Diagnosing engine noise SBC 350 - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #16 (permalink)  
Old 01-20-2011, 04:33 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,655
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
It`s kind of hard to tell, but check the clutch fan. Grab it and give it a shake, it shouldn`t move. Also check the water pump shaft. I had one spit the water pump bearing out and it made a noise exactly like yours.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 01-20-2011, 04:51 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by DQ81
mechanic had a listen and reckoned it was something like a pulley or even a cambolt loose and rubbing on the timing chain housing?
That has a 'tinny' sound to it, to me. I would still check by removing belts, but if that doesn't show you (or any other wiggling, etc.) I would strongly suspect a backed out cam gear bolt.

If it has been doing this for long enough, you may even see a witness mark forming on the outside of the timing cover.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 01-20-2011, 05:07 PM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: NL
Posts: 138
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by cobalt327
That has a 'tinny' sound to it, to me. I would still check by removing belts, but if that doesn't show you (or any other wiggling, etc.) I would strongly suspect a backed out cam gear bolt.

If it has been doing this for long enough, you may even see a witness mark forming on the outside of the timing cover.
Thankfully it's only run about 8 miles since it first made the noise. I HAD to run it back and forth to the shop for the insurance estimate but killed it at every light and ran it as little as possible.

So for the backed out cam gear bolt would be:

pull ac. belts, fan maybe rad. (it's a high truck so I have decent room up front)

Pull timing cover to inspect. Can I remove the timing cover without removing the waterpump? Is that phsyically possible?

DoubleVision

At the end of the vid you can see that the fan spins freely without making noise once the motor is off, I must admit however I don't know exactly how these clutches work. Is it centrifugal and thus wouldn't make any noise once it's pulley stops moving even if it was bad? The fan blades do look wobbly but they were always like that, pre-noise.

Can you elaborate on that waterpump shaft issue you had?


thanks
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 01-20-2011, 05:12 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Water pump has to come off, sorry.

To check the shaft of the water pump as well as the fan clutch, try to rock the shaft by alternately pushing in on one side of the fan as you pull outward on the other side, standing directly in front of the fan.

The shafts should only rotate, there should be no noticeable sideways movement of the water pump and just the slightest movement of the fan clutch shaft.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 01-21-2011, 08:22 AM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,655
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
A clutch fan works like this: There are 2 types, Thermal and Non thermal.
A Thermal works by engine temp. When the temp gets so high, the clutch locks so it`s turning at the same RPM as the engine. When the temp is below the locking point, the fan free wheels so it`s not causing the engine to use any power to turn it. Non thermal stays locked all the time.
Majority on small block V8`s were non thermal. loosen all your belts and grab the water pump pulley, if it wobbles then the bearing is gone.
Also check the fan clutch, grab the blade and see if you can wiggle it, it should move very little, if it has alot of wiggle to it it`s no good.
I was leaving the store in my Chevy truck which has a rather warmed up 4.3 V6. I tached it up to 6000 before shifting to second gear, when I did I hear something then I heard it making a sound like yours, I got home and opened the hood, at idle I seen the fan and pulley doing a mild dance. I yanked the shroud, the belt and the pully and looked at the water pump shaft, even so it wasn`t obvious the bearing was gone, it was just flopping around.
Since then I learned when you buy a cheap made in china water pump like I did and you tach it high one good time that`s the result.
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 01-27-2011, 12:16 PM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: NL
Posts: 138
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I'll finally have time for the truck this weekend. Thanks all and as soon I know what's going on I'll post it here so this thread doesn't remain open ended!
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 02-03-2011, 11:28 AM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: NL
Posts: 138
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ok crew, status update:

Pulled every accessory off one by one, no dice unfortunately. I'd have put money on the fa as it has excessive play but it's quiet.

Have pulled it all apart today got stuck at the harmonic balancer as my puller's dissappeard!

So yet to hopefully find a backed out cam bolt, we'll see tomorrow!

cheers,
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 02-03-2011, 12:05 PM
sqzbox's Avatar
My pipes are my music
 
Last photo:
Join Date: Sep 2009
Location: indiana
Age: 64
Posts: 2,938
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by DQ81
ok crew, status update:


Have pulled it all apart today got stuck at the harmonic balancer as my puller's dissappeard! ,
Not so. their hiding from you. Happens to me all the time. Been so long since I've used them, I can't remember where they are. Last tool I couldn't find was my vacuum gauge I use to set my A/F ratio. I called all my friends that I trusted enough to loan a tool too, that I knew had a carb, with no luck
Turns out after dropping a bolt on the floor, I spotted it under my tool chest where it had fallen after being pushed off the top from something I was working on and didn't notice what had happened. After looking for it for 3 weeks I was so mad I could have kicked my own butt if I could reach it. For 15 years it's always been in the 5th drawer down except for this 1 time.

