460 oil pressure

Matt1983

Member
Well I just fixed the coil issue and got the newly
rebuilt engine running. It sounded good until one
cylinder began misfiring. I came to find out that
the #3 cylinder push rod adjustments had backed
off and the valves weren't opening. So the
machinist must have forgotten to tighten them all
the way or something (which now causes me to doubt
his abilities but he has 40 years experience and
does this all the time soooo.... anyway..) So now
it runs and sounds great! but I have no oil
pressure at idle. It goes up to 30-40psi when I
rev it up, but its only about 5psi when its idling
(if that). I read a few posts on here about low
oil pressure, but would anyone like to offer a
list of items to check systematically? I checked
the gauge and that works fine. Im going to check
the 90 degree elbow that comes off the side of the
block. I also should note that I put a screw on
oil filter adapter on that was not on the old
engine. It uses the same mounting flange on the
side of the engine but it has an adapter on top,
Could this be causing an issue? Also just FYI I'm running straight 30 weight oil and there's no knocking but I took the oil capillary off and it just dribbled lightly while the engine was idling, so Im pretty certain I have low oil pressure. The oil pump was also pretty new before the rebuild but the machinist said he inspected it before re-installing it. Of course Im second guessing everything he says so Im not ruling it out, but it was fairly new before the rebuild. Anyway any advice is
better then tearing the engine out, so feel free
to share ideas and ask questions. I plan to attack
this in the morning.
 
I was just thinking about it and I remember that the little black plugs that go in when you do the oil pan gasket and are supposed to go on the rear bearing cap, were still in the gasket set when he gave it to me. What do those little black plugs do? Are they to seal oil passages maybe?
 
The two black plugs, (about 2" long) go one on each side of the rear main bearing cap to seal between the cap and block. If they are missing you will soon know it because it will leak oil at the back of the engine.
 
Thanks Owen. I noticed a little oil out the back
but assumed it was leaking hydraulic oil a little
from the tranny seal because I never changed that
seal and it always leaked just a little. But maybe
he didn't put them in. DO you think that would
effect oil pressure?
I am pulling the pan tomorrow and will know soon
enough. I will say I have learned at least one
lesson from all this. Ill have a machinist grind
my crank and rebuild a head, but I'm reassembling
my engines myself from now on.
 
First thing I would look at as far as oil pressure is the relief valve in the filter base. May just have a piece of gasket material stuck under the piston or similar problem. Next, I would suspect wrong filter base gasket unless you bolted the base onto block yourself. Gasket sets come with at least three different gaskets for different bases usually. Next, maybe he left out the oil gallery plug under front cover. The rubber plugs will not affect oil pressure, just leaks. If you do pull pan, air pressure applied to oil gallery might show you where oil is escaping.
 
I pulled the oil pressure plug out but didn"t see anything in there(btw does the spring go back in a certain way? One end of the spring coil is tightly wound, the other end is not. I put the tight end into the cap and the loose end against the plunger), there"s a little scoring on the plunger but before the rebuild the pressure was fine. I"ll check it again. What is the plug behind the cover you are referring to? Also do the rocker arm post bolts go into the oil passages? I think I saw some oil coming up around the post when I was running the engine with the valve cover off.
 
While you have the pan off plasti-gauge the rods & mains to check clearances to see if they are within specs. The only other place would be the cam bearings, if they weren't replaced this may be a contributor to low oil pressure at idle.
The next place would be the plate on the oil pump, perhaps too thick of a gasket causing excessive clearance between the housing & gears.
 
The IH dealer wants 30$ for the spring and another 120$ fire the plunger! is that what they really go for!?!
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top