Thread: Rebuilt V8 - Very Rattly ValveTrain!

Originally Posted by aRRon

Edward,
Based on the last few posts' info...
My feeling is that you are not getting oil supply to the pushrods and thence into the lifters which will pump out what you initially primed them with and then run dry!


The oil supply goes from inside the rocker shaft out into the rockers through the smaller side holes in the rocker shaft.
The rockers have a passageway drilled through them - hole inside the bearing surface through to the cup where the pushrod sits. So oil should flow out of the rocker cup and down onto the pushrod and into the lifter when all is pumping.

Good luck

For whatever reason the first part of your post is not correct , it may be the way you`ve tried to explain .

Each bank of lifters has its own gallery which feed oil to them and this happens before the oil gets as far as the head , pedestal or shaft .

G`day Edward ,

One thing that can upset lifers on a rebuilt engine if it had new cam bearings fitted is the fitting of the bearings .

If it`s not right the oil can`t flow properly , each bearing has a hole that lines up with a drilling .

Oil then goes to the crank .

I know you typed the pressure and flow is ok .


The link below explains , yours is without B . The lifters pretty much are first in line .
Rover SD1 Info

Thank you once again everyone for your replies and links We'll keep investigating and i'll report back with what we find. The lifters feel VERY hard to push down when primed - much harder than any other motor we have played with. Maybe this has something to do with it.

We did get the cam bearings replaced. We probably didn't check the oil holes as thoroughly as we could have though.

I don't know if it means anything, but the motor is dead quiet when turning over on the starter motor. The rattling only starts when it kicks.

Edward

Next you have the covers off with it running check that you can see all the push rods rotating .

You don`t say how many lifters are noisy but if there is a correlation between the noise and non rotation it give somewhere to look .


With the engine not running push down on the rocker arm push rod side , if it moves easily ( probably moves at all ) or feels spongy this would indicate a crook lifter .

Originally Posted by PLR

For whatever reason the first part of your post is not correct , it may be the way you`ve tried to explain .

Each bank of lifters has its own gallery which feed oil to them and this happens before the oil gets as far as the head , pedestal or shaft .

Thanks Peter,
I stand corrected - wasn't aware of the entire oil feed pathway, i.e through the cam bearings.
Could it be that the stiffness Edward is describing in the lifters is due to the same thing you point out? That is the lifters can't bleed down because the cam bearing shell is wrongly fitted and blocking the return path?

Originally Posted by PLR

Next you have the covers off with it running check that you can see all the push rods rotating .

You don`t say how many lifters are noisy but if there is a correlation between the noise and non rotation it give somewhere to look .


With the engine not running push down on the rocker arm push rod side , if it moves easily ( probably moves at all ) or feels spongy this would indicate a crook lifter .

Thanks PLR. All pushrods are rotating. On the driver side for example, 6 or spinning quite fast (many revolutions per second), with 2 spinning a bit slower (1 revolution per second).

Hard to tell how many lifters are noisy. I'd say at least 6 - 8. I'm not working on the truck today, but will be again tomorrow, so i'll have another listen. I'll see if i can take a video that i can (attempt to) upload here.

I'll double check if i can push the lifters down using the rocker.

Thanks again,

Edward

Originally Posted by aRRon

Thanks Peter,
I stand corrected - wasn't aware of the entire oil feed pathway, i.e through the cam bearings.
Could it be that the stiffness Edward is describing in the lifters is due to the same thing you point out? That is the lifters can't bleed down because the cam bearing shell is wrongly fitted and blocking the return path?

Not actually through the cam bearings but the same galleries .

I would expect the stiffness as this is what makes the lifter solid .

If the lifter has oil it should work unless for instance the check valve is not sealing etc as this makes the lifter solid by closing off the oil and the oil doesn`t compress .

I appreciate you reading my reply in the context it was meant , many here seem to take things i presume as personal attacks or other and don`t respond .

If i type something incorrect i would hope someone would point it out because i think there is reason to have somethings and areas as correct as possible .

Originally Posted by PLR

If the case your pedestals may be too tall but there will be a cause.

Originally Posted by aRRon

How confident are you in the lifter preload measurements? I found it quite difficult, utilising the projecting depth gauge of an electronic vernier caliper, v hard to keep it dead square to the top of the lifter for the harder to reach rearmost lifters, deducting from your measured depth the distance form the top lip of the lifter to the lower edge of the recessed groove where the retaining spring sits (? 0.011" from memory).

Good evening all,

We may have made some progress today. There is a fair amount of slop in the retaining rings of the lifters. I don't think we allowed enough clearance between the piston and the ring to account for the slop (even with our 25 thou shims removed), so the pistons may be kissing the rings. In order to give more preload it seems that we do need to machine down the pedestals. We hand filed one side of an old rocker shaft by 50 thou today, but did not have time to try it.

I was puzzled why we had to do this on what is a standard motor, but i found that the top of the new valves in my rebuilt 3.9 L heads sit 110 thou closer to the head than my old head (which is still in great nick), which would raise the pushrod side of the rocker and reduce the lifter preload.

Fingers crossed!

Thanks,

Edward