I bought a newly built 3.4 that began knocking. I was told it was from a 95 Camaro. The engine has new everything inside and has about 500 miles on it. I got the engine cheap enough to take the risk it is fixable but I am not sure where to begin looking. I know they did remove the valve covers and check for problems. Does anyone have any good ideas as to what could have made this knocking? It seems to quiet down quite a bit when the plug wire is off. Thanks Pat
I bought a newly built 3.4 that began knocking. I was told it was from a 95 Camaro. The engine has new everything inside and has about 500 miles on it. I got the engine cheap enough to take the risk it is fixable but I am not sure where to begin looking. I know they did remove the valve covers and check for problems. Does anyone have any good ideas as to what could have made this knocking? It seems to quiet down quite a bit when the plug wire is off. Thanks Pat
Is it actually a heavy knock, like a hammer, or is it lighter? Do you know if the engine is using high zinc break-in oil or what? I'm sorry. I didn't see the video at first. I just played it. The knock doesn't seem to be related to any particular cylinder in the audio. Is it?
[This message has been edited by eti engineer (edited 02-12-2022).]
That is really a bummer. To me it doesn't sound like it's coming from deep inside the motor. Have you tried the old 'tube stethoscope' trick? (One end of rubber hose in ear, the other end placed into contact with the surface of all the parts you can get to.
[safety first -- keep your fingers away from places they shouldn't be. ]
[This message has been edited by Notorio (edited 02-12-2022).]
Hard to tell from the video. First check that the ignition wires are in the correct position and in firing order 1-2-3-4-5-6-. Could be an exhaust pipe clank, a loose part, pulley or something internal.. Get a piece of heater or garden hose about 30" long and a cheap dollar store funnel. Duct tape the funnel to one end of the hose . Thats your ear piece. Now start the engine and put the hose in different areas (not near the belts please) and listen. Listen at the oil pan, the manifolds and near the transmission. That should pinpoint the problem
------------------ " 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 02-12-2022).]
Have you tried the old 'tube stethoscope' trick? (One end of rubber hose in ear, the other end placed into contact with the surface of all the parts you can get to.
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Originally posted by Dennis LaGrua:
Get a piece of heater or garden hose about 30" long and a cheap dollar store funnel. Duct tape the funnel to one end of the hose . Thats your ear piece.
Seriously guys, spring for a whole five bucks and get a proper mechanic's stethoscope.
When you moved the camera in line with the throttle body opening, it sounded like "chugs" coming out of the throttle body, not metal to metal contact. But then my hearing is shot so what do I know
[This message has been edited by IMSA GT (edited 02-12-2022).]
THANK YOU, THANK YOU and THANK YOU to everyone. Man, how awesome would that be to just have something as simple as a firing order or spark issue! I was ready to begin trying to dismantle the engine but had no idea where to even begin..all the suggestions and advice are more than helpful and I cannot wait to just see what the heck is going with this thing. I will get to messing with it and getting to the bottom of this. I sure appreciate all the help and advice! Thanks Pat
I'll temporarily ignore the fact that your video was the size of a postage stamp on my PC screen ... and I'll suggest that you not pull a spark plug cable off the coil terminal like you did and run the engine. That spark wants to go somewhere, and coil damage could result. Make sure to ground any coil terminal which has been disconnected for testing purposes.
⚠️ Warning: Running any GM engine w/ DIS w/ spark plug or there wires pulled even for seconds is often bad and easily blow coils and ICM.
Coils can flash HighV to LowV inside for many HighV problems and once done the coil is destroyed even if seems to work later. Why? Watch Wells/Airtex @ Parts Plus YT https://www.youtube.com/watch?v=zKYTl6sC-qk And No Test is available to general public or most parts stores for this problem. You need a High $ "meger" unit used by some building electricians that test for bad insulation.
Can't tell for sure what sound it. Careful feel around (don't touch) or use tube trick above often feel/hear exhaust leaks fast.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
⚠️ Warning: Running any GM engine w/ DIS w/ spark plug or there wires pulled even for seconds is often bad and easily blow coils and ICM.
