195,000 orig miles. Recently i came into a little money, searched and found it. Bought it back>Thank God it was well kept except for several more miles and some blow by...I have asked around and everyone says to put long block in it> dont think it really needs a complete rebuild just new seals and valve cover? Im not real familiar with engines and i would rather have it rebuilt back to original specs>>>No one does that around Sav Ga apparently>>>Should i keep driving and just put valve and rear main seals>>>>>still runs great or tear down and long block it? thanks Russ

 

[Sasquach]

Hello everyone, happy to b a part of a Jeep family! I have owned several Cj's and each one i have sold i wished i had it back>>Well about a year and a half ago i hesitantly sold my beloved 85 CJ7 stock Laredo . It had about 195,000 orig miles. Recently i came into a little money, searched and found it. Bought it back>Thank God it was well kept except for several more miles and some blow by...I have asked around and everyone says to put long block in it> dont think it really needs a complete rebuild just new seals and valve cover? Im not real familiar with engines and i would rather have it rebuilt back to original specs>>>No one does that around Sav Ga apparently>>>Should i keep driving and just put valve and rear main seals>>>>>still runs great or tear down and long block it? thanks Russ

Does it burn oil?
What compression #'s does it have?
Any odd noises?
These are some of the things it would be helpfull to know so that you can make an informed decision.

 

[Cheepjeep85]

Does it burn oil?
What compression #'s does it have?
Any odd noises?
These are some of the things it would be helpfull to know so that you can make an informed decision.

sasquach is on the right track, do a compression check. is oil pressure acceptable? any knockin, pingin, or timing chain slappin? if not re-seal it, clean it up and drive the out of it, save your money for when it really needs a rebuild.

 

[fzsk4p]

Hello everyone, happy to b a part of a Jeep family! I have owned several Cj's and each one i have sold i wished i had it back>>Well about a year and a half ago i hesitantly sold my beloved 85 CJ7 stock Laredo . It had about 195,000 orig miles. Recently i came into a little money, searched and found it. Bought it back>Thank God it was well kept except for several more miles and some blow by...I have asked around and everyone says to put long block in it> dont think it really needs a complete rebuild just new seals and valve cover? Im not real familiar with engines and i would rather have it rebuilt back to original specs>>>No one does that around Sav Ga apparently>>>Should i keep driving and just put valve and rear main seals>>>>>still runs great or tear down and long block it? thanks Russ

Thought these might help you. A compression guage should be available for rent from your auto parts store.

How to Perform a Compression Test on the Engine in a Jeep Grand Cherokee | eHow.com

Engine Compression Check-up for your Classic Car by Auto Media

Can someone chime in on what factory PSI numbers are ? That way the OP can compare. I do not feel qualified to answer on AMC 258 i6 / 4.2l `s.

90`s vintage 4.0`s avarage around 160 psi.

If the compression numbers come back reasonable then:

Would seriously consider replacing the timing chain and the oil pump pickup. Both are cheap and easy fixes.

The chain wears with age. and the fact that it controls the camshaft, oil pump, distributor, ignition timing and valve timing. It is cheap insurance.

The oil pump pickup screen gets clogged with sludge. Restricting oil flow. In fact replacing the whole pump might not be a bad idea.

Do the AMC 258 i6 / 4.2l `s have the baffles in the valve cover ? Again I am a 4.0 guy. So I don`t want t spread wrong information.

If you do have baffles then this is a good read;

Valve cover fresh air inlet question - JeepForum.com