Knocking on a new 3.4 (Page 1/2)
handymanpat FEB 12, 07:56 AM
https://youtube.com/shorts/...zoDqEw?feature=share

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

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pat moody

fierofool FEB 12, 08:35 AM
Knocking subsides with a plug wire off? Dad used to pull a plug wire to determine which cylinder was knocking, and it usually enhanced the sound.
eti engineer FEB 12, 09:03 AM

quote
Originally posted by handymanpat:

https://youtube.com/shorts/...zoDqEw?feature=share

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).]

Notorio FEB 12, 06:05 PM
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).]

Dennis LaGrua FEB 12, 06:09 PM
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

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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 "

[This message has been edited by Dennis LaGrua (edited 02-12-2022).]

Patrick FEB 12, 07:21 PM

quote
Originally posted by Notorio:

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.




quote
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.

IMSA GT FEB 12, 08:40 PM
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).]

La fiera FEB 12, 09:06 PM
I'm with Dennis. Check the firing order. To me it sounds like its firing on the exhaust
handymanpat FEB 12, 09:18 PM
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

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pat moody

Patrick FEB 12, 09:56 PM

quote
Originally posted by handymanpat:

I sure appreciate all the help and advice!



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.