WTF is this noise? Oil Pump? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 04-06-2010, 12:17 PM   #1
Junior Member
Thread Starter
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default WTF is this noise? Oil Pump?

This is a long post, and I kinda ramble a bit since I've edited it several times already....

I bought a used FM built motor (1999, wiseco, carillo, fidanza, fererra) a couple years ago. Took off the pan before I installed it, the oil looked good, and I didn't see or feel any signs of bearing issues as far as one can tell without removing the caps. Since the first time I started it up, it made an irregular 'loose' clattering sound that I initially thought was valvetrain (that kind of tappity sound). Previous owner made 500+ HP on E85. When I asked him about the noise, he said it always did that and thought it was either from the lightweight flywheel or piston slap, he put about 6K on the motor. Initially I was worried that I had bought a hurt motor, but I've got about 2000mi on it myself running 15psi and 7500RPM shifts. The noise comes and goes, but never got any worse. It usually doesn't make the noise for the first 5 seconds of a cold startup. It's at it's worst at idle, and goes away as revs increase. It seems to get better after driving the car hard, but not all the time. The knock sensor doesn't seem to pick it up, and I can only maybe hear it just a little through a stethescope on the block when I rev the motor up to 3K. I don't hear it at all while the motor is accelerating, and maybe just a bit at a steady 3K, then it gets noisy as the engine decelrates. It almost sounds like it's coming from outside the block rather than inside. When I release the throttle and the revs drop it makes a loose 'tappity tap tap tappity tap kinda sound' I now believe it's the oil pump, but I can't figure out what would make it rattle.

Here's what I've tried/checked:

1. There were a couple valve shims that were a bit out of spec but I fixed them anyway. No change.

2. Removed all accessory belts, this seemed to make it louder, or at least more regular.

3. Quadruple checked all the timing belt stuff to make sure the pulley's weren't moving and everything was torqued down properly.

4. Modified the factory oil pressure gauge and installed an 80psi sender in the factory location. Cold idle oil pressure is about 70psi, hot idle pressure is ~40psi. Cold driving pressure is 80+psi, hot driving pressure is about 60psi. I'm guessing a little since the gauge isn't linear. I run Rotella 5w-40 oil. Plenty of oil is getting to the head.

5. Noise is the same with the clutch engaged/disengaged.

6. Changed out the crank pulley.

7. Disassembled the last two oil filters looking for any metallic stuff, didn't find anything.

8. Ran the **** out of it hoping that whatever it was would get worse or break so I could stop worrying about it.

Here's my reasoning for the oil pump:

If I take the metal rod off the mechanics stethescope and place the open tube near the crank pulley, I can hear the tapping better than with the metal rod on the block! BUT the weird thing is that with the rod ON the stethescope, I may be crazy, but then it seems louder on the exhaust side of the head. I thought maybe the sound was from something on the exhaust cam and that the plastic timing cover was sorta ducting the sound down to the crank pully (biggest opening in the cover) but I can't think of anything else to check up there.

The noise miraculously went away for a whole afternoon right before my last oil change, when I changed the oil it came back full force.

But what the hell is there in the oil pump that would rattle??????
If the gears were broken I would expect more drama. Something wrong with the relief valve? Maybe the super-lightweight flywheel is making the crank rattle it as it drives the pump gear?

I had Ron Williams of RAW Performance (very respected Subaru engine builder that has built a few BP engines) look at it, and he said if the oil pressure was good, he wouldn't worry about it, but he didn't know what it could be. Had an e-mail discussion with Jeremy at FM. Didn't get much info besides try some heavier oil, and sometimes they are a little noisy. I understand that remote diagnosis is difficult though.

I've attached a best effort recording of the noise. this was at a 750ish RPM idle through the stethescope on the head. Too much 'air' noise to get a good recording through the tube to the crank pulley, but sounds similar.
Attached Files
File Type: zip Stupid_Noise_m4a.zip (238.4 KB, 101 views)
DammitBeavis is offline   Reply With Quote
Old 04-07-2010, 12:12 AM   #2
Junior Member
Thread Starter
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

Currently entertaining any crazy ideas......
DammitBeavis is offline   Reply With Quote
Old 04-07-2010, 01:25 AM   #3
Senior Member
iTrader: (18)
 
Join Date: May 2008
Location: Big Bear Ca
Posts: 990
Total Cats: 8
Default

It's your Fetzer valve, the bearings are bad.
dstn2bdoa is offline   Reply With Quote
Old 04-13-2010, 03:33 PM   #4
Newb
 
Join Date: Feb 2010
Posts: 23
Total Cats: 0
Default

If it is the pump, I would guess that there is a bit more clearance between the inner gear and the crank. Probably the gears and the housing have a little extra clearance too, allowing everything to float. I would think that the float could cause a rattle.

