3800SC whirring noise coming from right wheelhouse? (Page 1/4)
Dennis LaGrua FEB 15, 12:33 PM
Did a winter start of my 3800 a week ago and was greeted with a whirring/fast tapping sound. It happens at idle and when you rev the engine. In fishing around for the source it appears to be loudest coming from from the right wheelhouse. It still occurs when both belts are disconnected. Still trying to narrow down the problem and believe that it might be the harmonic balancer, the oil pump or in an odd instance a main bearing.
My suspicion is the harmonic balancer and we will do some further checking tomorrow. Anyone with a 3800 experience a similar issue? Is puzzling as the engine has less than 5000 miles on it.

.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Rickady88GT FEB 15, 07:50 PM

quote
Originally posted by Dennis LaGrua:

Did a winter start of my 3800 a week ago and was greeted with a whirring/fast tapping sound. It happens at idle and when you rev the engine. In fishing around for the source it appears to be loudest coming from from the right wheelhouse. It still occurs when both belts are disconnected. Still trying to narrow down the problem and believe that it might be the harmonic balancer, the oil pump or in an odd instance a main bearing.
My suspicion is the harmonic balancer and we will do some further checking tomorrow. Anyone with a 3800 experience a similar issue? Is puzzling as the engine has less than 5000 miles on it.

.




Miles may have little to nothing to do about it? Is it from a total car? Could it be from crash damage?
fierofool FEB 15, 08:25 PM
Use an old school stethoscope (3 foot length of heater or water hose), put one end to your ear and fish around the area with the other end. You'll know when you find it.
Dennis LaGrua FEB 16, 02:46 PM
Its actauly more like a rattling noise.
Lets try a video:
It appears that the knock is happening down below near the front of the engine.
Possible causes to be checked out:
oil pump noise
knocking harmonic balancer (possible)
rod knock (I hope not- only 5k miles on it)

Take a listen : knock

-Lift is tied up so we will need to get the up and probe in that area. In the worse case a spare engine is available
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 02-17-2019).]

olejoedad FEB 16, 04:29 PM
If it wasn't making the noise when parked, what has changed to cause this noise?

Dennis LaGrua FEB 16, 04:55 PM

quote
Originally posted by olejoedad:

If it wasn't making the noise when parked, what has changed to cause this noise?



That's a good question. Basically nothing changed. The only anomaly during the last winter storage start was a tapping noise caused by the edge of the supercharger belt shredding and a long thread hitting something. Installed a new belt and the problem went away for the next start. . Next time engine was started the noise you hear on the video began. Later I'll take the belts off again and inspect all pulleys and the balancer but last time they were removed the noise was still there.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

olejoedad FEB 16, 06:25 PM
Could you have a piece of the shredded belt tangled up in the balancer?
Dennis LaGrua FEB 16, 08:22 PM

quote
Originally posted by olejoedad:

Could you have a piece of the shredded belt tangled up in the balancer?



Thanks for the suggestion Joe. Its always appreciated. I hope that its as easy as that. The two belt shreds looked like they were only a couple of inches long but remained on the belt. . Replaced supercharger belt and the slap caused by the shreds went away. I'll recheck the balancer this week and dig in more. Stethoscope on the oil pan doesn't detect much sound until you get to the area in front near the balancer so best guess is the balancer came apart. With 5000 miles on the engine, and one that's meticulously maintained it shouldn't be a rod bearing knock..

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

OntarioKev FEB 16, 10:09 PM
You said 5000 miles a couple of times. Is this 5000 since a rebuild? I am sure you have heard that is the typical range when a rebuild will spin a rod bearing if its going to happen. Unfortunately it happens enough with these engines to be a thing.

Lets hope that's not what it is though!
Lou6t4gto FEB 17, 07:37 PM
make sure the Balancer BOLT is Tight ! I bought a 3800sc and they did not torque it properly after putting in a crank sensor, And it CRACKED the crank" snout" at the Keyway !!