Walk me through troubleshooting a knock - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old Feb 22nd, 07, 11:45 AM Thread Starter
Senior Tech
Johnney
 
Join Date: Mar 2005
Location: Villa Rica, GA
Posts: 286
Walk me through troubleshooting a knock

My dad built a 383 for me before he passed away last year, so I have lost my dad and my mechanic. Hopefully, you guys can walk me through this one.

I changed the oil after the first 500 miles, it has about 750 on it now. Anyway, I have been starting it about every week just to let it run, the last time I started it I heard a knock from the left side. I checked the oil and it was about 1 quart and 1/2 low and black (I was surprised). I put more oil and the knock quieted down. After it warmed up, it went away or at least I couldn't hear it. The next day, I started it up and heard the knock, but it seemed to go away again when it got warm. I have good oil pressure.

My first thought would be that I have a bad lifter. My question would be how would you go about troubleshooting, I haven't even pulled the valve cover yet, I have been a little worried about what I may find.

I had read that you could pull the spark plug to eliminate any issue with the upper valve train.

Anyways, where do I start to troubleshoot.

On a side note: I doubt this is related, but I never felt like my cousin and I got it tuned right. I always, had a bunch of white smoke on start up, if I get on it again a bunch of white smoke, spark knock under acceleration, sometimes a hesitation at WOT when reving in the garage. Here are some specs on the motor.

Camel Hump Heads - 194 valves with 62 CC heads - 3782461
Comp High Energy Dual Energy Cam - High Energy Cam Dur Int. 268 Exh. 268 Lift Int. .454 Lift Exh. .454
Edelbrock Perfomer - High Rise
Roller Rockers
Holley 780
Dynomax Headers
OC Nodular iron crank
5.7 OC re-con rods with ARP bolts
Hypereutectuc TRW flat top pistons
Moly rings & bearings
Balanced, Including new flexplate & balancer
Saturday Night Special. 1600-1800 rpm

John Hilts
1968 SS Camaro 383 (Sold) :-(
1967 Chevelle SS 396 Convertible (project not started - REAL 138 car)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by jhilts; Feb 22nd, 07 at 11:55 AM.
jhilts is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old Feb 22nd, 07, 12:11 PM
Gold Lifetime Member
John
 
Vintage 68's Avatar
 
Join Date: Mar 2002
Location: Moraga,Ca.,USA
Posts: 13,705
Re: Walk me through troubleshooting a knock

First, sorry to hear about the loss of you dad ...

Next is to accurately define the noise - is it a 'knock' or a ticking or a more a tapping ...

Next is it's reaction to engine temp.s - you are saying it goes away (or at least you can't hear it anymore (I'm gonna guess this is with just your ear to the engine compartment and not with a steathascope or other listing aid ...)after 'it warms up' ... Is this full operating temp (180 + ) or is this just after it's idled for a few seconds/minutes ???
Is it being started in much colder temps than you used to starting it.

Next would be general area of the noise - can you tell if it's up top or deeper in the engine ???

Next would be to use a listening aid and see if you can pin-point the exact area it sounds worse.

Next would be did you use the same oil and filter type originally installed?

It may just be a normal sound from the piston type or other slight internal component noise that rally won't effect the egnien reliability or life.
If you're really concerned or it gets constantly worse, I would take it to a reputable mechanic and have him give it a listen - he may be able to pin-point the sorce in minutes.

Hope this helps;
John

1968 Convertible
Some trucks
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Other V8 things - some of which float
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Other V6 things - none of which float
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Oh yeah, and 1 "Straight-Six" ...
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


If a man says something in the garage - and his wife can't hear him - is he still wrong !!!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Vintage 68 is offline  
post #3 of 9 (permalink) Old Feb 22nd, 07, 12:34 PM Thread Starter
Senior Tech
Johnney
 
Join Date: Mar 2005
Location: Villa Rica, GA
Posts: 286
Re: Walk me through troubleshooting a knock

Thanks for the info. I remember dad using an old hose for pinpointing the issue, I will try that first and get back to everyone.

I can answer one question, what I had meant by warming up was just idling after I guess the choke turns off (I could barely hear it, but it was there). I did drive it and got it up to 180 and I didn't hear anything. Granted I did not have a listening aid.

Noises are always so hard to explain. It is not a tick and I don't think it is knocking like a rod. Somewhere in between, maybe it is a tap, deeper than a tick, but not a knock. Geez. LOL

If I had to describe a location, I would say front of the motor, left side about where the lifters are located.

I will drive it tonight, get it up to 180 and see if I hear it with the hose. This would probably be the easiest test to eliminate a lot of problems.

Thanks again, I will get back with you.

John Hilts
1968 SS Camaro 383 (Sold) :-(
1967 Chevelle SS 396 Convertible (project not started - REAL 138 car)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
jhilts is offline  
 
post #4 of 9 (permalink) Old Feb 22nd, 07, 12:39 PM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,584
Garage
Re: Walk me through troubleshooting a knock

Sorry to read of your loss of your dad.

As Vintage suggests, you need to do alittle more in depth listening. You might put the car up on jack stands or ramps so you can crawl underneath to listen at the bottom side.

A light tick on the top would be lifter/rocker arm. A knock, like somebody knocking on the kitchen counter or door, and louder when listening from underneath, would a crankshaft knock, and finally, a slap would be piston slap against the cylinder wall.

