Bubbacalee

Here's the deal....2 yrs back i purchased a 94 GC 4.0 automatic with 80,000 miles on it.So far in those 2 yrs the only thing I replaced was the radiator.All and all a great vehicle.Unfortunatly long story short and 30,000 miles later,the motor is toast.Here's the rundown.I went to replace the air filter and noticed it was completly soaked in oil.So I did some research and learned about the whole ccv issue.So I did all the nessecary cleaning of the valve cover and elbows and all that.But apparently it was to late.I did a couple compression tests and determined worn piston rings and a bad head.Moneys tight so I'm going to end up buying a used 4.0 out of a 94 gc with 138000 miles and a bad tranny.I heard it run and it sounded good all the fluid was clean.My question is what can I do to prevent the same thing happening to this motor before I put it in.Because I know I'm taking a gamble with this motor.

jimgrms

just rebuild the motor you have , you don't know the history of the jy motor , just do rings and bearings and a valve job and your ready for another 100k

skeletonizer

I would make sure that you use a motor oil woth a high zinc content. They recently removed zinc from the vast majority of motor oils and engines that were disigned before the change can react poorly to the new oils.

I know Amsoil makes a high zinc oil. I use Shell Rotella in my ZJ and Mobil 1 15w50 in my 6.1 hemi.

You will notice a marked decrease in valve train noise.

Before you pull the old motor I would try the sea foam treatment. I have seen sticky rings freed up by sea foam and it made an amazing difference. If it doesn't work you are only out $20.

The Blacksmith

I reccomend both.

Put the junkyard motor in, replace a qt of oil with lucas oil stabalizer, because lucas ROCKS.

Keep your old motor and rebuild it slowly, and do it the right way, when its done, switch back.

tiwvr1

If your not having any drivability issues, leave it alone. Pretty much ever 4.0 that comes into work has the same thing with the air filter.