It is only a guess ....
Stuart_D is offline   Reply With Quote
Old 04-13-2010, 06:02 PM   #5
Senior Member
iTrader: (1)
 
Join Date: Oct 2008
Location: Trailer County
Posts: 530
Total Cats: -9
Default

I experienced oil pump failure and believe I had recently changed the oil less than 200 miles and it was clean with no metal shavings. Have had the same readings for the last 4 years (well since I have the mechanical gauge) and always they are true to specs, never experienced any grinding nise, loss of pressure, etc. Then one day it just shredded to pieces. What I am saying is good oil pressure does not mean a thing.

You want to know if the pump is healthy or not then open it up and check for clearances between the larger gear and pump housing and between the two gears.

IMO, it is NOT the oil pump, when mine failed it made a very high pitch sound very briefly a few seconds before blowing the gears to shrapnel. If it was the oil pump the sound would be faster and more gradual than rythmic and very high annoying pitch.

Ok, it sounds similar to when an electric drill reaches the corresponding setting # be it 12 16 etc on wood/metal and when it does it keeps on rotating as a safety mechanism and a grinding sound is heard and thats when you stop. So I was expecting a sound like that from the video clip. Not a lot could be distinguished but it seems it is the brief sound at the beginning of the clip and then it is not heard anymore, if not let me know.

I have heard many times forged pistons do make a somewhat similar sound especially on full floating pistons, but I have never heard a forged engine so cannot tell. Do have read on other forums of such sound and it is just piston slapping.
mazpr is offline   Reply With Quote
Old 04-13-2010, 06:22 PM   #6
Newb
 
Join Date: Feb 2010
Posts: 23
Total Cats: 0
Default

Quote:
Originally Posted by mazpr View Post
What I am saying is good oil pressure does not mean a thing.
Very true, we had a customer running a set of replacement gears in the wrong housing. There was .030 side clearance instead of the .004 it should have had. The pump when primed ran normal oil pressures. It would not hold the prime when shut off for more than 15 minutes, that was the only indication that there was a problem.
Stuart_D is offline   Reply With Quote
Old 04-19-2010, 01:09 PM   #7
Senior Member
iTrader: (1)
 
Join Date: Oct 2008
Location: Trailer County
Posts: 530
Total Cats: -9
Default

So what happened to this engine?

What was it?
mazpr is offline   Reply With Quote
Old 09-14-2010, 11:13 AM   #8
Junior Member
Thread Starter
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

Sorry, somehow I got unsubscribed from this thread, I didn't realize there were more posts. In the audio file, it's the rattle from :05 to :22. It doesn't sound 'deep' enough to be crank/rod/piston noise, but I've never heard forged piston slap either.

I've put about 600 miles on it since then driving back and forth to work with quite a few redline pulls at 15psi to get my fueling perfect. I changed to 15w40 oil to see if it made any difference when cold, and it doesn't. I removed the adjustable cam gear, and put locktite on the OEM cam gears and bolts to make sure they weren't somehow slipping and rattling. I'm out of ideas, It never gets any worse, so I just ignore it now. If something grenades, I'll let you know what it was.
DammitBeavis is offline   Reply With Quote
Old 09-14-2010, 11:59 PM   #9
Senior Member
iTrader: (12)
 
Join Date: May 2008
Location: Roselle, Illinois
Posts: 846
Total Cats: -35
Default

throwout bearing?
Hot_Wheels is offline   Reply With Quote
Old 09-15-2010, 09:52 AM   #10
Junior Member
Thread Starter
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

Quote:
Originally Posted by Hot_Wheels View Post
throwout bearing?
It sounds the same with the clutch engaged and disengaged.
DammitBeavis is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Moroso Air Oil Separator Catch Can Aroundcorner Miata parts for sale/trade 2 10-01-2015 04:20 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 03:13 PM.