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.
.
------------------ " 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 "
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?
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.
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)
-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).]
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 "
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 "
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.
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 !!
Removed wheelhouse and tried to isolate the tapping/rattling noise Listened at oil pan and area in back of the balancer and so far nothing. Balancer is tight and back and forth rotation by hand doesn't indicate looseness. As this ratttle is high speed it sure sounds like something is rubbing or possibly even an exhaust leak. It sounds like it is occurring at the speed of all cylinders combined. Now I'll add the funnel to the hose end and start listening again.
------------------ " 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 02-18-2019).]
Dennis that doesn't sound good at all. Have you warmed it up enough to see a normal oil pressure? Hope it's not a rod. I would start by pulling valve covers and inspect for loose rockers. A vac gauge in the right place may also help. Keep us posted with any updates.
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
I had a '67 396 Caprice many years ago. I over-revved it and it sucked part of a rubber valve cover grommet down into the valvetrain. Your noise sounds very similar to the noise it made. I also found this video on youtube that sounds very much like yours... https://www.youtube.com/watch?v=MNTycFKNNQU . I hope you find a relatively painless solution to this problem.
------------------ Rick Stewart 4.9 Yellow Formula in progress
The vid posted by Rick does sound very close to what we hear but unfortunately that clip listed no source or solution. I've got to say that in many years of building cars and working on engines this noise has been a tough problem to locate. The scary part is the the noise seems loudest in wheelhouse areas. A long shot is an exhaust rattle but very improbable. It doesn't sound like a rod knock but anything is possible. Changed oil, no water or metal bits there. Removed both belts and no improvement so all rotating accessories are fine. Next we'll check out for loose bolts on the flexplate. The stethoscope trick doesn't seem to locate much but if it is a collapsed lifter the sound will be contained somewhat by the, LIM, the intercooler and heavy supercharger that sits above it. At this point my best guess is valvetrain noise. What is most puzzling is that all this started on the third winter monthly start where the car had not been driven. The 4.9L ragtop is on the lift being finished so when it frees up we probe under the car . When the culprit is located I will definitely share it
------------------ " 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 "
He mentioned that in his 1st post, 2nd line. "It still occurs when both belts are disconnected"
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
Best guess at this point is a collapsed lifter but won't know for sure until the lift is available and my other project is started and running.
------------------ " 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 "
I've never heard a collapsed lifter making a whirring noise. Front cover area, non belt driven narrows it down to the oil pump, front main bearing, timing chain, cam bearing. It will be interesting to know what you find when you are able to finish the diagnosis.
I've never heard a collapsed lifter making a whirring noise. Front cover area, non belt driven narrows it down to the oil pump, front main bearing, timing chain, cam bearing. It will be interesting to know what you find when you are able to finish the diagnosis.
Had am expert mechanic friend come over today to provide his opinion. It appears that the sound is coming from down below the valve covers as you can hear sound from both wheel houses. His best guess is a cracked exhaust manifold or exhaust leak. The key is that the tapping/cliicking sound hits continuously on engine rotation. It also appears to be coming from outside the block not inside it. At this point I'll change my view and go with an exhaust leak. Soon to hopefully be found when we finally free up the lift and can check from below. Haven't had a chance to run the fuel, oil cooler, and water lines to get the 4.9L started in the ragtop. Only have a couple hours of work left before I can move that car off the lift then figure out how to adapt the Fiero throttle cable to the Cadillac throttle body. Going to see if I can adapt the Fiero TB pulley. that would make using the Fiero throttle cable easy.
quote
I've never heard a collapsed lifter making a whirring noise. Front cover area, non belt driven narrows it down to the oil pump, front main bearing, timing chain, cam bearing. It will be interesting to know what you find when you are able to finish the diagnosis.
Ruled out the lifter. All of what you have mentioned is suspect but with an engine with around 5000 miles on it, I would have to be pretty unlucky. This whole episode is really wearing on me so if I finish the 4.9L swap this week or not, the 3800 is going up on the lift. Once I start the engine and get under it we should know. ------------------ " 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 02-27-2019).]
Originally posted by Lou6t4gto: Great idea. if you suspect an exhaust leak, spray some pb blaster into the throttle body when it's running, the smoke should show you where the leak is.
Not yet. Delayed just a bit by the fact that the shop only has one rotary two post lift that is tied up and for completing the 85GT ragtop 4.9L swap. All that remains is to hook up the fuel lines, double secure the transmission cooler lines,add the fluids, plug in the ECM and fire her up. I'll dedicate one more day to finish the 4.9L swap before I can get the 3800SC car up on the lift. Decided not to go with your idea of shooting a shot of PB blaster into the intake to produce smoke as the supercharger lobes are coated in Telflon. What I will do is to check for exhaust leaks with the engine off, by using a vacuum cleaner on reverse hookup (blower side out) to pressurize the system , then spray soapy water and check for bubbles. I am praying that the sound is a cracked exhaust manifold, but in the worse case we have a spare engine here in the shop.
------------------ " 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 "
I have started the motor when cold and had about 2 or 3 minutes of not hot manifolds and put my hand near the suspected manifold. felt the air and shut down till cooled off. fixed leak. May not be safest way but for me it worked. just have a good idea where you think it might be so you can get to it right away before warm up. You can get the gloves that can withstand the heat and have a bit longer hunt.
