roscobbc

Lifters are hydraulic flat tappet George. I need to get my head around priority oiling - is it the bottom end that gets oil first - or the camshaft receives oiling first.?

hugie82

All true and good catch with the hot oil pressure being at 70 psi. Pulling the distributor and inspect the gear and drive for wear would be my next step. My 427 had to idle close to 900 rpm and oil pressure would stay about 45-50 when hot. If I backed the idle down to that nice staggered choppy idle I could get it down to 40 psi and that was with 20/50 weight oil.

roscobbc

Using 20.50 oil - using MSD distributor - did remove and gear seemed OK - took a quick look at it - couldn't see any issues.

roscobbc

Wondering about 'shot' camshaft bearings - inner journals? - harmonics causing camshaft to rattle around at certain rpm causing noise - any logic in thinking on these lines? - anyone on here experienced worn camshaft bearings?

Super6

What is going on in the pan with this high oil pressure? The pressure comes from jamming fluid through a fixed orifice which is basically the engine oiling system with all it's turns and passages and restrictions. To develop 70 psig at idle hot, you have to be pumping a lot of oil. Your hot idle pressure is twice mine. That means that you're pumping 40 percent more than my engine and it has a high volume pump in it. Is the pan staying full? Is this a extra capacity pan? What's the real oil pressure at 3000 rpm? Could it be dipping due to sucking in some air, but you don't see it because the gauge is already off scale. I would temporarily put a test gauge on the engine with a higher scale. I don't know how you could have high oil pressure, evacuate the pan and have a rod knock at the same time. Maybe the noise is coming from the 1-2 cylinder set, the furthest away from the oil pump.

Super6

Oh yeah, I would put 10W30 oil in there and see if it makes a difference. That will drop the pressure a little. The wear that we're normally trying to protect our engine's from occurs mostly at start-up and 10W30 is better at flowing at lower temps, like on a cold start.

A change to a different oil weight won't help if the pan is getting evacuated.

gkull

Forget 20W-50 on a tight motor try 10w-30 like suggested.

So called priority oiling is: the crank shaft gets a higher % Oil restrictors placed in stock blocks decrease the flow to the top end. Not recommended for H type lifters.

I personally have never had a failed H-flat lifter

roscobbc

Ok guys - couple of video's here taken at weekend - best listen on headphone or speakers to pick up bass noise and knocking sound. Apologies for 'T' roof squeaking!
Checked out oil pressure a bit more carefully and on cold engine at idle speed its 70/80lbs and off the gauge on cruise. When fully hot idle is 35/40lbs and 70/80lbs on cruise. Second video phone was fixed to firewall right beside drivers valve cover so valve gear sound is quite loud (even though flat tappet hydraulic) Revs during video were kept below 3500rpm. Tapping sound seems to tail off after 3000rpm and also on on a trailing gas pedal.

forman

I would check the compression on all cylinders It sounds like a dead one ,, it sounds like a pistons hitting the top of the head so it could be a wrist pin that went bad ,,I would not be driving it you could do alot more damage then you think,,,,
you could drop a valve and its game over ,,oil wont fix that noise ,,, Is the car burning any oil

Super6

That sure sounds like mechanical contact between valve train components, or maybe rockers and the valve cover. What kind of clearance do you have between the pushrod end of the rocker and the valve cover? Could a lifter be pumping up, growing and forcing a rocker to hit the valve cover? Maybe at 3000 plus, the oil pump bypass is opening and more oil is being thrown off the crank so the oil pressure at the lifters is actually lower than at lower rpm, even though the gauge is reading the same. So the problem goes away at higher rpm. Notice any drop-off in power when the noise occurs? The associated valve may not close if the lifter is pumped up.

It's a puzzle.

roscobbc

A badly worn wrist pin bearing was one of the more extreme or unusual things I had considered - no one I have spoken with has every had one fail - so wouldn't know what it would sound like!

roscobbc

Definately not rocker relatated - using 'tall' covers so clearance isn't at issue. Sound is far 'deeper' in centre of engine than valve gear. No drop in power when it occurs.

Super6

That noise was so loud, it seemed just on the other side of the cover. Well, having heard the volume of the racket and you saying it is deep within the engine, it seems that it is time to drop the pan and see if all of the rod bolts/nuts are tight, inspect some bearings and wrist pin/pistons from the underside. I would pull any suspicious looking piston sets, because it seems that you are about to hear a much louder "BANG" any second. As mentioned above by forman, I wouldn't run the engine any more until you get to the bottom of this. There obviously is metal to metal contact/impacting going on and I'd be afraid that you're just doing more damage by operating the engine. Have you cut open an oil filter to inspect the contents?

forman

The best advice I have for you is take the top end off the motor off and go through it ,, i have seen so much stupid stuff go wrong over the years everything ,,, it sounded like cyl, 1,3 ,,can you get a scope pull the plugs and drop the camera in there and look at the tops of the heads,, you would have to look hard cause it would only be minimum contact to make that sound

roscobbc

I thought again about this and if wrist pin bearings (small ends) were shot I would have thought that under cylinder pressure the clearance between piston and cylinder head would increase as piston moved downwards relative to worn bearings. Under decelleration piston to cylinder head would (IMNO) reduce with the risk of contact. Actual nnocking noise is under compression - and goes under decelleration conditions - so I don't think wrist pins are the issue.

roscobbc

Next job really has got to be pulling oil filter and cutting it open, inspecting and perhaps running the oil past a magnet.
Need to get myself a mindset together, look at this as an 'opportunity' and 'step' things up a bit - hydraulic or solid roller tappet.

427Hotrod

That sounds a little scary to me. I'd definitely cut the filter and then drop the pan to ck bearings if anything shows up in filter.


The plug wire trick can help narrow it down. Hold it at steady RPM where it's doing it and pull wire on/off and listen to noise.

JIM

cardo0

Its been 2 weeks since i suggested to pull a plug wire at a time and u still havent tried it. If it is 1 rod that will let u know. I dont know why your doing all kinds of other tests/videos when that test is so simple?.

Those video sounds are more tinny than a rod would make and the rod noise shouldnt come and go - but audio recording can lie. If i couldnt locate it by pulling plug wires i would try a cut open vlv cover (old) and install one side at a time and listen with a stethoscope (if needed). But the tinny sound may just go away with an open top vlv cover - and then u have the location.

cardo0

roscobbc

As you say a video recording can lie! - video will not pick up the bass notes - nor will it pick-up vibration. Unfortunately work and other commitments allow me limited time to work on car related issues - couple that with a debilitating lower back condition - it can take me a time to address things like this - using a pc keyboard doesn't cause my lower back to seize-up lol!

Indiancreek

A couple times I've had customers come in with a ghost noise like your's. Never could locate the problem. One of them even tore down the engine and couldn't find the source. He decided to drive it till it got worse or broke. Never did either. He's still driving it three years later. Still has a little noise that fades as it's driven.