Coils can flash HighV to LowV inside for many HighV problems and once done the coil is destroyed even if seems to work later. Why? Watch Wells/Airtex @ Parts Plus YT https://www.youtube.com/watch?v=zKYTl6sC-qk And No Test is available to general public or most parts stores for this problem. You need a High $ "meger" unit used by some building electricians that test for bad insulation.
Can't tell for sure what sound it. Careful feel around (don't touch) or use tube trick above often feel/hear exhaust leaks fast.
I used meggers for several years in my work as a high-voltage systems test engineer. The bottom end meggers which electricians use only go to 1000 volts. The next step up is 5000 volts and the more expensive ones go to 10 kv. Not sure this would help. There is a unit we used called a DC Hi-Pot that would go from zero to 100,000 VDC, but this would be overkill and is not available to the general public, although I have seen them on eBay and other such sites. We tested 12,000 volt cable at 63,000 VDC. It took that much of a differential to tell if anything was bad, so I don't know if a megger would work that well on an automotive coil, since the secondary voltage is tens of thousands of volts.
[This message has been edited by eti engineer (edited 02-13-2022).]
Originally posted by eti engineer: I used meggers for several years in my work as a high-voltage systems test engineer. The bottom end meggers which electricians use only go to 1000 volts. The next step up is 5000 volts and the more expensive ones go to 10 kv. Not sure this would help. There is a unit we used called a DC Hi-Pot that would go from zero to 100,000 VDC, but this would be overkill and is not available to the general public, although I have seen them on eBay and other such sites. We tested 12,000 volt cable at 63,000 VDC. It took that much of a differential to tell if anything was bad, so I don't know if a megger would work that well on an automotive coil, since the secondary voltage is tens of thousands of volts.
Once a flash over happens, often have carbon track might pass normal Ω meter power by and tested @ 1.5 - 9V and fail 500 - 1000v output megers. But yes, may not be a guaranty for a good/fried DIS coil. (You often see carbon tracks on Distributor Caps etc but many times read open tested w/ normal Ω meters too.)
I can't justify meger or Hi-Pot to use 1 to a few times. Many sold in 2nd hand markets often have major problems and need high dollar $ repair & calibration services to use them safe.
DIS used more power and volts vs HEI. Secondary side: DIS 37kV 80mA 65mJ for 14v 9A in HEI 32kV 45mA 62mJ for 14v 6A in Source Delphi datasheets. Either can hurt or kill depending how they shocks you.
As for the noise finder. I've tried the basic auto stethoscopes and have had better results with my hose and funnel. The way I see it the stethoscope detects noises in a solid while the hose can detect noises both in air and in solids. Put the stethoscope in a room with people talking and you'll hear nothing. Now try it with the hose and you will hear the voices. Just my experience.
------------------ " 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 "
As for the noise finder. I've tried the basic auto stethoscopes and have had better results with my hose and funnel. The way I see it the stethoscope detects noises in a solid while the hose can detect noises both in air and in solids.
My inexpensive Harbor Freight mechanic's stethoscope, which I bought years ago, came with a "horn". Unscrew the metal rod, install the horn... voilà... the ability to pick up air-borne sounds. I've gotta say though, it's been my experience that the metal rod has been way more useful than the horn when diagnosing engine sounds.
Exhaust leaks are often easy to find w/ a "tube trick" because is louder and often some exhaust hit the end as well. spare heater hose and other big heavy hose can work and could save you burning hitting exhaust trying to feel in tight places. Like Fiero V6 E-manifolds. ⚠️ Don't hold the tube tight to your ear!
Loud noises like above can hurt or damage your ear w/ a stethoscope too. Cartoons etc w/ yelling into doctor stethoscope isn't so funny when morons actually try that.
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... and I'll suggest that you not pull a spark plug cable off the coil terminal like you did and run the engine. That spark wants to go somewhere, and coil damage could result. Make sure to ground any coil terminal which has been disconnected for testing purposes.
