Odd Noise - Dry Sump Related?

[Tim Kay]

New to me, dry sump motor. RHD SPF with dry sump pump mounted on the right side of motor. Since I've never had a dry sump motor maybe someone here can advise.

The best description of an odd noise I'm hearing is what sounds like an extra loud fuel pump or a trans oil pump behind the right side bulkhead while driving. I don't hear it at start up but once i get on the road and start to accelerate the sound kicks on. But as I reduce speed to a stop it quiets down then picks up again as soon as the motor rpms go up.

Is this the sound the dry sump pump makes? being that it's belt driven I would assume it would be constant from start up to upper rpm. Or is there some kind of relationship between motor rpm and pump operation?

There are no other mechanical objects to cause this noise. Short of this noise generating from the dry sump pump I'm stumped!

Tim

 

[mark b.]

I've used an Aviaid that was quiet except when the belt was too loose then it sounded like a tappet going south from the belt skipping. I have a Daley now and I can hear the gears rattle or contact when cold, silent when warm.

 

[Randy V]

Possibly the pressure relief valve rattling. If you don't have a mechanical oil pressure guage you would probably not see the slight fluctuations in the needle.. I would bump the pressure up 5 PSI or so and see if it makes any difference.

Belts - make sure you check your belt tension hot. I've seen way too many people get the belt too tight cold and it takes out the front bearing on the oil pump or it wipes out the belt.

 

[Tim Kay]

Thanks for the replies

Randy, the belt has about 1/2" flux tension. Seems ok to me.

Another observation: I went out in the car cold, no sound until a few blocks down the road and when the water temp hit about 85c the sound started. After that whenever the rpm is over 1500-2000 the sound starts and continues through the rpm range but as soon as I slow down the sound tapers off around 1500 and inaudible at idle, the whole while the oil pressure is 60 psi. Randy, the gauge needle does get erratic when the sound is audible (needle bounces between 61-63ps) but is steady when the sound is inaudible.

Is it possible to have a pump that operates in stages? First, temp sensitive then rpm sensitive?

(Sorry, pic of pump upside down.:shrug

 

[Tim Kay]

I finally got a mirror out to see if I could find a name on the pump. Turns out it's a 3 stage "SCP" pump. Now the question is how it operates and is this sound normal, their website does not go into that detail. At least not that I could find.

 

[mark b.]

Belts - make sure you check your belt tension hot. I've seen way too many people get the belt too tight cold and it takes out the front bearing on the oil pump or it wipes out the belt.

X2 about the belt, good point, especially with the aluminum block.

 

[Tim Kay]

Spoke to the pump manufacturer this morning and the pump should not be making noise that can be heard over the loudness of the engine.

 

[Jac Mac]

Tim, I see on another thread you were asking Q's about the fuel system on the same car, you sure the possible pump sound your hearing is not a dud pump running with little or no load.Perhaps try switching pumps off while making the noise?
Only increase in noise from a dry sump pump is usually if the pump is out of line & belt not tracking correctly or if the drive extension on front of crank/balancer is not running true ( check it with the timing light while running ), square tooth gilmer belts are more noisy than round or curveliniear/HTD type belts

 

[Tim Kay]

Jac Mac, good suggestion. I've pretty much eliminated the sump pump causing the sound. All seems fine short of taking it off and sending it to the manufacturer for testing. The sound is really making me bang my head and scratch my balls! It occurs religiously when engine comes up to temp, not before, and gets louder through the rpm range. Then back to quiet at idle.

Now if what your suggesting Jac, could it be the engine temp rises at the same amount of time my fuel pump takes to start producing the sound, that would be a coincidence. Stranger things happen, right?

I checked alternator for any fouling, none. I was wondering if there could be any harmonics created in the expansion tank once water fluid starts flowing through the cooling system. There's not much else on the car to look for.

Tim

 

[Tim Kay]

Jac Mac, the two carter low pressure fuel pumps are on my dash toggle switch. On\off makes no difference, still hear the sound (forgot I had tried this early on a couple days ago. No surprise, I can't remember what I did a couple hours ago much less a couple days!)

 

[Seymour Snerd]

Is there any pitch to the sound, and if so does it track engine RPM or is it constant like an electric pump? BTW my aviaid oil pump makes no sound at all and it's right behind me with no sound deadening.

Is there any chance this is a water pump thing? Just wondering since it doesn't start until the temp is up...

