4.3 intechangeability

[olddog1946]

I have recently purchased a very straight 89 S10 pickup, with a bad 2.5 motor and 5 spd..and installed a rebuilt early 90's 4.3 Tbi motor and older 700r4 trans..
This motor sat on my engine stand for almost 7 years..to make along story short,,,the rockers are not getting oil...My question........I have a complete motor and trans from a 98 and a 95 (both 4x4) ..Is it possible to put the earlier heads and intake on one of these motors and then using the wiring harness for the earlier motor? Or does anyone know how to modify the newer harness to use in the 89??
Any help I can get would be appreciated...

[OverBoardProject]

I wouldn't know, but I wouldn't switch the wire harness to a newer one. That's just asking for problems.

Heres an idea though.

Why not remove the valve covers, rockers, and push rods.
See if the holes in the push rods are plugged. You probably know better than I do that you should be able to just blow through them.
Use a Turkey Baster to fill the lifters as much as possible.
And then use a screwdriver or something to try pumping up the lifter (I really recomend a wooden dowl if possible).
If it works you might have to add more oil and continue to pump them for a little while longer.

The most that it will cost you is some time, and gaskets that you'd still need to do that job you had planned + a little oil.

[olddog1946]

Your are right, I do have to take it apart anyway.....everything in this motor is new,,,I have a nasty feeling the cam bearings weren't put in right..using and oiler all i get is a dribble and when running it doesn't appear to get any oil.
Although the wiring seems like it would be a headache, I am not convinced that it would be all that hard to do if I can get some real wiring diagrams...the new motors have all the engine management under the hood, only thing that's not is the odbII test plug...A project for later,,but one i feel would be worth the effort...cheaper to buy a good used, newer motor than the 1350 I have invested in the one that isn't working, ....(for those that don't already have a few laying around)
thanks for the input...

[olddog1946]

Update> pulled the intake and the timing cover..ran the pump with an oiler and still no oil to the rockers...even checked the plugs in the lifter valley to be sure they weren't left out..they're there..an oil passage must be plugged or the cam bearings not aligned correctly..
I did find out that the intake from the 95 vortec will line up. So, I am taking the intake and throttle body and putting it and the wiring harness on the 95 motor...be gone for few days...but will let you all know how it goes...

[OverBoardProject]

Just wishing you luck on the job.
You'll have to let us know what the oil problem is

[olddog1946]

New update....I found the problem...the thrust plate for the cam had not been tightened down at the machine shop...Tightened it up and had 60 lbs. of pressure and oil to the rockers....