I have started the motor when cold and had about 2 or 3 minutes of not hot manifolds and put my hand near the suspected manifold. felt the air and shut down till cooled off. fixed leak. May not be safest way but for me it worked. just have a good idea where you think it might be so you can get to it right away before warm up. You can get the gloves that can withstand the heat and have a bit longer hunt.
Must apologize to everyone for not getting to address this problem sooner but the 85GT 4.9 ragtop has been holdng up use of the lift. The engine swap in that car is done. All it needs to be started up is to run the fuel lines. The fuel lines are ss braided hose and I misplaced the Koul Tool AN socket tool that is used for putting on the end fittings. As soon as that arrives we will get the hoses finished, start the car and move it to the other side of the garage so we will have use of the lift again. Got to get that 3800SC back on the road as car season is near.
------------------ " 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 "
Been out of town all week and didn't have a chance to work on the problem. My latest guess is a cracked front manifold or an exhaust leak at the crossover pipe connection. I know that I've said this before but should get to it this week. Stay tuned I must get this thing fixed.
------------------ " 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 "
Finally got a chance to get the car up on the lift today. Not an exhaust leak as previously thought. Using my funnel on hose trick, the noise is clearly coming from between the engine and transmission. It looks the chattering noise has been found. Could be a lose or broken flexplate or maybe not???. Also looking into starter clearance or possibly movement of the starter Removed the cover plate all looked OK in there but then re-started the car to move it t do an oil change on my Chrysler and the noise decreased. Really strange situation needs further evaluation. In the best case the flexplate bolts are just loose or maybe there was debris in the bell housing. In the worse case everything has to come down and a new flexplate installed. Hope that I can get this figured before Carlisle.
------------------ " 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 06-03-2019).]
You may be onto something Dennis. keyword being FLEX. In my younger years I had 2 flex plates go bad. One was a Dodge van and I believe it had 3 or 4 mounting ears. One of the ears cracked allowing the sprung ear to make a knocking sound on each revolution.
The other was a 71 Coupe DeVille and the entire center of the flex plate ripped out and I'm not a car abuser. Poor design the type that look like swiss cheese. The replacement was more solid except for a few holes for access and the dealer had one waiting for me in stock so they knew the weak spots on these vehicles.
If your lucky maybe its just loose bolts like you mentioned. A tube of Locktite and a few turns of the crank and your back in business.
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
This problem could very well be a cracked flex plate but what puzzles me is that the sound suddenly subsided? If the problem was a defective/broken flex plate then we didn't notice any grinding sound when the car is started. A break in the flex plate can affect starter alignment and do this. The sound is definitely where it was detected it but today I'll check again before taking things apart. Remote chance of a loose starter. At least we are now narrowing it down.
------------------ " 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 06-05-2019).]
Broken flex plates can do strange things. My partner and I had a Buick engine that would suddenly lock down. No warning. It would just lock down. There was no debris in the oil pan or anything to indicate it was internal. We finally decided it was the transmission, so we had it rebuilt and got a new torque converter. As we were preparing to reinstall it, we noticed the flexplate move and at that point found something similar to fieroguru's picture, except a little worse.
Broken flex plates can do strange things. My partner and I had a Buick engine that would suddenly lock down. No warning. It would just lock down. There was no debris in the oil pan or anything to indicate it was internal. We finally decided it was the transmission, so we had it rebuilt and got a new torque converter. As we were preparing to reinstall it, we noticed the flexplate move and at that point found something similar to fieroguru's picture, except a little worse.
One more check of the starter and it looks like the cradle is coming down. What is puzzling is that there is only 5000 miles on this powertrain. The problem is that two different flexplate part numbers are shown for a 2006 380SC Grand Prix engine. Somewhere along the line GM may have changed to a different crankshaft flange or torque converter bolt pattern. Confusing to say the least. Its either Pioneer FRA484 / ATPZ357 or Pioneer FRA574 / ATPZ609. GM part comes up as 12609154.
------------------ " 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 06-05-2019).]
This problem could very well be a cracked flex plate but what puzzles me is that the sound suddenly subsided? If the problem was a defective/broken flex plate then we didn't notice any grinding sound when the car is started. A break in the flex plate can affect starter alignment and do this. The sound is definitely where it was detected it but today I'll check again before taking things apart. Remote chance of a loose starter. At least we are now narrowing it down.
Since the flex plate is bolted around the perimeter to the torque converter, the ring gear placement can be very consistant even with the center section completely broke, and still run and drive. Noise is more pronounced with a less than smooth idle which creates larger oscillations in crankshaft speed and loads/unloads the broken parts. Just like the Getrag or F40 rattle - the smoother the engine runs, the less pronounced the noise is. Cold startup from storage vs. being up to temp will likely cause the noise to be different.
Time for a road test and here is my theory on what happened. Since the noise completely went away I now suspect that the starter solenoid somehow did not fully retract (maybe some debris got in there) and that the ring gear may have been just contacting the starter gear making the noise. The flexplate could still be broken but I figure that a few road miles will tell the story. At least we now know the area of where the problem lies. UPDATE 6/7/19 Did about 25 street and highway miles today some at speeds to 65 MPH with a couple of full throttle bursts. No sign of noise. This may confirm my theory that the starter solenoid gear was not fully retracting. This whole incident was really strange. ------------------ " 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 06-07-2019).]
