Hello, I am a new member and a new 80s series owner. I am generally mechanically inclined - worked on a lot of Jeeps over the years - but I am somewhat learning as a I go with the internals of an engine. I have done head gasket jobs on Jeep 4.0 before, somewhat successfully 
. I enjoy setting up suspensions and I am good at that stuff. I have experiencing regearing and setting up lockers in Jeep axles. I work in nuclear power. I am a cross between I&C, technology, and project management for my company. Sorry for the long post below, trying to be detailed.
A few months ago I picked up a project 80s series - a 94 with 300,000 miles on it. It needs a lot, but I enjoy working on vehicles and boats as a hobby. It was not running when I got it, the starter was locked up. I picked up a cheap starter just to get it running. Kept the old one for a rebuild later on.
It did start, however had a nasty miss. I found cylinder 6 plug looked brand new and found the wiring on injector 6 had crumbled to nothing. I fixed all that and a new connector on it, and it was then firing as it should, however running a little bit rough still, some slight loss of power going up a small hill in neighborhood. (No plates yet - only ever driven around my hood less than 25mph). Based on the condition of the radiator hoses (slightly expanded, definite gunk buildups) - it does appear like the vehicle had overheated and blew some hoses off perhaps. I replaced those and flushed the coolant. Every once in awhile a puff of white smoke will come out the exhaust, but it is not all the time - and it is only ever white.
There is no milk in the oil, oil looks super clean. There is oil in the coolant.
This past weekend I got around to a compression test / and a leak down test. I am hoping someone can help me interpret these numbers, possible next step.
Compression: Surprisingly good: (keep in mind both tests were done with cheaper harbor freight specials, but they seems ok)
1 - 170
2 - 170
3 - 180
4 - 175
5 - 185
6 -185
Leak Down test, where things got fun Compressor set for 100PSI
1 - Virtually no loss
2 - Virtually no loss
3 - Showed minimum loss, however was no able to get about around 80 PSI into it, could hear it leaking somewhere.
4 - Showed some significant loss - 30% or so. Could not get more than 70 PSI into it. Could feel air escaping from valve cover gasket right by the cylinder (Exhaust side, and could hear air escaping from oil cap when removed
5 - Virtually no loss
6 - F'ed. Definite bad head gasket here - air bubbles into radiator. Loss around 30%
So I know at minimum I need a head gasket, however cylinder 4 scares me, as from research this could mean piston rings are shot. I am not scared of replacing the HG from the research I have done, however bottom end work it outside my capacity. I guess my question is - could the air escaping I am having on 4 still be a result of the head gasket broken in another place? Possible between cylinder 3 and 4? or I am looking at a complete rebuild?
Thanks for reading my novel.
I
. I enjoy setting up suspensions and I am good at that stuff. I have experiencing regearing and setting up lockers in Jeep axles. I work in nuclear power. I am a cross between I&C, technology, and project management for my company. Sorry for the long post below, trying to be detailed. A few months ago I picked up a project 80s series - a 94 with 300,000 miles on it. It needs a lot, but I enjoy working on vehicles and boats as a hobby. It was not running when I got it, the starter was locked up. I picked up a cheap starter just to get it running. Kept the old one for a rebuild later on.
It did start, however had a nasty miss. I found cylinder 6 plug looked brand new and found the wiring on injector 6 had crumbled to nothing. I fixed all that and a new connector on it, and it was then firing as it should, however running a little bit rough still, some slight loss of power going up a small hill in neighborhood. (No plates yet - only ever driven around my hood less than 25mph). Based on the condition of the radiator hoses (slightly expanded, definite gunk buildups) - it does appear like the vehicle had overheated and blew some hoses off perhaps. I replaced those and flushed the coolant. Every once in awhile a puff of white smoke will come out the exhaust, but it is not all the time - and it is only ever white.
There is no milk in the oil, oil looks super clean. There is oil in the coolant.
This past weekend I got around to a compression test / and a leak down test. I am hoping someone can help me interpret these numbers, possible next step.
Compression: Surprisingly good: (keep in mind both tests were done with cheaper harbor freight specials, but they seems ok)
1 - 170
2 - 170
3 - 180
4 - 175
5 - 185
6 -185
Leak Down test, where things got fun
Compressor set for 100PSI1 - Virtually no loss
2 - Virtually no loss
3 - Showed minimum loss, however was no able to get about around 80 PSI into it, could hear it leaking somewhere.
4 - Showed some significant loss - 30% or so. Could not get more than 70 PSI into it. Could feel air escaping from valve cover gasket right by the cylinder (Exhaust side, and could hear air escaping from oil cap when removed
5 - Virtually no loss
6 - F'ed. Definite bad head gasket here - air bubbles into radiator. Loss around 30%
So I know at minimum I need a head gasket, however cylinder 4 scares me, as from research this could mean piston rings are shot. I am not scared of replacing the HG from the research I have done, however bottom end work it outside my capacity. I guess my question is - could the air escaping I am having on 4 still be a result of the head gasket broken in another place? Possible between cylinder 3 and 4? or I am looking at a complete rebuild?
Thanks for reading my novel.
I
