Strange sound when priming oil pump
 

I was using a heavy duty drill on an old Merc distributor with the gear removed to prime the oiling system on my BBC tonight. I was getting oil to all the rockers, but when I turn the drill off I hear a strange sound, almost like air bleeding out of somewhere as the oil pressure bleeds off. It sounds like it's coming from the front of the engine around the timing cover. I know that the front oil gallery plugs have small holes drilled in them to allow oil to get to the timing chain. Should I be hearing anything from this? Starting to wonder if my pump is sucking air. Don't have a gauge on it right now, that will probably be the next step, but I must be building pressure for it to make it up through the pushrods. I also noticed that it is barely coming out of the rocker holes - was expecting a steady spurt of oil here.

Do I have a problem here, or am I just being paranoid? Don't ever remember hearing anything like this before when I primed engines this way.

For the record, it is a Melling Select 10778C pump, stock pickup brazed all the way around, stock 8-quart GM pan with about 5 quarts in it. Maybe my level is too low, but I would think the pickup should be fully covered.

I would put the other 3 quarts in. Also do you rotate the engine while the drill is running? I tether the drill in the on position, and then put a wrench on the front pulley. Don't know if it helps or hinders.

Rookie, I turned it one full revolution between runs of the drill. It's a big ass drill, and I wouldn't feel comfortable just letting it run by itself without having someone else there to hold it. Would probably just spin around unless I had some kind of sturdy jig to hold it with.

I have primed several engines, and don't ever remember hearing anything like this. Leave it to this problem child to have all the weird issues.

I was going through a mental checklist, and specifically remember putting the o-ring back in under the rear main cap. Don't remember having any gallery plugs left over either.

Mine have done that. I just assumed it was the oil pressure bleeding down as soon as the drills stopped

I've heard some funny noises as my engines have bled down but thought it was more in the lifter galley area.

That bleed down noise you are hearing is normal. Oil will not squirt up through the pushrods with any force, while priming with a drill. As long as you are getting oil up to all of the rockers, even just a trickle, its all good.

Do you have an oil pressure gauge on it while priming?

Going to put one on it today. I was mainly just watching for oil flow up at the rockers. Thanks for the replies, guys. This motor has made me paranoid with all the funky issues I've had with it. :party-smiley-004: It's turning me into a "hydrochondriac". :)

im not sure why you put 5 qts in an 8 qt pan but you need to put the other 3 qts in it ,add a pressure gage and reprime it.would you run it 3 qts low in the boat?the noise you are hearing is probibally the pump sucking air instead of oil.

It's not my motor, so I say run it ! LOL.

On a serious note, I have a mechanical guage installed, look fo proper psi and look for oil out of all rockers. Oil flow thru rockers can take some time and some motors I have to rotate crank while priming for the oil to come up all of them.

Can't tell thru desciption if you weird noise is something wrong or not by description. Air entrapted in fluid purging thru small holes can make some good noises. Usually more like vagina farts. LOL.

I figured with a few quarts in the sump it would be enough to cover the pickup sufficiently to pump oil through the engine and prime it. Added 3 more quarts and still hearing the sound. SB, the sound is similar to the sound of air bubbling through fluid. Kind of a sputtering sound. Tried to video it with my phone, but not sure if it came out very good. Might try to post it.

WITHOUT BEING THERE TO HEAR IT FIRST HAND, I would speculate that you are hearing the normal sound of the air purging I have heard this many times in the past, due to the fact that the crank is not turning to allow the cross drilled passages to fill with oil and bleed out the air, along with the rockers have to pivot to allow the holes in the push rods to properly align with the rocker holes to pass the air. (that is why if you adjust a solid cam/lifters while running they will squirt then not as the rocker pivots, we would put shields on them so we could adjust them hot and running) I would say you are hearing normal noises!!! Sorry for the rambling!

Especially with that hole in the oil galley plug you could be hearing all kinds of bleed down.

If it's air purging out, shouldn't it go away at some point when the engine is completely primed? I have probably spun the drill ten times in this thing, and I hear it every time as soon as the drill stops. Obviously, I can't hear it when the drill is running because of all the noise. It does seems to be coming from behind the timing cover where the pipe plugs have the holes drilled in them. I guess it might just be air bleeding back into the upper air galleries when the oil tries to drain back to the pan.

Not necessarily an air bleeding noise as the oil itself needs to equalize with the drop in pressure within all the clearances throughout the motor, and you will hear this "bleed down sound" as the oil leaks out of all the "tolerances" from 40-60 lbs of pressure to no pressure. Once again without hearing it I'm speculating from my past experiences!!. Please keep us posted.

When I prime mine with a drill and stop the pressure in the system will spin the drill backwards for about 4 or 5 revs. and make noises. Warm it holds 40 lbs. at idle and 65 cruising. You need a gauge on it to tell what it's doing.

OK, I will be installing a gauge on it this evening, but if there is air getting into the oil from somewhere (such as under the main cap, through the pickup, etc.), would this be reflected in low oil pressure? It is a 10778c pump, and I have read that these can produce lower than normal pressures at idle, so I'm also wondering if this will skew my results.

Probably overthinking this (hey, it's how I roll), but the sound I am hearing makes me want to verify that I am not introducing any air into the oil flow through the engine. thinking about putting in a brass barb fitting at the port above the oil filter and attaching a piece of clear plastic tubing to it. That should tell me if any air is getting into the oil.

I would think as long as the oil pump does not "skip" while you are priming you should not be pumping any air.

fbc, I would agree, as long as there is nowhere for any air to get into the system. Most common places for these are in the main cap/block interface, at the attachment point where the oil pump meets the main cap, and the oil pickup where it goes into the pump body. I thought I took appropriate measures to make sure none of these could be an issue (i.e., remembered the o-ring under the cap, had the full circumference of the pickup brazed to the pump body, etc.), but with the kind of klusters I have had with this thing, nothing would surprise me at this point.

Found some REAL interesting info about performance oil pumps and particularly oil pickups in this article. Very informative reading material. Check it out - http://www.enginebuildermag.com/2009...mp-technology/

OK, hooked up a gauge to it, and I was seeing 66 PSI with the drill. That reading was taken from the top port behind the intake manifold. Starting to think I am hearing air getting sucked back into the oil gallery through the front plugs when the oil bleeds back down. I did notice that the oil coming out of the rockers is not crystal clear - kind of has a slight foaminess about it - not large bubbles or anything, just looks slightly "whipped".

budman,stop over thinking this,66 lbs on the drill is good.finish this thing and go to dyno!

HaHa! You just can't wait for that awesome dyno run I'm going to lay down, can you Mike? :D You're right, this damned thing is making me neurotic. :crazy:

i am looking foreward to good numbers and a happy budman!

Hey, I've been workinng hard out in my "magic room". I'm sure I'll break the dyno. Thanks for the help!

The real strange sound is going to be of the starter engaging with the flywheel. ie: starting the engine. LOL.

What's that ?

I think they erected the Roman collaseum in less time than its taking budman to finish this 489 chevy

Cmon pudman let's get this thing fired already !

You must have one hell of a drill to get 66lbs.

i use a 1/2 inch air drill.small but powerful.

will we loose budman after the engine is finally done?i predict he will start a new thread [REBUILDING MY BRAVO DRIVE].it will only last 2 years.:eekdrop:

Don't say that! :eek: That's the last thing I need, although it has crossed my mind to pick up a spare drive just in case.

It's one of those big-azz 3/4" industrial drills with the shoulder brace on it. Old as the hills, but still works great. I was afraid I was going to burn up my little cordless drill.