Don't give up!
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 02-05-2011, 09:55 AM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: NL
Posts: 138
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by sqzbox
Not so. their hiding from you. Happens to me all the time. Been so long since I've used them, I can't remember where they are. Last tool I couldn't find was my vacuum gauge I use to set my A/F ratio. I called all my friends that I trusted enough to loan a tool too, that I knew had a carb, with no luck
Turns out after dropping a bolt on the floor, I spotted it under my tool chest where it had fallen after being pushed off the top from something I was working on and didn't notice what had happened. After looking for it for 3 weeks I was so mad I could have kicked my own butt if I could reach it. For 15 years it's always been in the 5th drawer down except for this 1 time.

Don't give up!
Found it!

Pulled the balancer and well, a picture is worth a thousand words so here ya go. After pulling the timing cover this is EXACTLY how I found things to be!:





I'm pretty happy with this forum and the fact that I didn't ignore this and did something about it. 1 mile, maybe 2 more would have been the end of this 350!

As for the scoring mark, indeed! wasn't able to see it from up top at all. And I just didn't notice the raised part of the cover as it was so symmetrical.

Got a new timing chain, put it all back together with some locktight. Job done.

In any case great advice her and many thanks!



Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 02-05-2011, 10:36 AM
a67tempest455's Avatar
Registered User
 
Join Date: Nov 2004
Location: Fulton Michigan
Age: 35
Posts: 46
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I hope you got a new cover too!! they make little locking plates for the cam bolts that are dirt cheap ($5) and are supposed to be there from the factory some guys dont bother with them though when they are rebuilding or swapping cams. I personally don't trust lock tight inside the engine the heat and oil tend to make it not work. good job finding the problem!!!
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 02-05-2011, 11:49 AM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls, Washington
Posts: 5,229
Wiki Edits: 9

Thanks: 103
Thanked 131 Times in 122 Posts
And you should have a cam button, that cam is walking forward, that's what caused the hole and depression in the cover. It will walk, bolt locking plate or not.
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 02-05-2011, 11:54 AM
sqzbox's Avatar
My pipes are my music
 
Last photo:
Join Date: Sep 2009
Location: indiana
Age: 64
Posts: 2,938
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
WOW, hat's incredible that the bolt's backed out like that. First time I've seen that.
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 02-05-2011, 12:57 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,764
Wiki Edits: 0

Thanks: 4
Thanked 427 Times in 366 Posts
The attachment picture is what's needed beside a timing cover.

The cam is subject to a lot of vibration both transmitted through the chain and gear from the crank as well as from the lobe/lifter action speeding and slowing the cam. These bolts get rattled pretty hard as a result of all this. They will not stay in place with torque or even lock washers alone.

Bogie
Attached Files
File Type: doc Chevy retainer and bolts.doc (45.5 KB, 62 views)
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 02-05-2011, 02:29 PM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: NL
Posts: 138
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by oldbogie
The attachment picture is what's needed beside a timing cover.

The cam is subject to a lot of vibration both transmitted through the chain and gear from the crank as well as from the lobe/lifter action speeding and slowing the cam. These bolts get rattled pretty hard as a result of all this. They will not stay in place with torque or even lock washers alone.

Bogie
Hey thanks Bogie,

I got that retainer on there now, got it at the local parts place for 6 bucks. It baffles me to think someone had this thing apart and left it off.

I posted another video on youtube that transmits the sound better so just follow my other link if you think you're motor might be making a similar sound.

Thanks again guys. It's up and running well again.
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 02-05-2011, 02:53 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
The retainer wasn't left off- it never was installed by the OEM in the first place.

Use one if it makes you feel more secure. I've never had a cam bolt back out in my life, just torqued them to 20 ft/lbs w/blue loctite- if it was handy.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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 for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
diagnosing cracked head/gasket engine tear down 1960chevyapache Engine 2 04-17-2009 09:33 PM
Engine Noise mopar34 Engine 6 05-05-2008 02:21 AM
Help Diagnosing engine noise? Hanr3 Engine 4 03-08-2007 10:27 PM
I need engine noise help!!! 1931 steve Engine 7 07-28-2006 07:09 AM
engine noise stanjr41 Engine 5 01-04-2006 08:36 AM


All times are GMT -6. The time now is 02:57 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.