You have shown hyper pistons installed, and they may be just a bit too small or cylinder too big until the piston expands via heat and fills the bore.

As said, if you need help, see a mechanic to aid.

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - maybe this year, 2019 ...
Everett#2390 is offline  
post #5 of 9 (permalink) Old Feb 25th, 07, 06:59 AM
Senior Tech
Dave
 
Join Date: Oct 2005
Location: Rhode Island
Posts: 1,356
Re: Walk me through troubleshooting a knock

IMO, the knock is simply one (or more) your TRW pistons that is a tiny bit loose in the piston bore. Aluminum expands as it heats up and the knock goes away. Technically, it's called "piston slap" and Chevy engines are absolutely notorious for it. If recall serves me correctly, I believe Chevrolet actually declared "piston slap" as a normal condition for some of their engines, LOL.

Anyway, I have this symptom in my Chevy pickup truck and have had it in most Chevy engines (passenger or hot rod) I've owned. Just drive easy for the first mile or so and it shouldn't make any difference at all in the longevity of the engine. I've got 120,000 miles on my truck and it still runs like new, except for the piston slap at startup.........

-

Dave F. in Rhode Island
'68 Camaro SS Accel DFI 454 (SOLD - I'm a boring Corvette owner now)
Bought my first big-block Chevy in 1970
Chevy-SS is offline  
post #6 of 9 (permalink) Old Feb 25th, 07, 07:25 AM
Gold Lifetime Member
Jim
 
Join Date: Dec 1999
Location: Yorkville, Illinois USA
Posts: 22,121
Re: Walk me through troubleshooting a knock

My 04 pickup is also plagued with piston slap.

Piston slap is quiet at idle, and gets louder and louder as the rpm's come up, regardless of load. With all 8 "slapping" it can sound frightening above 3000 rpm. Piston slap that goes away when hot is harmless. Just keep the r's low until everything is sufficiently warm.

Connecting rods generally knock when they are unloaded. If you blip the throttle, the rod will knock right as the rpm peaks and stsarts to fall.

Lifters can knock all the time. They generally sound more like a light tapping.. Sound could change depending on temp & oil pressure, but not load.

Oil does get black quick, that's normal. The detergents in the oil suspend any microscopic crud in the motor and so the oil looks black.

You definitely need to tune out and spark knock but quick. Retard your timing a little at a time until it goes away.

Check for mechanical things that could be causing the noise. Eyeball the 3 bolts that hold the torque converter to the flexplate, make sure they are tight. Look up between the flexplate and the crank, see if the flexplate hub is cracking. Run the engine (briefly) with the accessory belts off to rule out the alternator, water pump, and power steering pump.

Adjust the valves. It's messy, but I like to do it running. I duct tape a towel to the lower valve cover rail and drape it over the headers to contain the mess, and for sure don't rev the engine, just let it idle. Do this hot. Run down the line, loosen till it clacks, tighten till it stops, plus a quarter to a half a turn. One side at a time to help minimize the mess.





To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
New website for my vert is coming together. Do ya like the slide show on the home page?
JimM is offline  
post #7 of 9 (permalink) Old Feb 25th, 07, 08:28 AM
Senior Tech
 
Join Date: Aug 2004
Location: New York
Posts: 166
Re: Walk me through troubleshooting a knock

I am sorry to read about your dad loosing a loved one is indeed one of the hardest things to bear in life, my condolences. About the noise in your eng. It is kind of easy to determine if it is a upper end or lower end noise just by the speed of it. The cam turns @ twice the speed of the crank so if it is in the valve train it will be fast. Like a typewriter, low end will be at half speed. Pistons tend to sound more like a cluck, rods and mains tend to be a knock. If you do a cylinder drop test it may change the noise if you unload the cyl. that the noise is in. I hope this is of some help.
Bolt is offline  
post #8 of 9 (permalink) Old Feb 25th, 07, 06:15 PM
Senior Tech
george
 
Join Date: Sep 2006
Location: detroit
Posts: 2,289
Re: Walk me through troubleshooting a knock

bolt
I am sure you meant to say that the cam rotates at 1/2 the speed of the crankshaft.A typo?
fatblock is offline  
post #9 of 9 (permalink) Old Feb 28th, 07, 11:45 AM Thread Starter
Senior Tech
Johnney
 
Join Date: Mar 2005
Location: Villa Rica, GA
Posts: 286
Re: Walk me through troubleshooting a knock

Thanks for all the input. I have been swamped this weekend. I finally started it yesterday and the noise is temperature sensitive. After the the motor ran for about 2 or 3 minutes, the noise was completely gone. I am going to check it out again today with a listening device and see if I get the same result.

Thanks again

John Hilts
1968 SS Camaro 383 (Sold) :-(
1967 Chevelle SS 396 Convertible (project not started - REAL 138 car)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
jhilts is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Detonation and octane jraustin Engine 58 Apr 12th, 06 05:21 PM
Knock in Bellhousing? wbeeson23 Troubleshooting 8 Mar 14th, 06 11:20 AM
396/325 Engine knock stope4 Engine 8 Jun 10th, 05 03:33 PM
Knock in engine jsouthco68camaro Engine 9 Jun 10th, 05 07:07 AM
Engine Knock? Slick Nick Troubleshooting 7 Dec 10th, 02 04:42 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome