HellaciousA

Car has a new 5.7 from Thompson motorsports, 799 heads, Texas speed cam, melling oil pump. Put 20w50 valvoline vr1 in per their instructions, car ran fine, no issues. Broke the motor in properly, waited til about 500 miles, changed the oil again. Had the car dyno'd, everything went fine. Another 500 miles have gone by, no issues. Today, I changed the oil again with valvoline vr1 10w30.

Start the car up and I'm getting a terrible metal on metal noise from the front of the motor. Pulled the serpentine belts, spun all the pulleys by hand, none of the accessories are making noise. Spun the motor by hand, couldnt hear any noise. Pulled the passenger valve cover as the noise seemed louder on that side. Nothing out of place, good amount of oil everywhere. Car was making 40-45 psi of oil pressure at idle, and climbed up to 55 or so when revving lightly.

At a loss for what it could be. I'm guessing either a lifter or multiple lifters is trashed or maybe the oil pump has a problem. Only minor oil shavings in the first oil change inside the filter, and even less this time when I cut it open.

Car appears to idle fine despite the noise, and no warning lights on the dash.

I've been through hell and back with this car, not sure what else to do at this point. Any suggestions would be greatly appreciated.

wannafbody

iTrader: (2)

Drain the oil and look for metal.

Che70velle

iTrader: (6)

Agreed. start The car with the belt off first. Sometimes an accessory won’t show its cards by just hand turning.
If she’s still noisy, cut the filter open again. Fortunately for you, Thompson will stand behind their engine.

HellaciousA

Pulled the belts off and ran it, noise still there. Drained the oil, no metal shavings, even ran a magnet through the oil and it didn't pick anything up. Pulled the filter and took it apart, spotless with no shavings in any of the pleats.

Should I go buy more 20w50 and try and run it again? Makes no sense how before the oil change everything was fine.

G Atsma

Something in the timing set/front cover? Cam sprocket bolt(s) loose? Retainer plate screws loose?

Darth_V8r

iTrader: (4)

Any chance it is the AC compressor and that is the one belt you did not pull?

Also to rat myself out -- I one time thought I had a god aweful bearing noise on the front of a motor after a cam swap. It was the iac shrieking. Put the intake tubing back on and solved.

Did you do a timing chain tensioner or just run the gear set?

May also be worth pulling rocker covers to make sure nothing loose.

milkey57

iTrader: (7)

Had a similar issue when the cam retainer plate gasket took a dump after my cam swap sounded god awful. Put a new on in and noise went away.

HellaciousA

I pulled the ac belt also, noise persisted. I used the original cam gear, new lower gear on the crank and a c5r timing chain. No tensioner on the ls1 timing chain.

I guess next step would be to pull the front cover off and see. Really hoping to not pull the motor again.

01CamaroSSTx

iTrader: (3)

That's where I'd start. Kind of strange that it started after changing oil. I personally don't get the 20w50 oil for the engine so I'm taking it your clearance is on the loose side of things and if that is the case running a thin oil could cause a loss of oil pressure.

HellaciousA

I've had collapsed lifters on other ls motors and this sound definitely wasn't that. Thompson gives specific instructions to not run thin synthetic oil for break in. I just am stumped how a thinner oil would uncover the noise. I followed the instructions for installing the oil pump and used the correct o ring also. Oil pressure was good when I discovered this problem also.

Che70velle

iTrader: (6)

Can you post up a video of the engine making this noise?

HellaciousA

I have to get more oil tomorrow and then I will take a short video.

HellaciousA

Belts are still off. I added 20w50 back in this morning. Noise has not changed.

wannafbody

iTrader: (2)

I wonder if it isn't the power steering pump.

85LSXTRUCK

iTrader: (2)

I bought there motor with zero problems with same oil directions they gave you. Sure sounds like something up front like timing chain rubbing something. I knew for sure the oil was not the culprit. Thompson will stand behind it 100%
I think your going to have to pull that front cover off. Wouldnt hurt to have TMS check that video out as well and chime in . Something broke or came loose i suspect.

HellaciousA

Pulled the front timing cover, timing chain, cam retainer plate, cam gear bolts, etc all are there and snug. I put my boroscope through the window area below the knock sensors and the cam lobes look smooth, no pitting or scraping, no heat marks.

While rotating the motor over by hand and my head by the pan, when one full revolution is about done, I can hear a small metal on metal noise as the rotation finishes. I guess I need to pull the oil pan and look at the windage tray/oil pump pick up tube.

01CamaroSSTx

iTrader: (3)

Hard to make anything from the clip. Where you able to pin point the noise with a piece of hose or an engine stethoscope?

Russ K

iTrader: (1)

Sounds like a vacuum leak. Any chance your catch can has a drain petcock that is loose/open?

Russ Kemp

HellaciousA

I am so stupid. I had emptied the can when I changed the oil and I had noticed the petcock had been leaking. I resealed it but when I installed it was wide open (but I thought I had closed it) I just took it off and sure as **** it was open. I've got the whole front end of the motor off, but I'll reinstall everything and try running it again.

LLLosingit

iTrader: (4)

Well if it is that it could be a little embarrassing but at least you're not dealing with a serious engine problem. Everyone has made silly mistakes at one time or another and trust me ….a couple of mine cost me a whole lot of time and money.