Topic: How to tell if it needs rebuilt

[the-rock-doc]

I've done alot of wrenching and modifying in my day but there is one question that I just can't find an answer for. 

Two or three weeks ago I took my stock 92 wheeling and broke all kinds of stuff, so much that I don't even wanna mention any of it.  Monday morning I went to start it and it wouldn't start, no big deal I thought so I did a diagnostics on it at the shop that afternoon.  What do you know, no error codes, so then I did a compression check on it, the first piston had about 45 PSI in it, the second 60 PSI, the third 60 PSI, and the fourth 35 PSI, not nearly enough to make the motor run so I have come to the conclusion that it either needs rebuilt or scraped all together.  I am not sure and I can't find anyone with the answer to this problem.  I don't want to do a full teardown only to find that it needs totally replaced.  Some help is much appreciated, thanx,

Scott

[Cheesemaker]

How's the oil/water look?  How many miles on the motor?  If you got alot of miles on it, it might just be beneficial to just put a rebuild in or have it rebuilt!  Did you have good oil pressure when you were driving it?  We need some more info!   

[Gittinit]

You need to find out why the compression is so low in those two cylinders.It could a blown head gasket or bent connecting rods, or just flat wore out. Heck you could even have a valve sticking slightly open, or bad valve seats, or seals.

I think it may be time for a rebuid, but don't go scrapping the motor all together. This may even be a good time for a swap, if you are inclined to do so.

It definately sounds like this is a problem in the top end of the motor. I do not suggest pulling the head and having it redone without doing a complete rebuild, top and bottom.

 

[*ROKTOY*]

With those readings I would say it needs rebuilt. The only way to tell for sure is to remove the head and mike the cylinders, this will give a good indication of how much wear there is. As far as rebuilding it or replacing it with a rebuilt, it might be cheaper to replace it. But do get one from a reputable builder.

[79coyotefrg]

stretched  the timing chain  and it  jumped  a  tooth or 2  on the cam,  thats why its  only showing  a little  compression

pull the valve cover,  put  crank pully on  zero timing mark  and see where the cam is

[*ROKTOY*]

stretched  the timing chain  and it  jumped  a  tooth or 2  on the cam,  thats why its  only showing  a little  compression

pull the valve cover,  put  crank pully on  zero timing mark  and see where the cam is

This is very much a possibility, do the check and make sure.

[the-rock-doc [OP]]

that may make the problem worse, I just got done doing a top end rebuild on it.  I had oil pressure before, there is no water in the oil and there is plenty of oil in the pan.  I will do the check the timing before going to far into it, thanks fellas,

Scott

[79coyotefrg]

put the crank on  0* and then  see where your cam   is,  i bet its a tooth off

[RABIDYOTA]

i have a ? on cam gear with crank set to  0 tdc where should be the mark on the cam gear be at?    see search works just need a little more info  thanks

[Gittinit]

i have a ? on cam gear with crank set to  0 tdc where should be the mark on the cam gear be at?    see search works just need a little more info  thanks

The cam timing mark should be at about 11:50.

[RABIDYOTA]

so the timing mark on the cam gear should NOT line up with the mark on the rocker shaft bridge???   opps

[RABIDYOTA]

any 1 got a photo???

[79coyotefrg]

  not yet  but i'll get one soon