Pressure and Volume

[Nelybel66]

Hi All!

Just wondering if anyone knows if it's possible to get a normal pressure reading from an oil pump but not have an adequate volume output from it.  It's really a long story, but in a nutshell, we are rebuilding a 1966 390 FE.  We are now on our second set of roller rockers, roller lifters, and a roller cam.  No matter what we do, the valve train is still terribly noisy.  We also have run the motor with a cut open valve cover to see what's going on in there....and we noticed something very interesting.  The second we shut off the motor, we can visually see the pushrods on the open valves start moving.  We assume this means the lifters are collapsing.  Oil pressure is great...70-75 psi cold and around 40 psi hot.  We are using a Melling high volume oil pump.  I figured it's along shot, but I was wondering if anyone thought it was possible that the pump, although indicating good pressure, wasn't sending the volume of oil where it needs to go.  Thanks!

[cjshaker]

Did you make sure the lifter oil passages have not previously been blocked for solids or restricted somehow? Is that hot oil pressure at idle or at speed? At idle that's pretty good cold and hot pressure. Even at speed it's not terrible. But the lifters should not suddenly collapse upon shutoff. All pressure and volume goes away once the engine is shut off, regardless, so to me they sound defective. What brand are the lifters and what is the engine built for (street, strip?).

[Nelybel66]

I should have provided more detail the first time.  Sorry about that....new to the forum thing.  The engine was totally rebuilt by a professional FE builder/restorer with 35+ years at it.  The block was completely worked over at the machine shop, and the oil passages were supposedly checked, cleaned, and enlarged to accommodate the larger oil pan and high volume oil pump.  The pressures are at idle....70-75 cold and around 40 hot.  It currently has an Erson cam and lifters, and T&D rockers.  An important thing I forgot to mention....on start up and until the oil pressure reaches about 50-55 psi, the engine is dead quiet.  She sounds like a fine sewing machine.  Around 50-55 psi, the annoying clatter starts....and once we're down around 40-45 psi, everyone starts shaking their heads and running for cover.  If it sounded hot like it does cold, I'd be thrilled. 

[sixty9cobra]

I'm guessing its a hydraulic roller correct?  What is your pre load cold? Is it an aluminum head motor or steel? sounds like your going from zero lash to something that the lifter cant correct for.
 

[Nelybel66]

Correct....it is a hydraulic roller.  Pre-load is 5/8 turn....original cast iron heads.

[cjshaker]

There are guys much more knowledgeable about hydraulic rollers than I am, so I'll let them chime in when they get a chance. I do know that some rollers have issues with the lifters oil holes lining up with the passages though, or being exposed at full lift. I wonder if that is the case here?

[gregb]

What spring pressure are you running?  Have you tried tightening up the pre load?  I haven't run hydraulic rollers in an FE (yet) but on some other engines it takes a full turn on the adjuster to keep em quiet, as opposed to the normal 1/2 on a regular cam.  What are your cam specs, I didn't think Erson was around anymore.  And with the cut up valve cover  how much oil did you see up top?

[Lenz]

You mentioned that you observed the action through a cut valve cover.  Were you able to see the rockers oiling before and after the clatter starts?  If it stays relatively the same I can't imagine what would cause the lifters to give up their charge so quickly on shutdown.

Is it at all possible that the lifters are misaligned with the galley so as to starve them once pressure drops off a bit?  Also, this might sound a bit off the wall but are you sure the gage is giving you a true reading? (if you can see the top end oiling while noisy I would think pressure should be sufficient to quiet the valve train though).

[Joe-JDC]

On some FE blocks, the roller lifters will expose the oil hole, losing some oil pressure while running, due to the bevel from  the machine when the block was machined.   You may need to install tall lifter bushings to cure that problem.  Major work, but worth the effort to use a roller camshaft.  Joe-JDC.

[Nelybel66]

Not sure of the spring pressure.  I'd have to find that out from the builder.  We talked about it and he said it wasn't excessive.  I do know he checked the spring pressures on his second time through the motor to make sure they are actually what they are supposed to be, and he said they are.  We have gone as far as a full turn as an experiment and no change.  Dead quiet when she's cold, and horrible once the oil pressure drops to about 40-45.  The builder and his contact at Erson designed this second cam to try to solve the problem.  It's very mild.  There seems to be plenty of oil up top....but to be honest, I can't say if I noticed a change in the amount before and after the clatter starts.  We are going to run it again either this afternoon or Monday.  I'll look for that.  I feel pretty confident the oil pressure reading we are seeing is accurate...it's been on 2 different run stands and a dyno and had several different pressure transmitters....and all the different readings are within a pound or two of each other.  This is my first post and it's awesome to hear the ideas.  We're all stumped, so hopefully with some help we can get this thing figured out!

[Nelybel66]

Joe-JDC....thanks for the suggestion.  I'll run that by the builder!

[Barry_R]

Lifter manufacturer? (Erson buys them from somebody - a pic might help - Morel, Shaver, Johnson, etc)

Lifter to lifter bore clearance?

Its an FE - not a SBF or SBC - needs at least a full turn down from zero to get .040ish of preload.

[Nelybel66]

I'll see if I can get a pic of the lifters...not sure who makes them.  We talked to a tech at Erson today.  He said to try up to 1 1/2 turns and see if that helps.  We'll try that next week and I'll report back.