258 Compression Problem

[cjvan]

HI
I have an 81 CJ7 with the AMC 258 i6 / 4.2l . The only change to the engine is the weber carb and of course stripping down the vaccum pcv system.

I have an excessive amount of oil flowing NOT BOILING out of the dipstick tube. I also have the following compression readings

Front to back

#1 125
#2 130
#3 120
#4 125
#5 125
#6 50

I suppose it can be blow by but the system cannot be over pressurizing the crankcase (I don't think). The reason I don't think it can is because the valve cover has the PCV which I think is working fine in the front and in the back of the cover there is an opening that just has an open connection to vent into a catch container.

Should I assume that I need to do the wet test and if the pressure comes up it is a ring problem?

If it is the ring in cylinder 6 then would it be the best to just sideline the jeep for now until I can pull together the parts and cash and space to do a rebuild? or should I drive it until I can do the rebuild?

 

[73CJ]

Should I assume that I need to do the wet test and if the pressure comes up it is a ring problem?

If it is the ring in cylinder 6 then would it be the best to just sideline the jeep for now until I can pull together the parts and cash and space to do a rebuild? or should I drive it until I can do the rebuild?

A wet test will probably confirm rings, but could also be a scored cylinder needing a bore job.

Well it's not going to get any better on it's own and only more expense if it grenades. . .

 

[Cheepjeep85]

Should I assume that I need to do the wet test and if the pressure comes up it is a ring problem?

If it is the ring in cylinder 6 then would it be the best to just sideline the jeep for now until I can pull together the parts and cash and space to do a rebuild? or should I drive it until I can do the rebuild?

first question: yes
second question: i would probably not drive it much, you could be doing more damage to the cyl wall than can be repaired, depending on whats wrong with it.

did you double check to make sure that the vac. line going to the pcv valve has a constant vac. on it while running, after installing the weber?

 

[priceg]

Leak down or bore scope it.

 

[Cheepjeep85]

wish i had a bore scope but damn they're expensive, especially for a shade tree mech like myself.