Ticking help

[gladiator]

I have a 1988 Ford Bronco II that has A loud tick all the time and seems low on power, adjusting the valves will make it quiet A while but will eventually go back, the other problem is half the engine doesn't seem to have proper oiling to the rockers causing the rockers to be scored but fear replacing the rocker arms and shaft for if it happens again.

 

[RonD]

Welcome to TRS

Good read here on the 2.9l: http://www.therangerstation.com/tech_library/2_9_Page.shtml

And tips here: http://www.therangerstation.com/tech_library/Kunz_Korner.shtml

Yes, the ticking was a common issue as the 2.9l got older, and yes there is a loss of power if you hear ticking because valve is not being opened and held open long enough.

2.9l has hydraulic lifters AND rocker adjustment, 4.0l didn't have adjusters.

Hydraulic lifters do two things, they pump oil thru the center hole of the push rod to oil the rocker and they get "stiffer" as oil pressure increases, higher RPM.

It reads like you have a collapsed lifter or a few.
Inside each lifter is a spring and valve, the valve allows oil to flow in the lower part of lifter but not out, so when the lifter is compressed the oil is compressed and flows out the hole at the top that lines up with push rod hole, the compression also stiffens lifter.
Spring expands lifter after it compresses
Broken spring and/or valve is a collapsed lifter, and it can work and then not work so adjusting can fix it but it will come back.

I think you have to pull the heads on the 2.9l to get all the lifters out.

The way to adjust 2.9l rocker with hydraulic lifter is to make sure lifter is down all the way on the cam, cam lobe opposite side, tighten until there is no play in the rocker, then turn adjuster one full turn then half a turn, this pushes lifter spring down about 1/3 of the way.

 

[gladiator]

Could that cause the rocker arms to not get proper oiling on one side? Requiring all the rocker arms and shaft be replaced on the one side. i have been a long time reader and only recently made an account and posted just was frustrated by all the posts and no resolutions.

 

[RonD]

Yes.

The 2.9l valve train's oiling is feed thru the 2 center cam bearings, when they get high miles pressure starts to drop in the valve train

But in your case the collapsed lifter(s) is causing less oiling of individual rocker and low power.

If you run thicker oil, like 10w40 it can help keep oil pressure up.

Oil pressure is Back Pressure
The oil pump pushes out too much oil, all that oil can't get out of the oil passages and bearings fast enough, so it starts to back up in the main passage, where oil pressure sender is and oil filter.
So oil pressure is Back pressure.
As bearings start to wear their gaps gets bigger, this means more oil can get out, this reduces the back pressure, and this is totally normal.
But gravity being what it is it takes a bit of pressure to get the oil to the top of the engine, Valve train.

If you are using 10w30 oil, it has a viscosity of 30 when warmed up, the lower the number the thinner the viscosity, the higher the number the thicker.
Think water, pancake syrup and ketchup, they each have a viscosity, one thicker than the other.

When you use a thicker viscosity oil then it flows thru the bearing gaps slower, increasing the back pressure, so overall pressure in the system goes up.

You could even go to 20w50.

This doesn't help the collapsed lifters just increases the oil pressure for the top end.

 

[Hitchner2009]

i second the oil viscosity recommendation from Ron. I ran 20w-50 in my truck for the remainder of its life until i swapped her because my oil pressure light was coming on at traffic lights. Grant it, this is only a temporary fix, but it will keep it running a little bit better and last a little longer than if you ran the standard 5w-30. Best of luck! You can run those 2.9 engines into the ground and they will still run, ran mine like that for about 2 years.

 

[gladiator]

I have tried various oil viscosity with roughly the same results but it just keeps on going even though the engine sounds terrible, luckily the oil pressure light stays of just still needing to check what it is. what is the recommended tool to remove the oil pressure sender? my motor mount seems to be blocking it so a socket is not much of an option.

 

[Hitchner2009]

I have found that a basic cresent wrench or an open ended wrench of that size works best. Easier to get it off from the bottom btw. I had to replace my sensor when I had my 2.9, and thats how I did it.

If your checking oil pressure, your specs are going to be 10psi per 1000rpm is a good base line. Thats your minimum. So if your at 2000rpm, you want 20psi, 3000 30psi, etc. Etc. If I remember correctly that oil pressure light doesnt come on until about 5-7 psi if I remember correctly.

 

[Josh P]

RonD is right. Rhoads makes some nice lifters that fit the 2.9L.