One other crazy idea, not knowing how your sump pump is plumbed: if the pressure section delivers to a hose, could the hose be vibrating with the pump's delivery pulses and touching something that's amplifying that sound (like the thin sheet metal of the "mono")?

 

[Tim Kay]

Alan, your diagnosis is in line with the symptom. One of the oil pump -12? (large) line fitting passes ever so close to the expansion tank I thought this might be the culprit but I can get a .028" feeler gauge when hot through it so I canned that idea. I'm looking for other possible vibration gremlins.

Sound is not a pitch, more like a electric pump that gets louder with increased rpm, but also has a vibration to it as well (like an electric pump). Again, it definitely coincides with the rpm cuz when I get back to idle it's hardly discernible.

 

[Jack Houpe]

I have a piece of equipment I bought 25 years ago, its called an engine ear and snap on use to sell them. Its a electronic microphone with a set of headphones, it has a rubber tip where the mic is mounted so you can touch parts of the engine and pick up sounds. I just finished a Ferrari project and heard a noise coming from the front of the motor so I thought I had a cam belt tensioner going out, got out the engine ear and started checking and to my surprise it was on the other end of the motor aft the clutch! The sound came all the way from the back to the front! My point being don't rule out something else that can be transmitting the noise forward.

What about timing chain?

 

[Tim Kay]

Thanks Jack, I think your right. I'd better expand my focus.

Alan, for the moment I'm gonna rule out the water pump. New, low milage, no play, no squeal and the cooling system works like a champ.

 

[mark b.]

I'll bet it is the belt, being square tooth. If the sound goes away, I would investigate with a little more due diligence.

 

[Tim Kay]

I'll bet it is the belt, being square tooth. If the sound goes away, I would investigate with a little more due diligence.

Stupid question but how so? The alignment seems correct, no drift off either pulley. The tension, cold, seems ok. I can twist the belt about 90 degrees, maybe too loose? What else should I check?

 

[Tim Kay]

Finally found the culprit after many hours of process of elimination. This car is new to me but in short order we've become quite intimate. The blessing in this painstaking event is I have disassembled and reassembled parts I would have never got to for months down the road if at all.

I was ready to throw in the perverbial towel but too stuburn to let it get the better of me. I decided to take Jack Houpe's advice and put an ear to anything I could get to. Up to this point I was doing everything solo but since this issue raised is ugly head easier while on the road I got together with a buddy. Removed the bulkhead panel to expose the front of the motor to the cockpit. I drove and my buddy sat backwards in the passenger side facing the open bulkhead. With long screwdriver in hand we ventured down the city streets. What a sight this had to be, me huntched over the steering wheel to avoid contact with the exposed runing motor and Billy, sitting backwards, holding onto me with one hand and leaning as close as he could get to all the engine parts with this long screwdriver stuck in his ear. Makes me laugh the sh$@ we'll do, huh?

Anyway, turns out it's what I originally was guessing. The sound\vibration is coming from the dry sump pump and it's more pronounced at the pressure outlet fitting than elsewhere on the pump. I have not resolved the issue but I'm happy to finally find the source.

My logic tells me it may be like Randy V says, the pump pressure valve is rattling and since drivetrain is solid mount it trasmits the vibration\sound throughout the chassis. But further thoughts seem to indicate that because it does not occur until some blocks down the street that the scavage side might have something to do with this. Is it possible the oil pan is emptying out faster than oil is coming in, creating a "cavitation" effect?

Ti

 

[Robert May Eng.]

The scavenge side of a dry sump pump will always cavitate. They are sized that way to the point where there are bleed offs to the rotors to keep them lubricated. If the pressure relief valve is chattering it might be down to excessive pump speed or an oversized pump. Dry sump pumps normally run at half engine speed. Worth checking.

Bob

 

[Tim Kay]

Bob, this pump is an SCP (Sprint Car Products) 3 stage with the 2" dia crank pully\4" pump pully which confirms your recommendation (not exact measurement but eyeballed with a measure). Not sure if it's oversized though.

Thanks for the info regarding the cavitation.

 

[mark b.]

Your oil tank is vented properly? What size supply line between the pump and tank? No kinks? Engine not filling up with oil? Level in the oil tank when the sounds start?

Can't remember the time but you'll go through a tank of oil pretty quick.

https://www.youtube.com/watch?v=k5pGa2JPVo4

https://www.youtube.com/watch?v=ow7OL0ddtI8

https://www.youtube.com/watch?v=0QpQxudwEPM

You might be running into something like the above, one reason I put a deaerator on my pump.

You say it starts a ways down the road?